Konjac oligosaccharide-based yoghurt and preparation method thereof

Abstract

The application relates to the technical field of food chemistry, and discloses a konjac oligosaccharide-based yoghourt and a preparation method thereof. The yoghourt is prepared by compounding skimmed milk, konjac oligosaccharide enzymolysis liquid, beta-glucanase, 1:1 acesulfame potassium and aspartame, and a compound lactic acid bacteria starter; the preparation process comprises directional enzymolysis, raw material mixing, constant-temperature fermentation and low-temperature post-ripening. The activity of konjac oligosaccharide is improved through directional enzymolysis of beta-glucanase, the synergistic effect of prebiotics and probiotics is realized, the product is low in fat and sugar, can regulate the intestinal tract, control sugar and reduce fat, has excellent sensory quality, the process is stable and suitable for industrialized production, and can be widely applied to the fields of functional fermented dairy products and health-care food.

Description

Technical Field

[0001] This invention relates to the field of food chemistry technology, and more specifically, to a yogurt based on konjac oligosaccharides and its preparation method. Background Technology

[0002] The main active ingredient in konjac is konjac glucomannan, which accounts for 70% to 80% of its content. The product obtained by hydrolyzing konjac glucomannan under the action of specific enzymes is called konjac oligosaccharide. It has a variety of physiological functions, such as anti-oxidation, enhancing immunity, promoting the proliferation of bifidobacteria, cleansing the intestines, lowering blood lipids, and preventing and treating hypertension. Its small molecular weight and good physicochemical properties allow it to better exert its unique health care functions and can be widely used in the food industry, biological products, medicine, pesticides and other fields.

[0003] In 2014, the Ministry of Health recognized konjac oligosaccharides as a new food raw material and one of the new food resources in the development of functional foods. It has a certain sweetness but does not raise blood sugar, is not digested by the human digestive tract, and has low energy production. It can promote the proliferation of intestinal bacteria such as Bifidobacterium and Lactobacillus acidophilus, thereby reducing the production of toxic fermentation products and harmful bacterial enzymes. It also has good effects in reducing the production of acetic acid in the intestine. When combined with yogurt, the two can complement each other. It can also maintain intestinal health, prevent colon cancer, and reduce cytotoxicity. Currently, it is a hot topic in oligosaccharide prebiotic research.

[0004] Yogurt originated in Bulgaria, but its production method is recorded in the ancient Chinese medical text *Qimin Yaoshu*. Yogurt is a curd-like product made from various high-quality dairy products. After pasteurization and cooling, it is fermented by two or more types of lactic acid bacteria. Lactose in dairy products is converted into lactic acid by lactase and lactic acid bacteria. When the pH reaches 4.6–4.7, casein coagulates and precipitates, forming yogurt. Lactic acid bacteria are a group of non-spore-forming, Gram-positive bacteria that produce large amounts of lactic acid from fermentable sugars. They are widely found in the intestines of humans, animals, and poultry, as well as in many foods, materials, and some clinical samples. Studies have shown that lactic acid bacteria can regulate the normal flora of the gastrointestinal tract, maintain microecological balance, lower serum cholesterol, control endotoxins, and inhibit the growth and reproduction of putrefactive bacteria and the production of putrefactive products in the intestines.

[0005] Following Mechnikov's "longevity theory" of yogurt in the early 20th century, people gained a deeper understanding of yogurt. Numerous studies have shown that it is rich in nutrients, easily digested and absorbed, and has various effects such as enhancing immunity, anti-cancer properties, and anti-aging. It can also alleviate lactose intolerance; in terms of antibacterial and intestinal regulation, it improves the gut microbiota and inhibits the growth of harmful bacteria; it promotes the absorption of phosphorus, calcium, and iron, and maintains the balance of B vitamins; its physiological functions are closely related to the body's life activities, and it can help prevent cardiovascular and liver diseases.

[0006] Existing yogurt products are mostly conventional flavored and have limited functions; there is insufficient research on the process of combining konjac oligosaccharides with yogurt, which can easily lead to problems such as flavor conflicts, rough texture, and whey separation. Furthermore, the enzymatic hydrolysis process is poorly compatible with the fermentation process, making it difficult to achieve large-scale production.

[0007] Therefore, developing konjac oligosaccharide yogurt with stable processing, excellent flavor, and dual health benefits is of great practical significance. Summary of the Invention

[0008] In view of this, the present invention proposes a yogurt based on konjac oligosaccharides and its preparation method, aiming to solve the defects of the current technology of yogurt having a single function and poor process of compounding konjac oligosaccharides with yogurt.

[0009] This invention proposes a yogurt based on konjac oligosaccharides, wherein the oligosaccharide yogurt comprises the following components in parts by weight: 100 parts skim milk, 15 parts konjac oligosaccharide hydrolysate, 0.04 parts sweetener, and 0.14 parts yogurt starter.

[0010] Furthermore, the sweetener is a mixture of acesulfame potassium and aspartame in a mass ratio of 1:1.

[0011] Furthermore, the konjac oligosaccharide hydrolysate is either a konjac oligosaccharide β-mannan hydrolysate or a konjac oligosaccharide β-glucan hydrolysate.

[0012] Furthermore, the fermenting agent for yogurt contains maltodextrin, Streptococcus thermophilus, Lactobacillus delbrueckii subsp. bulgaricus, Bifidobacterium lactis, Bifidobacterium bifidum, Bifidobacterium longum, Bifidobacterium breve, Bifidobacterium infantis, Lactobacillus plantarum, Lactobacillus acidophilus, and Lactobacillus casei.

[0013] A method for preparing yogurt based on konjac oligosaccharides includes the following steps: (1) Preparation of konjac oligosaccharide hydrolysate: Take konjac flour, add β-glucanase and water, mix well and then hydrolyze in a water bath to obtain konjac oligosaccharide hydrolysate; (2) Mixing raw materials: Add konjac oligosaccharide hydrolysate, acesulfame potassium, and aspartame to skim milk and stir well; (3) Inoculation and fermentation: Add the fermentation agent to the mixed raw materials, mix well and ferment at a constant temperature; (4) Cold-cold ripening: After fermentation, the product is ripened at low temperature to obtain yogurt containing konjac oligosaccharides.

[0014] Furthermore, in step (1), the ratio of konjac flour, β-glucanase, and water is 4g:0.04g:100mL; the enzymatic hydrolysis temperature is 45℃, and the enzymatic hydrolysis time is 3h.

[0015] Furthermore, the mixed raw materials mentioned in step (2) are 15 mL of konjac oligosaccharide hydrolysate, 0.02 g of acesulfame potassium, and 0.02 g of aspartame added to every 100 mL of skim milk.

[0016] Furthermore, in step (3), the amount of yogurt starter ② added is 0.14g per 100mL of skim milk; the fermentation parameters are: temperature 43℃ and time 12h.

[0017] Furthermore, the parameters for low-temperature post-ripening in step (4) are: temperature 5℃ and time 4h.

[0018] The present invention also provides the application of the konjac oligosaccharide-based yogurt described in the above technical solution, specifically the application of the konjac oligosaccharide-based yogurt in the preparation of weight-loss health foods and low-sugar, low-fat health foods that regulate intestinal microecology.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention employs directional enzymatic hydrolysis with β-glucanase, which provides mild conditions and preserves the complete activity of oligosaccharides. The formulation has been optimized through orthogonal experiments, resulting in stable fermentation and post-ripening parameters that are suitable for industrial production.

[0020] The oligosaccharide yogurt product prepared by this invention has a bright milky white color, a harmonious blend of milky aroma and konjac flavor, a delicate and uniform texture, no whey separation, and a moderately sweet and sour taste.

[0021] The oligosaccharide yogurt prepared by this invention has the effects of konjac oligosaccharides in regulating blood sugar and lipids and promoting the proliferation of prebiotics. It works synergistically with yogurt probiotics and is suitable for diabetic patients, people who want to lose weight, and ordinary consumers.

[0022] The konjac oligosaccharide prepared by this invention is a water-soluble dietary fiber that can lower serum cholesterol and triglyceride levels. It does not cause blood sugar fluctuations after ingestion and cannot be fermented by streptococci to produce insoluble glucan. It is an ideal anti-caries, low-corrosion functional sweetener that can help patients with hypertension and diabetes improve symptoms, control their condition, and prevent complications.

[0023] The konjac oligosaccharide prepared by this invention has immunogenicity. It can regulate immunity by interacting with protein receptors on the surface of intestinal villi immune cells or by interfering with the signaling system present in memory cells of lymph nodes and lamina propria. It can also bind to the eukaryotic cell surface of certain toxins and viruses as an adjuvant to these exogenous antigens, slowing down antigen absorption and increasing antigen titer, thereby enhancing the cellular and humoral immunity of animals. Attached Figure Description

[0024] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 A schematic diagram illustrating the effect of the amount of konjac oligosaccharide hydrolysate added on sensory quality; Figure 2 A schematic diagram illustrating the effect of the amount of acesulfame potassium and aspartame added on sensory quality; Figure 3 A schematic diagram illustrating the impact of the selection of yogurt starter on sensory quality; Figure 4 This is a process flow diagram for konjac oligosaccharide yogurt. Detailed Implementation

[0025] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention. It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the present invention.

[0026] Furthermore, regarding the numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included within this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0027] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0028] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0029] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0030] Unless otherwise specified, "parts" in this invention refer to parts by weight. In the following examples, the raw materials are weighed according to 1 part = 1g or 1 part = 1mL.

[0031] This invention proposes a yogurt based on konjac oligosaccharides, wherein the oligosaccharide yogurt comprises the following components in parts by weight: 100 parts skim milk, 15 parts konjac oligosaccharide hydrolysate, 0.04 parts sweetener, and 0.14 parts yogurt starter.

[0032] In this invention, the sweetener is a mixture of acesulfame potassium and aspartame in a mass ratio of 1:1.

[0033] In this invention, the konjac oligosaccharide hydrolysate is either a konjac oligosaccharide β-mannan hydrolysate or a konjac oligosaccharide β-glucan hydrolysate.

[0034] In this invention, the fermenting agent for yogurt contains maltodextrin, Streptococcus thermophilus, Lactobacillus delbrueckii subsp. bulgaricus, Bifidobacterium lactis, Bifidobacterium bifidum, Bifidobacterium longum, Bifidobacterium breve, Bifidobacterium infantis, Lactobacillus plantarum, Lactobacillus acidophilus, and Lactobacillus casei.

[0035] This invention adds a sweetener to the oligosaccharide yogurt, comprising acesulfame potassium and aspartame. Sweeteners are an indispensable part of food processing, and their use is becoming increasingly common as people's living standards improve. Using compound sweeteners in dairy products can increase sweetness, reduce costs, reduce the side effects of single sweeteners, improve taste, enhance food safety, and improve and ensure product stability.

[0036] A method for preparing konjac oligosaccharide-based yogurt includes the following steps: (1) Preparation of konjac oligosaccharide hydrolysate: Take konjac flour, add β-glucanase and water, mix well and then hydrolyze in a water bath to obtain konjac oligosaccharide hydrolysate; (2) Mixing raw materials: Add konjac oligosaccharide hydrolysate, acesulfame potassium, and aspartame to skim milk and stir well; (3) Inoculation and fermentation: Add the fermentation agent to the mixed raw materials, mix well and ferment at a constant temperature; (4) Cold-cold ripening: After fermentation, the product is ripened at low temperature to obtain yogurt containing konjac oligosaccharides.

[0037] Furthermore, in step (1), the ratio of konjac flour, β-glucanase, and water is 4g:0.04g:100mL; the enzymatic hydrolysis temperature is 45℃, and the enzymatic hydrolysis time is 3h.

[0038] In this invention, the mixed raw materials in step (2) are 15 mL of konjac oligosaccharide hydrolysate, 0.02 g of acesulfame potassium, and 0.02 g of aspartame added to every 100 mL of skim milk.

[0039] In this invention, the amount of yogurt starter ② added in step (3) is 0.14g per 100mL of skim milk; the fermentation parameters are: temperature 43℃ and time 12h.

[0040] In this invention, the parameters for low-temperature post-ripening in step (4) are: temperature 5°C and time 4h.

[0041] The present invention also provides the application of the konjac oligosaccharide-based yogurt described in the above technical solution, specifically the application of the konjac oligosaccharide-based yogurt in the preparation of weight-loss health foods and low-sugar, low-fat health foods that regulate intestinal microecology.

[0042] The konjac oligosaccharide prepared in this invention is a water-soluble dietary fiber that can lower serum cholesterol and triglyceride levels. It does not cause blood sugar fluctuations after ingestion and cannot be fermented by streptococci to produce insoluble glucans. It is an ideal anti-caries, low-corrosion functional sweetener that can help patients with hypertension and diabetes improve symptoms, control their condition, and prevent complications. Konjac oligosaccharide is immunogenic and can regulate immunity through interaction with protein receptors on the surface of intestinal villus immune cells or by interfering with signaling systems present in lymph node and lamina propria memory cells. It can also bind to the eukaryotic cell surface of certain toxins and viruses as an adjuvant to these exogenous antigens, slowing antigen absorption and increasing antigen titer, thereby enhancing cellular and humoral immunity in animals. Animal-secreted digestive enzymes such as amylase can only hydrolyze α-1,4 glycosidic bonds and hardly act on other bonds. Since konjac oligosaccharide contains very few α-1,4 glycosidic bonds, it cannot be utilized by the animal itself but can only be selectively utilized by beneficial bacteria to promote their growth, thereby inhibiting the growth of harmful bacteria and improving the intestinal environment.

[0043] In this invention, unless otherwise specified, all raw materials required for preparation are commercially available products well known to those skilled in the art.

[0044] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0045] Example 1 (1) Preparation of konjac oligosaccharide enzymatic hydrolysate ① Cellulose hydrolysate: Weigh 2.34 mL of glacial acetic acid and add it to 200 mL of water, take 30 mL of the solution, then weigh 8.166 g of sodium acetate and add it to 300 mL of water, take 70 mL of the solution, and mix them to prepare a 0.2 mol / L acetic acid-sodium acetate solution (pH 5); Weigh 5 portions of 10 g konjac flour, add 2.5 g of cellulase and 100 mL of buffer solution to each portion, and then enzymatically hydrolyze them in a 40℃ water bath for 3 h, 2.5 h, 2 h, 1.5 h, and 1 h respectively to obtain konjac oligosaccharide cellulose hydrolysate.

[0046] ② β-Mannan hydrolysate: Weigh 5 portions of 3g konjac flour, add 0.3g β-mannanase and 100mL water to each portion, and then enzymatically hydrolyze them in a 40℃ water bath for 8h, 7h, 6h, 5h and 4h respectively to obtain konjac oligosaccharide β-mannan hydrolysate.

[0047] ③ β-glucan hydrolysate: Weigh 5 portions of 4g konjac flour, add 0.04g β-glucanase and 100mL water to each portion, and then enzymatically hydrolyze them in a 45℃ water bath for 7h, 6h, 5h, 4h and 3h respectively to obtain konjac oligosaccharide β-glucan hydrolysate.

[0048] (2) Production method ① Mixing ingredients: Add the konjac oligosaccharide hydrolysate and the sweeteners acesulfame potassium and aspartame to 100mL of milk and stir thoroughly to mix them evenly.

[0049] ②Inoculation: Add the yogurt starter in the correct proportion and stir thoroughly to mix it evenly.

[0050] ③ Fermentation: After inoculation, place the mixed raw materials in an incubator and incubate at 43℃ for 12 hours.

[0051] ④ Post-ripening: Place the fermented konjac oligosaccharide yogurt in a constant temperature and humidity incubator at 5℃ for 4 hours for post-ripening.

[0052] Example 2 (1) Amount of konjac oligosaccharide hydrolysate added Take 5 portions of 100mL milk, add 0.03g of acesulfame potassium and 0.03g of aspartame to each portion, and then add 5mL, 10mL, 15mL, 20mL and 25mL of konjac oligosaccharide hydrolysate to each portion respectively. Stir well, then add 0.14g of yogurt starter ① to each portion and stir thoroughly to mix evenly. Ferment at 43℃ for 12h, then refrigerate at 5℃ for 4h for post-maturation. Finally, perform sensory analysis and evaluation.

[0053] Based on sensory evaluation by eight evaluators and the overall average score, the effect of the amount of konjac oligosaccharide hydrolysate added to the konjac oligosaccharide yogurt on the sensory quality of the yogurt is as follows: Figure 1 As shown, according to Figure 1 It can be seen that as the amount of konjac oligosaccharide hydrolysate added increases, the sensory score shows a trend of first increasing and then decreasing. As the amount of konjac oligosaccharide hydrolysate added increases, the unique aroma of yogurt becomes less obvious, the konjac flavor becomes too strong, and there is an unpleasant odor.

[0054] (2) Amount of sweetener added Take 5 portions of 100mL milk, add 10mL of konjac oligosaccharide hydrolysate to each portion, and add 0.01g, 0.02g, 0.03g, 0.04g, and 0.05g of acesulfame potassium and aspartame respectively in a 1:1 ratio. Stir thoroughly to mix evenly. Then add 0.14g of yogurt starter ① to each portion, stir evenly, ferment at 43℃ for 12h, and then refrigerate at 5℃ for 4h for post-ripening. Finally, perform sensory analysis and evaluation.

[0055] Based on sensory evaluation by eight evaluators and the average score, the effects of the addition amounts of acesulfame potassium and aspartame on the sensory quality of konjac oligosaccharide yogurt are as follows: Figure 2 As shown, according to Figure 2 It can be seen that as the amount of acesulfame potassium and aspartame gradually increases, the sensory score first gradually increases, reaching its optimal value at an addition of 0.03g:0.03g, and then gradually decreases with further increases in addition. When the amount of acesulfame potassium and aspartame is too small, the sweetness is insufficient, the flavor of the konjac oligosaccharide yogurt is unbalanced, and the texture is poor. As the amount of acesulfame potassium and aspartame increases, the sweet and sour flavor of the konjac oligosaccharide yogurt becomes more balanced, and the texture improves. The texture is optimal at an addition of 0.03g, but the sweetness is slightly too high at 0.03g and 0.04g, and excessively sweet at 0.05g, resulting in a cloying sweetness that exceeds people's tolerance.

[0056] (3) Selection of yogurt starter Take 5 portions of 100mL milk, add 10mL of konjac oligosaccharide hydrolysate, 0.03g of acesulfame potassium, and 0.03g of aspartame to each portion, stir thoroughly to mix evenly, then add 0.14g of yogurt starter ①~⑤ to each portion, stir evenly, ferment at 43℃ for 12h, then refrigerate at 5℃ for 4h for post-maturation, and finally perform sensory analysis and evaluation.

[0057] The types of yogurt starter cultures ① to ⑤ are shown in Table 1 below. Table 1 Types of yogurt starter cultures

[0058] Based on sensory evaluation by eight evaluators and the average score, the influence of the selection of yogurt starter in konjac oligosaccharide yogurt on the sensory quality of the yogurt is as follows: Figure 3 As shown, according to Figure 3 It can be seen that samples ②, ③, and ⑤ have higher sensory scores. They have relatively good coagulation properties and richer taste and aroma.

[0059] Example 3 (1) Orthogonal experimental design: Based on the single-factor experiments, the amount of konjac oligosaccharide hydrolysate added, the amount of acesulfame potassium:aspartame added, and the type of yogurt starter were used as experimental factors. L9(3) 3 Orthogonal experiments were conducted, and sensory scores calculated using fuzzy mathematics were used as the indicator to optimize the konjac oligosaccharide yogurt formula. The results are shown in Table 2. Table 2. Factor Level Table for Orthogonal Experiment

[0060] (2) Sensory evaluation design An evaluation panel composed of food science students conducted a sensory evaluation of the konjac oligosaccharide yogurt, assessing its texture (texture, coagulation, presence or absence of whey separation), flavor, taste, aroma, and color. The sensory evaluation criteria are shown in Table 3 below. Table 3 Sensory Evaluation Criteria

[0061] (3) Establishment of fuzzy mathematical model The evaluation criteria are based on texture, taste, aroma, and color, and rated as excellent, good, average, and poor. Factor set U = {Texture U1, Taste U2, Aroma U3, Color U4} The set of comments V = {Excellent V1, Good V2, Average V3, Poor V4} Based on the influence of texture, taste, aroma, and color on the sensory evaluation of konjac oligosaccharide yogurt, the weights of each sensory index were determined as follows: flavor and taste 0.4, texture 0.3, aroma 0.2, and color 0.1, with a total weight of 1. That is, the weight set X = (a1, a2, a3, a4) = (0.4, 0.3, 0.2, 0.1). By combining the quality factor weight set X with the fuzzy relation matrix R, we obtain the fuzzy relation evaluation set Y = X × R, thus obtaining the evaluation result Y for the i-th konjac oligosaccharide yogurt sample.i =X×R i .

[0062] Example 4 (1) Enzymes and degradation processes Konjac oligosaccharide enzymatic hydrolysate was prepared according to the experimental method. Fifteen konjac oligosaccharide yogurt samples were prepared and subjected to sensory evaluation by ten evaluators. The results are shown in Table 4. Table 4. Sensory evaluation results

[0063] As shown in Table 4, there are differences in the evaluation results of the 10 sensory evaluators. Based on this, a fuzzy matrix can be established for fuzzy mathematical analysis. Taking cellulase sample ① as an example, the flavor and taste results are: 0 people selected "excellent", 1 person selected "good", 6 people selected "medium", and 3 people selected "poor". Therefore, R0 风味口感 = (0 0.1 0.6 0.3), similarly R 组织状态 =(0 0 0.4 0.6)R 气味 =(0 0.2 0.4 0.4)R 色泽 =(0 0.4 0.2 0.4).

[0064] The sensory matrix of cellulase sample ① is as follows: Similarly, the evaluation matrix for other sample numbers can be obtained: Based on the formula Y = X × R, a fuzzy transformation is performed, and the calculation results are as follows: Y 纤① =(0 0.12 0.46 0.42)Y 纤② =(0 0.13 0.48 0.39) Y 纤③ =(0 0.18 0.53 0.29)Y纤④ =(0 0.19 0.45 0.36) Y 纤⑤ =(0 0.17 0.40 0.43) Y 甘① = (0.19 0.36 0.28 0.17); Y 甘② =(0.16 0.46 0.27 0.11) Y 甘③ = (0.24 0.48 0.16 0.12); Y 甘④ =(0.10 0.31 0.36 0.23) Y 甘⑤ = (0.17 0.33 0.40 0.10); Y 葡① = (0.19 0.43 0.30 0.08); Y 葡② = (0.18 0.41 0.35 0.06); Y 葡③ = (0.22 0.45 0.25 0.08); Y 葡④ =(0.27 0.47 0.20 0.06) Y 葡⑤ =(0.32 0.56 0.12 0).

[0065] The evaluation results are graded as Excellent, Good, Average, and Poor, with scores of 90, 80, 70, and 60 respectively. The final total score for each sample is obtained by multiplying each quantity of the comprehensive evaluation result after fuzzy transformation by its corresponding score and then summing them.

[0066] T 纤① =67.0, T 纤② =67.4、T 纤③ =68.9、T 纤④ =68.3、T 纤⑤ =67.4; T 甘① =75.7、T 甘② =76.7、T 甘③ =78.4、T 甘④ =72.8、T 甘⑤ =79.3; T 葡① =77.3、T 葡② =77.1、T 葡③ =78.1、T 葡④ =79.5, T 葡⑤ =82.0.

[0067] The sensory evaluation results above indicate that the optimal enzyme and degradation process is to add 0.04g of β-glucanase and 100mL of water to 4g of konjac flour and then enzymatically hydrolyze it in a 45℃ water bath for 3h.

[0068] (2) Sensory evaluation results and fuzzy mathematical evaluation Based on the factor levels in the orthogonal experiment in Table 2, the L9(3)9(3)9(4)9(5)9(6)9(7)9(8)9(9 ... 3 Nine konjac oligosaccharide yogurt samples were prepared and subjected to sensory evaluation by ten evaluators. The results are shown in Table 5. Table 5. Results of Sensory Evaluation Experiment

[0069] Based on the results in Table 5, a fuzzy matrix can be established for fuzzy mathematical analysis. The evaluation matrices for samples 1 to 9 are obtained as follows: Based on the formula Y = X × R, a fuzzy transformation is performed, and the result is as follows: Y1=(0.26 0.47 0.19 0.08); Y2=(0.25 0.46 0.12 0.16); Y3=(0.10 0.38 0.40 0.12); Y4=(0.26 0.43 0.31 0); Y5=(0.11 0.48 0.41 0); Y6=(0.19 0.65 0.16 0); Y7=(0.22 0.67 0.07 0.04); Y8=(0.38 0.49 0.05 0.08); Y9=(0.27 0.63 0.06 0.04).

[0070] (3) Results of orthogonal experiments Based on the formula Y = X × R, a fuzzy transformation was performed, and the evaluation score for each sample was calculated. The results are shown in Table 6. Table 6. Comprehensive Evaluation Results of Orthogonal Experiments

[0071] Table 6 clearly shows that the range R reflects the order of influence of the three factors on the quality of konjac oligosaccharide yogurt as A > C > B. Specifically, the amount of konjac oligosaccharide enzymatic hydrolysate added has the greatest impact on the sensory quality of the konjac oligosaccharide yogurt, followed by the type of yogurt starter. The amounts of acesulfame potassium and aspartame have relatively the least impact. The results indicate that A3B1C1 is the most popular combination, therefore it is selected as the optimal process formulation.

[0072] The optimal process formula is: 100mL milk, 15mL konjac oligosaccharide hydrolysate, 0.02g acesulfame potassium, 0.02g aspartame, 0.14g yogurt starter ②, fermentation for 12h, and refrigeration for 4h after ripening.

[0073] In summary, using konjac oligosaccharide enzymatic hydrolysate as the main raw material, the optimization of the konjac oligosaccharide yogurt formula was achieved through a combination of fuzzy mathematics, sensory evaluation, and orthogonal experiments. The results obtained are more scientific and reasonable, and can more intuitively reflect the optimal process formula as follows: 4g of konjac flour, 0.04g of β-glucanase, 100mL of water, enzymatic hydrolysis in a 45℃ water bath for 3h to obtain konjac oligosaccharide β-glucan enzymatic hydrolysate; 100mL of raw milk, 15mL of konjac oligosaccharide enzymatic hydrolysate, 0.02g of acesulfame potassium, 0.02g of aspartame, 0.14g of yogurt starter ②, fermentation for 12h, and post-fermentation in cold storage for 4h.

[0074] The above embodiments are merely preferred embodiments of the present invention and are not intended to limit the present invention. The scope of protection of the present invention is determined by the appended claims.

[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A yogurt based on konjac oligosaccharides, characterized in that, The oligosaccharide yogurt contains the following components in parts by weight: 100 parts skim milk, 15 parts konjac oligosaccharide hydrolysate, 0.04 parts sweetener, and 0.14 parts yogurt starter.

2. The yogurt based on konjac oligosaccharides according to claim 1, characterized in that, The sweetener is a mixture of acesulfame potassium and aspartame in a mass ratio of 1:

1.

3. The yogurt based on konjac oligosaccharides according to claim 1, characterized in that, The konjac oligosaccharide hydrolysate is either a konjac oligosaccharide β-mannan hydrolysate or a konjac oligosaccharide β-glucan hydrolysate.

4. The yogurt based on konjac oligosaccharides according to claim 1, characterized in that, The fermentation agent contains maltodextrin, Streptococcus thermophilus, Lactobacillus delbrueckii subsp. bulgaricus, Bifidobacterium lactis, Bifidobacterium bifidum, Bifidobacterium longum, Bifidobacterium breve, Bifidobacterium infantis, Lactobacillus plantarum, Lactobacillus acidophilus, and Lactobacillus casei.

5. A method for preparing yogurt based on konjac oligosaccharides according to any one of claims 1 to 4, characterized in that, Includes the following steps: (1) Preparation of konjac oligosaccharide hydrolysate: Take konjac flour, add β-glucanase or β-mannan and water, mix well and then hydrolyze in a water bath to obtain konjac oligosaccharide hydrolysate; (2) Mixing raw materials: Add konjac oligosaccharide hydrolysate, acesulfame potassium, and aspartame to skim milk and stir well; (3) Inoculation and fermentation: Add the fermentation agent to the mixed raw materials, mix well and ferment at a constant temperature; (4) Cold-cold ripening: After fermentation, the product is ripened at low temperature to obtain yogurt containing konjac oligosaccharides.

6. The method for preparing yogurt based on konjac oligosaccharides according to claim 5, characterized in that, The ratio of konjac flour, β-glucanase or β-mannan and water in step (1) is 4g:0.04g:100mL; the enzymatic hydrolysis temperature is 45℃ and the enzymatic hydrolysis time is 3h.

7. The method for preparing yogurt based on konjac oligosaccharides according to claim 5, characterized in that, The mixed raw materials mentioned in step (2) are 15 mL of konjac oligosaccharide hydrolysate, 0.02 g of acesulfame potassium, and 0.02 g of aspartame added to every 100 mL of skim milk.

8. The method for preparing yogurt based on konjac oligosaccharides according to claim 5, characterized in that, The amount of yogurt starter added in step (3) is 0.14g of yogurt starter per 100mL of skim milk; the fermentation parameters are: temperature 43℃ and time 12h.

9. The method for preparing yogurt based on konjac oligosaccharides according to claim 5, characterized in that, The parameters for low-temperature post-ripening in step (4) are: temperature 5℃ and time 4h.

10. An application of the yogurt based on konjac oligosaccharides as described in claim 1, characterized in that, The specific application is the use of konjac oligosaccharide-based yogurt in the preparation of weight-loss health foods and low-sugar, low-fat health foods that regulate intestinal microecology.

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