Instant brown yoghourt and preparation method thereof

Abstract

The invention belongs to the technical field of dairy product processing, and discloses instant brown yoghourt and a preparation method thereof, the instant brown yoghourt comprises the following raw materials: raw milk, reducing sugar and a leavening agent, and the reducing sugar is xylose or L-arabinose. The preparation method of the instant brown yoghurt comprises the following steps: preparing raw materials, proportioning and homogenizing, fermenting, refrigerating, demulsifying and filling. According to the method disclosed by the invention, the reducing sugar and the leavening agent are optimally selected, so that the energy consumption in the production process can be reduced while the browning treatment and fermentation time of the brown yoghurt can be shortened, the purposes of reducing cost and improving efficiency can be achieved, and powerful technical support is provided for large-scale and efficient production of the brown yoghurt.

Description

Technical Field

[0001] The invention relates to the technical field of dairy product processing, in particular to a quick-made brown yogurt and a preparation method thereof. Background Art

[0002] Brown yogurt, also known as "baked yogurt" or "cooked yogurt", is deeply loved by consumers for its attractive color, rich flavor and rich nutritional value. Compared with traditional yogurt, brown yogurt has an additional browning step in the production process. Specifically, before the yogurt base is fermented, the reducing sugar and milk protein undergo a browning process to undergo the Maillard reaction, thus forming a special dairy product with a unique brown appearance and a rich, sweet and caramel flavor.

[0003] Although brown yogurt has a unique color and flavor, there is still a significant problem in its production process: the browning time and fermentation time are too long. This not only slows down the production speed and increases the production cycle, but also greatly increases energy consumption and reduces the overall production efficiency and economic benefits.

[0004] In order to shorten the browning time, the prior art has made many improvements, mainly including increasing the browning reaction temperature, adding catalysts and increasing the raw material concentration. However, the above effects are not ideal. For example, increasing the reaction temperature can shorten the browning time, but it will also bring about defects such as quality degradation, nutritional loss and the production of harmful substances; while adding catalysts and increasing the raw material concentration will also increase the cost of raw materials, poor taste and increased process difficulty. Therefore, there is an urgent need to improve the brown yogurt formula and its process in the art to solve the defects of the prior art. Summary of the invention

[0005] The invention aims to provide a quick-made brown yogurt, the raw materials of which are simple and easily available. The raw materials of the invention can greatly shorten the preparation time of the brown yogurt, and the yogurt has strong practicability.

[0006] The technical solution adopted to achieve the purpose of the present invention is:

[0007] A quick-made brown yogurt comprises the following raw materials: raw milk, reducing sugar and a starter, wherein the reducing sugar is xylose or L-arabinose.

[0008] Furthermore, the fermentation agent is YO-MIX 381, FD-DVS Premium 5.0 or Yo-C701-F.

[0009] Furthermore, the amount of reducing sugar added is 1-15% of the total weight of the raw materials, and the amount of leavening agent added is 0.01-0.1% of the total weight of the raw materials.

[0010] Another object of the present invention is to provide a method for preparing quick-made brown yogurt, which is easy to prepare and convenient for large-scale production.

[0011] The technical solution adopted to achieve another purpose of the present invention is:

[0012] The invention discloses a method for preparing quick brown yogurt, which comprises the following steps: taking raw materials for standby use, and then sequentially performing batching, homogenization, browning and sterilization, fermentation, refrigeration, demulsification and filling.

[0013] Specifically, step S1, raw material preparation, preparing raw milk, reducing sugar and fermentation agent for use, wherein the reducing sugar is xylose or L-arabinose; the fermentation agent is YO-MIX 381, FD-DVS Premium 5.0 or Yo-C701-F;

[0014] Step S2, batching and homogenizing, adding reducing sugar to raw milk, stirring for 10 to 20 minutes until fully dissolved, and then homogenizing to obtain a uniform base material system;

[0015] Step S3, browning and sterilization, heating the base material system to carry out heat preservation and browning, and sterilizing at the same time, cooling after the browning is completed to obtain a browning emulsion;

[0016] Step S4, fermentation, adding a starter to the browning emulsion, and then heating for fermentation;

[0017] Step S5, refrigeration, demulsification and filling, after the fermentation is completed, the temperature is quickly reduced to 3-5°C for refrigeration and post-ripening, and then demulsification and filling are performed in sequence.

[0018] Furthermore, in step S2, the homogenization temperature is 60-70°C, the homogenization pressure is 18-22 MPa, and the homogenization time is 2.5-5 min.

[0019] Furthermore, in step S3, the base material system is heated to 85-95° C. and kept warm for 1-3 hours for browning and sterilization.

[0020] Furthermore, in step S4, the fermentation temperature is 40-45°C.

[0021] Furthermore, in step S5, the demulsification step is specifically: stirring the fermented yogurt at a stirring speed of 200 to 400 rpm for 2 to 4 minutes.

[0022] The beneficial effects of the present invention are as follows: the present invention optimizes the selection of raw materials, selects xylose or L-arabinose which is simple, easy to obtain and has good reaction activity, can participate in the Maillard reaction faster, thereby shortening the browning time; at the same time, selects a suitable fermentation agent for fermentation, further shortening the preparation time of brown yogurt. The present invention can shorten the browning treatment and fermentation time of brown yogurt by optimizing the selection of reducing sugar and fermentation agent, and can also reduce the energy consumption in the production process to achieve the purpose of reducing costs and increasing efficiency, and provide strong technical support for the large-scale and efficient production of brown yogurt. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a comparison chart of the browning appearance records in Experiment 1 of the present invention.

[0024] Figure 2 This is the acidity monitoring curve diagram in Experiment 3 of the present invention.

[0025] Figure 3 This is the acidity monitoring curve diagram in Experiment 4 of the present invention.

[0026] Figure 4 This is a comparison chart of appearance records before and after fermentation in Experiment 4 of the present invention. DETAILED DESCRIPTION

[0027] The examples are provided to better illustrate the present invention, but the present invention is not limited to the examples. Therefore, those skilled in the art may make non-essential improvements and adjustments to the implementation scheme according to the above invention content, which still fall within the protection scope of the present invention.

[0028] The fermentation agents involved in the present invention are all fermentation agents in the prior art, and the sources of each fermentation agent are as follows: fermentation agent YO-MIX 381, FD-DVS Premium 5.0 and FD-DVS YF-L903 were both purchased from Chr. Hansen; the starter PIONEER was purchased from Beijing Jiarui Fude Food Technology Co., Ltd.; the starter Yo-C701-F was purchased from Hebei Yiran Biotechnology Co., Ltd.; and the starter YC-M950 was purchased from Beijing Ketuo Hengtong Biotechnology Co., Ltd.

[0029] Example 1

[0030] A quick-made brown yogurt comprises the following raw materials: raw milk, reducing sugar and a fermentation agent, wherein the reducing sugar is xylose and the fermentation agent is YO-MIX 381. The amount of reducing sugar added accounts for 1% of the total weight of the raw materials, the amount of the fermentation agent added accounts for 0.01% of the total weight of the raw materials, and the balance is raw milk.

[0031] The preparation method of the above-mentioned quick-made brown yogurt is specifically as follows:

[0032] Step S1, raw material preparation, preparing raw milk, reducing sugar and starter for use.

[0033] Step S2, batching and homogenization, adding reducing sugar to raw milk, stirring for 15 minutes until fully dissolved, and then homogenizing to obtain a uniform base material system; in this step, Homogenization The temperature is 65°C, the homogenization pressure is 20MPa, and the homogenization time is 3min;

[0034] Step S3, browning and sterilization, heating the base material system for browning and sterilization, cooling after browning to obtain a browning emulsion; in this step, heating the base material system to 90°C and keeping it warm for 2.5h to carry out Browning and sterilization;

[0035] Step S4, fermentation, adding a starter to the browning emulsion, and then heating for fermentation;

[0036] Step S5, refrigeration, demulsification and filling, after the fermentation is completed, the temperature is quickly reduced to 4°C for refrigeration and post-ripening, and then demulsification and filling are performed in sequence. Among them, the demulsification step is specifically: the fermented yogurt is stirred at a stirring speed of 350 rpm for 3 minutes.

[0037] Embodiment 2-6

[0038] The preparation methods of Examples 2-6 are exactly the same as those of Example 1, except that the type and amount of reducing sugar and the type and amount of leavening agent are different. The following are the specific raw materials of Examples 2-6.

[0039] Example 2

[0040] A quick-made brown yogurt comprises the following raw materials: raw milk, reducing sugar and a fermentation agent, wherein the reducing sugar is xylose and the fermentation agent is FD-DVS Premium 5.0. Among them, the amount of reducing sugar added accounts for 8% of the total weight of the raw materials, the amount of starter added accounts for 0.05% of the total weight of the raw materials, and the balance is raw milk. Premium5.0 is a direct-injection yogurt starter, which is a composite bacterial strain and mainly includes Lactobacillus bulgaricus and Streptococcus thermophilus.

[0041] Example 3

[0042] A quick-made brown yogurt comprises the following raw materials: raw milk, reducing sugar and a fermentation agent, wherein the reducing sugar is xylose and the fermentation agent is Yo-C701-F. The amount of reducing sugar added accounts for 15% of the total weight of the raw materials, the amount of the fermentation agent added accounts for 0.1% of the total weight of the raw materials, and the balance is raw milk.

[0043] Example 4

[0044] A quick-made brown yogurt comprises the following raw materials: raw milk, reducing sugar and a fermentation agent, wherein the reducing sugar is L-arabinose and the fermentation agent is YO-MIX 381. The amount of reducing sugar added accounts for 1% of the total weight of the raw materials, the amount of the fermentation agent added accounts for 0.01% of the total weight of the raw materials, and the balance is raw milk.

[0045] Example 5

[0046] A quick-made brown yogurt comprises the following raw materials: raw milk, reducing sugar and a fermenting agent, wherein the reducing sugar is L-arabinose and the fermenting agent is FD-DVS Premium 5.0. Among them, the amount of reducing sugar added accounts for 8% of the total weight of the raw materials, the amount of starter added accounts for 0.05% of the total weight of the raw materials, and the balance is raw milk. Premium 5.0 is a direct-injection yogurt starter, which is a composite bacterial strain and mainly includes Lactobacillus bulgaricus and Streptococcus thermophilus.

[0047] Example 6

[0048] A quick brown yogurt comprises the following raw materials: raw milk, reducing sugar and a fermentation agent, wherein the reducing sugar is L-arabinose, the fermentation agent is Yo-C701-F, and the balance is raw milk. The amount of reducing sugar added accounts for 15% of the total weight of the raw materials, and the amount of the fermentation agent added accounts for 0.1% of the total weight of the raw materials.

[0049] Experiment 1: Screening of reducing sugars

[0050] At present, most of the brown yogurts on the market are browned with glucose raw materials, and the browning temperature is about 95°C and the browning time is about 3 hours. However, the current workshop processing control is difficult and the browning time is long. The present invention optimizes the selection of raw materials to further shorten the browning time. In order to ensure the good browning flavor of the product while reducing the browning time, the present invention screens reducing sugars. The use of the reduced sugars screened by the present invention for processing can significantly reduce the browning time and ensure the flavor and taste of the product.

[0051] In this experiment, the raw materials include raw milk and reducing sugar. Except for the different types of reducing sugar, the types, amounts and browning processing methods of the raw milk in each experimental group are exactly the same as those in Example 1 (since this experiment only involves browning, no leavening agent is required).

[0052] This experiment mainly observes the browning degree of the base material when different reducing sugars are selected, so as to select the reducing sugar that can shorten the browning time under the same conditions. The experiment of the present invention is as follows:

[0053] Three experimental groups were set up, named L-arabinose group, xylose group and glucose group, that is, the reducing sugars of the three experimental groups were L-arabinose, xylose and glucose respectively. The three groups of reducing sugars were mixed with raw milk and homogenized into the base material system. Then the three groups of base material systems were placed in transparent beakers respectively, and the three groups of base material systems were heated and kept warm for 3 hours. Within the first 90 minutes after the insulation was turned on, the browning index of each group was tested every 10 minutes, and the appearance of the browning was photographed and recorded; finally, the browning index of each group was tested at the end of 180 minutes, and the appearance of the browning was photographed and recorded.

[0054] The browning index during the experiment is shown in Table 1 below; the browning appearance during the experiment is recorded as follows: Figure 1 As shown, in Figure 1 In the figure, each group of photos from left to right are L-arabinose group, xylose group and glucose group.

[0055] Table 1 Browning index record of L-arabinose, xylose and glucose

[0056]

[0057] According to Table 1 and Figure 1 The results show that, under the same addition amount, the browning index of glucose after 180 minutes of browning is about 5, while xylose and L-arabinose reach 6.18788±0.0049 and 4.37619±0.0091 respectively at 20 minutes. This shows that under the same other conditions, when xylose and L-arabinose are selected as reducing sugars, the browning speed is much faster than that of glucose, and both have a good caramel flavor.

[0058] In order to further explore whether the fermentation process will affect browning, the present invention also designed Experiment 2.

[0059] Experiment 2: Studying the effect of fermentation on browning based on different reducing sugars

[0060] The raw milk and reducing sugar in this experiment are the same as those in Experiment 1. In this experiment, each group in Experiment 1 was fermented to observe the browning index of each group. Specifically, samples of the L-arabinose group, xylose group and glucose group with a browning index of about 5 were taken, and then the fermentation method in Example 1 of the present invention was used to ferment each group of samples. In this experiment, the starter of each group was selected from the common starter FD-DVS YF-L903. The browning index of each group was recorded before and after fermentation, and the specific results are shown in Table 2 below.

[0061] Table 2 Comparison of browning index of each group before and after fermentation

[0062]

[0063] According to the results in Table 2 above, when different reducing sugars are selected, the browning index after fermentation is not much different, indicating that the fermentation process does not affect browning.

[0064] Experiment 3: Screening of fermentation agents

[0065] During the processing of browning yogurt, browning will cause a certain degree of change in substances such as protein in the fermentation base, thereby slowing down the fermentation speed. The present invention considers optimizing the selection of raw materials to further shorten the browning time. In order to achieve a good fermentation flavor and reduce the fermentation time, the present invention screens the starter. The use of the starter screened by the present invention for processing can significantly reduce the fermentation time while ensuring the flavor and taste of the product.

[0066] In this experiment, the raw materials include raw milk, reducing sugar and fermentation agent. Except for the different types of fermentation agents, the types, dosages, and browning and fermentation processing methods of raw milk and reducing sugar in each experimental group are exactly the same as those in Example 1. This experiment is mainly to observe the acidity of brown yogurt after fermentation under different fermentation agents, so as to select a fermentation agent that can both ensure the product flavor and shorten the fermentation time under the same conditions. The experiment of the present invention is specifically as follows:

[0067] Five experimental groups and one control group were set up, named experimental groups A1-A5 and control group A, respectively. The raw materials of each group were raw milk, reducing sugar and fermentation agent, and the reducing sugar was glucose. The present invention selected the common fermentation agent FD-DVS YF-L903 as the control, and selected fast fermentation agents from different manufacturers for fermentation. Specifically, the fermentation agents of experimental groups A1-A5 were: YO-MIX 381, FD-DVS Premium 5.0, PIONEER, Yo-C701-F and YC-M950; the starter culture of control group A was FD-DVS YF-L903.

[0068] Brown yogurt was prepared according to the processing method of Example 1 of the present invention. The acidity of each group was monitored in the fermentation step. The specific results are as follows: Figure 2 As shown; during the fermentation process, the time when the pH reaches 4.5 was detected, the acidity after 7 hours of fermentation was detected, and the fermented product was tasted and its sensory evaluation was performed. The specific results are shown in Table 2 below.

[0069] Table 2 Comparison of relevant data of fermentation process

[0070]

[0071] according to Figure 2As shown in Table 2, experimental group A2 (starter culture was FD-DVS Premium 5.0) to pH 4.5 in the shortest time of 253min, and the acidity of fermentation can reach 77°T after 7h of fermentation, that is, under the same other conditions, the fermentation agent FD-DVS Premium 5.0 had the fastest fermentation speed, followed by experimental group A1 (fermentation agent was YO-MIX 381) and experimental group A4 (fermentation agent was Yo-C701-F), which had relatively fast fermentation speeds.

[0072] According to the sensory evaluation comparison in Table 2, experimental group A1, experimental group A2 and experimental group A4 (i.e., the fermentation agents were YO-MIX 381, FD-DVS Premium 5.0 and Yo-C701-F) have an acidity of about 74-78°T. The finished products produced later have a good flavor and moderate sweetness and sourness. These three strains can be selected for subsequent experiments.

[0073] Experiment 4: Effect of reducing sugar and starter culture on shortening the production time of brown yogurt

[0074] In order to shorten the browning and fermentation time at the same time, this experiment used the reducing sugars (xylose and L-arabinose) that can promote rapid browning obtained by screening in Experiment 1 and the strains that can promote rapid fermentation obtained by screening in Experiment 3 to make brown yogurt. The coordinated effect of the reducing sugar and the fermentation agent of the present invention can further shorten the production time of brown yogurt, and the finished product has a good flavor and moderate sweetness and sourness.

[0075] In this experiment, the raw materials include raw milk, reducing sugar and fermentation agent. Except for the different types of reducing sugar and fermentation agent, the types, dosages and browning and fermentation processing methods of raw milk in each experimental group are exactly the same as those in Example 1. This experiment is mainly to observe the acidity of brown yogurt after fermentation when different reducing sugars and fermentation agents are selected, so as to select the reducing sugar and fermentation agent combination that can both ensure the product flavor and shorten the overall preparation time under the same conditions. The experiment of the present invention is specifically as follows:

[0076] Seven experimental groups were set up, named experimental groups B1-B6 and control group B, and the raw materials of each group were raw milk, reducing sugar and fermentation agent. The reducing sugar and fermentation agent corresponding to experimental groups B1-B6 and control group B were as follows:

[0077] Experimental group B1: reducing sugar was xylose; fermentation agent was FD-DVS YoFlex Premium 5.0;

[0078] Experimental group B2: reducing sugar was xylose; fermentation agent was YO-MIX 381;

[0079] Experimental group B3: reducing sugar was xylose; fermentation agent was Yo-C701-F;

[0080] Experimental group B4: reducing sugar was L-arabinose; fermentation agent was FD-DVS YoFlex Premium 5.0;

[0081] Experimental group B5: reducing sugar was L-arabinose; starter culture was YO-MIX 38l;

[0082] Experimental group B6: reducing sugar was L-arabinose; starter culture was Yo-C701-F;

[0083] Control group B: the reducing sugar was glucose; the fermentation agent was FD-DVS YF-L903.

[0084] Brown yogurt was prepared according to the processing method of Example 1 of the present invention. The acidity of each group was monitored in the fermentation step. The specific results are as follows: Figure 3 As shown; during the fermentation process, the time when the pH reaches 4.5 was detected, the acidity after 7 hours of fermentation was detected, and the fermented product was tasted and its sensory evaluation was performed. The specific results are shown in Table 3 below.

[0085] Table 3 Comparison of relevant data of fermentation process

[0086]

[0087]

[0088] according to Figure 3 As shown in the results of Table 3, the shortest time for the pH of experimental group B4 (L-arabinose + FD-DVS YoFlex Premium 5.0) to reach 4.5 is 343min, and the acidity can reach 73°T after 8h of fermentation. Therefore, it can be seen that the fermentation speed of the synergistic scheme of L-arabinose and FD-DVS YoFlex Premium 5.0 is the fastest, and the finished product has a good flavor and moderate sweetness and sourness. The next are experimental group B4 (L-arabinose + YO-MIX 381) and experimental group B6 (L-arabinose + Yo-C701-F), both of which are faster than the control scheme. In addition, in this experiment, the fermentation speed of experimental groups B1-B3 (the scheme in which the reducing sugar is xylose) is slower than that of the control scheme, and the fermentation speed is slower than that of experimental groups B4-B5 and control group B. This shows that although xylose can accelerate browning and produce a caramel flavor similar to glucose, it has a certain effect on the fermentation speed of the starter.

[0089] 1. Effect of fermentation on browning

[0090] In order to further explore whether fermentation in this experiment will affect browning, this experiment also compared the appearance before and after fermentation under certain conditions to observe whether fermentation will affect browning from the appearance. Specifically, samples of experimental groups B1-B6 and control group B were taken, and samples with a browning index of about 5 were then fermented using the fermentation method in Example 1 of the present invention. Photos were taken before and after fermentation for comparison. Figure 4 shown.

[0091] For the convenience of comparison, the present invention divides the pictures into two groups for comparison. Taking the photos recorded before fermentation as an example, the four groups on the left are experimental group B3, experimental group B2, experimental group B2, and control group B; the four groups on the right are experimental group B6, experimental group B5, experimental group B4, and control group B.

[0092] according to Figure 4 It can be seen from the appearance comparison that the appearance color of each group of the present invention has almost no change before and after fermentation, which shows that the fermentation process in the present invention will not affect browning.

[0093] 2. Calculation of coordination

[0094] Based on the results of the above experiment 4, the present invention adopts the Bliss model to calculate the synergy.

[0095] The Bliss model is also called the product effect model, and its formula can be expressed as:

[0096]

[0097]

[0098] Where: SE represents the synergistic effect index; E E represents the actual effect value of the sugar-bacteria combination scheme; ET represents the theoretical effect value of the sugar-bacteria combination scheme; E1 represents the effect value of browning time; E2 represents the effect value of fermentation time.

[0099] When SE>1, it is a synergistic effect; when SE<1, it is an antagonistic effect; SE=1, it is an additive effect.

[0100] Based on the results of Experiment 4 above, substituting into the Bliss model, the following results are obtained as shown in Table 4:

[0101] Table 4 Calculation results of the synergy of each group

[0102]

[0103] According to Experiment 1, the browning time of the synergistic scheme of common reducing sugar and fermentation agent (i.e. glucose + FD-DVS YF-L903 in control group B) is 180 minutes; according to Experiment 3, the fermentation time of the synergistic scheme of common reducing sugar and fermentation agent (i.e. glucose + FD-DVS YF-L903 in control group B) is 374 minutes. That is, the browning + fermentation time of control group B is 554 minutes in total.

[0104] According to the results in Table 4, in experimental groups B1-B6, except for experimental group B1, the remaining schemes can significantly shorten the preparation time of brown yogurt. Experimental groups B4-B6 were calculated for synergy by the Bliss model, and their SE values ​​were all greater than 1, which indicates that synergy was produced by the synergy of reducing sugar and leavening agent in experimental groups B4-B6. Among them, the SE value of experimental group B4 was the largest (1.35), and its preparation time was 368min, which was 186min shorter than that of control group B; followed by experimental group B6 and experimental group B5. Therefore, in experimental groups B4-B6, the present invention uses the scheme corresponding to experimental group B4 as the best implementation scheme.

[0105] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be covered by the scope of the claims of the present invention.

Claims

1. A quick-made brown yogurt, characterized in that: The invention comprises the following raw materials: raw milk, reducing sugar and fermentation agent, wherein the reducing sugar is xylose or L-arabinose.

2. The instant brown yogurt according to claim 1, characterized in that The fermentation agents are YO-MIX 381 and FD-DVS Premium 5.0 or Yo-C701-F.

3. The quick-made brown yogurt according to claim 1 or 2, characterized in that: The amount of reducing sugar added accounts for 1-15% of the total weight of the raw materials, and the amount of leavening agent added accounts for 0.01-0.1% of the total weight of the raw materials.

4. The method for preparing the quick brown yogurt according to any one of claims 1 to 3, characterized in that: The preparation steps are: taking raw materials for use, and then sequentially carrying out batching, homogenization, browning and sterilization, fermentation, refrigeration, demulsification and filling.

5. The method for preparing quick brown yogurt according to claim 4, characterized in that: In the homogenization step, the homogenization temperature is 60-70° C., the homogenization pressure is 18-22 MPa, and the homogenization time is 2.5-5 min.

6. The method for preparing quick brown yogurt according to claim 4, characterized in that: In the browning and sterilization step, the base material system is heated to 85-95° C. and kept warm for 1-3 hours for browning and sterilization.

7. The method for preparing quick brown yogurt according to claim 4, characterized in that: In the fermentation step, the fermentation temperature is 40-45°C.

8. The method for preparing quick brown yogurt according to claim 4, characterized in that: The demulsification step is specifically as follows: stirring the fermented yogurt at a stirring speed of 200 to 400 rpm for 2 to 4 minutes.

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