Preparation method of low-cost and high-stability all-walnut peptide milk and walnut peptide-dendrobium polysaccharide composite beverage and product thereof

Abstract

The invention relates to the technical field of functional food preparation, and discloses a preparation method of low-cost and high-stability all-walnut peptide milk and walnut peptide-dendrobium polysaccharide composite drink and a product thereof, the method is characterized in that all walnut kernels are directly used as raw materials, pre-degreasing or protein separation is not needed, and the walnut peptide milk and the walnut peptide-dendrobium polysaccharide composite drink are prepared through a composite enzymolysis and in-situ emulsification technology. The ratio of the walnut peptide to the dendrobium polysaccharide is 0.5: 1-2: 1, and then a stable system and a homogenizing technology are combined, so that the ready-to-drink product which is high in protein content, clear, transparent and stable for a long time is prepared. The whole walnut peptide milk pays attention to basic nutrition, and the composite beverage has synergistic functionality. The preparation method is simple in process, low in cost and high in raw material utilization rate, solves the problems of stability and functionalization of traditional walnut milk, and has remarkable industrialization advantages.

Description

Technical Field

[0001] This invention relates to the field of functional food preparation technology, and in particular to a low-cost, high-stability method for preparing whole walnut peptide milk and walnut peptide-Dendrobium polysaccharide complex beverage, as well as the products thereof. Background Technology

[0002] Walnuts are rich in high-quality plant protein (15-20%) and unsaturated fatty acids (60-70%), making them an ideal raw material for developing high-end plant-based beverages. However, traditional walnut milk (such as "walnut milk") and its preparation process suffer from numerous technical bottlenecks, such as protein precipitation, layering, high additive usage, high cost, and significant nutrient loss. Existing processes (e.g., CN108935876A) typically employ complex procedures, resulting in high equipment investment, high energy consumption, and low protein recovery rates. Furthermore, unhydrolyzed macromolecular proteins have high allergenicity and low digestibility and absorption rates.

[0003] Dendrobium polysaccharides, as an active ingredient in traditional Chinese medicine, possess various biological activities, including immunomodulation, antioxidation, hypoglycemia, and anti-inflammation. Studies have shown that Dendrobium polysaccharides can exert health benefits through mechanisms such as activating immune pathways, scavenging free radicals, and improving insulin sensitivity. In recent years, the market for functional compound beverages has grown rapidly, but there are currently no reports on the application of combining whole walnut peptides with Dendrobium polysaccharides in ready-to-drink beverages.

[0004] The combination of walnut peptides and Dendrobium polysaccharides exhibits significant synergistic advantages: in neuroprotection, walnut peptides provide neurotransmitter precursors, while Dendrobium polysaccharides mitigate oxidative damage; in immune regulation, the two can synergistically activate innate and adaptive immunity; and in metabolic regulation, the complex can regulate blood glucose homeostasis at multiple targets. This combination holds promise for enhancing the overall functionality of the product, but compatibility, stability, and process integration issues need to be addressed.

[0005] Therefore, there is an urgent need in this field for a simplified, green, and low-cost preparation technology that can directly utilize whole walnut raw materials and integrate Dendrobium polysaccharides to produce a dual-functional product with high nutrition and high stability. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the purpose of this invention is to provide a low-cost, highly stable method for preparing whole walnut peptide milk and a walnut peptide-Dendrobium polysaccharide complex beverage, as well as the products thereof. The core of the method lies in utilizing a complex enzyme system to simultaneously achieve efficient protein hydrolysis, bitterness control, and endogenous emulsifier generation in whole walnut pulp, constructing a self-stabilizing peptide-lipid microemulsion system; and selectively adding Dendrobium enzymatic hydrolysate to introduce the active components of Dendrobium polysaccharides.

[0007] The solution of the present invention is: A low-cost, high-stability whole walnut peptide milk preparation method includes the following steps: a) Mix whole walnut kernels that have not been defatted and have not had their protein separated with water, and homogenize them under high shear to make a uniform walnut paste with a solid content of 8-12%; b) Alkaline protease and neutral protease are added sequentially to the walnut pulp for staged compound enzymatic hydrolysis. The hydrolysis conditions are a temperature of 50±1℃, a pH of 9.0±0.1, and a total duration of 2 to 8 hours. Lipase is added simultaneously during the addition of neutral protease. c) After enzymatic hydrolysis, inactivate the enzyme and adjust the pH back to 6.8–7.2; e) Add food-grade stabilizer, undergo two-stage high-pressure homogenization, sterilize and fill to obtain the product.

[0008] As a preferred technical solution, in step a), food-grade whole walnut kernels (moisture content ≤6%, acid value ≤3mg KOH / g) that have not been defatted and have not had their protein separated are taken, and softened water is added at a mass ratio of 1:4 to 1:19. The mixture is then circulated twice by a high-shear homogenizer at 8,000 to 15,000 rpm to produce a uniform walnut paste with a solid content of 8 to 12%.

[0009] As a preferred technical solution, in step b), the amount of alkaline protease added is 1.5-2.5% of the walnut kernel mass, and the enzymatic hydrolysis time is 2 hours; the amount of neutral protease added is 1.0-2.0% of the walnut kernel mass, and the enzymatic hydrolysis time is 2 hours; step b) further includes adding lipase simultaneously during the addition of neutral protease; the amount of lipase added is 0.05-0.2% of the walnut kernel mass. The addition of lipase can catalyze the in-situ generation of natural monoglycerides, acting as an endogenous emulsifier. The pH is maintained stable throughout the enzymatic hydrolysis process using an automatic metering pump.

[0010] As a preferred technical solution, in step b), the temperature of the walnut pulp is adjusted to 50±1℃, and the pH is adjusted and maintained at 9.0±0.1 using citric acid / sodium citrate buffer.

[0011] As a preferred technical solution, after the enzymatic hydrolysis in step c), the liquid is heated to 85-90°C and maintained for 10 minutes to inactivate the enzyme preparation; then food-grade phosphoric acid is used to adjust the pH back to 6.8-7.2.

[0012] As a preferred technical solution, the food-grade stabilizer is xanthan gum, or a mixture thereof with microcrystalline cellulose; the amount of xanthan gum added is 0.05 to 0.1% of the total mass of the final product, and the amount of microcrystalline cellulose added is 0 to 0.5% of the total mass of the final product.

[0013] As a preferred technical solution, in step e), the liquid is cooled to ≤40℃, and a food-grade stabilizer is added. When the food-grade stabilizer is xanthan gum, 0.05 to 0.1% of the total mass of the final product is added. When the food-grade stabilizer is a mixture of xanthan gum and microcrystalline cellulose (MCC), the mixture is prepared by mixing xanthan gum and MCC at a mass ratio of 1:2 to 5, and then fully dissolved using a high-speed disperser (3000 rpm, 5 to 10 min).

[0014] As a preferred technical solution, in step e), the conditions for the secondary high-pressure homogenization are a homogenization temperature of 60-70°C and a primary homogenization pressure of 25-30 MPa, used to break up fat globules; the secondary homogenization pressure is 5 MPa to prevent particle re-aggregation; the sterilization is one of ultra-high temperature instantaneous sterilization or 95°C hot filling sterilization, and the ultra-high temperature instantaneous sterilization conditions are maintained at 135-140°C for 4-8 seconds.

[0015] This invention also provides a method for preparing a low-cost, high-stability walnut peptide-Dendrobium polysaccharide complex beverage, wherein step d) is further included between steps c) and e) in the method for preparing a low-cost, high-stability whole walnut peptide milk: Step d) involves adding Dendrobium hydrolysate to achieve a final product with a mass ratio of walnut peptides (based on protein) to Dendrobium polysaccharides of 0.5:1 to 2:1.

[0016] As a preferred technical solution, the preparation of Dendrobium enzymatic hydrolysate can refer to existing methods (such as water extraction enzymatic hydrolysis), but is not limited to these.

[0017] As a preferred technical solution, the Dendrobium enzymatic hydrolysate is obtained by enzymatically hydrolyzing Dendrobium raw materials, and its polysaccharide content is not less than 30%.

[0018] The present invention also discloses a method for preparing whole walnut peptide milk with low cost and high stability, and the whole walnut peptide milk product obtained therefrom.

[0019] As a preferred technical solution, the product has a protein content ≥1.5 g / 100g, is a milky white to pale yellow clear liquid with no visible sediment, does not separate into layers after standing at 4-10℃ for 30 days, has a walnut aroma, and the total amount of food additives in the product does not exceed 0.6 wt%.

[0020] The present invention also discloses a method for preparing a low-cost, high-stability walnut peptide-Dendrobium polysaccharide complex beverage.

[0021] As a preferred technical solution, the beverage contains ≥1.5 g / 100g of protein and ≥1.0g / 100g of Dendrobium polysaccharide; the beverage is a light yellow clear liquid without layering or sedimentation; it has a complex flavor of walnut and Dendrobium; and the total amount of food additives in the beverage does not exceed 0.6 wt%.

[0022] Compared with the prior art, the advantages of the present invention are: (1) The process is revolutionary and simplified, and is green and environmentally friendly. It is the first to use the "one-pot" whole walnut enzymatic hydrolysis strategy, which eliminates unit operations such as protein extraction and defatting. The core process is shortened to less than 6 hours, and the efficiency is increased by more than 50%. There is no waste, which is in line with the concept of green manufacturing.

[0023] (2) Significant advantages in raw material utilization and cost. The utilization rate of whole walnut raw materials is as high as 98% or more, saving 15-20% of raw material costs compared with traditional processes. Natural emulsifiers are generated in situ by lipase, which can completely replace or significantly reduce the use of exogenous synthetic emulsifiers, reducing additive costs by more than 50%.

[0024] (3) Improved product stability: Through compound enzymatic hydrolysis and stabilization system, the product does not separate or precipitate after standing at 4-10℃ for 30 days.

[0025] (4) Nutrition and function: The whole walnut peptide milk protein content is ≥1.5 g / 100g, with a high proportion of small molecule peptides, high digestibility and absorption rate, and low allergenicity. The walnut peptide-densera polysaccharide compound beverage has the synergistic effects of walnut peptides and dendrobium polysaccharides, such as neuroprotection, immune regulation, antioxidation and metabolic regulation, and is suitable for people throughout the entire life cycle. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0027] Figure 1 This is a flowchart of the preparation process of the present invention; Figure 2 These are comparative photos of the stability of the product obtained in Example 1 of this invention after standing at 4°C for 30 days, where a is the product obtained in Example 1 and b is the product obtained by traditional walnut milk processing. Detailed Implementation

[0028] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below with reference to specific embodiments.

[0029] Example 1: Preparation of whole walnut peptide milk (UHT type) Take 10 kg of walnut kernels with light brown seed coat (protein content 12.5%, moisture 5.2%), add 40 kg of softened water, and process twice using a high-shear homogenizer (10,000 rpm) to obtain 50 kg of walnut pulp.

[0030] Pump the walnut pulp into an enzymatic hydrolysis tank, heat to 50°C, and adjust the pH to 9.0 with a 5% sodium citrate solution. Add 200 g of alkaline protease (2.0% of the walnut kernels) and stir continuously for 2 hours. Add 150 g (1.5%) of neutral protease and 5 g (0.05%) of lipase, and continue the reaction for 2 hours, maintaining the pH at 9.0 ± 0.1 during this period.

[0031] After the reaction, the temperature was raised to 88°C and held for 10 minutes to inactivate the enzymes. The pH was adjusted to 7.0 with food-grade phosphate, and the temperature was lowered to 40°C. 50 g of xanthan gum (0.1%) and 250 g of microcrystalline cellulose (0.5%) were added, and the mixture was dispersed at high speed for 10 minutes. The solution was heated to 65°C and subjected to two-stage high-pressure homogenization (stage 1: 30 MPa, stage 2: 5 MPa). Finally, the mixture was sterilized by a UHT system (138°C, 6 seconds) and aseptically filled.

[0032] The resulting product is a whole walnut peptide milk with a protein content of 2.5 g / 100g, pH 7.1, a milky white clear liquid with a light walnut aroma, and no stratification after standing at 4℃ for 30 days. (See...) Figure 2 a) Antioxidant activity test: The DPPH free radical scavenging method was used. The product of Example 1 was diluted to different concentrations and reacted with DPPH ethanol solution. The absorbance at 517 nm was then measured. The structure showed that the product achieved a DPPH free radical scavenging rate of 85.2% ± 2.1%, and its half-maximal concentration (IC50) was [not specified]. 50 The concentration was 0.32 mg / mL. This result confirms that the product of this invention has potent antioxidant activity by directly scavenging free radicals.

[0033] Example 2: Preparation of Walnut Peptide-Dendrobium Polysaccharide Complex Beverage (Hot Filling Type) The raw material pretreatment and compound enzymatic hydrolysis steps are the same as in Example 1. After enzyme inactivation and acid adjustment, Dendrobium hydrolysate is added: the Dendrobium hydrolysate is obtained by mixing Dendrobium officinale powder (polysaccharide content 50%) with water at a ratio of 1:10, followed by cellulase hydrolysis (50℃, pH 5.0, 2 hours) and filtration. The amount added is such that the ratio of walnut peptides (based on protein) to Dendrobium polysaccharides is 1:1 (i.e., the added Dendrobium hydrolysate contains approximately 3.2 kg of polysaccharides).

[0034] The mixture was then stabilized by adding 50 g (0.1%) xanthan gum and 250 g (0.5%) MCC, dispersing and homogenizing (under the same conditions as in Example 1). It was then hot-filled into PET bottles at 95°C.

[0035] The resulting product is a walnut peptide-densera polysaccharide compound beverage with a protein content of 1.65 g / 100g and a dendrobium polysaccharide content of 1.8 g / 100g. It is a pale yellow, clear liquid with both walnut aroma and dendrobium sweetness. It has a shelf life of 3 months at 10℃ and good stability.

[0036] Neuroprotective activity test: A rat pheochromocytoma PC12 cell line was used to establish an H2O2-induced oxidative damage model. The product from Example 2 was diluted to 50 μg / mL and 100 μg / mL, and the cells were pretreated for 24 hours before being treated with H2O2. The results showed that the cell viability in the model group significantly decreased to approximately 52%. However, after pretreatment with the obtained walnut peptide-Dendrobium polysaccharide compound beverage, the cell viability recovered to 78.5% and 86.3%, respectively, demonstrating a significant neuroprotective effect.

[0037] Example 3: Preparation of hot-filled whole walnut peptide milk The ratio was adjusted to walnut kernels:water = 1:9, and the other steps were the same as in Example 1.

[0038] The sterilization and filling process uses a 95℃ hot filling method, filling the bottles into heat-resistant PET bottles.

[0039] The resulting product has a protein content of 1.8 g / 100g and a refreshing taste. It has a shelf life of up to 3 months at room temperature and exhibits good stability.

[0040] Example 4: Preparation of UHT-type walnut peptide-Dendrobium polysaccharide compound beverage The raw material pretreatment and compound enzymatic hydrolysis steps are the same as in Example 1. The preparation method of Dendrobium enzymatic hydrolysate is the same as in Example 2. The amount added is such that the ratio of walnut peptide (based on protein) to Dendrobium polysaccharide is 0.5:1.

[0041] The mixture was then stabilized by adding 50 g (0.1%) xanthan gum and 250 g (0.5%) MCC, dispersing and homogenizing (under the same conditions as in Example 1). Finally, it was sterilized by a UHT system (138°C, 6 seconds) and aseptically filled.

[0042] The resulting product is a walnut peptide-densera polysaccharide compound beverage with a protein content of 1.6 g / 100g and a dendrobium polysaccharide content of 2.68 g / 100g. It is a pale yellow, clear liquid with both walnut aroma and dendrobium sweetness. It has a shelf life of 3 months at room temperature and good stability.

[0043] Example 5: Preparation of UHT-type walnut peptide-Dendrobium polysaccharide compound beverage The raw material pretreatment and compound enzymatic hydrolysis steps are the same as in Example 1. The preparation method of Dendrobium enzymatic hydrolysate is the same as in Example 2. The amount added is such that the ratio of walnut peptides (based on protein) to Dendrobium polysaccharides is 2:1.

[0044] The mixture was then stabilized by adding 50 g (0.1%) xanthan gum and 250 g (0.5%) MCC, dispersing and homogenizing (under the same conditions as in Example 1). Finally, it was sterilized by a UHT system (138°C, 6 seconds) and aseptically filled.

[0045] The resulting product is a walnut peptide-densera polysaccharide complex beverage with a protein content of 2.0 g / 100g and a dendrobium polysaccharide content of 1.2 g / 100g. It is a pale yellow, clear liquid with both walnut aroma and dendrobium sweetness. It has a shelf life of 3 months at room temperature and good stability.

[0046] Comparative Example 1: Traditional Walnut Milk Processing Using commercially available common processing methods: walnut kernels are peeled, ground, and filtered to remove some residue. 0.4% sucrose fatty acid ester and 0.1% xanthan gum are added as stabilizers. After homogenization, the mixture is sterilized and packaged. Under the same storage conditions, significant sedimentation and an oily floating layer appear after 30 days (see...). Figure 2 b).

[0047] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a low-cost, highly stable whole walnut peptide milk, characterized in that, Includes the following steps: a) Mix whole walnut kernels that have not been defatted and have not had their protein separated with water, and homogenize them under high shear to make a uniform walnut paste with a solid content of 8-12%; b) Alkaline protease and neutral protease were added to the walnut pulp in sequence for staged compound enzymatic hydrolysis. The hydrolysis conditions were 50±1℃, pH 9.0±0.1, and a total duration of 2 to 8 hours. c) After enzymatic hydrolysis, inactivate the enzyme and adjust the pH back to 6.8–7.2; e) Add food-grade stabilizer, undergo two-stage high-pressure homogenization, sterilize and fill to obtain the product.

2. The method as described in claim 1, characterized in that: In step b), the amount of alkaline protease added is 1.5-2.5% of the weight of the walnut kernel, and the enzymatic hydrolysis time is 2 hours; the amount of neutral protease added is 1.0-2.0% of the weight of the walnut kernel, and the enzymatic hydrolysis time is 2 hours. Step b) further includes adding lipase simultaneously during the addition of neutral protease; the amount of lipase added is 0.05 to 0.2% of the weight of the walnut kernel.

3. The method as described in claim 1, characterized in that: The food-grade stabilizer is xanthan gum, or a mixture thereof with microcrystalline cellulose; the amount of xanthan gum added is 0.05 to 0.1% of the total mass of the final product, and the amount of microcrystalline cellulose added is 0 to 0.5% of the total mass of the final product.

4. The method as described in claim 1, characterized in that: In step e), the conditions for the secondary high-pressure homogenization are a homogenization temperature of 60-70°C, a primary homogenization pressure of 25-30 MPa, and a secondary homogenization pressure of 5 MPa; the sterilization is either ultra-high temperature instantaneous sterilization or 95°C hot filling sterilization; wherein, the ultra-high temperature instantaneous sterilization conditions are maintained at 135-140°C for 4-8 seconds.

5. A method for preparing a low-cost, high-stability walnut peptide-Dendrobium polysaccharide complex beverage, characterized in that, In the method according to any one of claims 1 to 4, step d) is further included between step c) and step e): Step d) involves adding Dendrobium enzymatic hydrolysate to achieve a final product with a mass ratio of walnut peptides to Dendrobium polysaccharides of 0.5:1 to 2:

1.

6. The method as described in claim 5, characterized in that: The Dendrobium enzymatic hydrolysate is obtained by enzymatically hydrolyzing Dendrobium raw materials, and its polysaccharide content is not less than 30%.

7. A whole walnut peptide milk product prepared by the method according to any one of claims 1 to 4.

8. The product as described in claim 7, characterized in that: The product contains ≥1.5 g / 100g of protein, is a milky white to pale yellow clear liquid with no visible sediment, does not separate into layers after standing at 4-10℃ for 30 days, has a walnut aroma, and the total amount of food additives in the product does not exceed 0.6 wt%.

9. A walnut peptide-Dendrobium polysaccharide complex beverage prepared by the method as described in claim 5 or 6.

10. The beverage as described in claim 9, characterized in that: The beverage contains ≥1.5 g / 100g of protein and ≥1.0 g / 100g of Dendrobium polysaccharides; the beverage is a pale yellow clear liquid without layering or sedimentation; it has a complex flavor of walnut and Dendrobium; the total amount of food additives in the beverage does not exceed 0.6 wt%.

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