A set-type oat yogurt prepared by a stirring process and a method of preparing the same

Abstract

The application provides a set-type oat yogurt prepared by a stirring process and a preparation method thereof, and the raw materials of the set-type oat yogurt by mass percentage include: oat powder, white granulated sugar, plant protein, plant fat, a stabilizer, an emulsifier and a ferment; wherein, the plant fat has a freezing point of greater than or equal to 20 DEG C; the stabilizer has a gel point of less than or equal to 30 DEG C; and the stabilizer includes 0.03% to 0.05% gellan gum and 0.1% to 0.2% agar. The application also provides a preparation method of the above-mentioned oat yogurt, and the method is used to obtain the set-type oat yogurt under a stirring process. By adding the plant fat with a high freezing point and the stabilizer, the application solves the problem that the weak gel after fermentation of the oat yogurt leads to a thin taste of the product and the set-type oat yogurt cannot be realized, and improves the overall fat taste and smoothness of the product.

Description

Technical Field

[0001] This invention belongs to the food field, specifically relating to a set-type oat yogurt prepared by a stirring process and its preparation method. Background Technology

[0002] Conventional oat yogurt production often suffers from low firmness and poor shelf-life stability. Furthermore, due to the weak gelling properties of oat protein, fermented oat yogurt often results in a thin texture and an inability to achieve the desired set-like consistency.

[0003] The current method for preparing set-type oat yogurt involves first mixing the ingredients, then filling the packaging, and finally allowing it to ferment in the packaging. This requires a separate fermentation room, and the yogurt is then transferred to a cold storage after fermentation. This wastes production space and manpower. Furthermore, the conventional yogurt fermentation temperature is approximately 42-45℃, and the ripening process after cooling takes a very long time. Summary of the Invention

[0004] To address the above problems, this invention provides a set-type oat yogurt prepared using a stirring process and its preparation method.

[0005] The first aspect of this invention provides a set-type oat yogurt prepared by a stirring process. The raw materials of the set-type oat yogurt, by weight, include: 8%-20% oat flour, 2%-15% white sugar, 0-10% plant protein, 5%-15% vegetable oil, stabilizer, 0.05%-0.3% emulsifier, and starter culture.

[0006] The solidification point of the vegetable oil is ≥20℃;

[0007] The stabilizer has a gel point ≤30℃; the stabilizer comprises 0.03%-0.05% gellan gum and 0.1%-0.2% agar.

[0008] The oat yogurt provided by this invention is a set-type yogurt produced using a stirring process.

[0009] According to a specific embodiment of the present invention, the oat flour is enzymatically hydrolyzed oat flour;

[0010] Preferably, the enzyme used in the enzymatic hydrolysis of oat flour includes one or more of amylase, saccharifying enzyme, cellulase and protease; more preferably, it is amylase.

[0011] According to a specific embodiment of the present invention, the raw material further includes a sweetener, which includes one or more of fructose, glucose, steviol glycosides, sucralose, cyclamate, acesulfame potassium, erythritol, maltitol, aspartame, neotame, and xylitol.

[0012] Preferably, the sweetness of the oat yogurt (including the total sweetness of white sugar and sweeteners) converted to sucrose sweetness is 2%-15%;

[0013] More preferably, the sweetness of the oat yogurt, converted to sucrose sweetness, is 5%-10%.

[0014] According to a specific embodiment of the present invention, the fermenting agent includes one or more of the following: Lactobacillus acidophilus, Bifidobacterium lactis, Bifidobacterium longum, Lactobacillus helveticus, Lactobacillus casei, Lactobacillus rhamnosus GG, Streptococcus thermophilus, and Lactobacillus bulgaricus.

[0015] Preferably, the amount of starter culture is 0.1 U to 0.5 U per kilogram of fermented milk raw material; preferably, the viable bacteria content after fermentation reaches 10. 6 CFU / g or higher.

[0016] According to a specific embodiment of the present invention, the plant protein comprises a soy-based raw material; preferably, the soy-based raw material comprises one or more of soybeans, black beans, peas, and broad beans. Preferably, the amount of plant protein added is 2%-5%.

[0017] According to a specific embodiment of the present invention, preferably, the mass ratio of gellan gum to agar is 1:5-1:3.

[0018] Oat protein is a weak gelling protein. Even when it reaches the isoelectric point, the overall texture of the product is thin and cannot achieve the gel characteristics of milk-based proteins. This invention achieves a thick texture and solidified texture by combining high-freezing-point vegetable oils with low-freezing-point colloids.

[0019] This invention achieves the coagulation state and delicate texture of low-temperature yogurt using high-freezing-point vegetable oils. However, considering that the product may be left at room temperature for several hours during sales, purchase, and consumption, choosing vegetable oils with a freezing point ≥20℃ means that coconut oil will slowly melt after being left at room temperature for a period of time, resulting in a gradually thinner product texture. This invention further protects the product texture by using a combination of stabilizers including gellan gum and agar, ensuring a thick texture and coagulation state after being left at room temperature for a period of time.

[0020] The stabilizer used in this invention has the following advantages: gellan gum has excellent suspending properties and is suitable as a cold gel colloid for this invention. However, since the oat yogurt provided by this invention is a fermented product, excessive addition of gellan gum will affect fermentation and damage the product texture. Therefore, the amount of gellan gum added should not be too high. Thus, agar is added in addition. Agar has excellent gelling properties, but excessive addition will result in poor taste and a heavy gelling sensation. Therefore, by combining agar and gellan gum according to the preferred technical solution of this invention and controlling the amount added and the ratio of the two, oat yogurt in a set state with a good taste can be achieved.

[0021] According to a specific embodiment of the present invention, the emulsifier comprises one or a combination of two or more of diacetyl tartrate mono- and diglycerides, phospholipids, monoglycerides, and sucrose fatty acid esters. Preferably, the amount of the emulsifier is 0.1%-0.2%.

[0022] According to a specific embodiment of the present invention, the vegetable oil includes coconut oil and / or palm oil. Preferably, the amount of vegetable oil added is 5%-8%. The present invention uses coconut oil, palm oil, and other raw materials to improve the hardness of the set oat yogurt prepared by the stirring process after ripening at 4-6°C, a feature that has not been reported to date.

[0023] According to a specific embodiment of the present invention, the pH value of the oat yogurt is 4.8-5.0.

[0024] A second aspect of the present invention provides a method for preparing the oat yogurt, the method comprising the following steps: mixing, degassing, homogenizing, pasteurizing, fermenting, demulsifying, and filling;

[0025] Preferably, the homogenization conditions are: homogenization temperature 50℃-60℃, homogenization pressure 30-50 / 170-190 bar;

[0026] Preferably, the fermentation is terminated when the pH reaches 4.8-5.0. Preferably, the method further includes cooling the fermented milk to 30-35°C after demulsification via plate heat exchanger.

[0027] Preferably, the filling is carried out after the fermented milk has been demulsified and cooled to 30-35°C by plate heat exchanger.

[0028] Preferably, the method further includes a step of fermenting and then refrigerating at 4-6°C for post-fermentation maturation.

[0029] According to a specific embodiment of the present invention, the above preparation method may include the following specific steps:

[0030] (1) Preparation: Add enzymatically hydrolyzed oat flour, white sugar, broad bean protein, gellan gum, agar, coconut oil, and diacetyl tartaric acid mono- and diglycerides to water. Stir the mixture at 60℃-75℃ for 30-60 minutes, then add water to bring the volume to 1kg to obtain the prepared milk.

[0031] (2) Deaeration: Deaerate the milk mixture obtained in step (1).

[0032] (3) Homogenization: After degassing, the gas enters the homogenization system for homogenization. The homogenization temperature is 60℃ and the homogenization pressure is 30 / 180 bar.

[0033] (4) Pasteurization: After homogenization, the mixture is put into the sterilization system for pasteurization at a temperature of 95°C for 300 seconds.

[0034] (5) Fermentation: Cool the sample treated in step (4) to 43°C, add 0.1-0.5U of starter culture (Streptococcus thermophilus, Lactobacillus bulgaricus), and ferment at 43°C until the pH is 4.8-5.0, then stop fermentation.

[0035] (6) Cooling: After the qualified fermented milk is broken, it is cooled to 30-35℃ by plate heat exchange.

[0036] (7) Filling: Fill the product obtained in step (6) and place it in a refrigerator at 4-6℃ for ripening.

[0037] The method for preparing yogurt using the stirring process provided by this invention involves direct fermentation in a fermentation tank. Compared with the conventional settling process, this invention saves manpower and space for post-filling sorting and pushing into and out of the fermentation chamber. At the same time, the filling temperature of this invention is 30-35℃, while the fermentation temperature of conventional settling fermented milk is 40-45℃. Therefore, the time for this invention to cool down to the post-ripening temperature (4-6℃) after filling is also shorter.

[0038] This invention controls the fermentation endpoint to pH = 4.8-5.0, which is beneficial to the product's flavor and gelation properties.

[0039] (1) Regarding product taste: If the pH fermentation reaches the isoelectric point of the milk-based yogurt at pH ≤ 4.6, the product will have a noticeable fermented sour taste, resulting in low overall likability. Furthermore, continued fermentation will cause gel protein precipitation, resulting in a noticeable powdery texture. If the pH > 5.0, the yogurt fermentation flavor will not be obvious. Therefore, the present invention controls the fermentation endpoint to pH = 4.8-5.0, which can effectively avoid the above problems.

[0040] (2) Regarding the gel properties of the product: pH=5.0 is the isoelectric point of oat protein. Under this condition, the surface charge of oat protein is the lowest, the protein particle size is large, and it is easy to precipitate. At the same time, enzymatically hydrolyzed oats contain a lot of dextrins, which are also easy to precipitate. This invention ensures the flavor and gel properties of the product while further ensuring the texture of the product through a specific stabilization system.

[0041] The beneficial effects of this invention are:

[0042] 1. The oat yogurt produced by this invention is a set oat yogurt produced by a stirring process. The stirring process involves fermentation in a fermentation tank, followed by demulsification and then filling into packaging. Compared with the conventional set process, it does not require a separate fermentation room, thus saving space and manpower.

[0043] 2. The set-type oat yogurt produced by the stirring process proposed in this invention has a lower fermentation temperature compared with the conventional set-type process, thus requiring a shorter time for the fermented milk to cool and mature after breaking down.

[0044] 3. This invention improves the gelling properties of oat protein by controlling the pH value (4.8-5.0) at the end of fermentation, and at the same time solves the problem of poor flavor in oat fermentation.

[0045] 4. This invention solves the problem of thin texture and inability to achieve set oat yogurt due to weak gelation after fermentation by adding high-freezing-point vegetable oil (freezing point ≥20℃) and a stabilizer containing cold gel (0.3-0.5‰ gellan gum, 1-2‰ agar, gellan gum: agar = 1:5-1:3, gel point ≤30℃). It also improves the overall fat texture and smoothness of the product.

[0046] 5. By rationally combining vegetable oils and stabilizers, the present invention produces a set-type yogurt product that can maintain a thick texture and settling state after being left at room temperature for a period of time.

[0047] 6. By controlling the filling temperature (30-35℃), this invention avoids the situation where the filling pressure is too low, causing the colloid to break down and affecting the product hardness, and also avoids the situation where the temperature is too high, causing continuous fermentation or even inactivation of the bacteria.

[0048] By selecting the right oils, choosing the right types of stabilizing systems and controlling their proportions, controlling the pH value at the fermentation endpoint, and controlling the filling temperature, the final product exhibits a good solidification state after refrigeration and ripening, solving the problem of the thin texture of conventional oat yogurt, and also has a good flavor and smooth texture. Detailed Implementation

[0049] In order to provide a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention will now be described in detail below, but it should not be construed as limiting the scope of implementation of the present invention.

[0050] Example 1

[0051] This embodiment provides a method for preparing set-type oat yogurt using a stirring process, which includes the following steps:

[0052] (1) Preparation: Heat 734g of water to 70℃, add 105g of enzymatically hydrolyzed oat flour, 50g of white sugar, 35g of broad bean protein, 0.3g of gellan gum, 1g of agar, 74g of refined coconut oil, and 1g of diacetyl tartaric acid mono- and diglycerides. Stir the mixture at 70℃ for 40 minutes, then add water to bring the volume to 1kg to obtain the prepared milk.

[0053] (2) Degassing: The milk prepared in step (1) is degassed at 65°C and 18MPa pressure.

[0054] (3) Homogenization: After degassing, the gas enters the homogenization system for homogenization. The homogenization temperature is 60℃ and the homogenization pressure is 30 / 180 bar.

[0055] (4) Pasteurization: After homogenization, the mixture is put into the sterilization system for pasteurization at a temperature of 95°C for 300 seconds.

[0056] (5) Fermentation: Cool the sample treated in step (4) to 43°C, add 0.1U of fermentation agent (Streptococcus thermophilus, Lactobacillus bulgaricus), and ferment at 43°C until pH = 4.8, then stop fermentation.

[0057] (6) Cooling: After the qualified fermented milk is broken, it is cooled to 30°C by plate heat exchange.

[0058] (7) Filling: Fill the product obtained in step (6) and place it in a refrigerated container at 4-6℃ for 24 hours to ripen.

[0059] The viable bacteria count in the set oat yogurt prepared in this embodiment was measured to be 1.89 × 10⁻⁶. 8 CFU / g.

[0060] Example 2

[0061] This embodiment provides a method for preparing set-type oat yogurt using a stirring process, which includes the following steps:

[0062] (1) Preparation: Heat 722g of water to 70℃, add 135g of enzymatically hydrolyzed oat flour, 55g of white sugar, 20g of soy protein, 0.4g of gellan gum, 2g of agar, 64g of refined palm oil, and 1.5g of diacetyl tartaric acid mono- and diglycerides. Stir the mixture at 70℃ for 40 minutes, then add water to bring the volume to 1kg to obtain the prepared milk.

[0063] (2) Degassing: The milk prepared in step (1) is degassed at 65°C and 18MPa pressure.

[0064] (3) Homogenization: After degassing, the gas enters the homogenization system for homogenization. The homogenization temperature is 60℃ and the homogenization pressure is 30 / 180 bar.

[0065] (4) Pasteurization: After homogenization, the mixture is put into the sterilization system for pasteurization at a temperature of 95°C for 300 seconds.

[0066] (5) Fermentation: Cool the sample treated in step (4) to 43°C, add 0.1U of fermentation agent (Streptococcus thermophilus, Lactobacillus bulgaricus), and ferment at 43°C until pH = 4.9, then stop fermentation.

[0067] (6) Cooling: After the qualified fermented milk is broken, it is cooled to 33°C by plate heat exchange.

[0068] (7) Filling: Fill the product obtained in step (6) and place it in a 4-6℃ refrigerator for 20 hours to ripen.

[0069] The viable bacteria count in the set oat yogurt prepared in this embodiment was measured to be 2.63 × 10⁻⁶. 8 CFU / g.

[0070] Example 3

[0071] This embodiment provides a method for preparing set-type oat yogurt using a stirring process, which includes the following steps:

[0072] (1) Preparation: Heat 698g of water to 70℃, add 155g of enzymatically hydrolyzed oat flour, 60g of white sugar, 30g of soy protein, 0.5g of gellan gum, 1.5g of agar, 54g of refined coconut oil, and 1g of diacetyl tartaric acid mono- and diglycerides. Stir the mixture at 70℃ for 40 minutes, then add water to bring the volume to 1kg to obtain the prepared milk.

[0073] (2) Degassing: The milk prepared in step (1) is degassed at 65°C and 18MPa pressure.

[0074] (3) Homogenization: After degassing, the gas enters the homogenization system for homogenization. The homogenization temperature is 60℃ and the homogenization pressure is 30 / 180 bar.

[0075] (4) Pasteurization: After homogenization, the mixture is put into the sterilization system for pasteurization at a temperature of 95°C for 300 seconds.

[0076] (5) Fermentation: Cool the sample treated in step (4) to 43°C, add 0.1U of fermentation agent (Streptococcus thermophilus, Lactobacillus bulgaricus), and ferment at 43°C until pH = 5.0, then stop fermentation.

[0077] (6) Cooling: After the qualified fermented milk is broken, it is cooled to 35°C by plate heat exchange.

[0078] (7) Filling: Fill the product obtained in step (6) and place it in a refrigerated container at 4-6℃ for 15 hours to ripen.

[0079] The viable bacteria count in the set oat yogurt prepared in this embodiment was measured to be 1.99 × 10⁻⁶. 8 CFU / g.

[0080] Comparative Example 1

[0081] This comparative example provides a method for preparing set-type oat yogurt, which includes the following steps:

[0082] (1) Preparation: Heat 734g of water to 70℃, add 105g of enzymatically hydrolyzed oat flour, 50g of white sugar, 35g of broad bean protein, 0.3g of gellan gum, 1g of agar, 74g of refined coconut oil, and 1g of diacetyl tartaric acid mono- and diglycerides. Stir the mixture at 70℃ for 40 minutes, then add water to bring the volume to 1kg to obtain the prepared milk.

[0083] (2) Degassing: The milk prepared in step (1) is degassed at 65°C and 18MPa pressure.

[0084] (3) Homogenization: After degassing, the gas enters the homogenization system for homogenization. The homogenization temperature is 60℃ and the homogenization pressure is 30 / 180 bar.

[0085] (4) Pasteurization: After homogenization, the mixture is put into the sterilization system for pasteurization at a temperature of 95°C for 300 seconds.

[0086] (5) Fermentation: Cool the sample treated in step (4) to 43°C, add 0.1U of starter culture (Streptococcus thermophilus, Lactobacillus bulgaricus), and ferment at 43°C until pH = 5.5, then stop fermentation.

[0087] (6) Cooling: After the qualified fermented milk is broken, it is cooled to 30°C by plate heat exchange.

[0088] (7) Filling: Fill the product obtained in step (6) and place it in a refrigerator at 4-6℃ for ripening.

[0089] The viable bacteria count in the set oat yogurt prepared in this comparative example was measured to be 2.51 × 10⁻⁶. 8 CFU / g.

[0090] Comparative Example 2

[0091] This comparative example provides a method for preparing set-type oat yogurt, which includes the following steps:

[0092] (1) Preparation: Heat 734g of water to 70℃, add 105g of enzymatically hydrolyzed oat flour, 50g of white sugar, 35g of broad bean protein, 0.3g of gellan gum, 1g of agar, 74g of refined coconut oil, and 1g of diacetyl tartaric acid mono- and diglycerides. Stir the mixture at 70℃ for 40 minutes, then add water to bring the volume to 1kg to obtain the prepared milk.

[0093] (2) Degassing: The milk prepared in step (1) is degassed at 65°C and 18MPa pressure.

[0094] (3) Homogenization: After degassing, the gas enters the homogenization system for homogenization. The homogenization temperature is 60℃ and the homogenization pressure is 30 / 180 bar.

[0095] (4) Pasteurization: After homogenization, the mixture is put into the sterilization system for pasteurization at a temperature of 95°C for 300 seconds.

[0096] (5) Fermentation: Cool the sample treated in step (4) to 43°C, add 0.1U of fermentation agent (Streptococcus thermophilus, Lactobacillus bulgaricus), and ferment at 43°C until pH=4.6, then stop fermentation.

[0097] (6) Cooling: After the qualified fermented milk is broken, it is cooled to 30°C by plate heat exchange.

[0098] (7) Filling: Fill the product obtained in step (6) and place it in a refrigerator at 4-6℃ for ripening.

[0099] The viable bacteria count in the set oat yogurt prepared in this comparative example was measured to be 2.07 × 10⁻⁶. 8 CFU / g.

[0100] Comparative Example 3

[0101] This comparative example provides a method for preparing set-type oat yogurt, which includes the following steps:

[0102] (1) Preparation: Heat 734g of water to 70℃, add 105g of enzymatically hydrolyzed oat flour, 50g of white sugar, 35g of broad bean protein, 0.3g of gellan gum, 1g of agar, 74g of rapeseed oil, and 1g of diacetyl tartaric acid mono- and diglycerides. Stir the mixture at 70℃ for 40 minutes, then add water to bring the volume to 1kg to obtain the prepared milk.

[0103] (2) Degassing: The milk prepared in step (1) is degassed at 65°C and 18MPa pressure.

[0104] (3) Homogenization: After degassing, the gas enters the homogenization system for homogenization. The homogenization temperature is 60℃ and the homogenization pressure is 30 / 180 bar.

[0105] (4) Pasteurization: After homogenization, the mixture is put into the sterilization system for pasteurization at a temperature of 95°C for 300 seconds.

[0106] (5) Fermentation: Cool the sample treated in step (4) to 43°C, add 0.1U of fermentation agent (Streptococcus thermophilus, Lactobacillus bulgaricus), and ferment at 43°C until pH = 4.8, then stop fermentation.

[0107] (6) Cooling: After the qualified fermented milk is broken, it is cooled to 30°C by plate heat exchange.

[0108] (7) Filling: Fill the product obtained in step (6) and place it in a refrigerator at 4-6℃ for ripening.

[0109] The viable bacteria count in the set oat yogurt prepared in this comparative example was measured to be 2.74 × 10⁻⁶. 8 CFU / g.

[0110] Comparative Example 4

[0111] This comparative example provides a method for preparing set-type oat yogurt, which includes the following steps:

[0112] (1) Preparation: Heat 734g of water to 70℃, add 105g of enzymatically hydrolyzed oat flour, 50g of white sugar, 35g of broad bean protein, 0.3g of gellan gum, 1g of agar, 74g of refined coconut oil, and 1g of diacetyl tartaric acid mono- and diglycerides. Stir the mixture at 70℃ for 40 minutes, then add water to bring the volume to 1kg to obtain the prepared milk.

[0113] (2) Degassing: The milk prepared in step (1) is degassed at 65°C and 18MPa pressure.

[0114] (3) Homogenization: After degassing, the gas enters the homogenization system for homogenization. The homogenization temperature is 60℃ and the homogenization pressure is 30 / 180 bar.

[0115] (4) Pasteurization: After homogenization, the mixture is put into the sterilization system for pasteurization at a temperature of 95°C for 300 seconds.

[0116] (5) Fermentation: Cool the sample treated in step (4) to 43°C, add 0.1U of fermentation agent (Streptococcus thermophilus, Lactobacillus bulgaricus), and ferment at 43°C until pH = 4.8, then stop fermentation.

[0117] (6) Cooling: After the qualified fermented milk is broken, it is cooled to 40°C by plate heat exchange.

[0118] (7) Filling: Fill the product obtained in step (6) and place it in a refrigerator at 4-6℃ for ripening.

[0119] The viable bacteria count in the set oat yogurt prepared in this comparative example was measured to be 2.57 × 10⁻⁶. 8 CFU / g.

[0120] Comparative Example 5

[0121] This comparative example provides a method for preparing set-type oat yogurt, which includes the following steps:

[0122] (1) Preparation: Heat 734g of water to 70℃, add 105g of enzymatically hydrolyzed oat flour, 50g of white sugar, 35g of broad bean protein, 0.3g of gellan gum, 1g of agar, 74g of refined coconut oil, and 1g of diacetyl tartaric acid mono- and diglycerides. Stir the mixture at 70℃ for 40 minutes, then add water to bring the volume to 1kg to obtain the prepared milk.

[0123] (2) Degassing: The milk prepared in step (1) is degassed at 65°C and 18MPa pressure.

[0124] (3) Homogenization: After degassing, the gas enters the homogenization system for homogenization. The homogenization temperature is 60℃ and the homogenization pressure is 30 / 180 bar.

[0125] (4) Pasteurization: After homogenization, the mixture is put into the sterilization system for pasteurization at a temperature of 95°C for 300 seconds.

[0126] (5) Fermentation: Cool the sample treated in step (4) to 43°C, add 0.1U of fermentation agent (Streptococcus thermophilus, Lactobacillus bulgaricus), and ferment at 43°C until pH = 4.8, then stop fermentation.

[0127] (6) Cooling: After the qualified fermented milk is broken, it is cooled to 20°C by plate heat exchange.

[0128] (7) Filling: Fill the product obtained in step (6) and place it in a refrigerator at 4-6℃ for ripening.

[0129] The viable bacteria count in the set oat yogurt prepared in this comparative example was measured to be 2.18 × 10⁻⁶. 8 CFU / g.

[0130] Comparative Example 6

[0131] This comparative example provides a method for preparing set-type oat yogurt, which includes the following steps:

[0132] (1) Preparation: Heat 722g of water to 70℃, add 135g of enzymatically hydrolyzed oat flour, 55g of white sugar, 20g of soy protein, 0.4g of gellan gum, 0.8g of agar, 64g of refined palm oil, and 1.5g of diacetyl tartaric acid mono- and diglycerides. Stir the mixture at 70℃ for 40 minutes, then add water to bring the volume to 1kg to obtain the prepared milk.

[0133] (2) Degassing: The milk prepared in step (1) is degassed at 65°C and 18MPa pressure.

[0134] (3) Homogenization: After degassing, the gas enters the homogenization system for homogenization. The homogenization temperature is 60℃ and the homogenization pressure is 30 / 180 bar.

[0135] (4) Pasteurization: After homogenization, the mixture is put into the sterilization system for pasteurization at a temperature of 95°C for 300 seconds.

[0136] (5) Fermentation: Cool the sample treated in step (4) to 43°C, add 0.1U of fermentation agent (Streptococcus thermophilus, Lactobacillus bulgaricus), and ferment at 43°C until pH = 4.9, then stop fermentation.

[0137] (6) Cooling: After the qualified fermented milk is broken, it is cooled to 33°C by plate heat exchange.

[0138] (7) Filling: Fill the product obtained in step (6) and place it in a refrigerator at 4-6℃ for ripening.

[0139] The viable bacteria count in the set oat yogurt prepared in this comparative example was measured to be 2.3 × 10⁻⁶. 8 CFU / g.

[0140] Comparative Example 7

[0141] This comparative example provides a method for preparing set-type oat yogurt, which includes the following steps:

[0142] (1) Preparation: Heat 722g of water to 70℃, add 135g of enzymatically hydrolyzed oat flour, 55g of white sugar, 20g of soy protein, 0.4g of gellan gum, 3g of agar, 64g of refined palm oil, and 1.5g of diacetyl tartaric acid mono- and diglycerides. Stir the mixture at 70℃ for 40 minutes, then add water to bring the volume to 1kg to obtain the prepared milk.

[0143] (2) Degassing: The milk prepared in step (1) is degassed at 65°C and 18MPa pressure.

[0144] (3) Homogenization: After degassing, the gas enters the homogenization system for homogenization. The homogenization temperature is 60℃ and the homogenization pressure is 30 / 180 bar.

[0145] (4) Pasteurization: After homogenization, the mixture is put into the sterilization system for pasteurization at a temperature of 95°C for 300 seconds.

[0146] (5) Fermentation: Cool the sample treated in step (4) to 43°C, add 0.1U of fermentation agent (Streptococcus thermophilus, Lactobacillus bulgaricus), and ferment at 43°C until pH = 4.9, then stop fermentation.

[0147] (6) Cooling: After the qualified fermented milk is broken, it is cooled to 33°C by plate heat exchange.

[0148] (7) Filling: Fill the product obtained in step (6) and place it in a refrigerator at 4-6℃ for ripening.

[0149] The viable bacteria count in the set oat yogurt prepared in this comparative example was measured to be 1.89 × 10⁻⁶. 8 CFU / g.

[0150] Comparative Example 8

[0151] This comparative example provides a method for preparing set-type oat yogurt, which includes the following steps:

[0152] (1) Preparation: Heat 698g of water to 70℃, add 155g of enzymatically hydrolyzed oat flour, 60g of white sugar, 30g of soy protein, 1g of gellan gum, 1.5g of agar, 54g of refined coconut oil, and 1g of diacetyl tartaric acid mono- and diglycerides. Stir the mixture at 70℃ for 40 minutes, then add water to bring the volume to 1kg to obtain the prepared milk.

[0153] (2) Degassing: The milk prepared in step (1) is degassed at 65°C and 18MPa pressure.

[0154] (3) Homogenization: After degassing, the gas enters the homogenization system for homogenization. The homogenization temperature is 60℃ and the homogenization pressure is 30 / 180 bar.

[0155] (4) Pasteurization: After homogenization, the mixture is put into the sterilization system for pasteurization at a temperature of 95°C for 300 seconds.

[0156] (5) Fermentation: Cool the sample treated in step (4) to 43°C, add 0.1U of fermentation agent (Streptococcus thermophilus, Lactobacillus bulgaricus), and ferment at 43°C until pH = 5.0, then stop fermentation.

[0157] (6) Cooling: After the qualified fermented milk is broken, it is cooled to 35°C by plate heat exchange.

[0158] (7) Filling: Fill the product obtained in step (6) and place it in a refrigerator at 4-6℃ for ripening.

[0159] Experimental Example 1

[0160] This experimental example provides evaluation experiments of the products prepared in Examples 1-3 and Comparative Examples 1-8.

[0161] 1. Product sensory testing

[0162] Using Examples 1-3 and Comparative Examples 1-8 as test samples, a sensory evaluation of product preference was conducted, with a maximum score of 5 points. A higher score indicates a higher level of preference for the sample. The evaluation results from 30 professional sensory evaluators are shown in Table 1.

[0163] Table 1 Sensory test results

[0164]

[0165]

[0166] As can be seen from the results in Table 1, the product preference, fat content and fermentation flavor of Examples 1-3 are higher than those of Comparative Examples 1-8. This is mainly because Examples 1-3 were developed in accordance with the requirements of this invention, and the product taste was improved.

[0167] 2. Product hardness test

[0168] Using Examples 1-3 and Comparative Examples 1-8 as test samples, the hardness of the products and samples left at room temperature for 4 hours was tested. The test results are shown in Table 2.

[0169] Table 2 Product Hardness Results

[0170]

[0171] As can be seen from the results in Table 2, the hardness of the products in Examples 1-3 is higher than that of Comparative Examples 1, 3, 5, 6, and 8. Furthermore, after being placed at room temperature for 4 hours, the hardness of the products in Examples 1-3 is well maintained. This indicates that the preparation according to the formulation of Examples 1-3 (especially the combination of coconut oil, palm oil, and specific amounts and proportions of gellan gum and agar) as well as the process and process parameters (control of the pH value at the fermentation endpoint and control of the filling temperature) can well meet the product design requirements.

Claims

1. A set-type oat yogurt prepared by a stirring process, wherein the raw materials of the set-type oat yogurt, by weight, include: Oat flour 8%-20%, white sugar 2%-15%, vegetable protein 0-10%, vegetable oil 5%-15%, stabilizer, emulsifier 0.05%-0.3%, leavening agent; The solidification point of the vegetable oil is ≥20℃, and the vegetable oil includes coconut oil and / or palm oil; The stabilizer has a gel point ≤30℃; the stabilizer comprises 0.03%-0.05% gellan gum and 0.1%-0.2% agar, wherein the mass ratio of gellan gum to agar is 1:5-1:3; The pH value of the oat yogurt is 4.8-5.

0.

2. The oat yogurt according to claim 1, wherein, The oat flour is enzymatically hydrolyzed oat flour.

3. The oat yogurt according to claim 2, wherein, The enzymes used in the enzymatic hydrolysis of oat flour include one or more combinations of amylase, cellulase, and protease.

4. The oat yogurt according to claim 3, wherein, The amylase includes saccharifying enzymes.

5. The oat yogurt according to any one of claims 1-4, wherein, The raw material also contains sweeteners, including one or more of fructose, glucose, steviol glycosides, sucralose, cyclamate, acesulfame potassium, erythritol, maltitol, aspartame, neotame, and xylitol.

6. The oat yogurt according to claim 5, wherein, The sweetness of the oat yogurt, when converted to sucrose sweetness, is 2%-15%.

7. The oat yogurt according to claim 6, wherein, The sweetness of the oat yogurt, when converted to sucrose sweetness, is 5%-10%.

8. The oat yogurt according to any one of claims 1-4 and 6-7, wherein, The starter culture includes one or more of the following: Lactobacillus acidophilus, Bifidobacterium lactis, Bifidobacterium longum, Lactobacillus helveticus, Lactobacillus casei, Lactobacillus rhamnosus, Streptococcus thermophilus, and Lactobacillus bulgaricus.

9. The oat yogurt according to claim 8, wherein, The dosage of starter culture is 0.1 U to 0.5 U per kilogram of fermented milk raw material.

10. The oat yogurt according to claim 8, wherein, The live bacteria content after fermentation reaches 10. 6 CFU / g or higher.

11. The oat yogurt according to claim 5, wherein, The starter culture includes one or more of the following: Lactobacillus acidophilus, Bifidobacterium lactis, Bifidobacterium longum, Lactobacillus helveticus, Lactobacillus casei, Lactobacillus rhamnosus, Streptococcus thermophilus, and Lactobacillus bulgaricus.

12. The oat yogurt according to claim 11, wherein, The dosage of starter culture is 0.1 U to 0.5 U per kilogram of fermented milk raw material.

13. The oat yogurt according to claim 11, wherein, The live bacteria content after fermentation reaches 10. 6 CFU / g or higher.

14. The oat yogurt according to any one of claims 1-4, 6-7, and 9-13, wherein, The plant protein includes soybean-based ingredients.

15. The oat yogurt according to claim 14, wherein, The soybean-based raw materials include one or more of soybeans, black beans, peas, and broad beans.

16. The oat yogurt according to claim 5, wherein, The plant protein includes soybean-based ingredients.

17. The oat yogurt according to claim 16, wherein, The soybean-based raw materials include one or more of soybeans, black beans, peas, and broad beans.

18. The oat yogurt according to claim 8, wherein, The plant protein includes soybean-based ingredients.

19. The oat yogurt according to claim 18, wherein, The soybean-based raw materials include one or more of soybeans, black beans, peas, and broad beans.

20. The oat yogurt according to any one of claims 1-4, 6-7, 9-13, and 15-19, wherein, The emulsifier includes one or more of the following: diacetyl tartrate mono- and diglycerides, phospholipids, monoglycerides, and sucrose fatty acid esters.

21. The oat yogurt according to claim 5, wherein, The emulsifier includes one or more of the following: diacetyl tartrate mono- and diglycerides, phospholipids, monoglycerides, and sucrose fatty acid esters.

22. The oat yogurt according to claim 8, wherein, The emulsifier includes one or more of the following: diacetyl tartrate mono- and diglycerides, phospholipids, monoglycerides, and sucrose fatty acid esters.

23. The oat yogurt according to claim 14, wherein, The emulsifier includes one or more of the following: diacetyl tartrate mono- and diglycerides, phospholipids, monoglycerides, and sucrose fatty acid esters.

24. A method for preparing set-type oat yogurt using a stirring process according to any one of claims 1-23, the method comprising the following steps: Processing steps include: material preparation, degassing, homogenization, pasteurization, fermentation, demulsification, filling, and post-ripening.

25. The method according to claim 24, wherein, The homogenization conditions are: homogenization temperature 50℃-60℃, homogenization pressure 30-50 / 170-190 bar.

26. The method of claim 24, wherein, Fermentation is terminated when the pH reaches 4.8-5.

0.

27. The method according to claim 24, wherein, The method also includes cooling the fermented milk to 30-35°C after demulsification via plate heat exchange.

28. The method according to claim 24, wherein, The filling process involves cooling the fermented milk to 30-35°C after demulsification via plate heat exchanger.

29. The method according to claim 24, wherein, The method also includes a step of fermenting and then refrigerating at 4-6℃ for post-fermentation maturation.

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