Additive-free probiotic fermented milk and preparation method thereof

Abstract

The invention discloses additive-free probiotic fermented milk, which is prepared from the following components in parts by weight: 900 to 993 parts of cow milk, 7 to 100 parts of sweet substances, 20g / ton to 40g / ton of leavening agents and 15g / ton to 25g / ton of rhamnosus lactobacillus GG strains, the leavening agent is a # imgabs0 # AcidifixTM leavening agent; the invention also provides a preparation method of the probiotic fermented milk. According to the probiotic fermented milk, the composition of a specific leavening agent and the lactobacillus rhamnosus GG strain is controlled, and the proportion of all components in the probiotic fermented milk is controlled, so that the pH value of yoghourt of the prepared probiotic fermented milk in the shelf life is kept at about 4.5, and the product is sour and weak; meanwhile, the prepared probiotic fermented milk also contains more than 10 < 8 > CFU / g of a lactobacillus rhamnosus GG strain.

Description

Technical Field

[0001] The invention relates to the technical field of microbial fermentation, and in particular to an additive-free probiotic fermented milk and a preparation method thereof. Background Art

[0002] Probiotics are living microorganisms that are beneficial to human health when consumed in sufficient quantities. Probiotic species (strains) for food use should be species (strains) that can be used in food and published by the national health administrative department. Probiotics should be identified, evaluated for safety and health effects at the strain level. Lactobacillus rhamnosus GG strain is one of the strains approved by the Ministry of Health for use in infant food; in Europe, strains belonging to Lactobacillus rhamnosus have been given qualified safety recommendation (QPS) status by the European Food Safety Authority {EFSA Biological Hazards Expert Group (BIOHAZ) 2017}; in the United States, Lactobacillus rhamnosus GG is "generally regarded as safe (GRAS)" by the Food and Drug Administration (FDA) as an ingredient in infant formula for use in food for full-term infants at birth (GRN No. 231). Since 1990, Lactobacillus rhamnosus GG has not only a long history of safe use worldwide, but has also been tested in a large number of clinical trials. It has been studied in a number of different health areas, including newborns, premature infants, children, pregnant women, adults and the elderly, with a dose range of 1×10 8 to 2×10 12 CFU / day.

[0003] Fermented dairy products are good carriers of probiotics. The finished product of fermented milk containing Lactobacillus rhamnosus generally contains about 10 6 CFU / g, while a higher content of Lactobacillus rhamnosus will bring obvious after-acidity, affecting the flavor and taste of fermented milk products. During the shelf life of fermented milk, especially in a decooling environment, Lactobacillus rhamnosus will bring obvious after-acidity to fermented milk.

[0004] The prior art solves the problem of post-acidification of Lactobacillus rhamnosus yogurt by controlling the type and amount of added carbon source, controlling the fermentation speed of Lactobacillus rhamnosus in milk and thus controlling the late acidity of the yogurt product, while maintaining the number of live lactic acid bacteria in the yogurt (1.06-1.68×10 8 CFU / mL); the prior art prepares probiotic fermented milk by adding dietary fiber and specific sweeteners while ensuring the amount of Lactobacillus rhamnosus added. The acidity of the probiotic fermented milk prepared by the method changes slowly during the shelf life, and the taste is moderately sweet and sour, but the acidity changes significantly during the shelf life; the prior art solves the problem of post-acidification of yogurt containing Lactobacillus rhamnosus by hydrolyzing milk with lactase or adding apple juice, galacto-oligosaccharide, etc.

[0005] The existing technologies are all aimed at the post-acidification problem caused by fermenting Lactobacillus rhamnosus alone to prepare yogurt. Although fermenting Lactobacillus rhamnosus GG strain alone to prepare fermented milk can obtain a higher number of probiotics, the structure of the fermented milk is not good, and whey is very easy to precipitate during storage and transportation. The strain has a unique flavor and often requires the addition of stabilizers, sweeteners, flavors or jams and other raw materials to improve the quality of the product.

[0006] Fermenting lactic acid bacteria with rhamnosus Lactobacillus GG strain to produce yogurt can improve the quality problems when rhamnosus Lactobacillus GG strain is fermented alone, and the lactic acid bacteria fermentation time is short, the texture is good and the flavor is good. However, the number of live bacteria of rhamnosus Lactobacillus GG strain in the fermented milk cannot be too high, otherwise the acidity of the product will be too high, and the product quality and flavor will be greatly affected, especially in non-additive fermented milk with low sucrose addition, which will make the fermented milk seriously acidified during the shelf life, and thus lead to unacceptable acidity of the fermented milk.

[0007] Therefore, how to obtain fermented milk containing a high number of live Lactobacillus rhamnosus bacteria and without post-acidification is the key to developing healthy, additive-free, low-sugar / sugar-free probiotic fermented milk. Summary of the invention

[0008] The purpose of the present invention is to overcome the above-mentioned deficiencies of the prior art and to provide an additive-free probiotic fermented milk and a preparation method thereof.

[0009] The first object of the present invention is to provide a fermented composition.

[0010] The second object of the present invention is to provide the use of the fermentation composition in the preparation of probiotic fermented milk.

[0011] The third object of the present invention is to provide a probiotic fermented milk without additives.

[0012] The fourth object of the present invention is to provide a method for preparing additive-free probiotic fermented milk.

[0013] The fifth object of the present invention is to provide probiotic fermented milk prepared by the above preparation method.

[0014] In order to achieve the above object, the present invention is implemented by the following scheme:

[0015] A fermentation composition comprising a starter and a Lactobacillus rhamnosus GG strain;

[0016] The fermentation agent is Acidifix TM Leavening agent.

[0017] The present invention also claims to protect the use of the fermentation composition in preparing probiotic fermented milk.

[0018] The present invention also claims protection for a non-additive probiotic fermented milk, wherein the probiotic fermented milk is fermented with the fermentation composition.

[0019] Preferably, the probiotic fermented milk contains, by weight:

[0020] 900-993 parts of milk, 7-100 parts of sweetener, 20-40 g / ton of starter and 15-25 g / ton of Lactobacillus rhamnosus GG bacteria;

[0021] The fermentation agent is Acidifix TM Leavening agent.

[0022] In the present invention, the Acidifix TM The starter culture contains Lactobacillus delbrueckii subsp.bulgaricus and Streptococcus thermophilus; Acidifix TM The starter culture was sourced from Chr. Hansen (Beijing) Trading Co., Ltd.

[0023] Preferably, the sweetener is a natural sweetener.

[0024] More preferably, the natural sweetener is sucrose, P-type oligofructose, G-type oligofructose and / or inulin.

[0025] Wherein, when the natural sweetener is sucrose, the probiotic fermented milk contains, by weight, 993 parts of milk, 7 parts of sucrose, 20g / ton to 40g / ton of starter and 15g / ton to 25g / ton of Lactobacillus rhamnosus GG strain;

[0026] When the natural sweetener is P-type oligofructose, the probiotic fermented milk contains, by weight, 900 parts of milk, 100 parts of P-type oligofructose, 20g / ton to 40g / ton of starter and 15g / ton to 25g / ton of Lactobacillus rhamnosus GG strain;

[0027] When the natural sweetener is inulin, the probiotic fermented milk contains, by weight, 950 parts of milk, 50 parts of inulin, 20 g / ton to 40 g / ton of starter and 15 g / ton to 25 g / ton of Lactobacillus rhamnosus GG strain;

[0028] When the natural sweetener is P-type oligofructose and G-type oligofructose, the probiotic fermented milk contains, by weight, 910-920 parts of milk, 50-70 parts of P-type oligofructose, 20-30 parts of G-type oligofructose, 20g / ton-40g / ton of starter and 15g / ton-25g / ton of Lactobacillus rhamnosus GG strain;

[0029] When the natural sweeteners are G-type oligofructose and inulin, the probiotic fermented milk contains, by weight, 930-935 parts of cow's milk, 10-15 parts of G-type oligofructose, 35-45 parts of inulin, 20g / ton-40g / ton of starter and 15g / ton-25g / ton of rhamnosus Lactobacillus GG strain.

[0030] More preferably, the natural sweetener is sucrose.

[0031] Preferably, it contains 993 parts of cow's milk.

[0032] More preferably, the milk is raw milk.

[0033] Preferably, 7 parts of sweetener are contained.

[0034] Preferably, it contains 40 g / ton of starter culture.

[0035] Preferably, the Lactobacillus rhamnosus GG bacteria is contained in an amount of 25 g / ton.

[0036] More preferably, the Lactobacillus rhamnosus GG bacteria are live bacteria of Lactobacillus rhamnosus GG bacteria.

[0037] The probiotic fermented milk of the present invention controls the composition of the specific starter and the rhamnosus Lactobacillus GG strain, and controls the ratio of each component in the probiotic fermented milk, so that the probiotic fermented milk will not have post-acidification phenomenon during the shelf life, and the probiotic fermented milk also contains the rhamnosus Lactobacillus GG strain with a higher number of live bacteria.

[0038] The present invention also claims a method for preparing an additive-free probiotic fermented milk, comprising the following steps:

[0039] S1. After the milk is purified and sterilized, it is fully mixed with the sweetener and homogenized at 60-70°C. After homogenization, it is sterilized at 92-98°C to obtain a liquid feed;

[0040] The weight ratio of the milk to the sweetener is 900-993:7-100;

[0041] S2. Adding a starter and Lactobacillus rhamnosus GG bacteria to the liquid obtained in step S1 for fermentation, and cooling after the fermentation to obtain probiotic fermented milk;

[0042] The fermentation agent is Acidifix TM The fermentation agent has a content of 20 g / ton to 40 g / ton in the feed liquid; and the content of the Lactobacillus rhamnosus GG strain in the feed liquid is 15 g / ton to 25 g / ton.

[0043] Preferably, the sterilization in step S1 is pasteurization.

[0044] Preferably, the homogenization in step S1 includes primary homogenization and secondary homogenization; the primary homogenization pressure is 180-200 bar, and the secondary homogenization pressure is 30-50 bar.

[0045] Preferably, the fermentation conditions in step S2 are: fermentation temperature 35-39° C., and fermentation time 6-8 h.

[0046] More preferably, the fermentation temperature is 37° C. and the fermentation time is 6 h.

[0047] Preferably, the cooling in step S2 is cooling to 8-24°C.

[0048] More preferably, the temperature is cooled to 12-16°C.

[0049] The present invention also claims protection for the probiotic fermented milk prepared by any of the above-mentioned preparation methods.

[0050] Compared with the prior art, the present invention has the following beneficial effects:

[0051] The present invention provides an additive-free probiotic fermented milk, which contains, by weight: 900-993 parts of cow's milk, 7-100 parts of sweeteners, 20g / ton-40g / ton of starter and 15g / ton-25g / ton of rhamnosus lactobacillus GG strain; the starter is Acidifix TM The invention also provides a method for preparing the probiotic fermented milk. The probiotic fermented milk controls the composition of the specific fermenting agent and the Lactobacillus rhamnosus GG strain, and controls the ratio of each component in the probiotic fermented milk, so that the pH value of the prepared probiotic fermented milk is maintained at about 4.5 during the shelf life, and no strong post-acidification phenomenon occurs; at the same time, the prepared probiotic fermented milk also contains more than 10 8 CFU / g of Lactobacillus rhamnosus GG strain. DETAILED DESCRIPTION

[0052] The present invention is further described in detail below in conjunction with specific examples, which are only used to explain the present invention and are not used to limit the scope of the present invention. The test methods used in the following examples are conventional methods unless otherwise specified; the materials, reagents, etc. used are reagents and materials that can be obtained from commercial channels unless otherwise specified.

[0053] In the embodiment of the present invention, Acidifix TM The starter culture was from Chr. Hansen (Beijing) Trading Co., Ltd., which contained Lactobacillus delbrueckii subsp.bulgaricus and Streptococcus thermophilus, with the catalog number 716878;

[0054] Lactobacillus rhamnosus GG strain was purchased from Chr. Hansen (Beijing) Trading Co., Ltd.;

[0055] Premium 1.0 starter culture, YF-L904 starter culture, and Mild 1.0 starter culture were all purchased from Chr. Hansen (Beijing) Trading Co., Ltd. The catalog number of Premium 1.0 starter culture is 720633, and the catalog number of Mild 1.0 starter culture is 703028;

[0056] YO-MIX883 starter culture and YO-MIX495 starter culture were purchased from IFF;

[0057] P-type oligofructose and G-type oligofructose were purchased from Yunfu Xinjinshan Biotechnology Co., Ltd.;

[0058] The Lactobacillus rhamnosus GG strains added in the examples are all live cells of the Lactobacillus rhamnosus GG strain.

[0059] Example 1 A method for preparing non-additive probiotic fermented milk

[0060] A method for preparing additive-free probiotic fermented milk is as follows:

[0061] S1. After 993 g of raw milk was purified and pasteurized, it was mixed with 7 g of sucrose, stirred thoroughly, and then heated to 65° C. for homogenization. During the homogenization process, the primary homogenization pressure was controlled to be 180 bar, and the secondary homogenization pressure was controlled to be 50 bar. After homogenization, the temperature was raised to 95° C. for sterilization and maintained for 5 min to obtain a liquid;

[0062] S2. Inoculate the liquid obtained in step S1 Acidifix TMThe fermentation agent was added to a final concentration of 40 g / ton. At the same time, the rhamnosus Lactobacillus GG strain was inoculated into the slurry to a final concentration of 25 g / ton. The fermentation temperature was controlled at 37°C and the fermentation was carried out for 6 hours. The pH value was 4.62 after the fermentation was completed. After the fermentation was completed, the temperature was cooled to 12-16°C for cold demulsification and maintained for 10 hours to obtain probiotic fermented milk 1, which was stored in an environment of 8°C.

[0063] According to the preparation method described in Example 1, by changing the substances and proportions therein, and changing the conditions in the preparation method, Examples 2 to 13 and Comparative Examples 1 to 13 were respectively set up; wherein Examples 2 to 13 prepared probiotic fermented milk 2 to probiotic fermented milk 13, respectively, and Comparative Examples 1 to 12 prepared fermented milk 1 to fermented milk 13, respectively, as shown in Tables 1 to 4.

[0064] Table 1 Materials and corresponding parameters of Examples 1 to 6

[0065]

[0066]

[0067] Table 2 Materials and corresponding parameters of Examples 7 to 13

[0068]

[0069] Note: " / " in the table means that the substance is not added; the fructo-oligosaccharide mass fraction of P-type fructo-oligosaccharide is ≥95%, and the fructo-oligosaccharide mass fraction of G-type fructo-oligosaccharide is ≥55%.

[0070] Table 3 Materials and corresponding parameters of Comparative Examples 1 to 6

[0071]

[0072]

[0073] Note: “ / ” in the table means that the substance was not added or the parameter was not generated.

[0074] Table 4 Materials and corresponding parameters of Comparative Examples 7 to 13

[0075]

[0076]

[0077] Test Example 1 Probiotic fermented milk and performance test of fermented milk

[0078] 1. Experimental Methods

[0079] 1. Live bacteria count test

[0080] The number of viable LGG bacteria in probiotic fermented milk 1 to probiotic fermented milk 13 and fermented milk 1 to fermented milk 13 after one day of refrigeration was tested according to the “Test method for total viable bacteria count” shown in Appendix B of QB / T4575-2023 “Food Bacteria Preparations”.

[0081] 2. Acidity change test

[0082] The pH values ​​of probiotic fermented milks 1 to 13 and fermented milks 1 to 13 after refrigeration for 1 day, 10 days, and 25 days, respectively, were measured using a pH meter.

[0083] 3. Viscosity test after cooling

[0084] Detection of viscosity of fermented milk: A viscometer was used to detect the viscosity of probiotic fermented milk 1 to probiotic fermented milk 13 and fermented milk 1 to fermented milk 13 after refrigeration for 1 day, wherein the detection parameters of the viscometer were: 62# rotor, 10 seconds, rotation speed 2 rpm, and the sample temperature was controlled at 6-8°C.

[0085] 2. Experimental Results

[0086] The performance test results of probiotic fermented milk 1 to probiotic fermented milk 13 and fermented milk 1 to fermented milk 13 are shown in Table 5.

[0087] Table 5 Performance test results

[0088]

[0089]

[0090] Note: “ / ” in the table means that the indicator was not measured or there is no result for the indicator.

[0091] Based on the performance test results of fermented milk 1 to fermented milk 6 (Comparative Examples 1 to Comparative Examples 6) in Table 5, it can be seen that when 6 different starters were used to ferment with the rhamnosus Lactobacillus GG strain to prepare fermented milk, 5 of the starters (Premim 1.0 starter, YF-L904 starter, Mild 1.0 starter, YO-MIX883 starter and YO-MIX495 starter) were able to combine with the rhamnosus Lactobacillus GG strain to ferment normally to obtain fermented milk, and the number of viable LGG (rhamnosus Lactobacillus GG bacteria) in the fermented milk was about 10 8 CFU / g, but with the increase of refrigeration time, the pH value of fermented milk decreased significantly. The pH value in the later period of the shelf life (after 25 days of refrigeration) was around 4.0. The post-acidification phenomenon of fermented milk was obvious, producing a distinct sharp and sour taste, and the taste acceptance was extremely poor.

[0092] Based on the performance test results of probiotic fermented milk 1 and fermented milks 7 to 11 in Table 5, it can be seen that after adding 7g of sucrose to the formula, Acidifix TM The starter can be combined with the rhamnosus Lactobacillus GG strain to co-ferment and prepare probiotic fermented milk (probiotic fermented milk 1). The number of live LGG bacteria in the prepared probiotic fermented milk is positively correlated with the added amount of the rhamnosus Lactobacillus GG strain, and the pH value of the probiotic fermented milk will not change significantly during the shelf life (refrigerated for 25 days), that is, the prepared probiotic fermented milk will not produce a very strong post-acidification phenomenon.

[0093] After adding 7g of sucrose to the formula, although the Premium 1.0 starter can be used alone or in combination with the rhamnosus Lactobacillus GG strain to prepare fermented milk (fermented milk 7 to fermented milk 10), the pH of the fermented milk prepared during the shelf life (25 days of refrigeration) decreased significantly. As the storage time increased, the acidity of the fermented milk gradually increased, and the post-acidification phenomenon was obvious; while the number of viable LGG bacteria in the fermented milk 11 prepared as shown in Comparative Example 11 was less than 10 8 CFU / g.

[0094] The pH value of the fermented milk 12 prepared according to Comparative Example 12 did not change significantly during the shelf life (25 days of refrigeration), but the number of viable LGG bacteria contained therein was only 8.0×10 7 CFU / g, indicating that when the fermentation temperature is 43°C, it is impossible to obtain fermented milk containing a large amount of rhamnosus Lactobacillus GG strain and without post-acidification.

[0095] The pH value of fermented milk 13 prepared according to Comparative Example 13 did not change significantly during the shelf life (25 days of refrigeration), but the number of viable LGG bacteria contained in it was only 6.7×10 7 CFU / g, indicating that adding 10g / ton of rhamnosus casei GG strain during the fermentation process cannot ferment to obtain fermented milk containing a large amount of rhamnosus casei GG strain.

[0096] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. For ordinary technicians in this field, other different forms of changes or modifications can be made based on the above descriptions and ideas. It is not necessary and impossible to list all the implementation methods here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A fermentation composition, characterized in that Contains starter culture and Lactobacillus rhamnosus GG strain; The fermentation agent is Acidifix TM Leavening agent.

2. Use of the fermentation composition according to claim 1 in the preparation of probiotic fermented milk.

3. A non-additive probiotic fermented milk, characterized in that: Fermentation is carried out using the fermentation composition according to claim 1.

4. The probiotic fermented milk according to claim 3, characterized in that: In parts by weight, it contains: 900-993 parts of milk, 7-100 parts of sweetener, 20-40 g / ton of starter and 15-25 g / ton of Lactobacillus rhamnosus GG bacteria; The fermentation agent is Acidifix TM Leavening agent.

5. The probiotic fermented milk according to claim 4, characterized in that: The sweetener is a natural sweetener.

6. The probiotic fermented milk according to claim 5, characterized in that: The natural sweetener is sucrose, P-type oligofructose, G-type oligofructose and / or inulin.

7. A method for preparing additive-free probiotic fermented milk, characterized in that: The following steps are involved: S1. After the milk is purified and sterilized, it is fully mixed with the sweetener and homogenized at 60-70°C. After homogenization, it is sterilized at 92-98°C to obtain a liquid feed; The weight ratio of the milk to the sweetener is 900-993:7-100; S2. Adding a starter and Lactobacillus rhamnosus GG bacteria to the liquid obtained in step S1 for fermentation, and cooling after the fermentation to obtain probiotic fermented milk; The fermentation agent is Acidifix TM The fermentation agent has a content of 20 g / ton to 40 g / ton in the feed liquid; and the content of the Lactobacillus rhamnosus GG strain in the feed liquid is 15 g / ton to 25 g / ton.

8. The preparation method according to claim 7, characterized in that: The fermentation conditions in step S2 are: fermentation temperature 35-39° C., and fermentation time 6-8 h.

9. The preparation method according to claim 7, characterized in that: The cooling in step S2 is cooling to 8-24°C.

10. Probiotic fermented milk prepared by the preparation method according to any one of claims 7 to 9.

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