Preparation method of fermented oat flour with high digestibility

Abstract

The invention relates to the technical field of food processing, in particular to a preparation method of fermented oat flour with high digestibility, and the fermented oat flour is combined with kluyveromyces marxianus fermentation through double enzymolysis, so that the protein digestibility is improved. According to the method disclosed by the invention, a high-integration-degree continuous process path of front-end enzymolysis, two-stage fermentation at different temperatures and rear-end drying is realized through a strategy of separating enzymatic hydrolysate into supernate and precipitate and respectively applying the supernate and the precipitate to yeast propagation and secondary fermentation of thalli.

Description

Technical Field

[0001] This invention relates to the field of food processing technology, specifically to a fermented oat flour and its preparation method that improves protein digestibility through a combination of enzymatic hydrolysis and yeast fermentation. Background Technology

[0002] oat( Avena sativa As a nutrient-rich whole grain food, oats have received widespread attention in the health food field in recent years due to their abundance of beta-glucan, high-quality protein, unsaturated fatty acids, and various minerals. Especially in terms of its nutritional characteristics such as high protein, high fiber, and low glycemic index, oats are widely used in cereal beverages, meal replacement powders, and functional foods. However, although oats contain 12%–20% protein, their natural protein structure is complex and contains high levels of anti-nutritional factors (such as phytic acid and polyphenols), resulting in a low rate of digestion and absorption of their protein by the human body, thus limiting their potential as a high-quality plant protein source.

[0003] Traditional improvement methods mainly include physical puffing, chemical modification, and single enzymatic hydrolysis. While these methods can improve protein solubility and digestibility to some extent, they often suffer from problems such as insufficient protein degradation, significant nutrient loss, and poor process adaptability. Furthermore, pure enzymatic hydrolysis or pure fermentation methods are frequently constrained in practical applications by factors such as cost, time, and the control of the microbial growth environment.

[0004] In recent years, some studies have attempted to combine enzymatic hydrolysis with microbial fermentation to improve protein utilization efficiency and the synergistic release of complex nutrients. However, currently available technical solutions mainly focus on lactic acid bacteria fermentation, targeting non-lactic acid bacteria yeasts such as Kluyveromyces martensii (Kluyveromyces). Kluyveromyces marxianus There is limited research on the synergistic effect between enzymes and oat substrates, and there is a lack of systematic optimization of the separation and fermentation strategies for enzyme hydrolysates, which has failed to fully integrate resources and enhance product functionality.

[0005] Therefore, there is an urgent need to develop a composite processing method that can effectively improve the digestibility of oat protein while maintaining nutritional value and process stability, and to prepare fermented oat products with significant functionalities suitable for diverse food applications. Based on this technical background, this invention proposes a high-digestibility fermented oat flour and its preparation method by combining a "dual enzymatic hydrolysis—yeast fermentation—resource recycling" strategy to address the shortcomings of existing technologies. Summary of the Invention

[0006] This invention provides a highly digestible fermented oat flour and its preparation method, aiming to solve the problems of low protein digestibility, insufficient nutrient utilization, and poor process integration in traditional oat products. By performing dual enzymatic hydrolysis on oat flour and combining it with the expansion and fermentation process of Kluyveromyces martensii, this invention significantly improves protein release and digestibility while retaining functional components such as β-glucan, resulting in a highly nutritious and functional fermented oat flour. Furthermore, to further improve production efficiency and resource utilization, this invention also employs a strategy of separating the enzymatic hydrolysate into a supernatant and a precipitate, which are then used for yeast expansion and secondary fermentation, respectively. This achieves a highly integrated continuous process path of "front-end enzymatic hydrolysis—two-stage fermentation at different temperatures—back-end drying," demonstrating significant technological innovation and industrial application value.

[0007] On one hand, the present invention provides a fermented oat flour, wherein the fermented oat flour is fermented using Max Kluyveromyces (Kluyveromyces 'Max Kluyveromyces') Kluyveromyces marxianus The fermented oat substrate is generated, and the fermented oat flour has high protein digestibility. The fermented oat flour has any one or more of the following physicochemical characteristics: In some embodiments, the fermented oat flour has a β-glucan content of ≥5%, for example, it can be ≥6%, ≥7%, ≥8%, ≥9% or ≥10%, and further can be 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5% or 10%, etc.; In some embodiments, the fermented oat flour has a protein content of ≥20%, for example, ≥25%, ≥30%, ≥35% or ≥40%, and further can be 20%, 25%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39% or 40%, etc. In some embodiments, the fermented oat flour protein digestibility is >85%, for example, it can be >90%, >91%, >92%, >93%, >94%, >95%, >96%, >97%, >98%, >99% or =100%, for example, it can be 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100%, etc.; In some implementations, the fermented oat flour has an amino acid score >95, for example >96, >97, >98, >99 or =100, for example 96, 97, 98, 99 or 100, etc. In some embodiments, the amino acid fraction of the fermented oat flour after protein digestibility correction is ≥85, for example, it can be ≥90, ≥91, ≥92, ≥93, ≥94, ≥95, ≥96, ≥97, ≥98, ≥99 or =100, for example, it can be 85, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99 or 100, etc.

[0008] The Kluyveromyces martensii yeast selected in this invention has the characteristics of strong heat tolerance and high metabolic efficiency.

[0009] In some embodiments, the oat substrate form comprises pure oats, pure oat bran, or a mixture of oats and oat bran.

[0010] In some preferred embodiments, the oats and oat bran are mixed in a mass ratio of 1:5 to 5:1, for example, 1:2, 1:3, 1:4, 1:5, 2:1, 3:1, 4:1 or 5:1.

[0011] In some implementations, the oat substrate is further enzymatically hydrolyzed prior to fermentation with Max Kluyveromyces.

[0012] In some embodiments, the oat substrate protein content is 10%-20%, for example, it can be 10%-19%, 10-18%, 10-17%, 10%-16%, 10-15%, 10-14%, 10%-13%, 10-12%, etc., and more specifically, it can be 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, or 10%. In some preferred embodiments, the oat substrate protein content is 10%-14%.

[0013] In some embodiments, the Kluyveromyces martensii strain is accessed under the number CCTCC M20211604.

[0014] In some implementations, the enzymatic hydrolysis is a double enzymatic hydrolysis.

[0015] In some embodiments, the dual enzymatic hydrolysis is performed by using a thermostable α-amylase and a saccharifying enzyme, with the two enzymes added separately for enzymatic hydrolysis.

[0016] In some preferred embodiments, a heat-resistant α-amylase is first added. This process mainly disrupts the starch crystal structure, releases some of the bound proteins, and improves solubility.

[0017] In some preferred embodiments, a saccharifying enzyme is added later, which further saccharifies the residual starch, helping to provide the fermentable sugars required for fermentation, thereby improving yeast activity and product quality.

[0018] In some embodiments, the activity of the thermostable α-amylase is ≥150,000 U / mL, for example, it can be 150,000 U / mL, 160,000 U / mL, 170,000 U / mL, 180,000 U / mL, 190,000 U / mL or 200,000 U / mL, etc.

[0019] In some embodiments, the activity of the saccharifying enzyme is ≥200,000 U / g, for example, it can be 200,000 U / g, 210,000 U / g, 220,000 U / g, 230,000 U / g, 240,000 U / g or 250,000 U / g, etc.

[0020] In some implementations, the enzymatic hydrolysate produced by the enzymatic hydrolysis is produced using a separate fermentation strategy.

[0021] In some implementations, the separation fermentation strategy involves separating the enzymatic hydrolysate into a supernatant and a precipitate, which are used for yeast propagation and secondary fermentation of the cells, respectively.

[0022] In some embodiments, the fermented oat flour has a β-glucan content of ≥6%; and / or a protein content of ≥30%; and / or a protein digestibility of >95%; and / or an amino acid score of 100; and / or an amino acid score corrected for protein digestibility of 100.

[0023] In some embodiments, the amino acid composition of the fermented oat flour includes 0.5-3 g / 100 g dry matter of histidine, for example, 0.5-2.5 g / 100 g dry matter, 0.5-1.5 g / 100 g dry matter, 0.5-1.3 g / 100 g dry matter, 1-2.5 g / 100 g dry matter, 1-1.5 g / 100 g dry matter, or 1-1.3 g / 100 g dry matter, etc., and more specifically, 0.5, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.5, or 3 g / 100 g dry matter, etc. In some preferred embodiments, the amino acid composition of the fermented oat flour includes 1-2.5 g / 100 g dry matter of histidine.

[0024] In some embodiments, the amino acid composition of the fermented oat flour includes 1-5 grams of isoleucine per 100 grams of dry matter, for example, 1-4 grams per 100 grams of dry matter, 1-3 grams per 100 grams of dry matter, 2-3 grams per 100 grams of dry matter, 2-4 grams per 100 grams of dry matter, or 2-5 grams per 100 grams of dry matter, etc., and more specifically, 1, 1.5, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.5, 4, 4.5, or 5 grams per 100 grams of dry matter, etc. In some preferred embodiments, the amino acid composition of the fermented oat flour includes 1-3 grams of isoleucine per 100 grams of dry matter.

[0025] In some embodiments, the amino acid composition of the fermented oat flour contains 2-6 grams of leucine per 100 grams of dry matter, for example, 2-5 grams per 100 grams of dry matter, 2-4 grams per 100 grams of dry matter, 3-6 grams per 100 grams of dry matter, 3-5 grams per 100 grams of dry matter, 4-6 grams per 100 grams of dry matter, or 4-5 grams per 100 grams of dry matter, etc., and more specifically, 2, 2.5, 3, 3.5, 4, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5, 5.5, or 6 grams per 100 grams of dry matter, etc. In some preferred embodiments, the amino acid composition of the fermented oat flour contains 3-5 grams of leucine per 100 grams of dry matter.

[0026] In some embodiments, the amino acid composition of the fermented oat flour contains 1-5 grams of lysine per 100 grams of dry matter, for example, 1-4 grams per 100 grams of dry matter, 1-3 grams per 100 grams of dry matter, 2-3 grams per 100 grams of dry matter, 2-4 grams per 100 grams of dry matter, or 2-5 grams per 100 grams of dry matter, etc., and more specifically, 1, 1.5, 2, 2.5, 3, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4, 4.5, or 5 grams per 100 grams of dry matter, etc. In some preferred embodiments, the amino acid composition of the fermented oat flour contains 2-5 grams of lysine per 100 grams of dry matter.

[0027] In some embodiments, the amino acid composition of the fermented oat flour includes 0.3-1 g / 100 g dry matter of methionine, for example, 0.4-1 g / 100 g dry matter, 0.5-1 g / 100 g dry matter, 0.6-1 g / 100 g dry matter, 0.7-1 g / 100 g dry matter, 0.4-0.9 g / 100 g dry matter, 0.4-0.8 g / 100 g dry matter, 0.5-0.9 g / 100 g dry matter, 0.5-0.8 g / 100 g dry matter, etc. The amino acid composition of the fermented oat flour is 0.00 g dry matter, 0.6-0.9 g / 100 g dry matter, 0.6-0.8 g / 100 g dry matter, 0.7-0.9 g / 100 g dry matter, or 0.7-0.8 g / 100 g dry matter, and may further be 0.3, 0.4, 0.5, 0.6, 0.7, 0.7, 0.7, 0.7, 0.7, 0.7, 0.7, 0.7, 0.7, 0.7, 0.7, 0.8, 0.9, or 1 g / 100 g dry matter. In some preferred embodiments, the amino acid composition of the fermented oat flour includes 0.5-1 g / 100 g dry matter of methionine.

[0028] In some embodiments, the amino acid composition of the fermented oat flour contains 1-5 grams of cysteine ​​per 100 grams of dry matter, for example, 1-4 grams per 100 grams of dry matter, 1-3 grams per 100 grams of dry matter, 2-3 grams per 100 grams of dry matter, 2-4 grams per 100 grams of dry matter, or 2-5 grams per 100 grams of dry matter, etc., and more specifically, 1, 1.5, 2, 2.5, 3, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4, 4.5, or 5 grams per 100 grams of dry matter, etc. In some preferred embodiments, the amino acid composition of the fermented oat flour contains 1-4 grams of cysteine ​​per 100 grams of dry matter.

[0029] In some embodiments, the amino acid composition of the fermented oat flour includes 1-4 g / 100 g dry matter of phenylalanine, for example, 1-3 g / 100 g dry matter, 2-3 g / 100 g dry matter, or 2-4 g / 100 g dry matter, and further may be 1, 1.5, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.5, or 4 g / 100 g dry matter. In some preferred embodiments, the amino acid composition of the fermented oat flour includes 1-3 g / 100 g dry matter of lysine.

[0030] In some embodiments, the amino acid composition of the fermented oat flour contains 1-3 grams of tyrosine per 100 grams of dry matter, for example, 1-2.5 grams per 100 grams of dry matter, 1-2 grams per 100 grams of dry matter, 1-1.5 grams per 100 grams of dry matter, 1.5-3 grams per 100 grams of dry matter, 1.5-2.5 grams per 100 grams of dry matter, or 1.5-2 grams per 100 grams of dry matter, etc., and more specifically, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.5, or 3 grams per 100 grams of dry matter, etc. In some preferred embodiments, the amino acid composition of the fermented oat flour contains 1-2.5 grams of tyrosine per 100 grams of dry matter.

[0031] In some embodiments, the amino acid composition of the fermented oat flour contains 1-4 grams of threonine per 100 grams of dry matter, for example, 1-3 grams, 2-3 grams, or 2-4 grams per 100 grams of dry matter, and more specifically, 1, 1.5, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.5, or 4 grams per 100 grams of dry matter. In some preferred embodiments, the amino acid composition of the fermented oat flour contains 1-3 grams of threonine per 100 grams of dry matter.

[0032] In some embodiments, the amino acid composition of the fermented oat flour includes 0.1-0.5 g / 100 g dry matter of tryptophan, for example, 0.1-0.4 g / 100 g dry matter, 0.2-0.5 g / 100 g dry matter, 0.2-0.4 g / 100 g dry matter, 0.3-0.5 g / 100 g dry matter, or 0.3-0.4 g / 100 g dry matter, etc., and more specifically, 0.1, 0.15, 0.2, 0.25, 0.3, 0.31, 0.32, 0.33, 0.34, 0.35, 0.36, 0.37, 0.38, 0.39, 0.4, 0.45, or 0.5 g / 100 g dry matter. In some preferred embodiments, the amino acid composition of the fermented oat flour includes 0.2-0.4 g / 100 g dry matter of tryptophan.

[0033] In some embodiments, the amino acid composition of the fermented oat flour includes 0.2-2 g / 100 g dry matter of valine, for example, 0.2-1.5 g / 100 g dry matter, 0.2-1 g / 100 g dry matter, 0.2-0.6 g / 100 g dry matter, 0.3-2 g / 100 g dry matter, 0.3-1.5 g / 100 g dry matter, 0.3-1 g / 100 g dry matter, 0.3-0.6 g / 100 g dry matter, 0.4-2 g / 100 g dry matter, 0.4-1.5 g / 100 g dry matter, 0.4-1 g / 100 g dry matter, or 0.4-0.6 g / 100 g dry matter. The amino acid composition of the fermented oat flour is 0.5-2 g / 100 g dry matter, 0.5-1.5 g / 100 g dry matter, 0.5-1 g / 100 g dry matter, or 0.5-0.6 g / 100 g dry matter, and may further be 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.50, 0.51, 0.52, 0.53, 0.54, 0.55, 0.56, 0.57, 0.58, 0.59, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1, 1.5, or 2 g / 100 g dry matter. In some preferred embodiments, the amino acid composition of the fermented oat flour includes valine at 0.2-1 g / 100 g dry matter.

[0034] In some embodiments, the amino acid composition of the fermented oat flour contains 2-6 grams of aspartic acid per 100 grams of dry matter, for example, 2-5 grams per 100 grams of dry matter, 2-4 grams per 100 grams of dry matter, 3-6 grams per 100 grams of dry matter, 3-5 grams per 100 grams of dry matter, 4-6 grams per 100 grams of dry matter, or 4-5 grams per 100 grams of dry matter, etc., and more specifically, 2, 2.5, 3, 3.5, 4, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5, 5.5, or 6 grams per 100 grams of dry matter, etc. In some preferred embodiments, the amino acid composition of the fermented oat flour contains 3-5 grams of aspartic acid per 100 grams of dry matter.

[0035] In some embodiments, the amino acid composition of the fermented oat flour contains 1-4 grams of serine per 100 grams of dry matter, for example, 1-3 grams, 2-3 grams, or 2-4 grams per 100 grams of dry matter, and more specifically, 1, 1.5, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.5, or 4 grams per 100 grams of dry matter. In some preferred embodiments, the amino acid composition of the fermented oat flour contains 1-3 grams of serine per 100 grams of dry matter.

[0036] In some embodiments, the amino acid composition of the fermented oat flour contains 3-11 g / 100 g dry matter of glutamic acid, for example, 3-10 g / 100 g dry matter, 4-11 g / 100 g dry matter, 4-10 g / 100 g dry matter, 5-11 g / 100 g dry matter, 5-10 g / 100 g dry matter, 6-11 g / 100 g dry matter, or 6-10 g / 100 g dry matter, etc., and more specifically, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.1, 9.2, 9.3, 9.4, 9.5, 9.6, 9.7, 9.8, 9.9, 10, 10.5, or 11 g / 100 g dry matter, etc. In some preferred embodiments, the amino acid composition of the fermented oat flour contains 4-10 g / 100 g dry matter of glutamic acid.

[0037] In some embodiments, the amino acid composition of the fermented oat flour contains 1-4 grams of proline per 100 grams of dry matter, for example, 1-3 grams, 2-3 grams, or 2-4 grams per 100 grams of dry matter, and more specifically, 1, 1.5, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.5, or 4 grams per 100 grams of dry matter. In some preferred embodiments, the amino acid composition of the fermented oat flour contains 1-3 grams of proline per 100 grams of dry matter.

[0038] In some embodiments, the amino acid composition of the fermented oat flour contains 1-4 grams of glycine per 100 grams of dry matter, for example, 1-3 grams, 2-3 grams, or 2-4 grams per 100 grams of dry matter, and more specifically, 1, 1.5, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.5, or 4 grams per 100 grams of dry matter. In some preferred embodiments, the amino acid composition of the fermented oat flour contains 1-3 grams of glycine per 100 grams of dry matter.

[0039] In some embodiments, the amino acid composition of the fermented oat flour contains 1-5 grams of alanine per 100 grams of dry matter, for example, 1-4 grams per 100 grams of dry matter, 1-3 grams per 100 grams of dry matter, 2-3 grams per 100 grams of dry matter, 2-4 grams per 100 grams of dry matter, or 2-5 grams per 100 grams of dry matter, etc., and more specifically, 1, 1.5, 2, 2.5, 3, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4, 4.5, or 5 grams per 100 grams of dry matter, etc. In some preferred embodiments, the amino acid composition of the fermented oat flour contains 1-4 grams of alanine per 100 grams of dry matter.

[0040] In some embodiments, the amino acid composition of the fermented oat flour contains 1-6 grams of arginine per 100 grams of dry matter, for example, 1-5 grams per 100 grams of dry matter, 1-4 grams per 100 grams of dry matter, 1-3 grams per 100 grams of dry matter, 2-3 grams per 100 grams of dry matter, 2-4 grams per 100 grams of dry matter, 2-5 grams per 100 grams of dry matter, 3-6 grams per 100 grams of dry matter, 3-5 grams per 100 grams of dry matter, or 3-4 grams per 100 grams of dry matter, etc., and further, it can be 1, 1.5, 2, 2.5, 3, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4, 4.5, 5, 5.5, or 6 grams per 100 grams of dry matter, etc. In some preferred embodiments, the amino acid composition of the fermented oat flour contains 2-5 grams of arginine per 100 grams of dry matter.

[0041] In some embodiments, the amino acid composition of the fermented oat flour includes one or more of the above-mentioned amino acids.

[0042] In some embodiments, the amino acid composition of the fermented oat flour consists of essential amino acids.

[0043] In some embodiments, the essential amino acid comprises one or more selected from histidine, isoleucine, leucine, lysine, methionine, cysteine, phenylalanine, tyrosine, threonine, tryptophan, or valine.

[0044] In some embodiments, the fermented oat flour is a powder, granules, or instant preparation.

[0045] On the other hand, the present invention provides a method for preparing fermented oat flour, wherein the method comprises fermenting oat substrate with Kluyveromyces martensii, and the fermented oat flour has high protein digestibility. Kluyveromyces martensii exhibits strong heat tolerance and high metabolic efficiency.

[0046] In some embodiments, the oat substrate form comprises pure oats, pure oat bran, or a mixture of oats and oat bran.

[0047] In some preferred embodiments, the oats and oat bran are mixed in a mass ratio of 1:5 to 5:1, for example, 1:2, 1:3, 1:4, 1:5, 2:1, 3:1, 4:1 or 5:1.

[0048] In some embodiments, the Kluyveromyces martensii strain is accessed under the number CCTCC M20211604.

[0049] In some embodiments, the oat substrate protein content is 10%-20%, for example, it can be 10%-19%, 10-18%, 10-17%, 10%-16%, 10-15%, 10-14%, 10%-13%, 10-12%, etc., and more specifically, it can be 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, or 10%. In some preferred embodiments, the oat protein content is 10%-14%.

[0050] In some implementations, the oat substrate is further enzymatically hydrolyzed prior to fermentation with Max Kluyveromyces.

[0051] In some implementations, the enzymatic hydrolysis is a double enzymatic hydrolysis.

[0052] In some embodiments, the dual enzymes are thermostable α-amylase and saccharifying enzyme, which are added separately for enzymatic hydrolysis.

[0053] In some preferred embodiments, a heat-resistant α-amylase is first added. This process mainly disrupts the starch crystal structure, releases some of the bound proteins, and improves solubility.

[0054] In some preferred embodiments, a saccharifying enzyme is added later, which further saccharifies the residual starch, helping to provide the fermentable sugars required for fermentation, thereby improving yeast activity and product quality.

[0055] Some implementations include the following steps: (1) enzymatic hydrolysis; (2) separation; (3) yeast propagation; (4) mixing; and (5) sterilization and drying, wherein the yeast is Max Kluyveromyces.

[0056] In some implementations, the method includes the following steps: (1) Enzymatic hydrolysis: oat flour and / or oat bran obtained by crushing oat grains are mixed with water to prepare oat substrate, pH is adjusted, and heat-resistant α-amylase and saccharifying enzyme are added for enzymatic hydrolysis; (2) Separation process: The obtained enzymatic hydrolysate is centrifuged to obtain supernatant A and precipitate B. Supernatant A mainly contains soluble low molecular weight sugars, amino acids and partially dissolved proteins, which provide a nutrient substrate for yeast; precipitate B retains incompletely dissolved fibers, proteins and particulate matter, which are important components of the nutrition and structure of subsequent products; (3) Yeast expansion: Kluyveromyces martensii was inoculated into supernatant A and cultured to obtain bacterial suspension C. The bacterial suspension C was rich in active yeast cells, yeast metabolites (such as short peptides and B vitamins) and partially hydrolyzed proteins, which significantly improved the nutrient density of the mixture. (4) Mixing treatment: The precipitate B is mixed with the bacterial suspension C to form a mixture, and the mixture is further cultured to form fermentation products. This process fully integrates the solid phase rich in structural proteins in the early stage with the liquid phase rich in active bacteria and soluble nutrients in the later stage, so as to achieve functional complementarity between the solid and liquid phases. (5) Sterilization and drying: Sterilize the mixture and then dry it to obtain fermented oat flour.

[0057] In some embodiments, the activity of the thermostable α-amylase in step (1) is ≥150,000 U / mL, for example, it can be 150,000 U / mL, 160,000 U / mL, 170,000 U / mL, 180,000 U / mL, 190,000 U / mL or 200,000 U / mL, etc.

[0058] In some implementations, the enzyme activity of the saccharifying enzyme in step (1) is ≥200,000 U / g, for example, it can be 200,000 U / g, 210,000 U / g, 220,000 U / g, 230,000 U / g, 240,000 U / g or 250,000 U / g, etc.

[0059] In some implementations, the optimal particle size of the oat substrate in step (1) is 60-120 mesh, for example, it can be 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115 or 120 mesh, preferably 80-120 mesh.

[0060] In some implementations, the ratio of oat substrate to water in step (1) is 1:5 to 1:10, for example, it can be 1:5, 1:6, 1:7, 1:8, 1:9 or 1:10, preferably 1:5 to 1:8.

[0061] In some implementations, the pH is adjusted to 5.0-6.5 in step (1), for example, to 5.0, 5.5, 6.0 or 6.5, preferably 5.0-6.0.

[0062] In some embodiments, the amount of thermostable α-amylase added in step (1) is 0.1%-1% of the oat substrate mass, for example, it can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9% or 1%, preferably 0.1%-0.5%.

[0063] In some implementations, the amount of saccharifying enzyme added in step (1) is 0.1%-1% of the oat substrate mass, for example, it can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9% or 1%, preferably 0.1%-0.5%.

[0064] In some embodiments, in step (1), the thermostable α-amylase is hydrolyzed at 95℃-110℃ for 0.5-3 hours. For example, the hydrolysis temperature can be 95℃, 100℃, 105℃ or 110℃, and the hydrolysis time can be 0.5, 1, 1.5, 2, 2.5 or 3 hours, etc., preferably at 100℃-105℃ for 0.5-2 hours.

[0065] In some embodiments, in step (1), the saccharifying enzyme is enzymatically hydrolyzed at 50℃-70℃ for 2-6 hours. For example, the hydrolysis time can be 50℃, 55℃, 60℃, 65℃ or 70℃, and the hydrolysis time can be 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5 or 6 hours, etc., preferably at 55℃-65℃ for 2-4 hours.

[0066] In some preferred embodiments, step (1) involves mixing oat substrate ground to 60–120 mesh with water at a mass ratio of 1:5 to 1:10, adjusting the pH to 5.0–6.5, adding heat-resistant α-amylase (enzyme activity ≥150,000 U / mL) at a concentration of 0.1%–1% of the oat substrate mass, and liquefying the mixture at 95–110°C for 0.5–3 hours; subsequently adding saccharifying enzyme (enzyme activity ≥200,000 U / g) at a concentration of 0.1%–1% of the oat substrate mass, and further reacting the mixture at 50–70°C for 2–6 hours.

[0067] In some embodiments, in step (2), the enzymatic hydrolysate is centrifuged at 300-500 rpm for 10-30 minutes, for example, the centrifugation speed is 300, 350, 400, 450 or 500 rpm, and the centrifugation time is 10, 15, 20, 25 or 30 minutes, etc., preferably the enzymatic hydrolysate is centrifuged at 350-450 rpm for 10-20 minutes.

[0068] In some preferred embodiments, step (2) involves centrifuging the enzymatically hydrolyzed solution at 300-500 rpm for 10-20 minutes to separate the supernatant A and the precipitate B.

[0069] In some implementations, the amount of yeast inoculated in step (3) is 5%-10% of the volume of supernatant A, for example, it can be 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5% or 10%, preferably 5%-8%.

[0070] In some implementations, to enhance the nutritional conditions of the fermentation system, in step (3), before yeast expansion, the supernatant A is supplemented with 0.1%-0.8% ammonium sulfate, 0.05%-0.12% dipotassium hydrogen phosphate, and 0.01%-0.08% magnesium sulfate, based on the volume of supernatant A. For example, ammonium sulfate can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, or 0.8% of the volume of supernatant A, and dipotassium hydrogen phosphate can be added to the supernatant. The concentrations of ammonium sulfate (A) are 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.11%, or 0.12% of the volume of supernatant A, and magnesium sulfate can be 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, or 0.08% of the volume of supernatant A, preferably 0.1%-0.5% ammonium sulfate, 0.05%-0.1% dipotassium hydrogen phosphate, and 0.01%-0.05% magnesium sulfate. Ammonium sulfate provides a nitrogen source, dipotassium hydrogen phosphate provides a phosphorus source and maintains pH stability, and magnesium sulfate assists in maintaining enzyme activity and ion balance.

[0071] In some implementations, the culture temperature of supernatant A in step (3) is 25-35℃, for example, it can be 25℃, 26℃, 27℃, 28℃, 29℃, 30℃, 31℃, 32℃, 33℃, 34℃ or 35℃, etc., preferably 28℃-32℃.

[0072] In some implementations, the culture time of supernatant A in step (3) is 8-16 hours, for example, it can be 8, 9, 10, 11, 12, 13, 14, 15 or 16 hours, preferably 8-14 hours.

[0073] In some implementations, the shaking speed of the supernatant A in step (3) is 150-250 rpm, for example, it can be 150, 160, 170, 180, 190, 200, 210, 220, 230, 240 or 250 rpm, preferably 150-200 rpm.

[0074] In some preferred embodiments, step (3) involves selecting *Kluyveromyces martensii*, a yeast known for its high temperature tolerance and metabolic efficiency, for fermentation. The yeast is inoculated into supernatant A at a rate of 5%-10%. To enhance the nutritional conditions of the fermentation system, the following inorganic salt components can be added as fermentation feed: Ammonium sulfate: 0.1%-0.8%; Dipotassium hydrogen phosphate: 0.05%-0.12%; Magnesium sulfate: 0.01%-0.08%.

[0075] Fermentation was carried out at 25-35℃ and 150-250 rpm for 8-16 hours to obtain bacterial suspension C.

[0076] In some implementations, the mass ratio of precipitate B to bacterial suspension C in step (4) is 1:1 to 2:1, for example, it can be 1:1 or 2:1, preferably 1:1.

[0077] In some embodiments, the culture temperature of the mixture in step (4) is 32℃-55℃, for example, it can be 32℃, 33℃, 34℃, 35℃, 36℃, 37℃, 38℃, 39℃, 40℃, 45℃, 50℃ or 55℃, etc., preferably 35℃-50℃.

[0078] In some implementations, the culture time of the mixture in step (4) is 1-3 hours, for example, 1, 1.5, 2, 2.5 or 3 hours, preferably 1-1.5 hours.

[0079] In some embodiments, the shaking speed of the mixture in step (4) is 150-250 rpm, for example, it can be 150, 160, 170, 180, 190, 200, 210, 220, 230, 240 or 250 rpm, preferably 150-200 rpm.

[0080] In some embodiments, in step (5), the mixture is sterilized at 110℃-125℃ for 15-60 minutes. For example, the sterilization temperature can be 110℃, 115℃, 120℃, 121℃, 122℃, 123℃, 124℃, or 125℃, and the sterilization time can be 15, 20, 25, 30, 35, 40, 45, 50, 55, or 60 minutes, preferably 115℃-121℃ for 15-30 minutes. This step ensures microbial safety.

[0081] In some implementations, the drying method in step (5) is selected from any one of belt drying, spray drying, drum drying, hot air drying or fluidized bed drying.

[0082] In some preferred embodiments, the drying method is selected from any one of spray drying, drum drying, or fluidized bed drying.

[0083] In some preferred embodiments, the inlet air temperature of the spray dryer is 160℃-180℃, and the outlet air temperature is 80℃-90℃. For example, the inlet air temperature can be 160℃, 165℃, 170℃, 175℃, or 180℃, and the outlet air temperature can be 80℃, 81℃, 82℃, 83℃, 84℃, 85℃, 86℃, 87℃, 88℃, 89℃, or 90℃, etc.

[0084] In some preferred embodiments, the fluidized bed drying temperature is 90℃-100℃, and the particle size is controlled between 250-500 μm. For example, the temperature can be 90℃, 91℃, 92℃, 93℃, 94℃, 95℃, 96℃, 97℃, 98℃, 99℃, or 100℃, and the particle size can be 250, 300, 350, 400, 450, or 500 μm.

[0085] In some preferred embodiments, the surface temperature of the drum dryer is 110℃-150℃, the drum rotation speed is 3-10 rpm, and the film thickness is 0.5-1.5 mm. For example, the surface temperature of the drum dryer can be 110℃, 115℃, 120℃, 125℃, 130℃, 135℃, 140℃, 145℃, or 150℃, etc., the drum rotation speed can be 3, 4, 5, 6, 7, 8, 9, or 10 rpm, etc., and the film thickness can be 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, or 1.5 mm, etc.

[0086] In some preferred embodiments, the mixture is sterilized at 110-125°C for 15-60 minutes, followed by spray drying (inlet air temperature 160-180°C, outlet air temperature 80-90°C) to rapidly evaporate moisture and form an instant-soluble powder. Depending on the actual application requirements, this drying process can also employ drum drying or fluidized bed drying to enhance product stability and particle size control.

[0087] In some embodiments, the fermented oat flour is a powder, granules, or instant preparation.

[0088] In some embodiments, the fermented oat flour contains ≥5% β-glucan, for example, ≥6%, ≥7%, ≥8%, ≥9%, or ≥10%, and more specifically, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, or 10%. In some preferred embodiments, the fermented oat flour contains ≥6% β-glucan.

[0089] In some embodiments, the fermented oat flour has a protein content of ≥20%, for example, ≥25%, ≥30%, ≥35%, or ≥40%, and more specifically, 20%, 25%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, or 40%. In some preferred embodiments, the fermented oat flour has a protein content of ≥30%.

[0090] In some embodiments, the fermented oat flour protein digestibility is >85%, for example, it can be >90%, >91%, >92%, >93%, >94%, >95%, >96%, >97%, >98%, >99%, or =100%, for example, it can be 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100%. In some preferred embodiments, the fermented oat flour protein digestibility is >95%.

[0091] In some embodiments, the amino acid score of the fermented oat flour is >95, for example, >96, >97, >98, >99 or =100, for example, 96, 97, 98, 99 or 100, etc.; in some preferred embodiments, the amino acid score of the fermented oat flour is =100.

[0092] In some embodiments, the fermented oat flour has an amino acid fraction corrected for protein digestibility of ≥85, for example, it can be ≥90, ≥91, ≥92, ≥93, ≥94, ≥95, ≥96, ≥97, ≥98, ≥99 or =100, for example, it can be 85, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99 or 100. In some preferred embodiments, the amino acid fraction corrected for protein digestibility of the fermented oat flour is =100.

[0093] In some embodiments, the amino acid composition of the fermented oat flour includes 0.5-3 g / 100 g dry matter of histidine, for example, 0.5-2.5 g / 100 g dry matter, 0.5-1.5 g / 100 g dry matter, 0.5-1.3 g / 100 g dry matter, 1-2.5 g / 100 g dry matter, 1-1.5 g / 100 g dry matter, or 1-1.3 g / 100 g dry matter, etc., and more specifically, 0.5, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.5, or 3 g / 100 g dry matter, etc. In some preferred embodiments, the amino acid composition of the fermented oat flour includes 1-2.5 g / 100 g dry matter of histidine.

[0094] In some embodiments, the amino acid composition of the fermented oat flour includes 1-5 grams of isoleucine per 100 grams of dry matter, for example, 1-4 grams per 100 grams of dry matter, 1-3 grams per 100 grams of dry matter, 2-3 grams per 100 grams of dry matter, 2-4 grams per 100 grams of dry matter, or 2-5 grams per 100 grams of dry matter, etc., and more specifically, 1, 1.5, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.5, 4, 4.5, or 5 grams per 100 grams of dry matter, etc. In some preferred embodiments, the amino acid composition of the fermented oat flour includes 1-3 grams of isoleucine per 100 grams of dry matter.

[0095] In some embodiments, the amino acid composition of the fermented oat flour contains 2-6 grams of leucine per 100 grams of dry matter, for example, 2-5 grams per 100 grams of dry matter, 2-4 grams per 100 grams of dry matter, 3-6 grams per 100 grams of dry matter, 3-5 grams per 100 grams of dry matter, 4-6 grams per 100 grams of dry matter, or 4-5 grams per 100 grams of dry matter, etc., and more specifically, 2, 2.5, 3, 3.5, 4, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5, 5.5, or 6 grams per 100 grams of dry matter, etc. In some preferred embodiments, the amino acid composition of the fermented oat flour contains 3-5 grams of leucine per 100 grams of dry matter.

[0096] In some embodiments, the amino acid composition of the fermented oat flour contains 1-5 grams of lysine per 100 grams of dry matter, for example, 1-4 grams per 100 grams of dry matter, 1-3 grams per 100 grams of dry matter, 2-3 grams per 100 grams of dry matter, 2-4 grams per 100 grams of dry matter, or 2-5 grams per 100 grams of dry matter, etc., and more specifically, 1, 1.5, 2, 2.5, 3, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4, 4.5, or 5 grams per 100 grams of dry matter, etc. In some preferred embodiments, the amino acid composition of the fermented oat flour contains 2-5 grams of lysine per 100 grams of dry matter.

[0097] In some embodiments, the amino acid composition of the fermented oat flour includes 0.3-1 g / 100 g dry matter of methionine, for example, 0.4-1 g / 100 g dry matter, 0.5-1 g / 100 g dry matter, 0.6-1 g / 100 g dry matter, 0.7-1 g / 100 g dry matter, 0.4-0.9 g / 100 g dry matter, 0.4-0.8 g / 100 g dry matter, 0.5-0.9 g / 100 g dry matter, 0.5-0.8 g / 100 g dry matter, etc. The amino acid composition of the fermented oat flour is 0.00 g dry matter, 0.6-0.9 g / 100 g dry matter, 0.6-0.8 g / 100 g dry matter, 0.7-0.9 g / 100 g dry matter, or 0.7-0.8 g / 100 g dry matter, and may further be 0.3, 0.4, 0.5, 0.6, 0.7, 0.7, 0.7, 0.7, 0.7, 0.7, 0.7, 0.7, 0.7, 0.7, 0.7, 0.8, 0.9, or 1 g / 100 g dry matter. In some preferred embodiments, the amino acid composition of the fermented oat flour includes 0.5-1 g / 100 g dry matter of methionine.

[0098] In some embodiments, the amino acid composition of the fermented oat flour contains 1-5 grams of cysteine ​​per 100 grams of dry matter, for example, 1-4 grams per 100 grams of dry matter, 1-3 grams per 100 grams of dry matter, 2-3 grams per 100 grams of dry matter, 2-4 grams per 100 grams of dry matter, or 2-5 grams per 100 grams of dry matter, etc., and more specifically, 1, 1.5, 2, 2.5, 3, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4, 4.5, or 5 grams per 100 grams of dry matter, etc. In some preferred embodiments, the amino acid composition of the fermented oat flour contains 1-4 grams of cysteine ​​per 100 grams of dry matter.

[0099] In some embodiments, the amino acid composition of the fermented oat flour includes 1-4 g / 100 g dry matter of phenylalanine, for example, 1-3 g / 100 g dry matter, 2-3 g / 100 g dry matter, or 2-4 g / 100 g dry matter, and further may be 1, 1.5, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.5, or 4 g / 100 g dry matter. In some preferred embodiments, the amino acid composition of the fermented oat flour includes 1-3 g / 100 g dry matter of lysine.

[0100] In some embodiments, the amino acid composition of the fermented oat flour contains 1-3 grams of tyrosine per 100 grams of dry matter, for example, 1-2.5 grams per 100 grams of dry matter, 1-2 grams per 100 grams of dry matter, 1-1.5 grams per 100 grams of dry matter, 1.5-3 grams per 100 grams of dry matter, 1.5-2.5 grams per 100 grams of dry matter, or 1.5-2 grams per 100 grams of dry matter, etc., and more specifically, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.5, or 3 grams per 100 grams of dry matter, etc. In some preferred embodiments, the amino acid composition of the fermented oat flour contains 1-2.5 grams of tyrosine per 100 grams of dry matter.

[0101] In some embodiments, the amino acid composition of the fermented oat flour contains 1-4 grams of threonine per 100 grams of dry matter, for example, 1-3 grams, 2-3 grams, or 2-4 grams per 100 grams of dry matter, and more specifically, 1, 1.5, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.5, or 4 grams per 100 grams of dry matter. In some preferred embodiments, the amino acid composition of the fermented oat flour contains 1-3 grams of threonine per 100 grams of dry matter.

[0102] In some embodiments, the amino acid composition of the fermented oat flour includes 0.1-0.5 g / 100 g dry matter of tryptophan, for example, 0.1-0.4 g / 100 g dry matter, 0.2-0.5 g / 100 g dry matter, 0.2-0.4 g / 100 g dry matter, 0.3-0.5 g / 100 g dry matter, or 0.3-0.4 g / 100 g dry matter, etc., and more specifically, 0.1, 0.15, 0.2, 0.25, 0.3, 0.31, 0.32, 0.33, 0.34, 0.35, 0.36, 0.37, 0.38, 0.39, 0.4, 0.45, or 0.5 g / 100 g dry matter. In some preferred embodiments, the amino acid composition of the fermented oat flour includes 0.2-0.4 g / 100 g dry matter of tryptophan.

[0103] In some embodiments, the amino acid composition of the fermented oat flour includes 0.2-2 g / 100 g dry matter of valine, for example, 0.2-1.5 g / 100 g dry matter, 0.2-1 g / 100 g dry matter, 0.2-0.6 g / 100 g dry matter, 0.3-2 g / 100 g dry matter, 0.3-1.5 g / 100 g dry matter, 0.3-1 g / 100 g dry matter, 0.3-0.6 g / 100 g dry matter, 0.4-2 g / 100 g dry matter, 0.4-1.5 g / 100 g dry matter, 0.4-1 g / 100 g dry matter, or 0.4-0.6 g / 100 g dry matter. The amino acid composition of the fermented oat flour is 0.5-2 g / 100 g dry matter, 0.5-1.5 g / 100 g dry matter, 0.5-1 g / 100 g dry matter, or 0.5-0.6 g / 100 g dry matter, and may further be 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.50, 0.51, 0.52, 0.53, 0.54, 0.55, 0.56, 0.57, 0.58, 0.59, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1, 1.5, or 2 g / 100 g dry matter. In some preferred embodiments, the amino acid composition of the fermented oat flour includes valine at 0.2-1 g / 100 g dry matter.

[0104] In some embodiments, the amino acid composition of the fermented oat flour contains 2-6 grams of aspartic acid per 100 grams of dry matter, for example, 2-5 grams per 100 grams of dry matter, 2-4 grams per 100 grams of dry matter, 3-6 grams per 100 grams of dry matter, 3-5 grams per 100 grams of dry matter, 4-6 grams per 100 grams of dry matter, or 4-5 grams per 100 grams of dry matter, etc., and more specifically, 2, 2.5, 3, 3.5, 4, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5, 5.5, or 6 grams per 100 grams of dry matter, etc. In some preferred embodiments, the amino acid composition of the fermented oat flour contains 3-5 grams of aspartic acid per 100 grams of dry matter.

[0105] In some embodiments, the amino acid composition of the fermented oat flour contains 1-4 grams of serine per 100 grams of dry matter, for example, 1-3 grams, 2-3 grams, or 2-4 grams per 100 grams of dry matter, and more specifically, 1, 1.5, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.5, or 4 grams per 100 grams of dry matter. In some preferred embodiments, the amino acid composition of the fermented oat flour contains 1-3 grams of serine per 100 grams of dry matter.

[0106] In some embodiments, the amino acid composition of the fermented oat flour contains 3-11 g / 100 g dry matter of glutamic acid, for example, 3-10 g / 100 g dry matter, 4-11 g / 100 g dry matter, 4-10 g / 100 g dry matter, 5-11 g / 100 g dry matter, 5-10 g / 100 g dry matter, 6-11 g / 100 g dry matter, or 6-10 g / 100 g dry matter, etc., and more specifically, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.1, 9.2, 9.3, 9.4, 9.5, 9.6, 9.7, 9.8, 9.9, 10, 10.5, or 11 g / 100 g dry matter, etc. In some preferred embodiments, the amino acid composition of the fermented oat flour contains 4-10 g / 100 g dry matter of glutamic acid.

[0107] In some embodiments, the amino acid composition of the fermented oat flour contains 1-4 grams of proline per 100 grams of dry matter, for example, 1-3 grams, 2-3 grams, or 2-4 grams per 100 grams of dry matter, and more specifically, 1, 1.5, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.5, or 4 grams per 100 grams of dry matter. In some preferred embodiments, the amino acid composition of the fermented oat flour contains 1-3 grams of proline per 100 grams of dry matter.

[0108] In some embodiments, the amino acid composition of the fermented oat flour contains 1-4 grams of glycine per 100 grams of dry matter, for example, 1-3 grams, 2-3 grams, or 2-4 grams per 100 grams of dry matter, and more specifically, 1, 1.5, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.5, or 4 grams per 100 grams of dry matter. In some preferred embodiments, the amino acid composition of the fermented oat flour contains 1-3 grams of glycine per 100 grams of dry matter.

[0109] In some embodiments, the amino acid composition of the fermented oat flour contains 1-5 grams of alanine per 100 grams of dry matter, for example, 1-4 grams per 100 grams of dry matter, 1-3 grams per 100 grams of dry matter, 2-3 grams per 100 grams of dry matter, 2-4 grams per 100 grams of dry matter, or 2-5 grams per 100 grams of dry matter, etc., and more specifically, 1, 1.5, 2, 2.5, 3, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4, 4.5, or 5 grams per 100 grams of dry matter, etc. In some preferred embodiments, the amino acid composition of the fermented oat flour contains 1-4 grams of alanine per 100 grams of dry matter.

[0110] In some embodiments, the amino acid composition of the fermented oat flour contains 1-6 grams of arginine per 100 grams of dry matter, for example, 1-5 grams per 100 grams of dry matter, 1-4 grams per 100 grams of dry matter, 1-3 grams per 100 grams of dry matter, 2-3 grams per 100 grams of dry matter, 2-4 grams per 100 grams of dry matter, 2-5 grams per 100 grams of dry matter, 3-6 grams per 100 grams of dry matter, 3-5 grams per 100 grams of dry matter, or 3-4 grams per 100 grams of dry matter, etc., and further, it can be 1, 1.5, 2, 2.5, 3, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4, 4.5, 5, 5.5, or 6 grams per 100 grams of dry matter, etc. In some preferred embodiments, the amino acid composition of the fermented oat flour contains 2-5 grams of arginine per 100 grams of dry matter.

[0111] In some embodiments, the amino acid composition of the fermented oat flour includes one or more of the above-mentioned amino acids.

[0112] In some embodiments, the amino acid composition of the fermented oat flour consists of essential amino acids.

[0113] In some embodiments, the essential amino acid comprises one or more selected from histidine, isoleucine, leucine, lysine, methionine, cysteine, phenylalanine, tyrosine, threonine, tryptophan, or valine.

[0114] In another aspect, the present invention provides the application of the above-mentioned fermented oat flour or the fermented oat flour prepared according to the above-mentioned preparation method in the preparation of functional foods, wherein the functional foods are used to supplement nutrition.

[0115] In some implementations, the functional food is used for mammals such as mice, rabbits, sheep, cattle, monkeys, or humans.

[0116] In some implementations, the supplemental nutrition is an amino acid supplement.

[0117] In some implementations, the nutritional supplementation may also include supplementation of sugars, dietary fiber, and / or hydration.

[0118] In some preferred embodiments, the functional food is used by humans.

[0119] In some preferred embodiments, the amino acid is an essential amino acid for the human body.

[0120] In some preferred embodiments, the essential amino acid comprises one or more selected from histidine, isoleucine, leucine, lysine, methionine, cysteine, phenylalanine, tyrosine, threonine, tryptophan, or valine.

[0121] Advantages of this invention Compared with traditional methods, the present invention has the following significant advantages: 1. Improve protein digestibility and nutrient retention: Through a dual-enzyme hydrolysis strategy, complex polysaccharides and bound proteins in oats are effectively broken down, improving protein solubility; through yeast fermentation, they are further converted into absorbable short peptides and free amino acids, so that the protein digestibility of the final product reaches more than 85%, which is a major improvement over traditional oat products (digestibility 60% to 70%).

[0122] 2. High resource utilization and novel process route: This invention adopts a separation and fermentation strategy of enzymatic hydrolysate to maximize the utilization of fermentation nutrients and achieve complementary and synergistic effects between yeast and substrate. It solves the problem of difficult integration of traditional "solid + liquid" systems, while reducing the cost of culture medium and improving yield.

[0123] 3. Outstanding product functionality: The obtained powder contains ≥6% β-glucan, ≥30% protein, and ≥85% protein digestibility. It is also rich in functional amino acids such as lysine and glutamic acid, providing excellent nutritional supplementation.

[0124] 4. Precise fermentation control and strong adaptability: By adjusting the inoculation ratio, temperature, rotation speed and nutrient salt addition ratio, it can flexibly adapt to different scales and process requirements; using the Kluyveromyces martensii strain, it not only has a short fermentation cycle and wide temperature tolerance, but also produces a large number of extracellular enzymes, amino acids and beneficial metabolites, further enhancing the product function.

[0125] 5. Diverse drying methods facilitate industrialization: Terminal drying can employ rapid spray drying (suitable for large-scale powder preparation) or be combined with drum drying and fluidized bed drying (suitable for functional particle or instant formulation development), adapting to diverse market application needs. Attached Figure Description

[0126] Figure 1 A flowchart illustrating the preparation process of the fermented oat flour of the present invention is shown. Detailed Implementation

[0127] For the purpose of clarity and concise description, features are described herein as part of some identical or separate embodiments; however, it will be understood that the scope of this disclosure may include some embodiments having combinations of all or some of the described features. The technical solutions of the present invention will now be described clearly and completely. Obviously, based on the specific embodiments of the present invention, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of the present invention.

[0128] I. Definition In this disclosure, unless otherwise stated, scientific and technical terms used herein have the meanings commonly understood by those skilled in the art. Furthermore, the protein and nucleic acid chemistry, molecular biology, cell and tissue culture, microbiology, chemistry-related terms and laboratory procedures used herein are all widely used terms and routine procedures in their respective fields. To better understand this disclosure, definitions and explanations of relevant terms are provided below.

[0129] As used herein, the terms “comprising,” “having,” “including,” and “containing” should be interpreted as open-ended terms (i.e., meaning “including but not limited to”). “Multiple” as used in this disclosure refers to two or more. “And / or” describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. The character “ / ” generally indicates an “or” relationship between the preceding and following related objects, while the character “+” generally indicates an “and” relationship.

[0130] As used herein, references to “some embodiments,” “some implementations,” or “some implementation schemes” describe a subset of all possible embodiments, but it is understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0131] As used herein, the terms “optional,” “any,” “arbitrary,” or “any one” mean that the event or situation described below may, but does not have to, occur, including the circumstances in which the event or situation occurs or does not occur. As used herein, “a” and “an” are used in this disclosure to refer to one or more grammatical objects.

[0132] As used herein, the term “about” or “approximately” when used in conjunction with a numeric value means to cover a range of numeric values ​​having a lower limit of 10% less than the specified numeric value and an upper limit of 10% greater than the specified numeric value.

[0133] As used herein, the term "protein" refers to a polymer of two or more amino acid subunits, amino acid analogs, or peptide mimics, and there is no limit to the maximum number of amino acids. The term "amino acid" as used herein refers to natural and / or non-natural or synthetic amino acids, a general term for a class of organic compounds containing amino and carboxyl groups, the final product of protein hydrolysis, and the basic building blocks of proteins, including D and L optical isomers and amino acid analogs. Twenty amino acids are isolated from protein hydrolysates, among which "essential amino acids" are those that animals cannot synthesize or cannot synthesize in sufficient quantities to meet their needs, and must be obtained from food. Essential amino acids for humans include lysine, tryptophan, phenylalanine, methionine, threonine, isoleucine, leucine, valine, histidine, cysteine, and tyrosine.

[0134] As used herein, the term "protein digestibility" is used interchangeably with "protein digestibility" and refers to the ratio of protein absorbed from food to ingested protein, reflecting the degree to which protein is broken down and absorbed. Different proteins have different degrees of digestibility, absorption, and utilization; the higher the protein digestibility, the easier it is to absorb and utilize. Protein digestibility is affected by factors such as protein source, food particle size, raw material maturity, degree of protein modification, non-protein components, and processing technology. In some embodiments, the protein digestibility may be the in vitro protein digestibility.

[0135] As used herein, the term "enzyme" generally refers to a class of proteins with a specific spatial structure, composed of amino acids linked by peptide bonds. As biological catalysts, they efficiently and specifically accelerate chemical reactions within organisms by lowering the activation energy of these reactions, without undergoing any fundamental change in themselves before or after the reaction. Unless otherwise stated, enzymes can originate from any organism and can have native or mutated amino acid sequences. It is well known that enzymes may sometimes have multiple functions and / or multiple names depending on the organism from which they originate. The enzyme names used herein encompass orthologs, including enzymes that may have one or more additional functions or different names.

[0136] As used in this article, the term "enzymatic hydrolysis" refers to the process by which substrate molecules are broken down into smaller molecules through a hydrolytic reaction catalyzed by enzymes. For example, thermostable α-amylase can hydrolyze starch into short-chain dextrins and a small amount of low-molecular-weight sugars; glucoamylase, also known as glucoamylase, can break down starch and its hydrolysis products into small-molecule carbon sources such as glucose and maltose.

[0137] As used in this article, the term "yeast" refers to the order Yeast (Sacchariformes). Saccharomycetales Yeast is an organism that grows vegetatively through budding / bubbling of single-celled cells, and its carbon metabolism can be fermentative. In some embodiments, the yeast is *Kluyveromyces martensii* (Max Kluyveromyces). Kluyveromyces marxianus ).

[0138] As used in this article, the term "fermentation" refers to the process by which, under suitable conditions, specific metabolic pathways within biological cells transform external substrates to generate target products or microorganisms desired by humans.

[0139] As used herein, the term "drying" refers to the operation of using heat energy to decompose moisture in wet materials and using airflow or vacuum to remove the vaporized moisture, thereby obtaining dry materials. In some embodiments, the drying method is selected from any one of belt drying, spray drying, drum drying, hot air drying, or fluidized bed drying, more preferably any one of spray drying, drum drying, or fluidized bed drying.

[0140] As used herein, the term "separation fermentation strategy" refers to a method in which the enzymatic hydrolysate is separated into a supernatant and a precipitate, wherein the supernatant is used for yeast propagation, and the resulting bacterial suspension is then mixed with the precipitate for secondary fermentation of the cells.

[0141] As used herein, the term "Amino acid score (AAS)," also known as protein chemistry score, applies not only to the evaluation of single food proteins but also to the evaluation of mixed food proteins. The maximum score is 100; scores greater than 100 are considered 100. In some embodiments, the formula for the AAS is as follows: AAS = Amino acid content per gram of protein in the tested sample (mg) / Amino acid content per gram of protein in the reference sample (mg) × 100.

[0142] As used herein, the term "Protein Digestibility Corrected Amino Acids Score (PDCAAS)" is a protein evaluation index based on amino acid composition and digestibility. It comprehensively considers both the amino acid score and the actual digestibility, and can effectively evaluate protein quality. The maximum score is 100; a score greater than 100 is considered 100, indicating that the protein, after digestion, can provide 100% of the amino acids required by the body. In some implementations, the PDCAAS formula is as follows: PDCAAS = Uncorrected amino acid fraction × True digestibility.

[0143] II. Examples The present invention will be described in detail below through specific embodiments. It should be understood that the following embodiments are for explanation and illustration only and do not limit the scope of the present invention in any way.

[0144] In the following embodiments, unless otherwise specified, all biochemical reagents are conventional reagents in the art, which can be prepared according to conventional methods in the art or obtained commercially, and the specification is laboratory grade.

[0145] Example 1: Preparation of fermented oat flour using pure oat flour as a substrate 1. Material preparation: Oat flour: 80 mesh, provided by Pepsi Foods (China) Co., Ltd., with a protein content of approximately 10%-14%; Thermoresistant α-amylase (150,000 U / mL, purchased from Cangzhou Xiasheng Enzyme Preparation Co., Ltd.); Amylase (≥200,000 U / g, purchased from Nanning Dongheng Huadao Biotechnology Co., Ltd.); Yeast strain: Kluyveromyces martensii ( Kluyveromyces marxianus Accession number CCTCM20211604, deposited at the China Center for Type Culture Collection (CCTCC), on December 13, 2021. Water: Deionized water; Inorganic salt additives: ammonium sulfate, dipotassium hydrogen phosphate, magnesium sulfate.

[0146] 2. Process flow: The preparation process flow of this embodiment is as follows: Figure 1 As shown.

[0147] (1) Enzymatic hydrolysis: Mix 100 g of oat flour with 600 mL of deionized water and adjust the pH to 5.5. Add 0.3 g of heat-resistant α-amylase (0.3% of the oat flour mass), and incubate in a water bath at 103°C for 1 hour. This stage mainly involves liquefaction, breaking down the starch granules to form shorter-chain dextrins.

[0148] The reaction solution was then cooled to 60°C, and 0.2 g of saccharifying enzyme was added, with enzymatic hydrolysis continuing for 3 hours. This step further hydrolyzes dextrin into smaller carbon sources such as glucose and maltose.

[0149] (2) Centrifugal separation: After enzymatic hydrolysis was terminated, solid-liquid separation was performed using low-speed centrifugation (400 rpm) for 15 minutes. The supernatant A was a yellow, transparent liquid containing soluble sugars and a small amount of polypeptides; the precipitate B was a light yellow paste, mainly consisting of insoluble proteins and fibrous residues.

[0150] (3) Yeast propagation: Kluyveromyces martensii was inoculated into supernatant A at a volume ratio of 5%, and supplemented with 0.3% ammonium sulfate, 0.08% dipotassium hydrogen phosphate, and 0.02% magnesium sulfate. The culture was maintained at 30°C and 180 rpm in a shaker for 10 hours. The culture medium was milky yellow with a characteristic yeast aroma, and the cell density reached 1.2 × 10⁻⁶ cells / day. 8 CFU / mL.

[0151] (4) Mixed treatment: Precipitate B and bacterial suspension C were mixed at a 1:1 mass ratio and homogenized for 30 minutes to form a dense and homogeneous mixture. The mixture was then incubated at 50°C and 200 rpm for 1 hour. This mixture contains both undissolved proteins and is rich in yeast metabolites and live cells.

[0152] (5) Sterilization and drying: The mixture was placed in an autoclave and sterilized at 118°C for 20 minutes; then it was sent to a spray drying tower (inlet temperature 170°C, outlet temperature 85°C) to dry and obtain a light yellow instant powder. The dry powder has good flowability and a moisture content of approximately 6.8%.

[0153] 3. Finished product performance testing: The results are shown in Table 1. The protein content was determined by the first method of GB5009.5-2016 (protein conversion factor 5.83); dietary fiber was determined by enzyme gravimetric-liquid chromatography of GB5009.88-2023; moisture was determined by the first method of GB5009.3-2016; and β-glucan was determined by the Megazyme kit K-YBGL β-Glucan method.

[0154] Table 1: Test Results of Fermented Oat Flour

[0155] Example 2: Preparation of fermented oat flour using oat flour and oat bran as substrates 1. Material preparation: Oat flour: 80 mesh, provided by Pepsi Foods (China) Co., Ltd., with a protein content of approximately 10%-14%; Oat bran: 60 mesh, provided by Pepsi Foods (China) Co., Ltd., with a protein content of approximately 13%-16%; Thermoresistant α-amylase (150,000 U / mL, purchased from Cangzhou Xiasheng Enzyme Preparation Co., Ltd.); Amylase (≥200,000 U / g, purchased from Nanning Dongheng Huadao Biotechnology Co., Ltd.); Yeast strain: Kluyveromyces martensii ( Kluyveromyces marxianusAccession number CCTCM20211604, deposited at the China Center for Type Culture Collection (CCTCC), on December 13, 2021. Water: Deionized water; Inorganic salt additives: ammonium sulfate, dipotassium hydrogen phosphate, magnesium sulfate.

[0156] 2. Process flow: The preparation process flow of this embodiment is as follows: Figure 1 As shown.

[0157] (1) Enzymatic hydrolysis: Mix 100 g of oat flour and 20 g of oat bran with 680 mL of deionized water, and adjust the pH to 5.5. Add 0.3 g of thermostable α-amylase (0.3% of the oat flour mass), and incubate in a water bath at 103°C for 1 hour. This stage mainly involves liquefaction, breaking down the starch granules to form shorter-chain dextrins.

[0158] The reaction solution was then cooled to 60°C, and 0.2 g of saccharifying enzyme was added, with enzymatic hydrolysis continuing for 3 hours. This step further hydrolyzes dextrin into smaller carbon sources such as glucose and maltose.

[0159] (2) Centrifugal separation: After enzymatic hydrolysis was terminated, solid-liquid separation was performed using low-speed centrifugation (400 rpm) for 15 minutes. The supernatant A was a yellow, transparent liquid containing soluble sugars and a small amount of polypeptides; the precipitate B was a light yellow paste, mainly consisting of insoluble proteins and fibrous residues.

[0160] (3) Yeast propagation: Kluyveromyces martensii was inoculated into supernatant A at a volume ratio of 5%, and supplemented with 0.3% ammonium sulfate, 0.08% dipotassium hydrogen phosphate, and 0.02% magnesium sulfate. The culture was maintained at 30°C and 180 rpm in a shaker for 10 hours. The culture medium was milky yellow with a characteristic yeast aroma, and the cell density reached 1.2 × 10⁻⁶ cells / day. 8 CFU / mL.

[0161] (4) Mixed treatment: Precipitate B and bacterial suspension C were mixed at a 1:1 mass ratio and homogenized for 30 minutes to form a dense and homogeneous mixture. The mixture was then incubated at 50°C and 200 rpm for 1 hour. This mixture contains both undissolved proteins and is rich in yeast metabolites and live cells.

[0162] (5) Sterilization and drying: The mixture was placed in an autoclave and sterilized at 118°C for 20 minutes; then it was sent to a spray drying tower (inlet air temperature 170°C, outlet air temperature 85°C) to dry and obtain a light yellow instant powder. The dry powder has good flowability and a moisture content of about 5.2%.

[0163] 3. Finished product performance testing: The results are shown in Table 2. The protein content was determined by the first method of GB5009.5-2016 (protein conversion factor 5.83); dietary fiber was determined by enzyme gravimetric-liquid chromatography of GB5009.88-2023; moisture was determined by the first method of GB5009.3-2016; and β-glucan was determined by the Megazyme kit K-YBGL β-Glucan method.

[0164] Table 2. Detection of indicators in fermented oat flour

[0165] Example 3: Evaluation of two fermentation-drying methods Considering the differences in production equipment among small and medium-sized enterprises, the spray drying process in Example 1 was replaced with a drum drying process to evaluate the product.

[0166] The enzymatic hydrolysis, separation, yeast propagation, and sterilization steps are the same as in Example 1, and the drum drying process is controlled as follows: Roller surface temperature: 140℃; Drum speed: 6 rpm; Film thickness: 0.8mm.

[0167] The results showed that the obtained product was in the form of loose flakes and required further pulverization. Although the powder fineness was slightly worse than that of spray drying, there was no significant difference in protein content and β-glucan retention rate, indicating that this drying method can be used as a backup process for initial large-scale production.

[0168] Example 4: Amino acid fractions after digestibility correction of ordinary oat flour and fermented oat flour based on a dynamic biomimetic human gastrointestinal digestion simulation scheme. 1. Experimental Objective The purpose of this study is to simulate the digestion of food ingredients in the human body using a dynamic biomimetic human gastrointestinal tract, analyze the in vitro protein digestibility of two samples (ordinary oat flour and fermented oat flour), and calculate the protein digestibility corrected amino acid score (PDCAAS) based on the content of hydrolyzed amino acids in the two samples.

[0169] 2. Experimental methods and procedures 2.1 Experiment ①: Evaluation of protein digestibility based on dynamic biomimetic human gastrointestinal digestion simulation. 2.1.1 Test substance Two samples were randomly taken from ordinary oat flour and fermented oat flour prepared according to the method in Example 1, and the two samples were thoroughly mixed.

[0170] 2.1.2 Preparation of simulated gastrointestinal fluid The concentration formulas for gastrointestinal electrolyte reserve solutions are shown in Table 3.

[0171] Table 3: Electrolyte Reserve Solution Concentration Formula for Gastrointestinal Fluids

[0172] Gastric juice formulation: 400 mL gastric juice electrolyte stock solution, porcine pepsin (2000 U / mL in the final mixture), 0.22 mL 0.3 mol / L CaCl2, bring the volume to 500 mL, and adjust the pH to 3 using 6 mol / L HCl and 1 mol / L NaOH.

[0173] Intestinal fluid formulation: 400 mL intestinal fluid electrolyte stock solution, pancreatic enzyme (100 U / mL in the final mixture), porcine bile salts (final concentration 10 mmol / L), 1 mL 0.3 mol / L CaCl2, bring the volume to 500 mL, and adjust the pH to 7 using 6 mol / L HCl and 1 mol / L NaOH.

[0174] 2.1.3 Experimental Procedure 1) Accurately weigh 10g of each of the two samples (ordinary oat flour and basic fermented oat flour) and dissolve them in pure water for testing.

[0175] 2) Run the dynamic biomimetic in vitro human gastrointestinal digestive system and set the operating parameters. Insert the sample into the simulated oral esophagus and obtain a sample of the digested matter at the end of the digestion process.

[0176] 3) Protein content of the digested sample measured using the biuret method. The formula for calculating simulated digestibility (PDT) is as follows:

[0177] Where P0 is the protein content in the sample (g / 100g) and P1 is the protein content remaining in the digest (g / 100g).

[0178] 2.2 Experiment ②: Determination of hydrolyzed amino acid content The content of hydrolyzed amino acids in the two proteins was determined according to GB 5009.124-2016, "National Food Safety Standard - Determination of Amino Acids in Food".

[0179] 3. Data Calculation and Analysis 3.1 Analysis of the components of the test substance The digestibility of two samples (ordinary oat flour and fermented oat flour) was measured using a dynamic biomimetic human gastrointestinal digestion simulation scheme, as shown in Table 4. The simulated digestibility of ordinary oat flour was 83.47%, while that of fermented oat flour was 96.32%.

[0180] Table 4: Simulated digestibility of regular oat flour and fermented oat flour

[0181] 3.2 List of Amino Acid Detection Methods Table 5

[0182] 3.3 PDCAAS Evaluation 3.3.1 Essential amino acid content of protein after conversion The essential amino acid content of proteins can be calculated using the following formula, and the converted content is shown in Table 6.

[0183] The amino acid content (mg) per gram of protein in the test sample = Amino acid content (g) per 100g of sample / Protein content (g) per 100g of sample × 1000 Table 6: List of essential amino acid contents of proteins after conversion

[0184] 3.3.2 Amino Acid Score (AAS) The AAS formula is as follows, and the specific scoring results are shown in Table 7.

[0185] AAS = Amino acid content per gram of protein in the tested sample (mg) / Amino acid content per gram of protein in the reference sample (mg) × 100 In regular oat flour, the actual content of lysine and tryptophan scores relative to the recommended requirements are 71 and 85, respectively, both less than 100. Therefore, lysine and tryptophan are the limiting amino acids in regular oat flour. In contrast, the actual content of all amino acids in fermented oat flour has scores greater than 100 relative to the recommended requirements. Table 7 shows the original values ​​for better illustration, but amino acid scores (AAS) greater than 100 should be counted as 100.

[0186] Table 7: List of Amino Acid Scores (AAS)

[0187] 3.3.3 Protein digestibility corrected amino acid scoring method (PDCAAS) The PDCAAS formula is as follows, and the specific scoring results are shown in Table 8.

[0188] PDCAAS = Uncorrected amino acid fraction × True digestibility Of the two tested samples, the lowest PDCAAS value for ordinary oat flour was 59. Based on protein grading, this batch of ordinary oat flour cannot be considered high-quality protein. The amino acid composition of the fermented oat flour met the FAO / WHO recommendations, and the content of each essential amino acid, after true digestibility correction, was still higher than the FAO / WHO recommendations. Therefore, this batch of fermented oat flour had an in vitro PDCAAS score of 100, and can be considered high-quality protein. Table 8 shows the original values ​​for better illustration, but PDCAAS scores greater than 100 should be counted as 100.

[0189] Table 8: List of PDCAAS

[0190] The specific embodiments of the present invention have been described in detail above, but they are merely examples, and the present invention is not limited to the specific embodiments described above. For those skilled in the art, any equivalent modifications and substitutions to the present invention are also within the scope of the present invention. Therefore, all equivalent changes and modifications made without departing from the spirit and scope of the present invention are covered within the scope of the present invention.

Claims

1. A fermented oat flour, wherein, The fermented oat flour is produced from an oat substrate fermented by a strain of Kluyveromyces marxianus Kluyveromyces marxianus The fermented oat flour is produced from an oat substrate fermented by a strain of Kluyveromyces marxianus The fermented oat flour has a high protein digestibility, and the fermented oat flour has any one or more of the following physicochemical characteristics: (1) β-glucan content ≥ 5%; (2) protein content ≥ 20%; (3) protein digestibility > 85%; (4) amino acid score (AAS) > 95; (5) amino acid score corrected for protein digestibility ≥ 85.

2. The fermented oat flour of claim 1, wherein, The oat substrate form comprises pure oat, pure oat bran, a mixture of oat and oat bran; More preferably, the oat and oat bran are mixed at a mass ratio of 1:5 to 5:1; Preferably, the oat substrate is also subjected to enzymolysis before Kluyveromyces marxianus fermentation; Preferably, the enzymolysis is double enzymolysis; Preferably, the double enzymolysis is double enzymolysis by high-temperature-resistant α-amylase and saccharifying enzyme; Preferably, the enzyme activity of the high-temperature-resistant α-amylase is ≥ 150,000 U / mL; Preferably, the enzyme activity of the saccharifying enzyme is ≥ 200,000 U / g; Preferably, the protein content of the oat substrate is 10%-20%, more preferably 10%-14%; Preferably, the Kluyveromyces marxianus strain has the accession number CCTCC M20211604.

3. The fermented oat flour according to claim 1 or 2, wherein, The enzymolysis liquid produced by the enzymolysis is subjected to a separation fermentation strategy; Preferably, the separation fermentation strategy is to separate the enzymolysis liquid into supernatant and precipitate, which are respectively used for yeast propagation and secondary fermentation of the bacterial cells.

4. The fermented oat flour according to any one of claims 1-3, wherein, β-glucan content ≥ 6%; and / or protein content ≥ 30%; and / or protein digestibility > 95%; and / or amino acid score (AAS) = 100; and / or amino acid score corrected for protein digestibility = 100.

5. The fermented oat flour according to any one of claims 1-4, wherein, The fermented oat flour comprises the following amino acid composition: histidine content in the range of 0.5-3 g / 100 g dry matter; isoleucine content in the range of 1-5 g / 100 g dry matter; leucine content in the range of 2-6 g / 100 g dry matter; lysine content in the range of 1-5 g / 100 g dry matter; methionine content in the range of 0.3-1 g / 100 g dry matter; cysteine content in the range of 1-5 g / 100 g dry matter phenylalanine content in the range of 1-4 g / 100 g dry matter; tyrosine content in the range of 1-3 g / 100 g dry matter; threonine content in the range of 1-4 g / 100 g dry matter; tryptophan content in the range of 0.1-0.5 g / 100 g dry matter; valine content in the range of 0.2-2 g / 100 g dry matter; aspartate content in the range of 2-6 g / 100 g dry matter; serine content in the range of 1-4 g / 100 g dry matter; glutamate content in the range of 3-11 g / 100 g dry matter; proline content in the range of 1-4 g / 100 g dry matter; glycine content in the range of 1-4 g / 100 g dry matter; alanine content in the range of 1-5 g / 100 g dry matter; and / or arginine content in the range of 1-6 g / 100 g dry matter; Preferably, the fermented oat flour comprises the following amino acid composition: histidine content in the range of 1-2.5 g / 100 g dry matter; isoleucine content in the range of 1-3 g / 100 g dry matter; leucine content in the range of 3-5 g / 100 g dry matter; lysine content in the range of 2-5 g / 100 g dry matter; methionine content in the range of 0.5-1 g / 100 g dry matter; cysteine content in the range of 1-4 g / 100 g dry matter; phenylalanine content in the range of 1-3 g / 100 g dry matter; tyrosine content in the range of 1-2.5 g / 100 g dry matter; threonine content in the range of 1-3 g / 100 g dry matter; tryptophan content in the range of 0.2-0.4 g / 100 g dry matter; valine content in the range of 0.2-1 g / 100 g dry matter; aspartate content in the range of 3-5 g / 100 g dry matter; serine content in the range of 1-3 g / 100 g dry matter; glutamic acid content in the range of 4-10 g / 100 g dry matter; proline content in the range of 1-3 g / 100 g dry matter; glycine content in the range of 1-3 g / 100 g dry matter; alanine content in the range of 1-4 g / 100 g dry matter; and / or arginine content in the range of 2-5 g / 100 g dry matter; preferably, the amino acid composition of the fermented oat flour is essential amino acids; preferably, the essential amino acids comprise one or more selected from histidine, isoleucine, leucine, lysine, methionine, cysteine, phenylalanine, tyrosine, threonine, tryptophan or valine.

6. The fermented oat flour according to any one of claims 1-5, wherein, The fermented oat flour is in the form of a powder, granules or instant preparation.

7. A method of making a fermented oat flour, wherein, The method comprises fermenting an oat substrate by Kluyveromyces marxianus, and the fermented oat flour has a high protein digestibility; preferably, the form of the oat substrate comprises pure oat, pure oat bran, a mixture of oat and oat bran; preferably, the oat and oat bran are mixed at a mass ratio of 1:5 to 5:1; preferably, the strain of Kluyveromyces marxianus has a preservation number of CCTCC M20211604; preferably, the protein content of the oat substrate is 10%-20%, more preferably 10%-14%; preferably, the oat substrate is further subjected to enzymatic hydrolysis before fermentation by Kluyveromyces marxianus; preferably, the enzymatic hydrolysis is double enzymatic hydrolysis; preferably, the double enzymes are thermostable alpha-amylase and glucoamylase; preferably, the method comprises the following steps: (1) enzymatic hydrolysis treatment; (2) separation treatment; (3) yeast propagation; (4) mixing treatment; (5) sterilization and drying, wherein the yeast is Kluyveromyces marxianus; preferably, the method comprises the following steps: (1) enzymatic hydrolysis treatment: oat flour and / or oat bran prepared by crushing oat kernels are mixed with water to obtain an oat substrate, the pH is adjusted, and thermostable alpha-amylase and glucoamylase are added for enzymatic hydrolysis; (2) separation treatment: the obtained enzymatic hydrolysis liquid is centrifuged to obtain supernatant A and precipitate B; (3) yeast propagation: Kluyveromyces marxianus is inoculated into supernatant A for culture to obtain a bacterial suspension C; (4) mixing treatment: precipitate B is mixed with bacterial suspension C to form a mixture, and the mixture is further cultured to form a fermentation product; (5) sterilization and drying: the mixture is sterilized and then dried to obtain fermented oat flour; preferably, the enzyme activity of the thermostable alpha-amylase in step (1) is ≥150,000 U / mL. Preferably, the enzyme activity of the glucoamylase in step (1) is ≥200000 U / g; Preferably, the optimal particle size of the oat substrate in step (1) is 60-120 mesh, more preferably 80-120 mesh; Preferably, the mass ratio of the oat substrate to water in step (1) is 1:5-1:10, more preferably 1:5-1:8; Preferably, the pH in step (1) is adjusted to 5.0-6.5, more preferably 5.0-6.0; Preferably, the addition amount of the thermostable alpha-amylase in step (1) is 0.1%-1% of the mass of the oat substrate, more preferably 0.1%-0.5%; Preferably, the addition amount of the glucoamylase in step (1) is 0.1%-1% of the mass of the oat substrate, more preferably 0.1%-0.5%; Preferably, the thermostable alpha-amylase in step (1) is enzymolyzed at 95℃-110℃ for 0.5-3 hours, more preferably at 100℃-105℃ for 0.5-2 hours; Preferably, the glucoamylase in step (1) is enzymolyzed at 50℃-70℃ for 2-6 hours, more preferably at 55℃-65℃ for 2-4 hours; Preferably, the enzymolysis liquid in step (2) is centrifuged at 300-500 rpm for 10-30 minutes, more preferably at 350-450 rpm for 10-20 minutes; Preferably, the inoculation amount of the yeast in step (3) is 5%-10% of the volume of the supernatant A, more preferably 5%-8%; Preferably, the supernatant A in step (3) is supplemented with 0.1%-0.8% ammonium sulfate, 0.05%-0.12% dipotassium hydrogen phosphate, and 0.01%-0.08% magnesium sulfate, more preferably 0.1%-0.5% ammonium sulfate, 0.05%-0.1% dipotassium hydrogen phosphate, and 0.01%-0.05% magnesium sulfate, before the yeast is expanded; Preferably, the culture temperature of the supernatant A in step (3) is 25℃-35℃, more preferably 28℃-32℃; Preferably, the culture time of the supernatant A in step (3) is 8-16 hours, more preferably 8-14 hours; Preferably, the rotation speed of the shaker in step (3) is 150-250 rpm, more preferably 150-200 rpm; More preferably, the addition amount of the protease in step (3) is 0.05%-0.2% of the volume of the supernatant A, more preferably 0.1%; Preferably, the mass ratio of the precipitate B to the bacterial suspension C in step (4) is 1:1-2:1, more preferably 1:1; Preferably, the culture temperature of the mixture in step (4) is 32-55℃, more preferably 35℃-50℃; Preferably, the culture time of the mixture in step (4) is 1-3 hours, more preferably 1-1.5 hours; Preferably, the rotation speed of the shaker in step (4) is 150-250 rpm, more preferably 150-200 rpm; Preferably, the mixture in step (5) is sterilized at 110-125 °C for 15-60 minutes, more preferably at 115-121 °C for 15-30 minutes; Preferably, the drying method in step (5) is selected from any one of belt drying, spray drying, drum drying, hot air drying or fluidized bed drying; More preferably, the drying method is selected from any one of spray drying, drum drying or fluidized bed drying; More preferably, the spray drying has an inlet temperature of 160-180 °C and an outlet temperature of 80-90 °C; More preferably, the fluidized bed drying has a temperature of 90-100 °C and a particle size control of 250-500 pm; More preferably, the drum drying has a surface temperature of 110-150 °C, a drum rotation speed of 3-10 rpm and a material film thickness of 0.5-1.5 mm; Preferably, the fermented oat flour is in the form of a powder, granules or instant preparation.

8. The production method according to claim 7, wherein The fermented oat flour has any one or more of the following physicochemical characteristics: (1) a beta-glucan content of > 5%; (2) a protein content of > 20%; (3) a protein digestibility of > 85%; (4) an amino acid score of > 95; (5) an amino acid score corrected for protein digestibility of > 85%; Preferably, the beta-glucan content is > 6%; Preferably, the protein content is > 30%; Preferably, the protein digestibility is > 95%; Preferably, the amino acid score = 100; Preferably, the amino acid score corrected for protein digestibility = 100.

9. The production method according to claim 7 or 8, wherein, The fermented oat flour comprises the following amino acids: histidine content in the range of 0.5-3 g / 100 g dry matter; isoleucine content in the range of 1-5 g / 100 g dry matter; leucine content in the range of 2-6 g / 100 g dry matter; lysine content in the range of 1-5 g / 100 g dry matter; methionine content in the range of 0.3-1 g / 100 g dry matter; cysteine content in the range of 1-5 g / 100 g dry matter phenylalanine content in the range of 1-4 g / 100 g dry matter; tyrosine content in the range of 1-3 g / 100 g dry matter; threonine content in the range of 1-4 g / 100 g dry matter; tryptophan content in the range of 0.1-0.5 g / 100 g dry matter; valine content in the range of 0.2-2 g / 100 g dry matter; aspartate content in the range of 2-6 g / 100 g dry matter; serine content in the range of 1-4 g / 100 g dry matter; glutamate content in the range of 3-11 g / 100 g dry matter; proline content in the range of 1-4 g / 100 g dry matter; glycine content in the range of 1-4 g / 100 g dry matter; alanine content in the range of 1-5 g / 100 g dry matter; and / or arginine content in the range of 1-6 g / 100 g dry matter; Preferably, the fermented oat flour comprises the following amino acid composition: histidine content in the range of 1-2.5 g / 100 g dry matter; isoleucine content in the range of 1-3 g / 100 g dry matter; leucine content in the range of 3-5 g / 100 g dry matter; lysine content in the range of 2-5 g / 100 g dry matter; methionine content in the range of 0.5-1 g / 100 g dry matter; cysteine content in the range of 1-4 g / 100 g dry matter; phenylalanine content in the range of 1-3 g / 100 g dry matter; tyrosine content in the range of 1-2.5 g / 100 g dry matter; threonine content in the range of 1-3 g / 100 g dry matter; tryptophan content in the range of 0.2-0.4 g / 100 g dry matter; valine content in the range of 0.2-1 g / 100 g dry matter; aspartate content in the range of 3-5 g / 100 g dry matter; serine content in the range of 1-3 g / 100 g dry matter; glutamate content in the range of 4-10 g / 100 g dry matter; proline content in the range of 1-3 g / 100 g dry matter; glycine content in the range of 1-3 g / 100 g dry matter; alanine content in the range of 1-4 g / 100 g dry matter; and / or arginine content in the range of 2-5 g / 100 g dry matter; preferably, the amino acid composition of the fermented oat flour is essential amino acids; preferably, the essential amino acids comprise one or more selected from the group consisting of histidine, isoleucine, leucine, lysine, methionine, cysteine, phenylalanine, tyrosine, threonine, tryptophan or valine.

10. Use of the fermented oat flour according to any one of claims 1 to 6 or prepared according to the method of any one of claims 7 to 9 in the manufacture of a functional food, wherein, the functional food is for nutritional supplementation; preferably, the functional food is for a mammal; preferably, the nutritional supplementation is for amino acid supplementation; more preferably, the functional food is for a human; more preferably, the amino acid is an essential amino acid for humans; more preferably, the essential amino acid for humans comprises one or more selected from the group consisting of histidine, isoleucine, leucine, lysine, methionine, cysteine, phenylalanine, tyrosine, threonine, tryptophan or valine.

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