Walnut probiotic fermented beverage and preparation method thereof

Abstract

The invention discloses a walnut probiotic fermented beverage and a preparation method thereof. The beverage is prepared from walnut kernels as a preparation raw material through probiotic fermentation. The walnut kernels are used as preparation raw materials, the beverage is prepared through probiotic fermentation, and the beverage has the advantages of being good in taste, rich in nutrient substance, high in oxidation resistance and the like. The lactobacillus plantarum subsp. Plantarum RF17 and the lactobacillus rhamnosus GOLDGUT-M520 are combined for fermentation, so that the content of total flavonoids in the fermented beverage is increased, and the enterococcus faecalis 2010-JR-01 and the lactobacillus paracasei LCX25 are combined for fermentation, so that the content of total phenols in the fermented beverage is increased.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of food engineering, and particularly relates to a walnut probiotic fermented beverage and a preparation method thereof. BACKGROUND

[0003] In recent years, walnut beverage, as an important category of plant protein beverage, has rapidly risen due to its unique nutritional value and health benefits. Studies have shown that walnuts are rich in alpha-linolenic acid, vitamin E, zinc and polyphenols, which can improve brain health through seven major pathways such as antioxidant and synaptic plasticity improvement. However, the content of polyphenols and flavonoids in walnut beverage is not high, and increasing the content of polyphenols and flavonoids in walnut beverage by fermentation is a topic worthy of research in the field. SUMMARY

[0004] The application aims to provide a walnut probiotic fermented beverage and a preparation method thereof.

[0005] A walnut probiotic fermented beverage, which is prepared from walnut kernels as raw materials and fermented by probiotics.

[0006] The probiotics are Lactobacillus plantarum subsp. plantarum RF17 and Lacticaseibacillus rhamnosus GOLDGUT-M520; the Lactobacillus plantarum subsp. plantarum RF17 has a preservation number of CCTCC NO: M 2012085 and is purchased from the China Center for Type Culture Collection; and the Lacticaseibacillus rhamnosus GOLDGUT-M520 has a preservation number of CGMCC No. 26205 and is purchased from the China General Microbiological Culture Collection Center.

[0007] The probiotics are Enterococcus faecalis 2010-JR-01 and Lactobacillus paracasei LCX25; the Enterococcus faecalis 2010-JR-01 has a preservation number of CGMCC No.7738 and is purchased from China General Microbiological Culture Collection Center; the Lactobacillus paracasei LCX25 has a preservation number of CGMCC No.16713 and is purchased from China General Microbiological Culture Collection Center.

[0008] The preparation method of the walnut probiotic fermented beverage is carried out according to the following steps:

[0009] (1) raw material pretreatment: fresh walnut kernels are taken, washed and peeled, water is added at a weight ratio of 1:(2-5), and juice is squeezed in a juicer to obtain walnut slurry;

[0010] (2) adding pectinase to the walnut slurry obtained in step (1) for enzymolysis, then adding chitosan for precipitation, and then filtering through diatomite, vacuum concentrating to obtain walnut juice;

[0011] (3) taking the probiotics after freeze-drying treatment to prepare a bacterial agent;

[0012] (4) sterilizing the fruit juice, cooling, inoculating the probiotic bacterial agent prepared in step (3) into the sterilized fruit juice at an inoculation amount of 0.5-2%, and fermenting at a constant temperature of 20-40°C for 24-64h, and then transferring to 4°C for 2-4 days of post-ripening to obtain a fermented mature liquid;

[0013] (5) after the fermented mature liquid is qualified, it is aseptically filled to obtain the beverage, which is stored at a low temperature of 0-4°C.

[0014] The addition amount of the pectinase in step (2) is 0.5-1.5g / L; and the enzymolysis conditions are as follows: enzymolysis at a temperature of 50°C and a pH of 3-4 for 2-6h.

[0015] The addition amount of the chitosan in step (2) is 0.1-0.5g / L.

[0016] The preparation method of the bacterial agent in step (3) is as follows: the probiotics are added into 15% skimmed milk powder medium sterilized at 115°C for 30min and cooled to room temperature, the inoculation amount is 1%, and the probiotic bacterial agent is obtained after culturing at a constant temperature of 20-40°C for 24h.

[0017] The sterilization conditions of the fruit juice in step (4) are as follows: sterilization at 121°C for 20min.

[0018] The walnut probiotic fermented beverage is prepared from walnut kernels as raw materials through fermentation of probiotics. DETAILED DESCRIPTION

[0019] In order to facilitate the understanding of the present application, the present application will be described more fully below. However, the present application can be realized in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0020] Example 1

[0021] A walnut probiotic fermented beverage is prepared from walnut kernels as raw materials through fermentation of probiotics. The probiotics are Lactobacillus plantarum subsp. plantarum RF17 and Lacticaseibacillus rhamnosus GOLDGUT-M520. The Lactobacillus plantarum subsp. plantarum RF17 has a preservation number of CCTCC NO: M 2012085 and is purchased from China Center for Type Culture Collection. The Lacticaseibacillus rhamnosus GOLDGUT-M520 has a preservation number of CGMCC No. 26205 and is purchased from China General Microbiological Culture Collection Center.

[0022] The preparation method of the walnut probiotic fermented beverage is carried out according to the following steps:

[0023] (1) Raw material pretreatment: fresh walnut kernels are taken, washed and dehulled, water is added at a ratio of 1:3 by weight, and juice is extracted in a juicer to obtain walnut slurry;

[0024] (2) Pectinase is added to the walnut slurry obtained in step (1) for enzymatic hydrolysis, then chitosan is added for precipitation, and then diatomite filtration and vacuum concentration are carried out to obtain walnut juice. The addition amount of pectinase is 1 g / L. The enzymatic hydrolysis conditions are as follows: enzymatic hydrolysis at a temperature of 50℃ and a pH of 3.5 for 4h. The addition amount of chitosan is 0.25 g / L;

[0025] (3) taking the probiotic bacteria after freeze-drying treatment, preparing a bacterial agent; the preparation method of the bacterial agent is as follows: the probiotic bacteria are added into 15% defatted milk powder medium sterilized at 115°C for 30 min and cooled to room temperature, the inoculation amount is 1%, after being cultured at a constant temperature of 30°C for 24 h, the probiotic bacterial agent is obtained;

[0026] (4) the fruit juice is sterilized, cooled, inoculated with the probiotic bacterial agent prepared in step (3) with an inoculation amount of 1% into the sterilized fruit juice; after being fermented at a constant temperature of 30°C for 48 h, it is transferred to 4°C for 3 days of post-ripening, and a fermented and ripened liquid is obtained; the sterilization conditions of the fruit juice are as follows: sterilization at 121°C for 20 min;

[0027] (5) after the fermented and ripened liquid is qualified, the beverage is obtained by aseptic filling and stored at 4°C.

[0028] Example 2

[0029] A walnut probiotic fermented beverage is prepared by using walnut kernels as raw materials and by fermentation with probiotic bacteria. The probiotic bacteria are Enterococcus faecalis 2010-JR-01 and Lactobacillus paracasei LCX25; the Enterococcus faecalis 2010-JR-01 has a preservation number of CGMCC No. 7738 and is purchased from the China General Microbiological Culture Collection Center; the Lactobacillus paracasei LCX25 has a preservation number of CGMCC No. 16713 and is purchased from the China General Microbiological Culture Collection Center.

[0030] The preparation method of the walnut probiotic fermented beverage is carried out according to the following steps:

[0031] (1) raw material pretreatment: fresh walnut kernels are taken, washed and peeled, water is added at a weight ratio of 1:4, and juice is extracted in a juicer to obtain walnut pulp;

[0032] (2) pectinase is added to the walnut pulp obtained in step (1) for enzymolysis, then chitosan is added for precipitation, and then diatomite filtration and vacuum concentration are carried out to obtain walnut juice; the addition amount of the pectinase is 0.8 g / L; the enzymolysis conditions are as follows: enzymolysis at a temperature of 50°C and a pH of 4 for 5 h; the addition amount of the chitosan is 0.2 g / L;

[0033] (3) taking the probiotic bacteria after freeze-drying treatment, preparing a bacterial agent; the preparation method of the bacterial agent is as follows: the probiotic bacteria are added into 15% defatted milk powder medium sterilized at 115°C for 30 min and cooled to room temperature, the inoculation amount is 1%, and after being cultured at a constant temperature of 20-40°C for 24 h, the probiotic bacterial agent is obtained;

[0034] (4) the fruit juice is sterilized, cooled, inoculated with the probiotic bacterial agent prepared in step (3) with an inoculation amount of 1.5% into the sterilized fruit juice; after being fermented at a constant temperature of 37°C for 64 h, it is transferred to 4°C for 3 days of post-ripening, and a fermented and ripened liquid is obtained; the sterilization condition of the fruit juice is as follows: 121°C sterilization for 20 min;

[0035] (5) after the fermented and ripened liquid is qualified, the beverage is obtained by aseptic filling and stored at 4°C.

[0036] Example 3

[0037] A walnut probiotic fermented beverage is prepared from walnut kernels as raw materials and fermented by probiotic bacteria; the probiotic bacteria are Lactobacillus plantarum subsp. plantarum RF17 and Lacticaseibacillus rhamnosus GOLDGUT-M520; the Lactobacillus plantarum subsp. plantarum RF17 has a preservation number of CCTCC NO: M 2012085 and is purchased from China General Microbiological Culture Collection Center; the Lacticaseibacillus rhamnosus GOLDGUT-M520 has a preservation number of CGMCC No. 26205 and is purchased from China General Microbiological Culture Collection Center.

[0038] The preparation method of the walnut probiotic fermented beverage is carried out according to the following steps:

[0039] (1) raw material pretreatment: fresh walnut kernels are taken, washed and peeled, water is added at a weight ratio of 1:2, and juice is extracted in a juicer to obtain walnut pulp;

[0040] (2) pectinase is added to the walnut pulp obtained in step (1) for enzymolysis, then chitosan is added for precipitation, and then diatomite filtration, vacuum concentration are carried out to obtain walnut juice; the addition amount of the pectinase is 1.2 g / L; the enzymolysis conditions are as follows: enzymolysis at a temperature of 50°C and a pH of 4 for 5 h; the addition amount of the chitosan is 0.4 g / L;

[0041] (3) taking the freeze-dried probiotics to prepare a bacterial agent; the preparation method of the bacterial agent is as follows: the probiotics are added into 15% skimmed milk powder medium sterilized at 115°C for 30 min and cooled to room temperature, the inoculation amount is 1%, and the medium is cultured at a constant temperature of 32°C for 24 h to obtain the probiotic bacterial agent;

[0042] (4) the fruit juice is sterilized, cooled, inoculated with the probiotic bacterial agent prepared in step (3) at an inoculation amount of 1.2% into the sterilized fruit juice, fermented at a constant temperature of 32°C for 54 h, and then transferred to 4°C for 3 days of post-ripening to obtain a fermented and ripened liquid; the sterilization condition of the fruit juice is 121°C for 20 min;

[0043] (5) after the fermented and ripened liquid is qualified, the beverage is obtained by aseptic filling and stored at 4°C.

[0044] Comparative Example 1

[0045] A walnut probiotic fermented beverage is prepared from walnut kernels as raw materials through probiotic fermentation. The probiotic is Lactobacillus plantarum subsp. plantarum RF17; the preservation number of the Lactobacillus plantarum subsp. plantarum RF17 is CCTCC NO: M 2012085, which is purchased from the China Center for Type Culture Collection.

[0046] The preparation method of the walnut probiotic fermented beverage is carried out according to the following steps:

[0047] (1) raw material pretreatment: fresh walnut kernels are washed and peeled, water is added at a weight ratio of 1:3, and a juicer is used to obtain walnut pulp;

[0048] (2) pectinase is added to the walnut pulp obtained in step (1) for enzymolysis, then chitosan is added for precipitation, and then diatomite filtration and vacuum concentration are carried out to obtain walnut juice; the addition amount of the pectinase is 1 g / L; the enzymolysis condition is 4 h at a temperature of 50°C and a pH of 3.5; and the addition amount of the chitosan is 0.25 g / L;

[0049] (3) taking the freeze-dried probiotics to prepare a bacterial agent; the preparation method of the bacterial agent is as follows: the probiotics are added into 15% skimmed milk powder medium sterilized at 115°C for 30 min and cooled to room temperature, the inoculation amount is 1%, and the medium is cultured at a constant temperature of 32°C for 24 h to obtain the probiotic bacterial agent;

[0050] (4) sterilize the fruit juice, cool it, inoculate the probiotic bacterial inoculum prepared in step (3) into the sterilized fruit juice at an inoculation amount of 1%, ferment it at 30°C for 48 h, and then transfer it to 4°C for 3 days of post-ripening to obtain a fermented and ripened liquid; the sterilization conditions of the fruit juice are 121°C for 20 min;

[0051] (5) after the fermented and ripened liquid passes the inspection, it is aseptically filled to obtain a beverage, which is stored at 4°C.

[0052] Comparative Example 2

[0053] A walnut probiotic fermented beverage is prepared from walnut kernels as raw materials through probiotic fermentation. The probiotic bacteria are Lacticaseibacillus rhamnosus GOLDGUT-M520, which has a preservation number of CGMCC No. 26205 and is purchased from the China General Microbiological Culture Collection Center.

[0054] The preparation method of the walnut probiotic fermented beverage is as follows:

[0055] (1) raw material pretreatment: fresh walnut kernels are washed and peeled, water is added at a ratio of 1:3 by weight, and a juice extractor is used to obtain walnut slurry;

[0056] (2) pectinase is added to the walnut slurry obtained in step (1) for enzymatic hydrolysis, then chitosan is added for precipitation, and then diatomite filtration and vacuum concentration are performed to obtain walnut juice; the addition amount of the pectinase is 1 g / L; the enzymatic hydrolysis conditions are 50°C and pH 3.5 for 4 h; and the addition amount of the chitosan is 0.25 g / L;

[0057] (3) a probiotic bacterial inoculum is prepared from freeze-dried probiotic bacteria; the preparation method of the inoculum is as follows: the probiotic bacteria are added to 15% skimmed milk powder medium that has been sterilized at 115°C for 30 min and cooled to room temperature at an inoculation amount of 1%, and then the medium is cultured at 30°C for 24 h to obtain a probiotic bacterial inoculum;

[0058] (4) the fruit juice is sterilized, cooled, inoculated with the probiotic bacterial inoculum prepared in step (3) at an inoculation amount of 1%, fermented at 30°C for 48 h, and then transferred to 4°C for 3 days of post-ripening to obtain a fermented and ripened liquid; the sterilization conditions of the fruit juice are 121°C for 20 min;

[0059] (5) after the fermented and ripened liquid passes the inspection, it is aseptically filled to obtain a beverage, which is stored at 4°C.

[0060] Comparative Example 3

[0061] A walnut probiotic fermented beverage is prepared from walnut kernels as raw material by probiotic fermentation. The probiotic is Enterococcus faecalis 2010-JR-01; the Enterococcus faecalis 2010-JR-01 has a preservation number of CGMCC No. 7738 and is purchased from China General Microbiological Culture Collection Center.

[0062] The preparation method of the walnut probiotic fermented beverage is carried out according to the following steps:

[0063] (1) Raw material pretreatment: fresh walnut kernels are taken, washed and peeled, water is added at a ratio of 1:4 by weight, and juice is extracted in a juicer to obtain walnut slurry;

[0064] (2) Pectinase is added to the walnut slurry obtained in step (1) for enzymatic hydrolysis, then chitosan is added for precipitation, and then diatomite filtration and vacuum concentration are carried out to obtain walnut juice; the addition amount of the pectinase is 0.8 g / L; the enzymatic hydrolysis conditions are: enzymatic hydrolysis at a temperature of 50°C and a pH of 4 for 5h; the addition amount of the chitosan is 0.2 g / L;

[0065] (3) The probiotic after freeze-drying treatment is prepared into a bacterial agent; the preparation method of the bacterial agent is: the probiotic is added to 15% skimmed milk powder medium sterilized at 115°C for 30 min and cooled to room temperature, the inoculation amount is 1%, and after incubation at a constant temperature of 20-40°C for 24h, the probiotic bacterial agent is obtained;

[0066] (4) The fruit juice is sterilized, cooled, inoculated with the probiotic bacterial agent prepared in step (3) at an inoculation amount of 1.5% into the sterilized fruit juice; incubated at 37°C for 64h, and then transferred to 4°C for 3 days of post-ripening to obtain a fermented and matured liquid; the sterilization conditions of the fruit juice are: sterilization at 121°C for 20 min;

[0067] (5) After the fermented and matured liquid passes the inspection, it is aseptically filled to obtain the beverage, which is stored at 4°C.

[0068] Comparative Example 4

[0069] A walnut probiotic fermented beverage is prepared from walnut kernels as raw material by probiotic fermentation. The probiotic is Lactobacillus paracasei LCX25; the Lactobacillus paracasei LCX25 has a preservation number of CGMCC No. 16713 and is purchased from China General Microbiological Culture Collection Center.

[0070] The preparation method of the walnut probiotic fermented beverage is carried out according to the following steps:

[0071] (1) Raw material pretreatment: fresh walnut kernels are taken, washed and peeled, water is added at a ratio of 1:4 by weight, and juice is squeezed in a juicer to obtain walnut slurry;

[0072] (2) Pectinase is added to the walnut slurry obtained in step (1) for enzymatic hydrolysis, then chitosan is added for precipitation, and then diatomite filtration and vacuum concentration are carried out to obtain walnut juice; the addition amount of the pectinase is 0.8 g / L; the enzymatic hydrolysis conditions are: enzymatic hydrolysis for 5 h at a temperature of 50℃ and a pH of 4; the addition amount of the chitosan is 0.2 g / L;

[0073] (3) The probiotic bacteria after freeze-drying treatment are taken to prepare a bacterial agent; the preparation method of the bacterial agent is: the probiotic bacteria are added to 15% skimmed milk powder medium sterilized at 115℃ for 30 min and cooled to room temperature, the inoculation amount is 1%, and after culturing at a constant temperature of 20-40℃ for 24 h, a probiotic bacterial agent is obtained;

[0074] (4) The fruit juice is sterilized, cooled, inoculated with the probiotic bacterial agent prepared in step (3) at an inoculation amount of 1.5% in the sterilized fruit juice, fermented at 37℃ for 64 h, and then transferred to 4℃ for 3 days of post-ripening to obtain a fermented and matured liquid; the sterilization conditions of the fruit juice are: sterilization at 121℃ for 20 min;

[0075] (5) After the fermented and matured liquid passes the inspection, the beverage is aseptically filled and stored at 4℃.

[0076] Experimental example

[0077] The flavonoid content in the fermented beverage samples prepared in Examples 1, 3 and Comparative Examples 1-2 is determined by the following method: a standard stock solution is prepared by taking 0.02 g of rutin in a clean beaker, ultrasonically dissolving it with 70% ethanol, and then diluting to 100 mL in a volumetric flask. Accurately transfer 0, 1, 2, 3, 4, 5, and 6 mL of the above solution into 25 mL volumetric flasks, and add 70% ethanol to 6 mL, then add 1 mL of NaNO2 solution, shake well and stand for 5 min, then add 1 mL of Al(NO3)3 solution, shake well and stand for 5 min, then add 10 mL of NaOH solution, dilute to volume with deionized water, stand for 15 min, measure the absorbance A value at a wavelength of 505 nm, and draw a standard curve. Take 2.0 mL of the product, and perform color development as described above. Repeat the determination of A value 3 times under the same conditions, and calculate the average value. The total flavonoid content in the beverage is calculated by the standard curve.

[0078] The experimental results are statistically analyzed by SPSS 24.0 software, and the measurement data results are expressed as The data normality test was performed by Kolmogorov-Smirnov test method, for the data conforming to normal distribution, the mean difference between two groups was compared by t test, P<0.05 was considered statistically significant, and the determination results are shown in Table 1:

[0079] Table 1

[0080]

[0081] Note: * represents P<0.05 compared with Example 1 group.

[0082] The total phenol content in the fermented beverage samples prepared in Examples 2, 3 and Comparative Examples 3-4 was determined, and the determination method was performed according to the Folin-phenol method disclosed by Sun Shuyi (Sun Shuyi, Study on Litchi Juice Mixed Fermentation Process and Functional Active Ingredients[D]. South China Agricultural University, 2016). The content of total phenol was calculated by taking gallic acid as a standard substance, and the result was expressed as g / L.

[0083] The experimental results were statistically analyzed by SPSS 24.0 software, and the measurement data results were expressed as The data normality test was performed by Kolmogorov-Smirnov test method, for the data conforming to normal distribution, the mean difference between two groups was compared by t test, P<0.05 was considered statistically significant, and the determination results are shown in Table 2:

[0084] Table 2

[0085]

[0086] Note: * represents P<0.05 compared with Example 2 group.

[0087] The above examples only express several embodiments of the present application, and the description is more specific and detailed, but it cannot be understood as limiting the scope of the patent. It should be noted that for ordinary skilled in the art, without departing from the concept of the present application, a number of variations and improvements can be made, which are within the scope of the present application. Therefore, the protection scope of the present application patent should be subject to the appended claims.

Claims

1. A walnut probiotic fermented beverage, characterized in that, The beverage is prepared from walnut kernels as raw materials, and is fermented by probiotics.

2. The walnut probiotic fermented beverage according to claim 1, characterized in that, The probiotics are Lactobacillus plantarum subsp. plantarum RF17 and Lacticaseibacillus rhamnosus GOLDGUT-M520; the Lactobacillus plantarum subsp. plantarum RF17 has a preservation number of CCTCC NO: M 2012085; and the Lacticaseibacillus rhamnosus GOLDGUT-M520 has a preservation number of CGMCC No. 26205.

3. The walnut probiotic fermented beverage according to claim 1, characterized in that, The probiotics are Enterococcus faecalis 2010-JR-01 and Lactobacillus paracasei LCX25; the Enterococcus faecalis 2010-JR-01 has a preservation number of CGMCC No. 7738; and the Lactobacillus paracasei LCX25 has a preservation number of CGMCC No. 16713.

4. The method for preparing the walnut probiotic fermented beverage according to claim 1, characterized in that, The following steps are performed: (1) raw material pretreatment: fresh walnut kernels are taken, washed and peeled, water is added at a weight ratio of 1: (2-5), and juice is extracted in a juicer to obtain walnut slurry; (2) pectinase is added to the walnut slurry obtained in step (1) for enzymatic hydrolysis, then chitosan is added for precipitation, and then diatomite filtration and vacuum concentration are performed to obtain walnut juice; (3) probiotics after freeze-drying treatment are prepared into a bacterial agent; (4) the fruit juice is sterilized, cooled, inoculated with the probiotic bacterial agent prepared in step (3) at an inoculation amount of 0.5-2%, and then inoculated into the sterilized fruit juice; fermentation is performed at a constant temperature of 20-40℃ for 24-64h, and then transferred to 4℃ for 2-4 days of post-ripening to obtain a fermented and ripened liquid; (5) after the fermented and ripened liquid passes inspection, it is aseptically filled to obtain the beverage, which is stored at a low temperature of 0-4℃.

5. The method for preparing the walnut probiotic fermented beverage according to claim 4, characterized in that, The addition amount of the pectinase in step (2) is 0.5-1.5g / L; and the enzymatic hydrolysis conditions are as follows: enzymatic hydrolysis is performed at a temperature of 50℃ and a pH of 3-4 for 2-6h.

6. The method of producing the walnut probiotic fermented beverage according to claim 4, characterized in that, The addition amount of the chitosan in step (2) is 0.1-0.5g / L.

7. The method of producing the walnut probiotic fermented beverage according to claim 1, characterized in that, The preparation method of the bacterial agent in step (3) is as follows: the probiotics are added to 15% skimmed milk powder medium that has been sterilized at 115℃ for 30min and cooled to room temperature, the inoculation amount is 1%, and then incubation is performed at a constant temperature of 20-40℃ for 24h to obtain the probiotic bacterial agent.

8. The process for the preparation of Prune Plum fermented beverage as claimed in claim 1 wherein, The sterilization conditions of the fruit juice in step (4) are as follows: sterilization is performed at 121℃ for 20min.

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