Citrus pectin dietary fiber yogurt beverage and preparation method thereof

Abstract

The invention discloses a citrus pectin dietary fiber sour milk beverage and a preparation method thereof, belongs to the technical field of sour milk beverage, and is composed of the following components in parts by mass: citrus pectin / whey protein isolate composite gel 0.1-2%, gellan gum 0.05-0.25%, white granulated sugar 0.5-3%, sucrose 0.5-3%, acidity regulator 0.01-0.1%, roxburghii freeze-dried powder 0.05-0.2%, strychnine oil vine seed extract 0.3-0.6%, edible flavor 0-0.05%, and the remainder is milk. The present invention is compounded into a composite gel by citrus pectin extract, whey protein isolate, and Acanthopanax senticosus extract, and the interaction between each component is used to play an emulsifier effect, reduce surface charge and electrostatic interaction, inhibit protein aggregation, Acanthopanax senticosus extract can maintain structure, and the milk beverage system is stable and uniform, and the mouthfeel is delicate and smooth. The extract of Psoralea corylifolia seeds is added during fermentation to supplement the nitrogen source for lactic acid bacteria and promote the increase of live bacteria. It can resist foreign bacteria and oxidation, optimize the fermentation environment and protect probiotics during the shelf life, thereby improving the quality and efficacy of yogurt beverages.

Description

Technical Field

[0001] The invention belongs to the technical field of sour milk beverages, and in particular relates to a citrus pectin dietary fiber sour milk beverage and a preparation method thereof. Background Art

[0002] Yogurt is a dairy product made from milk, which is first pasteurized, then fermented with fermentation agents such as Lactobacillus bulgaricus and Streptococcus thermophilus, and fermented at a suitable temperature. In addition to milk, its raw materials may also include sugar, jam, etc. During production, it undergoes pretreatment, fermentation and post-ripening steps. According to the tissue state of the finished product, it can be divided into coagulation type and stirring type. According to the taste, it has original flavor, fruity flavor, sweet flavor, etc., and according to the fat content, it can be divided into full-fat, low-fat and skim yogurt. Nutritionally, it is rich in protein, carbohydrates, fat, multiple vitamins and minerals. Among them, protein is high-quality and contains essential amino acids, carbohydrates contain lactose and lactic acid, fat varies depending on the type of milk, and vitamins and minerals are important for many functions of the human body. Yogurt is good for health and can regulate intestinal flora. Its lactic acid bacteria can inhibit the growth of harmful bacteria and maintain intestinal balance; it can improve digestive function, and the organic acids produced by fermentation can promote gastrointestinal motility; it can also enhance immunity, stimulate the immune system and provide nutritional support for it.

[0003] However, yogurt drinks often face the problem of sedimentation at the bottom of the bottle during the shelf life. This phenomenon not only affects the appearance quality of the product, but may also cause consumers to have doubts about the product quality. At present, the main means to solve this problem is to reasonably add a compound emulsifying thickener, among which citrus pectin is a commonly used one. Citrus pectin has good emulsifying and thickening properties, and can improve the stability of yogurt drinks to a certain extent. During the storage and transportation of yogurt, it is difficult to ensure that the temperature environment is always suitable for the survival of probiotics. Therefore, during the shelf life of yogurt, there is a situation where the number of probiotics gradually decreases. Probiotics are one of the important ingredients for yogurt to exert health effects, and the reduction in their number will affect the regulatory effect of yogurt on intestinal health and other beneficial functions. Therefore, how to maintain the stability of the number of probiotics during the shelf life while ensuring the stability of yogurt drinks, and not affecting the flavor, has become an important problem to be solved in this technical field. Summary of the invention

[0004] In view of the above situation, in order to overcome the defects of the prior art, the present invention can effectively solve the problem of sedimentation at the bottom of the bottle of yogurt beverages during the shelf life, and can also significantly increase the number of probiotics during the shelf life through the action of special ingredients such as the extract of the seeds of the star oil vine while maintaining the stability of the yogurt beverage, so that it can better play a beneficial role in human health, and ensure that the product has a good flavor and taste, thereby providing consumers with a new type of yogurt beverage that is rich in nutrition, excellent in quality and has unique health functions.

[0005] In order to achieve the above-mentioned purpose, the following technical scheme is adopted: the present invention provides a citrus pectin dietary fiber yogurt milk beverage, which is composed of the following components in parts by weight: 0.1-2% of citrus pectin / whey protein isolate composite gel, 0.05-0.25% of gellan gum, 0.5-3% of white sugar, 0.5-3% of sucrose, 0.01-0.1% of acidity regulator, 0.05-0.2% of roxburghii freeze-dried powder, 0.3-0.6% of strychnos nucifera seed extract, 0-0.05% of edible flavor, and the balance is cow's milk.

[0006] Furthermore, the citrus pectin / whey protein isolate composite gel is prepared by the following steps:

[0007] S1. After mixing the dried citrus peel with hydrogen peroxide, add 1 mol / L sodium hydroxide solution, stir for 1-2 hours, cool to room temperature, adjust to neutrality with 0.1 mol / L hydrochloric acid, add anhydrous ethanol, react for 0.5-2 hours, centrifuge to separate the precipitate, dry and crush, and pass through an 80-mesh sieve to obtain citrus fiber, add the citrus fiber to a ball mill, grind at a speed of 400-500 rpm for 3-5 hours, and then pass through a 40-mesh sieve to obtain citrus fiber powder;

[0008] S2, adding citrus fiber powder to deionized water, adjusting the pH range to 4-5 with 0.1 mol / L hydrochloric acid, then heating to 37°C, adding cellulase and protease, keeping the water bath for enzymolysis for 0.5-3h, then heating to 90°C for 15min to inactivate the enzyme, then cooling to room temperature, and freeze-drying to obtain citrus pectin extract;

[0009] S3. Add citrus pectin extract and whey protein isolate into deionized water, stir and disperse, and continue stirring for 12 hours, then add Acanthopanax senticosus extract, add citric acid to adjust the pH to 6.5, heat in an 85°C water bath for 20 minutes, then cool to 5°C and continue stirring for 12 hours to gel, and then shear at a speed of 10000-20000 rpm for 5-10 minutes to obtain a citrus pectin / whey protein isolate composite gel.

[0010] The extract of star oil vine seeds is rich in unsaturated fatty acids, proteins, vitamins, phenolics, alcohols, and secondary metabolites such as saponins and coumarins. The protein content of vine seed extract is relatively high, about 27%, which can provide a nitrogen source for microorganisms such as lactic acid bacteria in yogurt fermentation, meet their growth and reproduction needs, and promote the increase in the number of live bacteria. The extract of star oil vine seeds contains phenolic substances such as γ and δ tocopherol, with a content of more than 200 mg / kg. Phenolic substances and secondary metabolites such as saponins and coumarins have anti-bacterial and antioxidant activities, which can help regulate the fermentation environment and promote the fermentation of lactic acid beverages.

[0011] Acanthopanax extract contains acanthopanax glycosides, polysaccharides, flavonoids and a variety of essential amino acids for the human body. Acanthopanax glycosides can improve learning and memory functions by regulating the release of neurotransmitters and enhancing the activity of neurons in the hippocampus of the brain. Polysaccharides play a key role in the immune regulation process and can enhance the body's immunity. Flavonoids can protect the cardiovascular system. Acanthopanax extract contains oleanolic acid and ursolic acid, which have anti-inflammatory and antioxidant effects, and can scavenge free radicals, thereby protecting cells from oxidative damage.

[0012] The freeze-dried powder of sea buckthorn contains extremely high levels of vitamin C and vitamin P (i.e. bioflavonoids) which can enhance its activity. It has powerful antioxidant and vascular health-maintaining effects; it contains minerals such as calcium, iron, and zinc, which are of great significance to bones, hematopoiesis, enzyme activity, etc.; it contains amino acids including essential and non-essential amino acids for the human body; it contains organic acids such as malic acid and citric acid which can promote digestion and regulate acid-base balance; and it also contains polysaccharides with immune-regulating properties.

[0013] Furthermore, in step S1, the mass ratio of citrus peel, hydrogen peroxide and sodium hydroxide solution is 1:20-30:2-5.

[0014] Furthermore, the ball-to-material mass ratio in step S1 is 30-40:1.

[0015] Furthermore, in step S2, the mass ratio of citrus fiber powder, deionized water, cellulase and protease is 1:20-30:0.02-0.04:0.01-0.03.

[0016] Furthermore, the enzymatic activities of cellulase and protease in step S2 are 100,000 U / g.

[0017] Furthermore, in step S3, the mass ratio of citrus pectin extract, whey protein isolate, Acanthopanax senticosus extract and deionized water is 1:5-15:0.1-0.5:40-50.

[0018] Furthermore, the acidity regulator is one or more of lactic acid, citric acid, sodium citrate, sodium lactate, sodium DL-malate and sodium gluconate.

[0019] The present invention also provides a citrus pectin dietary fiber sour milk beverage, comprising the following steps: adding cow's milk into an emulsifying device, adding citrus pectin / whey protein isolate composite gel and gellan gum after shearing for 5-10 minutes, continuing shearing for 4-6 minutes, adding the remaining raw materials, heating to 60-70°C, homogenizing under the condition of 160-200 bar, heating to 94-96°C, pasteurizing for 280-300 seconds, cooling to 43-45°C, inoculating mixed bacteria of Lactobacillus bulgaricus, Streptococcus thermophilus and Bifidobacterium, conveying to a fermentation device, stirring for 3-5 minutes, fermenting at 40-43°C for 5-6 hours, then quickly breaking the emulsion, restoring to room temperature, and homogenizing for a second time under the condition of 20-30 bar to obtain the citrus pectin dietary fiber sour milk beverage.

[0020] Furthermore, the inoculation amount of Lactobacillus bulgaricus is 5×10 5 -4.5×10 6 CFU / mL, the inoculum size of the thermophilic Streptococcus was 4.5×10 6 -7.5×10 6 CFU / mL, the inoculum size of the bifidobacterium was 5×10 6 -4.5×10 7 CFU / mL.

[0021] The beneficial effects of the present invention are:

[0022] (1) The present invention prepares a composite gel by compounding citrus pectin extract, whey protein isolate and Acanthopanax senticosus extract. The interaction between the components of the composite gel has the effect of an emulsifier, and the surface charge is reduced accordingly. According to the principle of colloid chemistry, electrostatic interaction is closely related to the surface charge of particles. The reduction of surface charge directly leads to a reduction in electrostatic interaction, and the aggregation of whey protein isolate and other proteins is inhibited. The polysaccharide compounds in the Acanthopanax senticosus extract may be adsorbed around protein and pectin molecules to form protection, thereby preventing excessive aggregation of protein and pectin molecules. The ketone compounds in the Acanthopanax senticosus extract have certain antioxidant properties, which can reduce the damage of free radicals in the system to the molecular structure of proteins and pectins, thereby making the milk beverage system stable and uniform, avoiding the granularity or precipitation caused by the aggregation of yogurt proteins. In terms of macroscopic taste, the composite gel can also serve as a thickener, so that the milk beverage has a more delicate and smooth texture when drinking, greatly improving the taste quality of the product and bringing a better drinking experience to consumers.

[0023] (2) The extract of the seeds of the Astragalus melongena seed added in the fermentation process of the present invention has a high protein content, which can supplement the nitrogen source for the fermentation of lactic acid bacteria, meet the needs of growth and reproduction, and promote the increase of the number of live bacteria. The phenolic substances and secondary metabolites such as saponins and coumarins contained in the extract have anti-bacterial and antioxidant activities, optimize the fermentation environment, and promote the fermentation of lactic acid beverages. During the shelf life, these active substances continue to protect the probiotics, reduce the impact of external adverse factors, maintain and increase the number of live bacteria, and enable the sour milk beverage to better play the role of probiotics in promoting health. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The stability evaluation result of a citrus pectin dietary fiber yogurt beverage of the present invention;

[0025] Figure 2 The present invention provides an evaluation result of the acidity change of a citrus pectin dietary fiber yogurt beverage.

[0026] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0028] Unless otherwise defined, all professional and scientific terms used herein have the same meanings as those familiar to those skilled in the art. In addition, any methods and materials similar or equivalent to those described herein may be applied to the present invention. The preferred implementation methods and materials described herein are for demonstration purposes only and are not intended to limit the content of this application.

[0029] The experimental methods in the following examples are conventional methods unless otherwise specified, and the experimental materials used in the following examples are purchased from commercial channels unless otherwise specified.

[0030] Lactobacillus bulgaricus is Lactobacillus delbruechii subsp. bulgaricus, with a deposit number of CGMCC 1.2161, and is deposited in the China General Microbiological Culture Collection Center.

[0031] Streptococcus thermophilus is Streptococcus thermophilus, with a deposit number of CGMCC1.6472, and is deposited in the China General Microbiological Culture Collection Center.

[0032] Bifidobacterium is Bifidobacterium animalis subsp. lactis, with the deposit number of CGMCC 1.15623, and is deposited in the China General Microbiological Culture Collection Center.

[0033] Example 1

[0034] A citrus pectin dietary fiber yogurt beverage is composed of the following components in parts by mass: 2% of citrus pectin / whey protein isolate composite gel, 0.25% of gellan gum, 3% of white sugar, 3% of sucrose, 0.1% of acidity regulator, 0.2% of roxburghii freeze-dried powder, 0.6% of strychnos nux vomica seed extract, 0.05% of edible flavor, and the balance of milk.

[0035] The citrus pectin / whey protein isolate composite gel is prepared by the following steps:

[0036] S1. After the dried citrus peel is mixed with hydrogen peroxide in a mass ratio, 1 mol / L sodium hydroxide solution is added, and the mass ratio of citrus peel, hydrogen peroxide and sodium hydroxide solution is 1:20:2. After stirring for 2 hours, it is cooled to room temperature, and then adjusted to neutral with 0.1 mol / L hydrochloric acid, anhydrous ethanol is added, and the reaction is carried out for 2 hours. The precipitate is separated by centrifugation, dried and crushed, and passed through an 80-mesh sieve to obtain citrus fiber. The citrus fiber is added to a ball mill and ground at a speed of 500 rpm for 5 hours. The ball-to-material mass ratio is 40:1, and then passed through a 40-mesh sieve to obtain citrus fiber powder;

[0037] S2, citrus fiber powder, deionized water, cellulase and protease were mixed in a mass ratio of 1:30:0.04:0.03 (the enzymatic activities of cellulase and protease were 100000U / g), the pH was adjusted to 5 with 0.1mol / L hydrochloric acid, and then heated to 37°C, kept in a water bath for enzymolysis for 3h, and then heated to 90°C for 15min to inactivate the enzyme, and then cooled to room temperature and freeze-dried to obtain citrus pectin extract;

[0038] S3. Add citrus pectin extract, whey protein isolate, Acanthopanax senticosus extract and deionized water in a mass ratio of 1:15:0.5:50 into deionized water, stir and disperse, and continue stirring for 12 hours, add citric acid to adjust the pH to 6.5, heat in an 85°C water bath for 20 minutes, then cool to 5°C and continue stirring for 12 hours to gel, and then shear at a speed of 20,000 rpm for 10 minutes to obtain a citrus pectin / whey protein isolate composite gel.

[0039] The acidity regulator is a combination of lactic acid and citric acid in a mass ratio of 1:1:2.

[0040] A method for preparing a citrus pectin dietary fiber yogurt beverage comprises the following steps: adding cow milk to an emulsifying device, adding citrus pectin / whey protein isolate composite gel and gellan gum after shearing for 10 minutes, continuing shearing for 6 minutes, adding the remaining raw materials, heating to 70°C, homogenizing under the condition of 200 bar, heating to 96°C, pasteurizing for 300 seconds, cooling to 45°C, inoculating Lactobacillus bulgaricus (inoculation amount is 4.5×10 6 CFU / mL), Streptococcus thermophilus (inoculation volume 7.5×10 6 CFU / mL) and Bifidobacterium (inoculation size was 4.5×10 7 CFU / mL), and then transported to a fermentation device, stirred for 5 minutes, fermented at 43°C for 6 hours, and then quickly demulsified, restored to room temperature, and homogenized for the second time at 30 bar to obtain the citrus pectin dietary fiber yogurt beverage.

[0041] Example 2

[0042] A citrus pectin dietary fiber yogurt beverage is composed of the following components in parts by mass: 0.1% of citrus pectin / whey protein isolate composite gel, 0.05% of gellan gum, 0.5% of white sugar, 0.5% of sucrose, 0.01% of acidity regulator, 0.05% of roxburghii freeze-dried powder, 0.3% of strychnos nux vomica seed extract, 0% of edible flavor, and the balance of milk.

[0043] The citrus pectin / whey protein isolate composite gel was prepared by the following steps:

[0044] S1. After the dried citrus peel is mixed with hydrogen peroxide in a mass ratio, 1 mol / L sodium hydroxide solution is added, and the mass ratio of citrus peel, hydrogen peroxide and sodium hydroxide solution is 1:30:5. After stirring for 1 hour, it is cooled to room temperature, and then adjusted to neutral with 0.1 mol / L hydrochloric acid, anhydrous ethanol is added, and the reaction is performed for 0.5 hour. The precipitate is separated by centrifugation, dried and crushed, and passed through an 80-mesh sieve to obtain citrus fiber. The citrus fiber is added to a ball mill and ground at a speed of 400 rpm for 3 hours. The ball-to-material mass ratio is 30:1, and then passed through a 40-mesh sieve to obtain citrus fiber powder;

[0045] S2, citrus fiber powder, deionized water, cellulase and protease were mixed in a mass ratio of 1:20:0.02:0.01 (the enzymatic activities of cellulase and protease were 100000U / g), the pH was adjusted to 4 with 0.1mol / L hydrochloric acid, and then heated to 37°C, kept in a water bath for enzymolysis for 0.5h, and then heated to 90°C for 15min to inactivate the enzyme, and then cooled to room temperature and freeze-dried to obtain citrus pectin extract;

[0046] S3. Add citrus pectin extract, whey protein isolate, Acanthopanax senticosus extract and deionized water in a mass ratio of 1:5:0.1:40 into deionized water, stir and disperse, and continue stirring for 12 hours, add citric acid to adjust the pH to 6.5, heat in an 85°C water bath for 20 minutes, then cool to 5°C and continue stirring for 12 hours to gel, and then shear at a speed of 10,000 rpm for 5 minutes to obtain a citrus pectin / whey protein isolate composite gel.

[0047] The acidity regulator is a combination of lactic acid, citric acid, sodium lactate and sodium DL-malate in a mass ratio of 2:1:1:1.

[0048] A method for preparing a citrus pectin dietary fiber yogurt beverage comprises the following steps: adding cow milk to an emulsifying device, adding citrus pectin / whey protein isolate composite gel and gellan gum after shearing for 5 minutes, continuing shearing for 4 minutes, adding the remaining raw materials, heating to 60°C, homogenizing under the condition of 160 bar, heating to 94°C, pasteurizing for 280 seconds, cooling to 43°C, inoculating Lactobacillus bulgaricus (inoculation amount is 5×10 5 CFU / mL), Streptococcus thermophilus (inoculation volume 4.5×10 6 CFU / mL) and Bifidobacterium (inoculation size was 5×10 6 CFU / mL), and then transported to a fermentation device, stirred for 3 minutes, fermented at 40°C for 5 hours, and then quickly demulsified, restored to room temperature, and homogenized for the second time at 20 bar to obtain the citrus pectin dietary fiber yogurt milk beverage.

[0049] Example 3

[0050] A citrus pectin dietary fiber yogurt beverage, comprising the following components in parts by weight:

[0051] Citrus pectin / whey protein isolate composite gel 1%, gellan gum 0.15%, white sugar 1.75%, sucrose 1.75%, acidity regulator 0.055%, roxburghii freeze-dried powder 0.125%, strychnos nucifera seed extract 0.45%, edible flavor 0.025%, and the balance is milk.

[0052] The citrus pectin / whey protein isolate composite gel is prepared by the following steps:

[0053] S1. After the dried citrus peel is mixed with hydrogen peroxide in a mass ratio, 1 mol / L sodium hydroxide solution is added, and the mass ratio of citrus peel, hydrogen peroxide and sodium hydroxide solution is 1:25:4. After stirring for 1.5 hours, the mixture is cooled to room temperature, and then adjusted to neutral with 0.1 mol / L hydrochloric acid. Anhydrous ethanol is added and reacted for 1.25 hours. The precipitate is separated by centrifugation, dried and crushed, and passed through an 80-mesh sieve to obtain citrus fiber. The citrus fiber is added to a ball mill and ground at a speed of 450 rpm for 4 hours. The ball-to-material mass ratio is 35:1, and then passed through a 40-mesh sieve to obtain citrus fiber powder;

[0054] S2, citrus fiber powder, deionized water, cellulase and protease were mixed in a mass ratio of 1:25:0.03:0.02 (the enzymatic activities of cellulase and protease were 100000U / g), the pH was adjusted to 4.5 with 0.1mol / L hydrochloric acid, and then heated to 37°C, kept in a water bath for enzymolysis for 1.75h, and then heated to 90°C for enzyme inactivation for 15min, and then cooled to room temperature and freeze-dried to obtain citrus pectin extract;

[0055] S3. Add citrus pectin extract, whey protein isolate, Acanthopanax senticosus extract and deionized water in a mass ratio of 1:10:0.3:45 into deionized water, stir and disperse, and continue stirring for 12 hours, add citric acid to adjust the pH to 6.5, heat in an 85°C water bath for 20 minutes, then cool to 5°C and continue stirring for 12 hours to gel, and then shear at a speed of 15000 rpm for 7.5 minutes to obtain a citrus pectin / whey protein isolate composite gel.

[0056] The acidity regulator is a combination of lactic acid, citric acid, sodium lactate and sodium gluconate in a mass ratio of 2:1:1:1.

[0057] A method for preparing a citrus pectin dietary fiber yogurt beverage comprises the following steps: adding cow milk to an emulsifying device, adding citrus pectin / whey protein isolate composite gel and gellan gum after shearing for 7.5 minutes, continuing shearing for 5 minutes, adding the remaining raw materials, heating to 65°C, homogenizing under the condition of 180 bar, heating to 95°C, pasteurizing for 290 seconds, cooling to 44°C, inoculating Lactobacillus bulgaricus (inoculation amount is 2.5×10 6 CFU / mL), Streptococcus thermophilus (inoculation volume 6×10 6 CFU / mL) and Bifidobacterium (inoculation size was 2.5×10 7CFU / mL), and then transported to a fermentation device, stirred for 4 minutes, fermented at 41.5°C for 5.5 hours, and then quickly demulsified, restored to room temperature, and homogenized for the second time at 25 bar to obtain the citrus pectin dietary fiber yogurt milk beverage.

[0058] Example 4

[0059] In this comparative example, the acidity regulator is a combination of lactic acid, citric acid, sodium lactate, sodium DL-malate and sodium gluconate in a mass ratio of 2:1:1:1:0.5, and the rest is the same as Example 3.

[0060] Comparative Example 1

[0061] In this comparative example, an equal amount of citrus pectin extract replaced the citrus pectin / whey protein isolate composite gel, and the rest was the same as in Example 3.

[0062] Comparative Example 2

[0063] The citrus pectin / whey protein isolate composite gel in this comparative example does not contain Acanthopanax senticosus extract, and the rest is the same as Example 3.

[0064] Comparative Example 3

[0065] The components of this comparative example do not contain the extract of Astragalus melongena seeds, and the rest are the same as those in Example 3.

[0066] Test Example 1

[0067] Sensory evaluation of yogurt beverage

[0068] 80 people of different ages were invited to conduct sensory evaluation on the sour milk beverages prepared in the embodiments of the present invention and the comparative examples, including color, flavor and taste, with a full score of 10 points. The results are shown in Table 1.

[0069] Table 1 Sensory evaluation results of sour milk beverages

[0070]

[0071]

[0072] As can be seen from Table 1, the color score of the products in each embodiment is high, the flavor score is excellent, and the taste is delicate and smooth, which exceeds the control example. This is due to the uniform dispersibility of the citrus pectin / whey protein isolate composite gel. The preparation process of the present invention allows the components to be fully mixed, avoiding color abnormalities caused by uneven components, and helps to form a stable and uniform system, so that the product presents a more natural and attractive color. The secondary metabolites such as phenolic substances, saponins and coumarins in the extract of the seeds of the star oil vine have anti-bacterial effects, can inhibit the growth of undesirable microorganisms, and reduce the production of odors. At the same time, the various nutrients in the freeze-dried pear powder and the active ingredients in the Acanthopanax senticosus extract enrich the flavor of the product to a certain extent, making the yogurt beverage have a unique and harmonious flavor rather than a single sweet and sour taste. The role of the citrus pectin / whey protein isolate composite gel as a thickener, the interaction between whey protein isolate and pectin molecules, and the protective effect of the polysaccharide compounds in the Acanthopanax senticosus extract on protein and pectin molecules effectively inhibit protein aggregation, making the beverage texture uniform and free of granularity, giving consumers a better taste experience when drinking.

[0073] Test Example 2

[0074] Evaluation of stability of yogurt beverages

[0075] The yogurt beverages of the embodiment and the comparative example were stored in a constant temperature box at 28°C, and the viscosity was measured every 7 days to evaluate the stability of the yogurt beverages. Figure 1 .

[0076] Depend on Figure 1 It can be seen that during the storage process, the viscosity of the sour milk beverage prepared in each embodiment does not change much, while the viscosity of the sour milk beverage prepared in the comparative example changes significantly, indicating that the sour milk beverage prepared by the present invention has good dispersibility. This is due to the special structure and performance of the citrus pectin / whey protein isolate composite gel. In the preparation of the composite gel, citrus pectin extract and whey protein isolate are compounded, and the two interact with each other, which reduces the surface charge and reduces electrostatic interaction, thereby inhibiting protein aggregation. The formed composite gel has a stable structure, and the polysaccharide compounds in the Acanthopanax extract are adsorbed around the protein and pectin molecules, further enhancing this stability, making it difficult for the sour milk beverage to stratify, precipitate, etc. during storage, thereby maintaining good dispersibility.

[0077] Test Example 3

[0078] Evaluation of acidity changes in yogurt and milk beverages

[0079] The yogurt milk beverages of the embodiment and the comparative example were stored in a constant temperature box at 28°C, and the acidity of the yogurt milk beverages was measured every 7 days. Figure 2 .

[0080] from Figure 2 It can be seen that the acidity of the sour milk beverage prepared in each embodiment is almost unchanged, thanks to the overall synergistic effect of the formula. On the one hand, the stable structure of the citrus pectin / whey protein isolate composite gel can maintain the chemical balance of the system and prevent excessive fermentation or deterioration caused by changes in ingredients. On the other hand, the active substances in the extract of Astragalus membranaceus seeds have antioxidant properties, which can reduce the impact of free radicals on the system, protect the nutrients and microbial environment in the sour milk beverage, thereby avoiding abnormal fluctuations in acidity and helping to maintain the acidity stability of the system.

[0081] Test Example 4

[0082] Determination of viable bacteria count during shelf life of yogurt and milk beverages

[0083] The viable bacterial counts of the yogurt beverages of the embodiments of the present invention and the comparative examples during shelf storage were measured, and the results are shown in Table 2. Table 2 Results of viable bacterial count measurement of yogurt beverages during shelf storage

[0084]

[0085] It can be seen from the above table that the number of live bacteria in the embodiment during the shelf life is significantly higher than that in the control example. The key lies in the addition of the Aster oleifera seed extract. Due to its high protein content, it can provide sufficient nitrogen source for microorganisms such as lactic acid bacteria during the fermentation process to meet their growth and reproduction needs, thereby promoting the increase in the number of live bacteria. The Aster oleifera seed extract provides good nutritional support for probiotics. In addition, the phenolic substances and secondary metabolites such as saponins and coumarins contained in the Aster oleifera seed extract have anti-bacterial and antioxidant activities, which can continuously protect the probiotics during the shelf life, reduce the impact of external adverse factors on the probiotics, maintain a high number of live bacteria, and ensure that the yogurt beverage can continue to exert its beneficial effects.

[0086] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

[0087] The present invention and its implementation methods are described above, which is not restrictive. The drawings are only one of the implementation methods of the present invention, and the actual application is not limited thereto. In short, if ordinary technicians in the field are inspired by it and design methods and embodiments similar to the technical solution without creativity without departing from the purpose of the invention, they should all fall within the protection scope of the present invention.

Claims

1. A citrus pectin dietary fiber yogurt beverage, characterized in that: The invention is composed of the following components in parts by weight: 0.1-2% of citrus pectin / whey protein isolate composite gel, 0.05-0.25% of gellan gum, 0.5-3% of white sugar, 0.5-3% of sucrose, 0.01-0.1% of acidity regulator, 0.05-0.2% of lychee roxburghii freeze-dried powder, 0.3-0.6% of strychnos nux vomica seed extract, 0-0.05% of edible flavor, and the balance of milk; The citrus pectin / whey protein isolate composite gel is prepared by the following steps: S1. After mixing the dried citrus peel with hydrogen peroxide, add 1 mol / L sodium hydroxide solution, stir for 1-2 hours, cool to room temperature, adjust to neutrality with 0.1 mol / L hydrochloric acid, add anhydrous ethanol, react for 0.5-2 hours, centrifuge to separate the precipitate, dry and crush, and pass through an 80-mesh sieve to obtain citrus fiber, add the citrus fiber to a ball mill, grind at a speed of 400-500 rpm for 3-5 hours, and then pass through a 40-mesh sieve to obtain citrus fiber powder; S2, adding citrus fiber powder to deionized water, adjusting the pH range to 4-5 with 0.1 mol / L hydrochloric acid, then heating to 37°C, adding cellulase and protease, keeping the water bath for enzymolysis for 0.5-3h, then heating to 90°C for 15min to inactivate the enzyme, then cooling to room temperature, and freeze-drying to obtain citrus pectin extract; S3. Add citrus pectin extract and whey protein isolate into deionized water, stir and disperse, and continue stirring for 12 hours, then add Acanthopanax senticosus extract, add citric acid to adjust the pH to 6.5, heat in an 85°C water bath for 20 minutes, then cool to 5°C and continue stirring for 12 hours to gel, and then shear at a speed of 10000-20000 rpm for 5-10 minutes to obtain a citrus pectin / whey protein isolate composite gel.

2. The citrus pectin dietary fiber sour milk beverage according to claim 1, characterized in that: In step S1, the mass ratio of citrus peel, hydrogen peroxide and sodium hydroxide solution is 1:20-30:2-5.

3. The citrus pectin dietary fiber sour milk beverage according to claim 2, characterized in that: The mass ratio of the balls to the materials in step S1 is 30-40:

1.

4. The citrus pectin dietary fiber sour milk beverage according to claim 3, characterized in that: In the step S2, the mass ratio of citrus fiber powder, deionized water, cellulase and protease is 1:20-30:0.02-0.04:0.01-0.

03.

5. The citrus pectin dietary fiber yogurt beverage according to claim 4, characterized in that: The enzymatic activities of cellulase and protease in step S2 are 100,000 U / g.

6. The citrus pectin dietary fiber yogurt beverage according to claim 5, characterized in that: In step S3, the mass ratio of citrus pectin extract, whey protein isolate, Acanthopanax senticosus extract and deionized water is 1:5-15:0.1-0.5:40-50.

7. The citrus pectin dietary fiber yogurt beverage according to claim 6, characterized in that: The acidity regulator is one or more of lactic acid, citric acid, sodium citrate, sodium lactate, sodium DL-malate and sodium gluconate.

8. The method for preparing the citrus pectin dietary fiber sour milk beverage according to any one of claims 1 to 7, characterized in that: The following steps are involved: The cow's milk is added to an emulsifying device, and after shearing for 5-10 minutes, citrus pectin / whey protein isolate composite gel and gellan gum are added, and the shearing is continued for 4-6 minutes, and then the remaining raw materials are added, and the temperature is raised to 60-70°C, and homogenized at 160-200 bar. The temperature is then raised to 94-96°C, and pasteurized for 280-300 seconds. The milk is then cooled to 43-45°C, and a mixed bacteria of Lactobacillus bulgaricus, Streptococcus thermophilus and Bifidobacterium is added. The milk is then transported to a fermentation device, stirred for 3-5 minutes, and fermented at 40-43°C for 5-6 hours. The milk is then quickly demulsified, restored to room temperature, and homogenized for a second time at 20-30 bar to obtain the citrus pectin dietary fiber yogurt milk beverage.

9. The method for preparing the citrus pectin dietary fiber sour milk beverage according to any one of claim 8, characterized in that: The inoculum amount of Lactobacillus bulgaricus is 5×10 5 -4.5×10 6 CFU / mL, the inoculum size of the thermophilic Streptococcus was 4.5×10 6 -7.5×10 6 CFU / mL, the inoculum size of the bifidobacterium was 5×10 6 -4.5×10 7 CFU / mL.

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