A slow-digesting pregelatinized yam powder loaded with anthocyanins and its preparation method

Abstract

This invention discloses a slow-digesting pregelatinized yam powder loaded with anthocyanins and its preparation method, relating to the field of food ingredient technology. The preparation method includes the following steps: Step S1, preparation of multi-field assisted yam milk; Step S2, pregelatinization; Step S3, loading with anthocyanins; Step S4, spray drying. The yam powder disclosed in this invention exhibits high slow-digesting performance, excellent anthocyanin dispersibility and stability, and good color and taste.

Description

Technical Field

[0001] This invention relates to the field of food ingredient technology, and in particular to a slow-digesting pregelatinized yam powder loaded with anthocyanins and its preparation method. Background Technology

[0002] With the development of food science and the improvement of people's living standards, people's awareness of nutrition and health has undergone fundamental changes. Beyond simply being satisfied with food and drink, consumers have come to recognize the impact of nutrition on health. A scientifically sound dietary structure and proactive and effective dietary interventions are effective ways to prevent and control metabolic-related chronic diseases (such as diabetes, obesity, and cardiovascular diseases).

[0003] Yam, also known as Chinese yam, is the tuber of the vine *Dioscorea opposita*. Its fleshy, thick tuber is slightly cylindrical and contains essential amino acids, proteins, polysaccharides, calcium, phosphorus, iron, vitamins, and other nutrients. Yam is not only a nutritious and health-promoting food but also a commonly used medicinal herb, possessing both culinary and medicinal value. Regular consumption of yam can enhance immune function, delay cell aging, prevent collagen diseases such as rheumatoid arthritis and scleroderma, maintain blood vessel elasticity, and prevent premature atherosclerosis. However, the main component of yam is starch. Rapid starch digestion can easily cause blood sugar fluctuations, and long-term consumption may lead to chronic diseases such as diabetes. Therefore, slowing down starch digestion is one direction for the development of starch-based foods.

[0004] Slow-digesting pregelatinized yam powder is a key ingredient in gluten-free bread suitable for diabetics. It has a relatively low glycemic index (GI), helping to maintain blood sugar levels and providing energy slowly and consistently. Consuming foods containing slow-digesting pregelatinized yam powder can increase satiety, improve glycemic tolerance, and lower blood lipid levels, helping to prevent various chronic diseases. To improve the color of slow-digesting pregelatinized yam powder or maintain its original color, pigments are usually added during processing. The use of natural pigments is receiving increasing attention. Anthocyanins are a class of natural pigments widely found in plants and possess certain biological activities, such as inhibiting the activity of starch-digesting enzymes, which can be used to improve starch digestibility. Adding anthocyanins to pregelatinized starch not only gives the product a certain color but also effectively slows down starch digestibility. However, anthocyanins have poor stability and are easily oxidized and decomposed during food processing, leading to color changes in the product. Therefore, how to protect the stability of anthocyanins during food processing is a hot research topic. On the other hand, existing anthocyanin-loaded slow-digesting pregelatinized yam powders are relatively rare, and they suffer from technical defects such as uneven dispersion, low loading, and easy fading during the loading process. Furthermore, there are currently no commercially available anthocyanin-loaded slow-digesting pregelatinized yam powders on the market; most are still in the laboratory research and development stage. Existing products have low slow-digesting performance, unstable processing, inconvenient operation control, and their taste needs further improvement, making them difficult to apply in actual food processing.

[0005] It is evident that developing a slow-digesting pregelatinized yam powder loaded with anthocyanins, characterized by high slow digestibility, excellent anthocyanin dispersibility and stability, and good color and flavor, along with its preparation method, meets market demands, possesses broad market value and application prospects, and is of great significance for promoting the development of food ingredient technology. Summary of the Invention

[0006] The main objective of this invention is to provide a slow-digesting pregelatinized yam powder loaded with anthocyanins, which has high slow-digesting performance, good anthocyanin dispersibility, sufficient stability, good color and taste, and its preparation method.

[0007] To achieve the above objectives, the present invention provides a method for preparing slow-digesting pregelatinized yam powder loaded with anthocyanins, comprising the following steps:

[0008] Step S1: Preparation of yam milk with multi-energy field assistance: Using yam, a plant that is both food and medicine, as raw material, after washing, peeling, and cutting into pieces, hot water is added, and the mixture is fully crushed and pulped. After being processed with multi-energy field assistance, yam milk is obtained.

[0009] Step S2, Pregelatinization: The yam milk prepared in step S1 and the auxiliary composition are added to a saccharification pot for pregelatinization to obtain pregelatinized yam milk; the auxiliary composition includes the following components in parts by weight: sodium alginate 1-3 parts, barley grass powder 3-5 parts, inulin 3-5 parts, soybean protein powder 2-4 parts, and selenium-enriched Ganoderma lucidum spore powder 0.6-1.2 parts;

[0010] Step S3, Loading anthocyanins: Add anthocyanins and pigment excipients to the pregelatinized yam milk prepared in step S2, and disperse evenly by ultrasonication;

[0011] Step S4, spray drying: spray drying the anthocyanin-loaded material to obtain anthocyanin-loaded slow-digesting pregelatinized yam powder.

[0012] Preferably, the multi-energy field assisted processing in step S1 includes ultrasonic processing, microwave processing, and steady magnetic field processing.

[0013] Preferably, the ultrasonic treatment has an ultrasonic frequency of 35-45kHz, a processing power of 800-1000W, and a processing time of 18-32min; the microwave treatment has a microwave frequency of 1.8-3.2GHz, a processing power of 900-1500W, and a processing time of 10-15min; and the steady magnetic field treatment has a steady magnetic field strength of 0.8-2.8T and a processing time of 6-12min.

[0014] Preferably, the temperature of the hot water in step S1 is 50-60℃; and its weight is 6-9 times the weight of the yam after it has been cut into pieces.

[0015] Preferably, the pregelatinization temperature in step S2 is 80-90℃, and the pregelatinization time is 8-13 min.

[0016] Preferably, the mass ratio of the yam milk and the auxiliary composition in step S2 is (15-20):1.

[0017] Preferably, the mass ratio of the pregelatinized yam milk, anthocyanin, and pigment excipients in step S3 is (15-20):1:(0.1-0.3).

[0018] Preferably, the anthocyanin is any one of geranium pigment, cornflower pigment, sorghum red pigment, mulberry red pigment, and grape skin pigment.

[0019] Preferably, the pigment excipient comprises the following components by weight: 4-6 parts of plant polysaccharide, 1-3 parts of tea polyphenol, and 0.03-0.1 parts of citric acid.

[0020] Preferably, the plant polysaccharide is at least one of the following: Tremella fuciformis polysaccharide, Ophiopogon japonicus polysaccharide, Lycium barbarum polysaccharide, and Bamboo leaf polysaccharide.

[0021] Preferably, the frequency of the ultrasound in step S3 is 80-100KHz.

[0022] Preferably, the inlet temperature of the spray dryer in step S4 is 175°C and the outlet temperature is 80°C.

[0023] Another object of the present invention is to provide an anthocyanin-loaded slow-digesting pregelatinized yam powder prepared by the above-described method for preparing anthocyanin-loaded slow-digesting pregelatinized yam powder.

[0024] Due to the application of the above technical solution, the present invention has the following beneficial effects:

[0025] (1) The method for preparing anthocyanin-loaded slow-digesting pregelatinized yam powder disclosed in this invention is simple, easy to operate, and the raw materials are readily available. It has high preparation efficiency and high finished product qualification rate, low energy consumption, and is easy to carry out continuous production. It also reduces the use of large amounts of organic reagents and does not pollute the environment. The anthocyanin-loaded slow-digesting pregelatinized yam powder prepared has higher nutritional value and lower glycemic index, has broad market potential, and has high social and economic benefits.

[0026] (2) The anthocyanin-loaded slow-digesting pregelatinized yam powder disclosed in this invention, prepared using multi-field assisted yam milk, can effectively improve the slow digestibility of the product, resulting in a high-quality product and overcoming the shortcomings of low efficiency and poor thermal stability of existing conventional methods. On the other hand, it can also allow water to fully penetrate into the interior of the yam, forming a well-uniform dispersion system, thereby improving the quality and color of the final product. In addition, it is also beneficial for de-clustering pregelatinization.

[0027] (3) The anthocyanin-loaded slow-digesting pregelatinized yam powder disclosed in this invention pregelatinizes yam milk and auxiliary composition together, and the auxiliary components are reasonably selected including the following components by weight: sodium alginate 1-3 parts, barley grass powder 3-5 parts, inulin 3-5 parts, soybean protein powder 2-4 parts, and selenium-enriched Ganoderma lucidum spore powder 0.6-1.2 parts; through the synergistic effect between the components, the nutritional balance of the yam powder product can be effectively improved, and the health care effect, color and flavor can be improved; in addition, it can also inhibit the combination of yam powder and digestive enzymes, thereby reducing the enzymatic hydrolysis rate and improving the slow digestibility of the product, which is beneficial to slow down the blood sugar fluctuations of diabetic patients who consume starch-based foods and prevent insulin secretion disorders.

[0028] (4) The slow-digesting pregelatinized yam powder loaded with anthocyanins disclosed in this invention, through pregelatinization, can increase the viscosity of the yam powder when used in gluten-free bread during kneading, allowing the gluten network to form more fully during the kneading process; during the loading of anthocyanins, the addition of pigment excipients can not only improve the stability of anthocyanins and enhance the color of the product, effectively preventing fading, but also reduce the amount of anthocyanins used, thereby saving application costs. The pigment excipients include the following components by weight: 4-6 parts of plant polysaccharides, 1-3 parts of tea polyphenols, and 0.03-0.1 parts of citric acid; through the synergistic effect between the components, the antioxidant properties and stability of the pigments can be improved, and the health benefits, color, and flavor of the product can be further improved. Detailed Implementation

[0029] The following description is intended to disclose the invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art. Example 1

[0030] A method for preparing slow-digesting pregelatinized yam powder loaded with anthocyanins includes the following steps:

[0031] Step S1: Preparation of yam milk with multi-energy field assistance: Using yam, a plant that is both food and medicine, as raw material, after washing, peeling, and cutting into pieces, hot water is added, and the mixture is fully crushed and pulped. After being processed with multi-energy field assistance, yam milk is obtained.

[0032] Step S2, Pregelatinization: The yam milk prepared in step S1 and the auxiliary composition are added to the saccharification pot for pregelatinization to obtain pregelatinized yam milk; the auxiliary composition includes the following components in parts by weight: 1 part sodium alginate, 3 parts barley grass powder, 3 parts inulin, 2 parts soybean protein powder, and 0.6 parts selenium-enriched Ganoderma lucidum spore powder.

[0033] Step S3, Loading anthocyanins: Add anthocyanins and pigment excipients to the pregelatinized yam milk prepared in step S2, and disperse evenly by ultrasonication;

[0034] Step S4, spray drying: spray drying the anthocyanin-loaded material to obtain anthocyanin-loaded slow-digesting pregelatinized yam powder.

[0035] The multi-energy field assisted processing in step S1 includes ultrasonic processing, microwave processing, and steady magnetic field processing; the ultrasonic processing has an ultrasonic frequency of 35kHz, a processing power of 800W, and a processing time of 18min; the microwave processing has a microwave frequency of 1.8GHz, a processing power of 900W, and a processing time of 10min; the steady magnetic field processing has a steady magnetic field strength of 0.8T and a processing time of 6min.

[0036] The temperature of the hot water in step S1 is 50℃; the weight is 6 times the weight of the yam after it is cut into pieces; the temperature of the pregelatinization in step S2 is 80℃, and the pregelatinization time is 8 minutes; the mass ratio of the yam milk and the auxiliary composition in step S2 is 15:1.

[0037] In step S3, the mass ratio of pregelatinized yam milk, anthocyanin, and pigment excipients is 15:1:0.1; the anthocyanin is geranium pigment; the pigment excipients include the following components by weight: 4 parts plant polysaccharide, 1 part tea polyphenol, and 0.03 parts citric acid; the plant polysaccharide is tremella polysaccharide; the frequency of ultrasound in step S3 is 80 kHz; the inlet temperature of spray drying in step S4 is 175°C, and the outlet temperature is 80°C.

[0038] An anthocyanin-loaded slow-digesting pregelatinized yam powder prepared by the above-mentioned method for preparing anthocyanin-loaded slow-digesting pregelatinized yam powder. Example 2

[0039] A method for preparing slow-digesting pregelatinized yam powder loaded with anthocyanins includes the following steps:

[0040] Step S1: Preparation of yam milk with multi-energy field assistance: Using yam, a plant that is both food and medicine, as raw material, after washing, peeling, and cutting into pieces, hot water is added, and the mixture is fully crushed and pulped. After being processed with multi-energy field assistance, yam milk is obtained.

[0041] Step S2, Pregelatinization: The yam milk prepared in step S1 and the auxiliary composition are added to a saccharification pot for pregelatinization to obtain pregelatinized yam milk; the auxiliary composition includes the following components in parts by weight: 1.5 parts sodium alginate, 3.5 parts barley grass powder, 3.5 parts inulin, 2.5 parts soybean protein powder, and 0.8 parts selenium-enriched Ganoderma lucidum spore powder;

[0042] Step S3, Loading anthocyanins: Add anthocyanins and pigment excipients to the pregelatinized yam milk prepared in step S2, and disperse evenly by ultrasonication;

[0043] Step S4, spray drying: spray drying the anthocyanin-loaded material to obtain anthocyanin-loaded slow-digesting pregelatinized yam powder.

[0044] The multi-energy field assisted treatment in step S1 includes ultrasonic treatment, microwave treatment, and steady magnetic field treatment; the ultrasonic treatment has an ultrasonic frequency of 38kHz, a processing power of 850W, and a processing time of 22min; the microwave treatment has a microwave frequency of 2.1GHz, a processing power of 1100W, and a processing time of 12min; the steady magnetic field treatment has a steady magnetic field strength of 1.3T and a processing time of 8min; the temperature of the hot water in step S1 is 53℃; and the weight is 7 times the weight of the yam after it is cut into pieces.

[0045] In step S2, the pregelatinization temperature is 83℃ and the pregelatinization time is 10 min; the mass ratio of yam milk and auxiliary composition in step S2 is 17:1; the mass ratio of pregelatinized yam milk, anthocyanin, and pigment excipient in step S3 is 17:1:0.15; the anthocyanin is cornflower pigment; the pigment excipient includes the following components by weight: 4.5 parts plant polysaccharide, 1.5 parts tea polyphenols, and 0.05 parts citric acid; the plant polysaccharide is Ophiopogon japonicus polysaccharide; the ultrasonic frequency in step S3 is 85 kHz; the inlet temperature of spray drying in step S4 is 175℃ and the outlet temperature is 80℃.

[0046] An anthocyanin-loaded slow-digesting pregelatinized yam powder prepared by the above-mentioned method for preparing anthocyanin-loaded slow-digesting pregelatinized yam powder. Example 3

[0047] A method for preparing slow-digesting pregelatinized yam powder loaded with anthocyanins includes the following steps:

[0048] Step S1: Preparation of yam milk with multi-energy field assistance: Using yam, a plant that is both food and medicine, as raw material, after washing, peeling, and cutting into pieces, hot water is added, and the mixture is fully crushed and pulped. After being processed with multi-energy field assistance, yam milk is obtained.

[0049] Step S2, Pregelatinization: The yam milk prepared in step S1 and the auxiliary composition are added to the saccharification pot for pregelatinization to obtain pregelatinized yam milk; the auxiliary composition includes the following components in parts by weight: 2 parts sodium alginate, 4 parts barley grass powder, 4 parts inulin, 3 parts soybean protein powder, and 0.9 parts selenium-enriched Ganoderma lucidum spore powder.

[0050] Step S3, Loading anthocyanins: Add anthocyanins and pigment excipients to the pregelatinized yam milk prepared in step S2, and disperse evenly by ultrasonication;

[0051] Step S4, spray drying: spray drying the anthocyanin-loaded material to obtain anthocyanin-loaded slow-digesting pregelatinized yam powder.

[0052] The multi-energy field assisted processing in step S1 includes ultrasonic processing, microwave processing, and steady magnetic field processing; the ultrasonic processing has an ultrasonic frequency of 40kHz, a processing power of 900W, and a processing time of 24min; the microwave processing has a microwave frequency of 2.5GHz, a processing power of 1300W, and a processing time of 13min; the steady magnetic field processing has a steady magnetic field strength of 1.8T and a processing time of 9min.

[0053] The temperature of the hot water in step S1 is 55℃; the weight is 7.5 times the weight of the yam after cutting into pieces; the temperature of pregelatinization in step S2 is 85℃, and the pregelatinization time is 11 min; the mass ratio of yam milk and auxiliary composition in step S2 is 18:1; the mass ratio of pregelatinized yam milk, anthocyanin, and pigment excipient in step S3 is 18:1:0.2; the anthocyanin is sorghum red pigment; the pigment excipient includes the following components by weight: 5 parts plant polysaccharide, 2 parts tea polyphenols, and 0.06 parts citric acid; the plant polysaccharide is wolfberry polysaccharide; the frequency of ultrasound in step S3 is 90 kHz; the inlet temperature of spray drying in step S4 is 175℃, and the outlet temperature is 80℃.

[0054] An anthocyanin-loaded slow-digesting pregelatinized yam powder prepared by the above-mentioned method for preparing anthocyanin-loaded slow-digesting pregelatinized yam powder. Example 4

[0055] A method for preparing slow-digesting pregelatinized yam powder loaded with anthocyanins includes the following steps:

[0056] Step S1: Preparation of yam milk with multi-energy field assistance: Using yam, a plant that is both food and medicine, as raw material, after washing, peeling, and cutting into pieces, hot water is added, and the mixture is fully crushed and pulped. After being processed with multi-energy field assistance, yam milk is obtained.

[0057] Step S2, Pregelatinization: The yam milk prepared in step S1 and the auxiliary composition are added to a saccharification pot for pregelatinization to obtain pregelatinized yam milk; the auxiliary composition includes the following components in parts by weight: sodium alginate 2.5 parts, barley grass powder 4.5 parts, inulin 4.5 parts, soybean protein powder 3.5 parts, and selenium-enriched Ganoderma lucidum spore powder 1.1 parts;

[0058] Step S3, Loading anthocyanins: Add anthocyanins and pigment excipients to the pregelatinized yam milk prepared in step S2, and disperse evenly by ultrasonication;

[0059] Step S4, spray drying: spray drying the anthocyanin-loaded material to obtain anthocyanin-loaded slow-digesting pregelatinized yam powder.

[0060] The multi-energy field assisted processing in step S1 includes ultrasonic processing, microwave processing, and steady magnetic field processing; the ultrasonic processing has an ultrasonic frequency of 43kHz, a processing power of 950W, and a processing time of 30min; the microwave processing has a microwave frequency of 3.0GHz, a processing power of 1400W, and a processing time of 14min; the steady magnetic field processing has a steady magnetic field strength of 2.5T and a processing time of 11min.

[0061] The temperature of the hot water in step S1 is 58℃; the weight is 8.5 times the weight of the yam after cutting into pieces; the temperature of pregelatinization in step S2 is 88℃, and the pregelatinization time is 12 min; the mass ratio of yam milk and auxiliary composition in step S2 is 19:1; the mass ratio of pregelatinized yam milk, anthocyanin, and pigment excipient in step S3 is 19:1:0.25; the anthocyanin is mulberry red pigment; the pigment excipient includes the following components by weight: 5.5 parts of plant polysaccharide, 2.5 parts of tea polyphenols, and 0.09 parts of citric acid; the plant polysaccharide is a mixture formed by mixing Tremella fuciformis polysaccharide, Ophiopogon japonicus polysaccharide, Lycium barbarum polysaccharide, and Bamboo leaf polysaccharide in a mass ratio of 1:2:2:3; the frequency of ultrasound in step S3 is 95KHz; the inlet temperature of spray drying in step S4 is 175℃, and the outlet temperature is 80℃.

[0062] An anthocyanin-loaded slow-digesting pregelatinized yam powder prepared by the above-mentioned method for preparing anthocyanin-loaded slow-digesting pregelatinized yam powder. Example 5

[0063] A method for preparing slow-digesting pregelatinized yam powder loaded with anthocyanins includes the following steps:

[0064] Step S1: Preparation of yam milk with multi-energy field assistance: Using yam, a plant that is both food and medicine, as raw material, after washing, peeling, and cutting into pieces, hot water is added, and the mixture is fully crushed and pulped. After being processed with multi-energy field assistance, yam milk is obtained.

[0065] Step S2, Pregelatinization: The yam milk prepared in step S1 and the auxiliary composition are added to the saccharification pot for pregelatinization to obtain pregelatinized yam milk; the auxiliary composition includes the following components in parts by weight: 3 parts sodium alginate, 5 parts barley grass powder, 5 parts inulin, 4 parts soybean protein powder, and 1.2 parts selenium-enriched Ganoderma lucidum spore powder.

[0066] Step S3, Loading anthocyanins: Add anthocyanins and pigment excipients to the pregelatinized yam milk prepared in step S2, and disperse evenly by ultrasonication;

[0067] Step S4, spray drying: spray drying the anthocyanin-loaded material to obtain anthocyanin-loaded slow-digesting pregelatinized yam powder.

[0068] The multi-energy field assisted treatment in step S1 includes ultrasonic treatment, microwave treatment, and steady magnetic field treatment; the ultrasonic treatment has an ultrasonic frequency of 45kHz, a processing power of 1000W, and a processing time of 32min; the microwave treatment has a microwave frequency of 3.2GHz, a processing power of 1500W, and a processing time of 15min; the steady magnetic field treatment has a steady magnetic field strength of 2.8T and a processing time of 12min; the temperature of the hot water in step S1 is 60℃; and the weight is 9 times the weight of the yam after it is cut into pieces.

[0069] In step S2, the pregelatinization temperature is 90℃ and the pregelatinization time is 13 min; the mass ratio of yam milk and auxiliary composition in step S2 is 20:1; the mass ratio of pregelatinized yam milk, anthocyanin, and pigment excipient in step S3 is 20:1:0.3; the anthocyanin is grape skin pigment; the pigment excipient includes the following components by weight: 6 parts plant polysaccharide, 3 parts tea polyphenols, and 0.1 parts citric acid; the plant polysaccharide is bamboo leaf polysaccharide; the ultrasonic frequency in step S3 is 100 kHz; the inlet temperature of spray drying in step S4 is 175℃ and the outlet temperature is 80℃.

[0070] An anthocyanin-loaded slow-digesting pregelatinized yam powder prepared by the above-mentioned method for preparing anthocyanin-loaded slow-digesting pregelatinized yam powder.

[0071] Comparative Example 1

[0072] A slow-digesting pregelatinized yam powder loaded with anthocyanins and its preparation method are basically the same as those in Example 1, except that there is no multi-field assisted treatment.

[0073] Comparative Example 2

[0074] A slow-digesting pregelatinized yam powder loaded with anthocyanins and its preparation method are basically the same as those in Example 1, except that no auxiliary composition and pigment excipients are added.

[0075] To further illustrate the beneficial technical effects of the anthocyanin-loaded slow-digesting pregelatinized yam powder prepared according to the various embodiments of the present invention, relevant performance tests were conducted on the anthocyanin-loaded slow-digesting pregelatinized yam powder prepared in Examples 1-5 and Comparative Examples 1-2. The test results are shown in Table 1, and the test methods are as follows:

[0076] (1) Slow digestibility: The content of slow digestible starch was determined by the Englyst method.

[0077] (2) Pigment stability: Place each product in an indoor light-exposed area for 30 days and observe whether there is obvious fading. If there is no fading, the pigment stability is passed; otherwise, it is unqualified.

[0078] (3) Sensory evaluation: Each product was brewed with boiling water and then randomly distributed to volunteers for tasting. Each group consisted of 10 people, with 10 points as the maximum score. The average score of the 10 people was taken as the score of the group. The scores were evaluated from two aspects: taste and color.

[0079] As can be seen from Table 1, the slow-digesting pregelatinized yam powder loaded with anthocyanins disclosed in the embodiments of the present invention has better slow digestibility and pigment stability than the comparative product, and also has better taste and color; the addition of multi-field assisted treatment, auxiliary composition and pigment excipients is beneficial to improving the above properties.

[0080] Table 1

[0081] project Slow-digesting starch content / % Pigment stability Taste rating / points Color rating / point Example 1 52.21 pass 9.8 10 Example 2 53.43 pass 9.8 10 Example 3 54.05 pass 9.9 10 Example 4 54.87 pass 10 10 Example 5 55.13 pass 10 10 Comparative Example 1 45.72 pass 9.6 9.8 Comparative Example 2 44.47 Unqualified 9.3 9.6

[0082] 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 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 claimed invention. The scope of protection claimed by the appended claims and their equivalents is defined.

Claims

1. A method for preparing slow-digesting pregelatinized yam powder loaded with anthocyanins, characterized in that, Includes the following steps: Step S1: Preparation of multi-energy field assisted yam milk: Using yam, a plant that is both medicinal and edible, as raw material, the yam is washed, peeled, and cut into pieces. Hot water is added, and the mixture is thoroughly pulverized and pulped. After multi-energy field assisted treatment, yam milk is obtained. The multi-energy field assisted treatment includes ultrasonic treatment, microwave treatment, and steady magnetic field treatment. The ultrasonic treatment has an ultrasonic frequency of 35-45kHz, a processing power of 800-1000W, and a processing time of 18-32min. The microwave treatment has a microwave frequency of 1.8-3.2GHz, a processing power of 900-1500W, and a processing time of 10-15min. The steady magnetic field treatment has a steady magnetic field strength of 0.8-2.8T and a processing time of 6-12min. Step S2, Pregelatinization: The yam milk prepared in step S1 and the auxiliary composition are added to a saccharification pot for pregelatinization to obtain pregelatinized yam milk; the auxiliary composition includes the following components in parts by weight: sodium alginate 1-3 parts, barley grass powder 3-5 parts, inulin 3-5 parts, soybean protein powder 2-4 parts, and selenium-enriched Ganoderma lucidum spore powder 0.6-1.2 parts; Step S3, Loading anthocyanins: Add anthocyanins and pigment excipients to the pregelatinized yam milk prepared in step S2, and disperse evenly by ultrasonication; the pigment excipients include the following components by weight: 4-6 parts of plant polysaccharides, 1-3 parts of tea polyphenols, and 0.03-0.1 parts of citric acid; Step S4, spray drying: spray drying the anthocyanin-loaded material to obtain anthocyanin-loaded slow-digesting pregelatinized yam powder.

2. The method for preparing anthocyanin-loaded slow-digesting pregelatinized yam powder according to claim 1, characterized in that, The temperature of the hot water in step S1 is 50-60℃; the weight is 6-9 times the weight of the yam after it is cut into pieces.

3. The method for preparing anthocyanin-loaded slow-digesting pregelatinized yam powder according to claim 1, characterized in that, The pregelatinization temperature in step S2 is 80-90℃, and the pregelatinization time is 8-13 min; the mass ratio of yam milk and auxiliary composition in step S2 is (15-20):

1.

4. The method for preparing slow-digesting pregelatinized yam powder loaded with anthocyanins according to claim 1, characterized in that, The mass ratio of the pregelatinized yam milk, anthocyanin, and pigment excipients in step S3 is (15-20):1:(0.1-0.3).

5. The method for preparing anthocyanin-loaded slow-digesting pregelatinized yam powder according to claim 4, characterized in that, The anthocyanin is any one of geranium pigment, cornflower pigment, sorghum red pigment, mulberry red pigment, and grape skin pigment.

6. The method for preparing anthocyanin-loaded slow-digesting pregelatinized yam powder according to claim 1, characterized in that, The plant polysaccharide is at least one of the following: Tremella fuciformis polysaccharide, Ophiopogon japonicus polysaccharide, Lycium barbarum polysaccharide, and Bamboo leaf polysaccharide.

7. The method for preparing anthocyanin-loaded slow-digesting pregelatinized yam powder according to claim 1, characterized in that, The frequency of the ultrasound in step S3 is 80-100kHz; the inlet temperature of the spray dryer in step S4 is 175℃ and the outlet temperature is 80℃.

8. A slow-digesting pregelatinized yam powder loaded with anthocyanins, characterized in that, It was prepared using the method for preparing anthocyanin-loaded slow-digesting pregelatinized yam powder according to any one of claims 1-7.