Preparation method of mulberry and macadamia nut plant-based fermented yoghurt

Abstract

The invention provides a preparation method of mulberry and macadamia nut plant-based fermented yoghurt, and belongs to the technical field of food microbial fermentation. Mulberries are sequentially subjected to pretreatment, pulping, boiling and cooling, and mulberry pulp is obtained; sequentially baking, pulping, filtering and heating the macadamia nuts to obtain macadamia nut milk; mulberry pulp, macadamia nut milk, chlorella pyrenoidosa, cane sugar, pectin and propylene glycol alginate are mixed and homogenized, and a fermentation substrate is obtained; the mulberry and macadamia nut plant-based fermented yoghurt is obtained by sequentially sterilizing, cooling, fermenting, refrigerating and after-ripening the fermentation substrate, and the yoghurt has a relatively good antioxidant function, better conforms to the modern nutrition and health concept and is also more suitable for being absorbed by a human body; the prepared plant-based yoghurt integrates the fine taste of macadamia nuts, high-protein nutritional ingredients, the fruity flavor of mulberries and the unique flavor of chlorella pyrenoidosa, not only has better taste and flavor, but also has better functionality.

Description

Technical Field

[0001] The invention belongs to the technical field of food microbial fermentation, and particularly relates to a method for preparing mulberry macadamia nut plant-based fermented yogurt. Background Art

[0002] Plant-based yogurt is a lactic acid fermentation product rich in plant protein. It mainly uses high-protein plant products as raw materials for fermentation, such as macadamia nuts, soybeans, oats, etc. Plant-based yogurt uses plant protein instead of animal protein. Compared with traditional yogurt products, plant-based yogurt has natural raw materials, does not contain cholesterol, is low in fat and high in protein, and is more suitable for special groups such as chronic disease patients, vegetarians, and people allergic to animal protein who need to consume high-quality protein.

[0003] At present, the existing plant-based yogurts have poor functionality and their flavor and taste cannot meet the needs of the public, and it is difficult to meet the current market demand. Therefore, there is an urgent need for a plant-based yogurt with antioxidant function, rich nutrition, and suitable flavor and taste. Summary of the invention

[0004] In view of this, an object of the present invention is to provide a method for preparing a mulberry macadamia nut plant-based fermented yogurt. The fermented yogurt obtained by the present invention has good taste and flavor, good functionality, and good antioxidant capacity.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] The present invention provides a method for preparing mulberry macadamia nut plant-based fermented yogurt, comprising the following steps:

[0007] S1. Pre-treating, pulping, boiling and cooling mulberries to obtain mulberry pulp;

[0008] S2. baking, beating, filtering and heating the macadamia nuts in sequence to obtain macadamia nut milk;

[0009] S3. mixing mulberry pulp, macadamia nut milk, chlorella pyrenoidosa, sucrose, pectin, and propylene glycol alginate to obtain a fermentation matrix;

[0010] S4. The fermentation substrate is sterilized, fermented, and refrigerated and ripened to obtain mulberry and macadamia nut plant-based fermented yogurt.

[0011] Preferably, the pretreatment method in S1 is: selecting fresh mulberries that are moderately mature and not spoiled or rotten as raw materials, and completing the pretreatment by removing stems and washing.

[0012] Preferably, the boiling time in S1 is 0.5 to 2 minutes. Rapid boiling can achieve sterilization and reduce the adverse effects on the nutritional flavor of mulberries.

[0013] Preferably, the baking temperature in S2 is 120-135° C. and the baking time is 6-12 min.

[0014] Preferably, the solid-to-liquid ratio of pulping in S2 is 1:(2-4).

[0015] Preferably, the heating temperature in S2 is 65-75° C. and the heating time is 5-15 min. The present invention ensures sufficient sterilization through the heating temperature while not affecting the texture and flavor of the yogurt.

[0016] Preferably, the mass ratio of mulberry pulp, macadamia nut milk, chlorella, sucrose, pectin and propylene glycol alginate in S3 is (8-12):(78-82):(0.3-0.5):(4-6):(2-4):(0.05-2).

[0017] Preferably, the homogenizing speed in S3 is 8000-12000 r / min, and the time is 0.5-1.5 min.

[0018] Preferably, the sterilization in S4 is carried out by high temperature sterilization, the sterilization temperature is 90-95° C., and the time is 3-6 minutes.

[0019] Preferably, the fermentation agent used in the S4 fermentation process is a composite strain of Streptococcus thermophilus and Lactobacillus bulgaricus;

[0020] The mass ratio of thermophilic streptococcus to bulgaricus lactobacillus in the fermentation agent is 1:1

[0021] The addition amount of the leavening agent is 3% of the mass of the fermentation substrate.

[0022] Preferably, the fermentation temperature is 40° C. and the fermentation time is 7 hours. Under the fermentation conditions of the present invention, the yogurt is promoted to solidify and form and produce acid and aroma.

[0023] Preferably, the temperature of the S4 refrigerated ripening is 4° C. and the time is 24 hours. The present invention further enhances the flavor through the ripening process to improve the taste and flavor of the yogurt.

[0024] Contains at least the following beneficial technical effects:

[0025] In the preparation process of the present invention, mulberry juice is added, which is rich in polysaccharides, anthocyanins, etc., can effectively remove free radicals, and has good antioxidant function; macadamia nuts are rich in plant protein, which is more in line with modern nutrition and health concepts and more suitable for human absorption compared with animal protein; protein nucleus chlorella is also added to increase the protein content of plant-based yogurt and play the role of supplementing various vitamins, enhancing immunity, activating human cells, etc. The prepared plant-based yogurt combines the delicate taste of macadamia nuts, high-protein nutrients and mulberry fruity aroma, as well as the unique flavor of protein nucleus chlorella, and has both good flavor and taste and good functionality. DETAILED DESCRIPTION

[0026] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0027] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0028] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0029] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present application description and examples are exemplary only.

[0030] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0031] The "room temperature" and "normal temperature" mentioned in the present invention are all calculated as 25±2°C unless otherwise specified.

[0032] Example 1

[0033] This embodiment provides a method for preparing mulberry macadamia nut plant-based fermented yogurt, comprising the following steps:

[0034] S1. Selecting fresh mulberries that are moderately mature and not spoiled or rotten as raw materials, removing the stems, washing, beating, boiling for 1 minute and cooling to obtain mulberry pulp;

[0035] S2. Wash the macadamia kernels and bake them at 130°C for 8 min, beat them into pulp at a material-liquid ratio of 1:3, filter and remove the residue, and heat them at 70°C for 10 min to obtain macadamia milk;

[0036] S3. The mulberry pulp, macadamia nut milk, chlorella, sucrose, pectin, and propylene glycol alginate were mixed in a mass ratio of 10:81.5:0.45:5.3:3:0.12, and then homogenized in a high-speed homogenizer at 10000r / min for 1min to obtain a fermentation matrix;

[0037] S4. sterilize the fermentation matrix at 93°C for 5 minutes to ensure sufficient sterilization without affecting the texture and flavor of the yogurt, then quickly cool the fermentation matrix to below 42°C, add a composite strain of thermophilic Streptococcus and bulgaricus (the mass ratio of thermophilic Streptococcus and bulgaricus in the starter is 1:1), and ferment at 40°C for 7 hours to promote the coagulation and formation of the yogurt and produce acid and aroma. After the yogurt fermentation is completed, refrigerate and post-ripen at 4°C for 24 hours to further enhance the aroma through the post-ripening process and improve the taste and flavor of the yogurt.

[0038] Example 2

[0039] This embodiment provides a method for preparing mulberry macadamia nut plant-based fermented yogurt, comprising the following steps:

[0040] S1. Select fresh mulberries that are moderately mature and not spoiled or rotten as raw materials, remove the stems, wash, and pulp them, boil them for 0.5 minutes, and cool them to obtain mulberry pulp;

[0041] S2. Wash the macadamia kernels and bake them at 120°C for 6 min, pulp them at a material-liquid ratio of 1:3, filter and remove the residue, and heat them at 65°C for 5 min to obtain macadamia milk;

[0042] S3. The mulberry pulp, macadamia nut milk, chlorella, sucrose, pectin, and propylene glycol alginate were mixed in a mass ratio of 8:78:0.3:4:2:0.05, and then homogenized in a high-speed homogenizer at 8000r / min for 0.5min to obtain a fermentation matrix;

[0043] S4. Sterilize the fermentation matrix at 90°C for 3 minutes to ensure sufficient sterilization without affecting the texture and flavor of the yogurt, then quickly cool the fermentation matrix to below 42°C, then add a composite strain of thermophilic Streptococcus and bulgaricus (the mass ratio of thermophilic Streptococcus and bulgaricus in the starter is 1:1), and ferment at 40°C for 7 hours to promote the coagulation and formation of the yogurt and the production of acid and aroma. After the yogurt fermentation is completed, refrigerate and post-ripen at 4°C for 24 hours. The post-ripening process further enhances the aroma and improves the taste and flavor of the yogurt.

[0044] Example 3

[0045] This embodiment provides a method for preparing mulberry macadamia nut plant-based fermented yogurt, comprising the following steps:

[0046] S1. Selecting fresh mulberries that are moderately mature and not spoiled or rotten as raw materials, removing the stems, washing, beating, boiling for 2 minutes and cooling to obtain mulberry pulp;

[0047] S2. Wash the macadamia kernels and bake them at 135°C for 12 min, beat them into pulp at a material-liquid ratio of 1:3, filter and remove the residue, and heat them at 75°C for 15 min to obtain macadamia milk;

[0048] S3. The mulberry pulp, macadamia nut milk, chlorella, sucrose, pectin, and propylene glycol alginate were mixed in a mass ratio of 12:82:0.5:6:4:2, and homogenized in a high-speed homogenizer at 12000r / min for 1.5min to obtain a fermentation matrix;

[0049] S4. sterilize the fermentation matrix at 95°C for 6 minutes to ensure sufficient sterilization without affecting the texture and flavor of the yogurt, then quickly cool the fermentation matrix to below 42°C, add a composite strain of thermophilic Streptococcus and bulgaricus (the mass ratio of thermophilic Streptococcus and bulgaricus in the starter is 1:1), and ferment at 40°C for 7 hours to promote the coagulation and formation of the yogurt and the production of acid and aroma. After the yogurt fermentation is completed, refrigerate and post-ripen at 4°C for 24 hours to further enhance the aroma through the post-ripening process and improve the taste and flavor of the yogurt.

[0050] Comparative Example 1

[0051] The preparation method of this comparative example is the same as that of Example 1, except that mulberry juice is not added.

[0052] Comparative Example 2

[0053] The preparation method of this comparative example is the same as that of Example 1, except that Chlorella pyrenoidosa is not added.

[0054] Experimental Example 1

[0055] With reference to T / WSJD 12-2020 "Plant Protein Beverage Plant Yogurt", 10 food professionals, 5 men and 5 women, were selected to form a sensory evaluation team. According to Table 1, a sensory evaluation was conducted on the color, flavor, taste, and texture of the yogurt, with 20 points for color, 30 points for smell, 30 points for taste, and 20 points for texture, with a full score of 100 points.

[0056] The sensory scores of each embodiment and comparative example are shown in Table 2.

[0057] Table 1 Sensory scoring criteria for yogurt

[0058]

[0059] Table 2

[0060] project Color Flavor Taste Organization Status Total score Example 1 excellent excellent excellent excellent 93.9 Example 2 excellent excellent excellent excellent 90.2 Example 3 excellent excellent excellent excellent 91.8 Comparative Example 1 good Difference good Difference 81.5 Comparative Example 2 good good Difference Difference 82.9

[0061] Experimental Example 2

[0062] Determination of yogurt's physical and chemical indicators, microbiological indicators and antioxidant capacity.

[0063] (1) Determination of physical and chemical indicators

[0064] pH value determination: Use PHS-3TC digital pH meter to determine.

[0065] Acidity determination: Determined according to the second method pH meter method in GB 5009.239-2016 "National Food Safety Standard Determination of Acidity in Foods".

[0066] Protein determination: Protein determination is based on GB 5009.5-2016 “National Food Safety Standard Determination of Protein in Food”.

[0067] Water holding capacity determination:

[0068] Refer to the method of Tang Muguo et al. and make some modifications. Take 20mL of yogurt and put it into a centrifuge tube. The mass of the centrifuge tube is M1, and the total mass after adding yogurt is M2. Centrifuge at 4000r / min for 10min, let stand for 10min, and remove the supernatant. The remaining mass is M3. Water holding capacity calculation formula:

[0069]

[0070] Where:

[0071] M1——the mass of centrifuge tube;

[0072] M2——total mass of yogurt;

[0073] M3 – the remaining mass after removing the supernatant.

[0074] (2) Determination of microbial indicators

[0075] ① Escherichia coli determination

[0076] Escherichia coli is determined in accordance with GB 4789.3-2016 “National Food Safety Standard Food Microbiology Examination Coliform Count”.

[0077] ②Salmonella determination

[0078] Salmonella is determined in accordance with GB 4789.4-2016 "National Food Safety Standard Food Microbiology Examination Salmonella Examination".

[0079] ③ Staphylococcus aureus assay

[0080] Staphylococcus aureus was determined according to GB 4789.10-2016 “National Food Safety Standard Food Microbiology Examination Staphylococcus aureus Examination”.

[0081] (3) Antioxidant capacity determination

[0082] The method for determining the antioxidant activity of yogurt was referred to by Duan Boan et al., with slight modifications. 1g of yogurt and 1g of yogurt without Chlorella pyrenoidosa and mulberries (control group) were diluted 10 times with anhydrous ethanol for later use.

[0083] Determination of DPPH free radical scavenging ability:

[0084] Accurately measure 0.0197g of DPPH, use 95% anhydrous ethanol to dissolve it in a 500mL volumetric flask to obtain a DPPH-ethanol solution with a concentration of 0.1mmol / L. Take 2.0mL of diluted yogurt and 2.0mL of 0.1mmol / L DPPH-ethanol solution, mix them evenly, and react them in the dark at room temperature for 30 minutes, and finally measure its absorbance at a wavelength of 517nm. The diluted yogurt is the control group. Repeat the measurement 3 times and take the average value of the results. DPPH clearance rate is calculated according to formula (1).

[0085] DPPH free radical scavenging rate (%) = [1- (A i -A j ) / A0]×100……………… (1)

[0086] Where: A i It is the absorbance value of 2 mL DPPH-ethanol solution and 2 mL diluted yogurt;

[0087] A j It is the absorbance value of 2.0mL 95% anhydrous ethanol and 2.0mL diluted yogurt;

[0088] A0 is the absorbance of 2 mL DPPH-ethanol solution and 2.0 mL 95% anhydrous ethanol.

[0089] Determination of hydroxyl radical scavenging ability:

[0090] Add 2.0mL 9mmol / L FeSO4, 2.0mL 9mmol / L salicylic acid and 2.0mL diluted yogurt into a test tube, then add 2.0mL 8.8mmol / L H2O2 solution to start the reaction, react at 37℃ for 30min, and measure the absorbance at 510nm. The blank sample is replaced by distilled water. The diluted yogurt is the control group. Repeat the measurement 3 times and take the average value. The hydroxyl radical scavenging rate is calculated using formula (2).

[0091] Hydroxyl radical scavenging rate (%) = [A0-(A x -A x0 )] / A0×100…………………(2)

[0092] Where: A x is the absorbance of diluted yogurt; A0 is the absorbance of blank control sample; A x0 The background absorbance value of H2O2 replaced by water.

[0093] The parameters of the embodiments and comparative examples are shown in Table 3.

[0094] Table 3

[0095]

[0096]

[0097] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing mulberry and macadamia nut plant-based fermented yogurt, characterized in that: The following steps are involved: S1. Pre-treating, pulping, boiling and cooling mulberries to obtain mulberry pulp; S2. baking, beating, filtering and heating the macadamia nuts in sequence to obtain macadamia nut milk; S3. mixing mulberry pulp, macadamia nut milk, chlorella pyrenoidosa, sucrose, pectin, and propylene glycol alginate to obtain a fermentation matrix; S4. The fermentation substrate is sterilized, cooled, fermented, and refrigerated to obtain mulberry and macadamia plant-based fermented yogurt.

2. The preparation method according to claim 1, characterized in that: The baking temperature in S2 is 120-135° C. and the baking time is 6-12 minutes.

3. The preparation method according to claim 1, characterized in that: The solid-liquid ratio of pulping in S2 is 1:(2-4).

4. The preparation method according to claim 1, characterized in that: The heating temperature in S2 is 65-75° C. and the heating time is 5-15 min.

5. The preparation method according to claim 1, characterized in that: The mass ratios of mulberry pulp, macadamia nut milk, chlorella, sucrose, pectin and propylene glycol alginate in S3 are (8-12):(78-82):(0.3-0.5):(4-6):(2-4):(0.05-2).

6. The preparation method according to claim 1, characterized in that: The homogenization speed in S3 is 8000-12000 r / min, and the time is 0.5-1.5 min.

7. The preparation method according to claim 1, characterized in that: The sterilization in S4 is carried out by high temperature sterilization, the sterilization temperature is 90-95° C., and the time is 3-6 minutes.

8. The preparation method according to claim 1, characterized in that: The fermentation agent used in the S4 fermentation process is a composite strain of thermophilic Streptococcus and bulgaricus Lactobacillus; The mass ratio of thermophilic streptococcus to bulgaricus lactobacillus in the fermentation agent is 1:1; The addition amount of the leavening agent is 3% of the mass of the fermentation substrate.

9. The preparation method according to claim 8, characterized in that: The fermentation temperature is 40°C and the fermentation time is 7 hours.

10. The preparation method according to claim 1, characterized in that: The temperature of the S4 refrigerated ripening is 4° C. and the time is 24 hours.

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