Longan yoghurt added with resistant starch-food gum compound and preparation method of longan yoghurt

Abstract

The invention belongs to the technical field of food processing, and discloses longan yoghurt added with a resistant starch-food gum compound and a preparation method of the longan yoghurt. The invention discloses a resistant starch-food gum compound, which is obtained by carrying out cold plasma treatment on resistant starch and food gum, and provides the resistant starch-food gum compound. According to the resistant starch-food gum compound, cold plasma treatment driving is adopted to enable resistant starch and food gum to be cross-linked to form a molecular-level synergistic gel network structure, when the resistant starch-food gum compound is used for yogurt preparation, flavor fusion enhancement, accurate physical property regulation and control (pH fluctuation + / -0.1, and the precipitation rate is smaller than or equal to 1.5%) and shelf life extension can be synchronously achieved, the stability of yogurt is remarkably improved, and the product quality is improved. Whey is prevented from being separated out, and the taste is optimized.

Description

Technical Field

[0001] The invention belongs to the technical field of food processing, and particularly relates to longan yogurt added with a resistant starch-food gum complex and a preparation method thereof. Background Art

[0002] As a traditional fermented dairy product, yogurt has become one of the most consumed dairy products in the world due to its unique flavor and nutritional functions. In recent years, flavored yogurt has become an important direction for dairy product innovation by combining sensory experience with regional cultural characteristics. Among them, the application of fruits with medicinal and edible properties, such as longan, has attracted much attention: longan flesh is rich in polyphenols and amino acids, and has antioxidant and sleep-improving effects, but the reducing sugars and organic acids in its juice easily undergo Maillard reactions with milk proteins, causing traditional longan yogurt to brown severely and lose its flavor quickly during storage. Although the existing process uses the method of adding longan pulp after enzymatic hydrolysis to partially retain the active ingredients, the change in the pH value of the fermentation system accelerates the precipitation of nutrients such as protein and polyphenols, affecting the texture uniformity of the product.

[0003] Resistant starch (RS) has become a popular alternative to traditional thickeners due to its prebiotic properties and dietary fiber-enhancing properties. Studies have shown that RS2 (high-amylose corn starch) and RS3 (retrograded starch) are effective in regulating intestinal flora and delaying postprandial blood sugar rise. However, their solubility and dispersibility in acidic systems are low, and their direct addition can lead to a noticeably grainy yogurt and uneven viscosity distribution. Regarding texture improvement, while food colloids (such as gellan gum and xanthan gum) can stabilize the milk protein network through hydrogen bonding, high addition levels (>0.5%) can easily produce a colloidal fishy odor, which conflicts with the sweet flavor of longan. Notably, the combination of resistant starch and food colloids (such as guar gum) can form a dynamic entrapment structure: the hydrophobic regions of the starch molecules can fix longan's volatile flavor compounds, while the hydrophilic chains of the colloids inhibit polyphenol and protein precipitation through steric hindrance, thereby simultaneously achieving flavor lock and system stability. However, previous studies have not revealed the evolution of the relevant behaviors of such compounds during lactic acid bacteria fermentation, nor have they lacked a compound addition strategy adapted to the processing characteristics of longan yogurt.

[0004] Existing longan-flavored yogurts generally suffer from technical bottlenecks such as low utilization of functional ingredients, easy loss of characteristic flavor, and insufficient texture stability. The simple combination of traditional thickeners and functional bases fails to meet the market demand for the synergistic enhancement of "flavor, function, and texture." Therefore, the development of a longan yogurt system based on a resistant starch-food gum complex, which achieves the triple effects of active ingredient protection, flavor release, and gel network strengthening through molecular interaction design, is of great value in promoting the upgrading of the specialty flavored yogurt industry. Summary of the Invention

[0005] The present invention aims to develop a longan yogurt system based on a resistant starch-food gum complex, which achieves the triple effects of active ingredient protection, flavor substance sustained release, and gel network strengthening through molecular interaction design, thereby promoting the upgrading of the specialty flavor yogurt industry.

[0006] The first aspect of the present invention aims to provide a resistant starch-food gum complex.

[0007] The second aspect of the present invention aims to provide an application of the resistant starch-food gum complex of the first aspect of the present invention.

[0008] The third aspect of the present invention aims to provide a yogurt.

[0009] The fourth aspect of the present invention aims to provide a method for preparing the yogurt according to the third aspect of the present invention.

[0010] In order to achieve the above object, the technical solution adopted by the present invention is:

[0011] The first aspect of the present invention provides a resistant starch-food gum complex, which is obtained by treating resistant starch and food gum with cold plasma.

[0012] In some embodiments of the present invention, the cold plasma treatment is performed under a condition of a constant power of 30 to 80 W for 3 to 10 minutes.

[0013] In some preferred embodiments of the present invention, the cold plasma treatment is carried out under the condition of using air as a carrier and maintaining a constant power of 40 to 60 W for 3 to 8 minutes.

[0014] In some more preferred embodiments of the present invention, the cold plasma treatment is carried out under the condition of using air as a carrier and maintaining a constant power of 50 W for 3 to 8 minutes.

[0015] In some embodiments of the present invention, the resistant starch includes at least one of cereal starch, root starch, and legume starch.

[0016] In some embodiments of the present invention, the cereal starch includes but is not limited to at least one of corn starch, wheat starch, rice starch, and sorghum starch.

[0017] In some embodiments of the present invention, the root starch includes but is not limited to at least one of potato starch, sweet potato starch, cassava starch, yam starch, and konjac starch.

[0018] In some embodiments of the present invention, the bean starch includes but is not limited to at least one of mung bean starch, pea starch, and broad bean starch.

[0019] In some embodiments of the present invention, the food colloid comprises at least one of a plant-derived colloid, a microbial fermentation colloid, an animal-derived colloid, or a chemically modified colloid.

[0020] In some embodiments of the present invention, the plant-derived colloid includes but is not limited to at least one of pectin, carrageenan, agar, gum arabic, and peach gum.

[0021] In some embodiments of the present invention, the microbial fermentation colloid includes but is not limited to at least one of gellan gum, curdlan gum, xanthan gum, and pullulan.

[0022] In some embodiments of the present invention, the animal-derived colloid includes but is not limited to gelatin and collagen polypeptide.

[0023] In some embodiments of the present invention, the chemically modified colloid includes but is not limited to at least one of sodium carboxymethyl cellulose, hydroxypropyl phosphate starch, carboxymethyl hydroxypropyl guar gum, cross-linked sodium alginate, oxidized cellulose, and hydroxypropyl konjac gum.

[0024] In some embodiments of the present invention, the mass ratio of the resistant starch to the food gum is (1-10):1.

[0025] In some preferred embodiments of the present invention, the mass ratio of the resistant starch to the food gum is (2-8):1.

[0026] In some more preferred embodiments of the present invention, the mass ratio of the resistant starch to the food gum is (2-5):1.

[0027] In some embodiments of the present invention, the method for preparing the resistant starch-food gum complex comprises the following steps: mixing resistant starch, food gum and a solvent to obtain a mixed solution; subjecting the mixed solution to cold plasma treatment and drying to obtain the resistant starch-food gum complex.

[0028] In some embodiments of the present invention, the solvent comprises water.

[0029] In some embodiments of the present invention, the drying condition is drying at 35-45°C.

[0030] The second aspect of the present invention provides the use of the resistant starch-food gum complex of the first aspect of the present invention in any one of (1) to (7):

[0031] (1) Yogurt preparation;

[0032] (2) preparing products for yogurt preparation;

[0033] (3) Improvement of dairy product quality and enhancement of its functions;

[0034] (4) Prepare products with improved texture and enhanced functionality of dairy products;

[0035] (5) Development of low-fat / low-sugar foods;

[0036] (6) Functional upgrade of baked and flour products;

[0037] (7) Special foods for the elderly and people with metabolic syndrome.

[0038] The third aspect of the present invention provides a yogurt comprising the resistant starch-food gum complex of the first aspect of the present invention, a sweetener, a bacterial agent, milk and an additive.

[0039] In some embodiments of the present invention, the yogurt includes, by mass, 0.05 to 1 parts of resistant starch-food gum complex, 4 to 12 parts of sweetener, 0.1 to 1 part of bacterial agent, 70 to 90 parts of milk and 0 to 20 parts of additives.

[0040] In some preferred embodiments of the present invention, the yogurt includes, by mass, 0.1 to 0.5 parts of resistant starch-food gum complex, 6 to 10 parts of sweetener, 0.1 to 0.5 parts of bacterial agent, 70 to 90 parts of milk and 0 to 15 parts of additives.

[0041] In some more preferred embodiments of the present invention, the yogurt includes, by mass, 0.1-0.3 parts of resistant starch-food gum complex, 6-8 parts of sweetener, 0.1-0.2 parts of bacterial agent, 70-85 parts of milk and 10-15 parts of additives.

[0042] In some embodiments of the present invention, the bacterial agent includes at least one of Lactobacillus delbrueckii (Lactobacillus delbrueckii subsp. bulgaricus), Bifidobacterium (such as Bifidobacterium adolescentis, Bifidobacterium infantis, Bifidobacterium longum, Bifidobacterium breve, Bifidobacterium animalis (including Bifidobacterium animalis lactis subsp. lactis), Bifidobacterium bifidum, Bifidobacterium lactis or Bifidobacterium thermophilus), Lactobacillus bulgaricus, Streptococcus thermophilus (Streptococcus salivarius thermophilus subsp. thermophilus), Lactobacillus casei, Lactobacillus reuteri, Lactobacillus acidophilus and Lactococcus acidi.

[0043] In some preferred embodiments of the present invention, the bacterial agent includes Streptococcus salivarius subsp. thermophilus, Lactobacillus delbrueckii subsp. bulgaricus, and Bifidobacterium animalis subsp. lactis.

[0044] In some embodiments of the present invention, the sweetener is at least one of sucrose, beet sugar, maltose, glucose, fructose, lactose, fructose syrup, sugar alcohol sweeteners, sucralose, acesulfame potassium, aspartame and cyclamate; preferably sucrose.

[0045] In some embodiments of the present invention, the additives include at least one of jam additives (such as strawberry jam, apple jam, blueberry jam, hawthorn jam, mulberry jam, yellow peach jam, coconut jam), fruit additives (apple cubes / juice / pulp, orange pieces / juice, pear cubes / juice / pulp, pineapple cubes / juice / pulp, mango cubes / juice / pulp, cherry / juice / pulp, grape / juice / pulp, raisin / juice / pulp, pomegranate / juice / pulp, yellow peach cubes / juice / pulp, longan cubes / juice / pulp, etc.), nut additives (such as almonds, walnuts, peanuts, pine nuts, hazelnuts, pistachios, melon seeds, cashews, macadamia nuts, etc.), and grain additives (such as sweet corn, black rice, coix seed, glutinous rice, mung beans, red beans, etc.).

[0046] In some preferred embodiments of the present invention, the additive is longan pulp, and the preparation method of the longan pulp is as follows: peel and core fresh longan, take the pulp, add an appropriate amount of drinking water (2 to 10 times the weight of the pulp) and a color preservative (prepared by mixing 0.1% citric acid, vitamin C, and cysteine solution in a mass ratio of 1:1:1) and beat the pulp to obtain longan pulp.

[0047] The fourth aspect of the present invention provides a method for preparing the yogurt of the third aspect of the present invention, comprising the following steps: mixing a resistant starch-food gum complex, a sweetener, an additive and milk, and sterilizing the mixture; obtaining a mixed solution; and mixing the mixed solution with a bacterial agent, fermenting the mixture and obtaining yogurt.

[0048] In some embodiments of the present invention, the sterilization condition is sterilization in a water bath at 80-100° C. for 5-15 minutes.

[0049] In some embodiments of the present invention, the fermentation condition is a constant temperature fermentation at 40-45° C. for 12-24 hours.

[0050] In some embodiments of the present invention, the preparation method further comprises a post-ripening step, and the post-ripening conditions are 3-5° C. for 2-6 hours.

[0051] In some embodiments of the present invention, the preparation method further comprises sterilization, and the sterilization comprises pasteurization.

[0052] The preparation method of the yogurt provided by the present invention has a simple preparation process, improves fermentation efficiency, and can also extend the shelf life, and combines the advantages of quality, nutrition and process.

[0053] The beneficial effects of the present invention are:

[0054] The present invention provides a resistant starch-food gum complex. The resistant starch-food gum complex is driven by cold plasma treatment to cross-link the resistant starch and the food gum to form a "molecular-level synergistic" gel network structure. When used in yogurt preparation, the resistant starch-food gum complex can simultaneously achieve flavor fusion enhancement, precise control of physical properties (pH fluctuation ±0.1, precipitation rate ≤1.5%) and shelf life extension, significantly improving the stability of yogurt, preventing whey precipitation and optimizing the taste.

[0055] The yogurt provided by the present invention has good sensory perception, uniform texture, and fruit (longan) flavor. The yogurt system prepared from the resistant starch-food gum complex is stable, improves the survival rate of lactic acid bacteria, increases the dietary fiber content of the yogurt, can assist in regulating blood sugar and intestinal health, and has health care value. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0057] Figure 1 The figure is a comparison chart of the sensory evaluation scores of the longan yogurts of various embodiments.

[0058] Figure 2 It is a comparison chart of pH value of longan yogurt in each embodiment.

[0059] Figure 3 1 is a comparison chart of the whey precipitation rates of the longan yogurts of various embodiments.

[0060] Figure 4 This is the SEM image of the resistant starch-food gum complex (corn starch-xanthan gum) in Example 1. DETAILED DESCRIPTION

[0061] The following will clearly and completely describe the concept and technical effects of the present invention in conjunction with the embodiments to fully understand the purpose, features and effects of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of the present invention.

[0062] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or those recommended by the manufacturer. All reagents or instruments used, if the manufacturer is not specified, are commercially available conventional products.

[0063] The bacterial powder in the embodiment is a mixed bacteria of Yo-cul982 (purchased from Weikang Probiotics (Suzhou) Co., Ltd., containing two bacteria, Streptococcus salivarius subspecies thermophilic and Lactobacillus delbrueckii subspecies bulgaricus) and Bifidobacterium animalis subspecies lactis BLa80 (purchased from Weikang Probiotics (Suzhou) Co., Ltd.), wherein Yo-cul982 contains 40g / 200U and Bifidobacterium animalis subspecies lactis BLa80 contains 6×10 11 CFU / g.

[0064] The features and performance of the present invention are further described in detail below with reference to the embodiments.

[0065] Example 1

[0066] A longan yogurt is prepared from the following raw materials, calculated by mass percentage: 0.15% of a resistant starch-food gum complex, 0.2% of bacterial powder, 6% of sucrose, 15% of longan pulp, and 78.65% of fresh milk (3.5g / 100g of protein and 3.5g / 100g of fat).

[0067] The resistant starch-food gum composite was prepared by the following method: corn starch (Zhejiang Yinuo Biotechnology Co., Ltd., food grade) and xanthan gum were mixed in a mass ratio of 3:1 to prepare a 5% aqueous solution, which was then treated with cold plasma (the aqueous solution containing the resistant starch-food gum was evenly spread on a glass dish (thickness ≤ 1 mm) and placed in a reaction chamber, with air as the carrier gas, maintaining a constant power of 50 W for 5 minutes), followed by drying at 40°C, grinding and sieving to obtain the resistant starch-food gum composite;

[0068] The longan pulp is prepared by the following method: peeling and removing the core of fresh longan, taking out the pulp, adding drinking water 3 times the weight of the pulp and 0.1% of the weight of the pulp (a color preservative (0.1% citric acid, vitamin C and cysteine solution mixed in a weight ratio of 1:1:1)) to pulp, and obtaining the longan pulp;

[0069] The preparation method of the longan yogurt comprises the following steps:

[0070] (1) Preparation: Weigh each raw material separately, add the resistant starch-food gum complex, longan pulp and sucrose to fresh milk, homogenize (25 MPa, 10 min), and then sterilize in an 80°C water bath for 15 min to obtain a mixed solution;

[0071] (2) Inoculation: Balance the mixed solution temperature at 43°C, add bacterial powder, homogenize and seal;

[0072] (3) Fermentation: Place in a 43°C constant temperature fermentation box and ferment for 18 hours;

[0073] (4) After-ripening: After fermentation, the product is transferred to a refrigerator at 4°C and left for 4 hours for after-ripening to obtain longan yogurt;

[0074] (5) Bottling and sterilization: The yogurt obtained after ripening is bottled in a quantitative manner, then pasteurized, and cooled to obtain the finished product.

[0075] Example 2

[0076] A longan yogurt is made from the following raw materials, calculated by mass percentage: 0.2% of resistant starch-food gum compound, 0.4% of bacterial powder, 8% of sucrose, 12% of longan pulp and 79.4% of fresh milk

[0077] The resistant starch-food gum composite is prepared by the following method: corn starch and curdlan are mixed in a mass ratio of 2:1 to prepare a 4% aqueous solution, which is then treated with cold plasma (the aqueous solution containing the resistant starch-food gum is evenly spread in a glass dish (thickness ≤ 1 mm) and placed in a reaction chamber, with air as the carrier gas, and a constant power of 50 W is maintained for 5 minutes), followed by drying at 37°C, grinding and sieving to obtain the resistant starch-food gum composite;

[0078] The longan pulp is prepared by the following method: peeling and removing the core of fresh longan, taking out the pulp, adding drinking water 3 times the weight of the pulp and 0.1% of the weight of the pulp (a color preservative (0.1% citric acid, vitamin C and cysteine solution mixed in a weight ratio of 1:1:1)) to pulp, and obtaining the longan pulp;

[0079] The preparation method of the longan yogurt comprises the following steps:

[0080] (1) Preparation: Weigh each raw material separately, add the resistant starch-food gum complex, longan pulp and sucrose to fresh milk, homogenize (25 MPa, 10 min), and then sterilize in a 100°C water bath for 15 min to obtain a mixed solution;

[0081] (2) Inoculation: Balance the mixed solution temperature at 43°C, add bacterial powder, homogenize and seal;

[0082] (3) Fermentation: Place in a 43°C constant temperature fermentation box and ferment for 18 hours;

[0083] (4) After-ripening: After fermentation, the product is transferred to a refrigerator at 4°C and left for 4 hours for after-ripening to obtain longan yogurt;

[0084] (5) Bottling and sterilization: The yogurt obtained after ripening is bottled in a quantitative manner, then pasteurized, and cooled to obtain the finished product.

[0085] Example 3

[0086] A longan yogurt is prepared from the following raw materials, calculated by mass percentage: 0.15% of a resistant starch-food gum complex, 0.2% of bacterial powder, 6% of sucrose, 10% of longan pulp, and 83.65% of fresh milk;

[0087] The resistant starch-food gum composite was prepared by the following method: potato starch (Zhejiang Yinuo Biotechnology Co., Ltd., food grade) and carrageenan were mixed in a mass ratio of 5:1 to prepare an 8% aqueous solution, which was then treated with cold plasma (the aqueous solution containing the resistant starch-food gum was evenly spread on a glass dish (thickness ≤ 1 mm) and placed in a reaction chamber, with air as the carrier gas, maintaining a constant power of 50 W for 5 minutes), followed by drying at 37°C, grinding and sieving to obtain the resistant starch-food gum composite;

[0088] The longan pulp is prepared by the following method: peeling and removing the core of fresh longan, taking out the pulp, adding drinking water 3 times the weight of the pulp and 0.1% of the weight of the pulp (a color preservative (0.1% citric acid, vitamin C and cysteine solution mixed in a weight ratio of 1:1:1)) to pulp, and obtaining the longan pulp;

[0089] The preparation method of the longan yogurt comprises the following steps:

[0090] (1) Preparation: Weigh each raw material separately, add the resistant starch-food gum complex, longan pulp and sucrose to fresh milk, homogenize (25 MPa, 10 min), and sterilize in a 90°C water bath for 15 min to obtain a mixed solution;

[0091] (2) Inoculation: Balance the mixed solution temperature at 43°C, add bacterial powder, homogenize and seal;

[0092] (3) Fermentation: Place in a 43°C constant temperature fermentation box and ferment for 18 hours;

[0093] (4) After-ripening: After fermentation, the product is transferred to a refrigerator at 4°C and left for 4 hours for after-ripening to obtain longan yogurt;

[0094] (5) Bottling and sterilization: The yogurt obtained after ripening is bottled in a quantitative manner, then pasteurized, and cooled to obtain the finished product.

[0095] Example 4

[0096] A longan yogurt is prepared from the following raw materials, calculated by mass percentage: 0.2% of a resistant starch-food gum complex, 0.3% of bacterial powder, 6% of sucrose, 12% of longan pulp, and 81.5% of fresh milk;

[0097] The resistant starch-food gum composite was prepared by the following method: pea starch (food grade, Hangzhou Fuchun Food Additive Co., Ltd.) and sodium carboxymethyl cellulose were mixed in a mass ratio of 4:1 to prepare a 6% aqueous solution, which was then treated with cold plasma (the aqueous solution containing the resistant starch-food gum was evenly spread in a glass dish (thickness ≤ 1 mm) and placed in a reaction chamber, with air as the carrier gas, maintaining a constant power of 50 W for 5 minutes), followed by drying at 37°C, grinding and sieving to obtain the resistant starch-food gum composite;

[0098] The longan pulp is prepared by the following method: peeling and removing the core of fresh longan, taking out the pulp, adding drinking water 3 times the weight of the pulp and 0.1% of the weight of the pulp (a color preservative (0.1% citric acid, vitamin C and cysteine solution mixed in a weight ratio of 1:1:1)) to pulp, and obtaining the longan pulp;

[0099] The preparation method of the longan yogurt comprises the following steps:

[0100] (1) Preparation: Weigh each raw material separately, add the resistant starch-food gum complex, longan pulp and sucrose to fresh milk, homogenize (25 MPa, 10 min), and sterilize in a 95°C water bath for 15 min to obtain a mixed solution;

[0101] (2) Inoculation: Balance the mixed solution temperature at 43°C, add bacterial powder, homogenize and seal;

[0102] (3) Fermentation: Place in a 43°C constant temperature fermentation box and ferment for 18 hours;

[0103] (4) After-ripening: After fermentation, the product is transferred to a refrigerator at 4°C and left for 4 hours for after-ripening to obtain longan yogurt;

[0104] (5) Bottling and sterilization: The yogurt obtained after ripening is bottled in a quantitative manner, then pasteurized, and cooled to obtain the finished product.

[0105] Example 5

[0106] A longan yogurt is provided, which differs from Example 1 only in that cold plasma treatment is not used during the preparation of the resistant starch-food gum complex.

[0107] Example 6

[0108] A longan yogurt, compared with Example 1, is different only in that the cold plasma treatment condition during the preparation of the resistant starch-food gum complex is to maintain a constant power of 80W for 5 minutes.

[0109] Example 7

[0110] A longan yogurt, compared with Example 1, is different only in that the cold plasma treatment condition during the preparation of the resistant starch-food gum complex is to maintain a constant power of 30W for 4 minutes.

[0111] Example 8

[0112] A longan yogurt differs from Example 1 only in that the preparation method of the resistant starch-food gum complex is different, specifically comprising the following steps: preparing corn starch into a 5% aqueous solution, then treating the solution using cold plasma (using a glass dish to evenly spread the aqueous solution containing resistant starch (thickness ≤ 1 mm) and placing it in a reaction chamber, using air as a carrier gas, and maintaining a constant power of 50 W for 5 minutes), then drying at 40°C, grinding and sieving to obtain a processed corn resistant starch, and mixing the processed corn resistant starch with xanthan gum in a ratio of 3:1 to obtain a resistant starch-food gum complex.

[0113] Example 9

[0114] A longan yogurt differs from Example 1 only in that the preparation method of the resistant starch-food gum complex is different, specifically comprising the following steps: preparing xanthan gum into a 5% aqueous solution, then treating the solution using cold plasma (using a glass dish to evenly spread the aqueous solution containing the food gum (thickness ≤1 mm) and placing it in a reaction chamber, using air as a carrier gas, and maintaining a constant power of 50 W for 5 minutes), then drying at 40°C, grinding and sieving to obtain a xanthan gum-treated product, and mixing the xanthan gum with corn starch in a ratio of 1:3 to obtain the resistant starch-food gum complex.

[0115] Example 10

[0116] A longan yogurt differs from Example 1 in that a processed corn resistant starch is used instead of the resistant starch-food gum complex. The processed corn resistant starch is prepared by preparing a 5% aqueous solution of the corn resistant starch, which is then treated using cold plasma (the aqueous solution containing the resistant starch is evenly spread in a glass dish (thickness ≤ 1 mm) and then placed in a reaction chamber, with air used as a carrier gas and a constant power of 50 W maintained for 5 minutes). The product is then dried at 40° C., ground, and sieved to obtain the processed corn resistant starch.

[0117] Example 11

[0118] A longan yogurt differs from Example 1 in that a xanthan gum treated material is used instead of a resistant starch-food gum complex. The xanthan gum treated material is prepared by preparing xanthan gum into a 5% aqueous solution, which is then treated using cold plasma (the resistant starch-containing aqueous solution (thickness ≤ 1 mm) is evenly spread in a glass dish and placed in a reaction chamber, with air used as a carrier gas and a constant power of 50 W maintained for 5 minutes). The xanthan gum treated material is then dried at 40°C and ground and sieved to obtain the xanthan gum treated material.

[0119] Effect embodiment

[0120] For the convenience of comparison, this embodiment further distinguishes the raw materials of the above embodiments 1 to 11 and makes a comparison table, as shown in Table 1 below.

[0121] Table 1 Raw materials of longan yogurt of Examples 1 to 11

[0122]

[0123] The longan yogurts of Examples 1 to 11 were subjected to a sensory evaluation as follows: 10 evaluators who were familiar with yogurt products and had undergone sensory training were invited to score the yogurts according to the sensory evaluation criteria shown in Table 2 below. The average score was calculated after removing the highest and lowest scores. Finally, the total sensory score was calculated and the samples were ranked according to preference.

[0124] Table 2 Sensory evaluation standards for yogurt

[0125]

[0126] Note: * in Table 2 indicates retesting after storage at 4℃ for 5 days.

[0127] Whey precipitation rate: Refrigerate the yogurt sample to be tested at 4°C for 24 hours. Stir gently 5 times after opening. Weigh 50.00g of sample into a centrifuge tube (accurate to ±0.1g) and centrifuge at 3000×g for 15 minutes, maintaining the temperature at 4°C. After centrifugation, pour the supernatant into a measuring cylinder to avoid disturbing the curd layer at the bottom, and record the volume of precipitated whey (mL). Record data: Initial sample mass m 总 =50.00g,m 乳清 = whey volume (mL) × 1.032 g / mL (density coefficient).

[0128] Whey precipitation rate (%) = (m whey / m total) × 100.

[0129] pH value test: Take 5±0.1g homogenized yogurt and place it in a 50mL beaker, immerse the electrode sensing part, and record the pH value.

[0130] In vitro digestion: The digestibility of the longan resistant starch in Examples 1 to 11 was determined using a glucose assay kit GOPOD (Megazyme, Ireland), and the contents of rapidly digestible starch (RDS), slowly digestible starch (SDS), and resistant starch (RS) were calculated.

[0131] RDS=0.9(G 20 –G0) / TS×100%;

[0132] SDS=0.9(G 120 –G 20 ) / TS×100%;

[0133] RS = 1–(RDS + SDS);

[0134] Among them, G0, G 20 and G 120 represents the glucose content at 0, 20, and 120 min, respectively. TS represents the total starch content, and 0.9 is the conversion factor between glucose and starch.

[0135] After testing by a professional tasting panel, Longan Yogurt performed well in terms of sensory dimensions ( Figure 1 ), wherein, Examples 1 to 4 adopt the starch-food glue overall plasma treatment process to successfully construct a dense composite gel network. This structure promotes cross-linking and reorganization of the resistant starch and food glue molecular chains through synchronous activation, significantly improves the texture performance of yogurt, eliminates the granularity, and optimizes the fusion of longan fruit aroma and fermented cream aroma. The natural light amber color does not rely on artificial pigments, highlighting the authenticity of the raw materials. In contrast, although Example 6 (80W high pressure) and Example 7 (30W low pressure) adopt cold plasma treatment, although 80W high pressure enhances starch cleavage, it fails to cross-link with the colloid synchronously, forming a fragmented structure of local over-degradation, and the curd is rough and has a significant granularity; 30W low pressure is insufficient due to insufficient energy, insufficient activation of starch molecular chains, weak cross-linking with the colloid, and obvious separation of longan fruit aroma and cream aroma. The step-by-step treatment (i.e., the longan yogurts of Examples 8-9) resulted in a loose network and a rough taste due to insufficient cross-linking. The single-component modification (i.e., the longan yogurts of Examples 10-11) lacked synergistic effects, resulting in a single flavor or separation. The longan yogurt containing only xanthan gum (Example 11) had a thin texture, which was the most prominent.

[0136] The pH stability dimension reveals the buffering mechanism of the composite gel network. The pH values of Examples 1 to 4 were precisely maintained in the range of 4.31 to 4.47 (fluctuation of only ±0.1) ( Figure 2 This advantage is due to the abundant hydroxyl (—OH) and carboxyl (—COOH) groups exposed by the overall treatment process, which bind lactic acid through hydrogen bonds and disperse H +, which not only inhibits local over-acidity but also provides a stable environment for the bacterial flora. The comparative example verifies the situation of process deviation: Example 5 has not been treated with plasma, the basic formula has not been modified, and the pH value change depends only on the natural metabolism of lactic acid bacteria, which is relatively uniform overall. Higher power causes large overall fluctuations, and lower power treatment causes insufficient starch cross-linking and gel collapse. Example 9, which is treated step by step, has an uneven structure of the composite, and the local pH rises to 4.52, which reduces the ability to inhibit the activity of lactic acid bacteria; Example 10, which only treats starch, lacks colloidal buffering, resulting in an increase in pH. The chart data further confirms that when the pH deviates from the threshold of 4.3 to 4.5, the bacterial activity and sensory score collapse nonlinearly.

[0137] The whey precipitation rate is closely related to the water holding capacity of the gel. The longan yogurt of Examples 1 to 4 locks water through the three-dimensional network, and the precipitation rate is stably controlled at 1.2%, which is nearly 40% lower than the critical threshold (2.0%). Figure 3 The microscopic mechanism shows that the starch-colloid cross-linked structure formed by plasma activation ( Figure 4 ), enhancing the interfacial stability between the longan pulp and the colloidal matrix, and reducing the precipitation rate by 1.44% (Comparing Example 1 with Example 5). In contrast, Examples 8-11: Due to cross-linking defects, the precipitation rates of Examples 8-9, which were processed step by step, rose to 1.58% and 1.83%, respectively. The loose texture exacerbated the risk of flavor loss. Example 11, which contained only starch, lacked the xanthan gum skeleton support, resulting in a precipitation rate as high as 3.54%, a thin texture, and exceeding the quality safety boundary. This comparison highlights the irreplaceable water-holding structure of the resistant starch-food gum complex.

[0138] The digestibility characteristics (RDS, SDS, and RS) of resistant starch-food gum complexes are closely related to the type of raw materials and processing methods, providing an important theoretical basis for the development of functional longan yogurt. Experiments show that the "starch-food gum integrated processing" method (such as Examples 1-4) significantly increases the resistant starch content (RS of 79.66% to 85.98%) while reducing the contents of rapidly digestible starch (RDS of 3.17% to 6.93%) and slowly digestible starch (SDS of 10.85% to 16.09%). The xanthan gum complex performs particularly well (RS of 85.98% in Example 1) (Table 3). These characteristics make the resistant starch-xanthan gum complex an ideal ingredient for longan yogurt: First, its high resistant starch content significantly reduces the glycemic index of yogurt, meeting the demand for low-GI foods; second, the water-binding properties of xanthan gum improve the texture and mouthfeel of low-fat recipes, avoiding the common mouthfeel defects of traditional low-fat yogurts. In addition, the prebiotic properties of resistant starch help promote intestinal health and are particularly suitable for the elderly and people with metabolic syndrome. Compared with step-by-step processing or single component processing (RS of Examples 5 to 11 is only 49.05% to 61.96%), the overall compounding process can maximize functional benefits. In the development of longan yogurt, the overall compounding process of corn starch and xanthan gum is used, which not only maintains the smooth texture of yogurt, but also enhances satiety by delaying digestion, while providing the health benefits of dietary fiber. This innovative formula not only retains the natural flavor of longan, but also gives the product multiple functional advantages such as sugar control and digestion promotion, providing a new technical direction for the development of functional dairy products.

[0139] Table 3 RDS, SDS and RS of resistant starch-food gum complex

[0140]

[0141] Note: The “-” in Table 3 indicates that the digestion mechanism of xanthan gum is fundamentally different from that of starch, and the starch digestibility cannot be measured using the method of measuring starch digestibility, so there is no corresponding data.

[0142] The core of the longan yogurt of the present invention is: the overall plasma treatment drives the cross-linking of resistant starch and food glue to form a "molecular-level synergistic" gel network structure, simultaneously achieving flavor fusion enhancement, precise control of physical properties (pH fluctuation ±0.1, precipitation rate ≤1.5%) and shelf life extension. Comparative data suggest that attempts to split the composite process (such as step-by-step treatment or single modification) will lead to incomplete systems and cause differences in physical properties. This technical path provides a replicable technical path for process innovation of plant-based dairy products.

[0143] While the embodiments of the present invention have been described in detail above with reference to the accompanying drawings, the present invention is not limited to the embodiments described above. Various modifications may be made within the scope of knowledge possessed by a person skilled in the art without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof may be combined with one another unless there is a conflict.

Claims

1. A resistant starch-food gum complex, obtained by treating resistant starch and food gum with cold plasma.

2. The resistant starch-food gum complex according to claim 1, characterized in that The cold plasma treatment condition is a constant power of 30 to 80 W for 3 to 10 minutes.

3. The resistant starch-food gum complex according to claim 1, characterized in that The resistant starch includes at least one of cereal starch, root starch, and legume starch; and / or the food gum includes at least one of plant-derived colloids, microbial fermentation colloids, animal-derived colloids, and chemically modified colloids.

4. The resistant starch-food gum complex according to any one of claims 1 to 3, characterized in that The mass ratio of the resistant starch to the food gum is (1-10):

1.

5. The resistant starch-food gum complex according to claim 4, characterized in that The preparation method of the resistant starch-food gum complex comprises the following steps: mixing resistant starch, food gum and a solvent to obtain a mixed solution; and subjecting the mixed solution to cold plasma treatment and drying to obtain the resistant starch-food gum complex.

6. Use of the resistant starch-food gum complex according to any one of claims 1 to 5 in any one of (1) to (7): (1) Yogurt preparation; (2) preparing products for yogurt preparation; (3) Improvement of dairy product quality and enhancement of its functions; (4) Preparation of dairy products with improved texture and enhanced functionality; (5) Development of low-fat / low-sugar foods; (6) Functional upgrade of baked and flour products; (7) Special foods for the elderly and people with metabolic syndrome.

7. A yogurt comprising the resistant starch-food gum complex according to any one of claims 1 to 5, a sweetener, a bacterial agent, milk and additives.

8. The yogurt according to claim 7, characterized in that Calculated by mass, the yogurt comprises 0.05 to 1 parts of resistant starch-food gum complex, 4 to 12 parts of sweetener, 0.1 to 1 part of bacterial agent, 70 to 90 parts of milk and 0 to 20 parts of additives.

9. The yogurt according to claim 7, characterized in that The bacterial agent includes at least one of Lactobacillus delbrueckii, Bifidobacterium, Lactobacillus bulgaricus, Streptococcus thermophilus, Lactobacillus casei, Lactobacillus reuteri, Lactobacillus acidophilus and Lactococcus lactis; and / or the sweetener is at least one of sucrose, beet sugar, maltose, glucose, fructose, lactose, fructose syrup, sugar alcohol sweeteners, sucralose, acesulfame potassium, aspartame and cyclamate; and / or the additive includes at least one of jam additive, fruit additive, nut additive and cereal additive.

10. The method for preparing the yogurt according to any one of claims 7 to 9, comprising the following steps: The resistant starch-food gum complex, sweetener, additives and milk are mixed and sterilized; A mixed solution is obtained; the mixed solution is mixed with a bacterial agent, and fermented to obtain yogurt.

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