CN115349552A - Non-cooked flavored milk and preparation method thereof - Google Patents

Abstract

The invention provides milk without cooking flavor and a preparation method thereof. The preparation method comprises the following steps: (1) ultrafiltration: ultrafiltering raw milk to obtain trapped fluid and penetrating fluid; (2) sterilization: respectively sterilizing the trapped fluid and the first part of penetrating fluid; (3) blending: blending and homogenizing the sterilized trapped fluid and the sterilized penetrating fluid. The preparation method can reduce cooked flavor and sulfur smell of dairy products, has better organoleptic properties, and reduces dairy product waste and consumer complaints which are considered unacceptable due to undesirable flavor, smell or color.

Description

Non-cooked flavored milk and preparation method thereof

technical field

The invention belongs to the technical field of milk processing, and in particular relates to a method for preparing milk without steamed taste.

Background technique

With the development of the economic level, consumers' consumption tastes and concepts are becoming more and more refined and personalized, especially for UHT dairy products. For some consumers: milk taste is too light, cooked flavor, There is a little bit of fishy smell and insufficient mouth wrapping. These flavor reasons have always been the key technical problems of UHT sterilized milk, and they are also problems that hinder the upgrading of UHT dairy products. Therefore, need badly a kind of preparation method that eliminates bad flavor in milk.

Contents of the invention

The object of the present invention is to provide a method for the preparation of non-cooked milk, which can reduce the cooked flavor, sulfur smell of dairy products, have better organoleptic properties, and reduce the risk of being rejected due to undesired flavor, smell or color. Considered unacceptable dairy waste and consumer complaints.

Another object of the present invention is to provide a non-cooked milk.

In order to achieve the above object, the present invention provides a method for preparing non-cooked milk, comprising the following steps: (1) ultrafiltration: ultrafiltration of raw milk to obtain retentate and permeate; (2) sterilization: retentate And the first part of the permeate is sterilized respectively; (3) deployment: the sterilized retentate and permeate are prepared and homogenized.

In the present invention, the retentate (protein-rich part) and permeate (lactose-rich part) are sterilized step by step, and the sterilized protein-rich composition is prepared with the sterilized lactose-rich component to form a finished product Dairy products, and finished dairy products were consistent with routine samples for protein, fat, and lactose. The sample prepared by step-by-step sterilization does not have a cooking smell, and the fururine is significantly lower than that of the conventional sample, mainly because: on the one hand, the separate sterilization of the protein-rich part and the milk sugar-rich part can reduce the chance of Maillard reaction On the other hand, lactose in milk, as a reducing sugar, undergoes a Maillard reaction with lysine of milk protein during heat treatment to form an intermediate product (lactulosyl lysine) which can be hydrolyzed by acid to generate furosine. However, step-by-step sterilization is to separate concentrated milk and lactose to avoid Maillard reaction between lactose and lysine in milk protein.

The blending ratio in the blending step of the above step (3) needs to be blended according to the process requirements, otherwise the product indicators will not meet the product requirements, resulting in unqualified products and obvious differences in taste.

According to some specific embodiments of the present invention, performing reverse osmosis treatment on the remaining permeate is also included between step (2) and step (3) to obtain reverse osmosis water.

According to some specific embodiments of the present invention, the raw milk is skimmed milk, which is obtained by preheating dairy products at 50-55°C for centrifugal defatting, wherein the fat (cream) that has been removed is pasteurized for backup use.

According to some specific embodiments of the present invention, the first part of permeate in step (2) accounts for 70%-80% of the total volume of permeate.

According to some specific embodiments of the present invention, the preparation step in step (3) further includes adding reverse osmosis water, preferably, the added reverse osmosis water is sterilized reverse osmosis water.

According to some specific embodiments of the present invention, in the preparation step of step (3), the homogenization temperature is 50-55° C., and the homogenization pressure is 50/250 bar. After adjusting the index according to the comparison ratio, it must be homogenized, otherwise the fat will float up during the shelf life and affect the product quality.

According to some specific embodiments of the present invention, the operating temperature of each step is kept at 1-8° C., and the storage time of the milk product in each step is not more than 6 hours, so as to ensure microbial safety.

According to some specific embodiments of the present invention, the method of sterilization is ultra-high temperature sterilization, and the ultra-high temperature sterilization is selected from direct sterilization or indirect sterilization, the direct sterilization is preferably immersion sterilization, and the indirect sterilization is preferably Tube sterilization.

According to some specific embodiments of the present invention, the temperature of the indirect sterilization is 138±1°C, and the sterilization time is 3-5s; the temperature of the direct sterilization is 142±1°C, and the sterilization time is 3-5s. The above-mentioned direct sterilization and indirect sterilization temperature fluctuations should not be greater than ±1°C to avoid the risk of microbial growth.

According to some specific embodiments of the present invention, the molecular weight cut off by ultrafiltration is not lower than 10000 Daltons.

The present invention also provides non-cooked milk prepared by the above preparation method.

The non-cooked milk provided by the present invention can reduce the undesired cooked flavor and sulfur smell of dairy products, and can produce dairy products with better organoleptic properties. Furthermore, sterilizing the milk protein-rich fraction of raw milk separately from the lactose-rich fraction (or derivatives thereof) and then combining these fractions together produces a dairy product that is superior to sterilizing the protein and lactose components together The fururine content in the obtained dairy product, and finally the obtained dairy product is significantly reduced.

Description of drawings

Fig. 1 is the process roadmap of the preparation method of non-cooked milk according to Example 1 of the present invention;

Fig. 2 is the process roadmap of the preparation method of non-cooked milk according to Example 2 of the present invention;

Fig. 3 is a comparison chart of furosine detection results of milk prepared in Example 1-2 and Comparative Example 1-2 of the present invention.

Detailed ways

In order to more clearly understand the technical features, purpose and beneficial effects of the present invention, the technical solution of the present invention will now be further described in detail. It should be understood that the following specific implementations are only exemplary, and the technical solution of the present invention is not limited to the following specific implementations.

The object of the present invention is to provide a method for the preparation of non-cooked milk, which can reduce the cooked flavor, sulfur smell of dairy products, have better organoleptic properties, and reduce the risk of being perceived as undesired flavor, smell or color. Dairy waste is unacceptable and consumers complain.

Another object of the present invention is to provide a non-cooked milk.

For this reason, the present invention provides a kind of preparation method of non-cooking milk, comprising the following steps: (1) ultrafiltration: the raw milk is subjected to ultrafiltration to obtain a retentate and a permeate; (2) sterilization: the retentate and the second Part of the permeate is sterilized separately; (3) deployment: the sterilized retentate and permeate are prepared and homogenized.

According to a specific embodiment, between step (2) and step (3), it also includes performing reverse osmosis treatment on the remaining permeate to obtain reverse osmosis water.

According to a specific embodiment, the above-mentioned raw milk is skimmed milk, which is obtained by preheating dairy products at 50-55° C. for centrifugal defatting, wherein the fat (cream) removed is pasteurized for later use.

According to a specific embodiment, the first part of permeate in step (2) accounts for 70%-80% of the volume of the total permeate, preferably 75%.

According to a specific embodiment, the preparation step in step (3) further includes adding reverse osmosis water, preferably, the added reverse osmosis water is sterilized reverse osmosis water.

According to some specific embodiments of the present invention, in the preparation step of step (3), the homogenization temperature is 50-55° C., and the homogenization pressure is 50/250 bar. After adjusting the index according to the comparison ratio, it must be homogenized, otherwise the fat will float up during the shelf life and affect the product quality.

According to a specific embodiment, the operating temperature of each step is kept at 1-8° C., and the storage time of the milk product in each step is not more than 6 hours, so as to ensure the microbiological safety.

According to a specific embodiment, the above-mentioned sterilization method is ultra-high temperature sterilization, and the above-mentioned ultra-high temperature sterilization is selected from direct sterilization or indirect sterilization. The above-mentioned direct sterilization is preferably immersion-type sterilization, and the above-mentioned indirect sterilization is preferably tube-type sterilization.

According to a specific embodiment, the above-mentioned indirect sterilization temperature is 138±1°C, and the sterilization time is 3-5s; the above-mentioned direct sterilization temperature is 142±1°C, and the sterilization time is 3-5s. The above-mentioned direct sterilization and indirect sterilization temperature fluctuations should not be greater than ±1°C to avoid the risk of microbial growth.

According to a specific embodiment, the molecular weight cut off by ultrafiltration is not lower than 10000 Daltons.

The present invention also provides non-cooked milk prepared by the above preparation method.

The non-cooked milk provided by the present invention can reduce the undesired cooked flavor and sulfur smell of dairy products, can produce dairy products with better organoleptic properties, and in turn can reduce the undesired flavor of dairy products for consumers , odor or color complaints, further reduces waste. Furthermore, separate pasteurization of the milk protein-rich and lactose (or derivatives thereof) rich fractions of raw milk can result in a finished dairy product with less culinary flavor. Also, the furosine content in the dairy product of the present invention is significantly reduced compared to a dairy product obtained by sterilizing protein and lactose components together.

Example 1

This embodiment provides a method for preparing non-cooked milk, the process roadmap is shown in Figure 1, and the specific steps are as follows:

(1) Raw milk: test the physical and chemical indicators of raw milk and record the storage temperature.

(2) Preheating: preheating the raw milk whose physical and chemical indicators have been tested to 50-55°C.

(3) Separation: Separating the above-mentioned preheated raw milk into skim milk at a separation temperature of 50-55°C.

(4) Standardization:

Homogenization: Homogenize the above-mentioned skim milk, the homogenization temperature is 50-55°C, and the homogenization pressure is 30/180±5bar.

Pre-sterilization: The homogenized skim milk is further pre-sterilized, and the pre-sterilization condition is 75-90°C/15s to obtain pasteurized milk.

Cooling: Cool the pre-sterilized pasteurized milk to 1-8°C.

(5) Ultrafiltration (UF) concentration: immerse the pre-sterilized and cooled pasteurized milk into the ultrafiltration membrane system, keep it separated and concentrated at 1-8°C, and the ultrafiltration treatment product is divided into two parts, one part is ultrafiltration interception liquid (concentrated milk), and the other part is ultrafiltration permeate (lactose liquid and its derivatives); the molecular weight intercepted by the ultrafiltration membrane system is not less than 10,000 Daltons.

(6) Ultrafiltration (UF) permeate treatment: 3/4 of the ultrafiltration permeate obtained by ultrafiltration concentration is subjected to ultra-high temperature sterilization, and 1/4 of the ultrafiltration permeate is subjected to reverse osmosis (RO) treatment.

Among them, the 3/4 ultrafiltration permeate is operated as follows:

Vacuum degassing: vacuum degree -35～-80kPa;

Homogenization temperature: 70-75°C, homogenization pressure 50/250±5bar;

Ultra-high temperature sterilization (indirect sterilization: tube sterilization): 138±1°C/4s.

Cooling: Cool the ultrafiltration permeate after ultra-high temperature sterilization to 20-30°C.

The above 1/4 ultrafiltration permeate is carried out as follows:

RO treatment: The above 1/4 ultrafiltration permeate is subjected to RO treatment to obtain RO water and RO retentate.

RO water treatment: carry out indirect sterilization on the above RO water at 138±1°C/4s.

Cooling: Cool the RO water after ultra-high temperature sterilization to 20-30°C.

(7) Ultrafiltration (UF) retentate treatment: the ultrafiltration retentate after ultrafiltration concentration is carried out as follows:

Vacuum degassing: vacuum degree -35～-80kPa.

Homogenization temperature: 70-75°C, homogenization pressure 50/250±5bar.

Indirect sterilization (tube sterilization): 138±1°C/4s.

Cooling: Cool the ultrafiltration retentate after indirect sterilization to 20-30°C.

(8) Preparation: Sample preparation was carried out according to the expected indexes of each component in Comparative Example 1 (ie, in terms of mass percentage, including 4.07% fat, 3.30% protein, 4.43% lactose, and 12.77% dry matter).

(9) Homogenization: Homogenize the prepared materials, the homogenization temperature is 50-55°C, and the homogenization pressure is 50/250bar.

Among them, the physical and chemical indicators of each process are shown in Table 1:

Table 1

Example 2

This embodiment provides a method for preparing non-cooked milk, the process roadmap is shown in Figure 2, and the specific steps are as follows:

(1) Raw milk: test the physical and chemical indicators of raw milk and record the storage temperature.

(2) Preheating: preheating the raw milk whose physical and chemical indicators have been tested to 50-55°C.

(3) Separation: Separating the above-mentioned preheated raw milk into skim milk at a separation temperature of 50-55°C.

(4) Standardization:

Homogenization: Homogenize the above-mentioned skim milk, the homogenization temperature is 50-55°C, and the homogenization pressure is 30/180±5bar.

Pre-sterilization: The homogenized skim milk is further pre-sterilized, and the pre-sterilization condition is 75-90°C/15s to obtain pasteurized milk.

Cooling: Cool the pre-sterilized pasteurized milk to 1-8°C.

(5) Ultrafiltration (UF) concentration: immerse the pre-sterilized and cooled pasteurized milk into the ultrafiltration membrane system, keep it separated and concentrated at 1-8°C, and the ultrafiltration treatment product is divided into two parts, one part is ultrafiltration interception liquid (concentrated milk), and the other part is ultrafiltration permeate (lactose liquid and its derivatives); the molecular weight intercepted by the ultrafiltration membrane system is not less than 10,000 Daltons.

(6) Ultrafiltration (UF) permeate treatment: 3/4 of the ultrafiltration permeate obtained by ultrafiltration concentration is subjected to ultra-high temperature sterilization, and 1/4 of the ultrafiltration permeate is subjected to reverse osmosis (RO) treatment.

Among them, the 3/4 ultrafiltration permeate is operated as follows:

Immersion sterilization: 142±1℃/4s.

Vacuum degassing: vacuum degree -35～-80kPa.

Homogenization after sterilization: homogenization temperature 70-75°C, homogenization pressure 50/250±5bar.

Cooling: Cool the homogenized ultrafiltration permeate to 20-30°C.

The above 1/4 ultrafiltration permeate is carried out as follows:

RO treatment: The above 1/4 ultrafiltration permeate is subjected to RO treatment to obtain RO water and RO retentate.

RO water treatment: Ultra-high temperature sterilization of the above RO water (immersion type 142±1°C/4s).

Cooling: Cool the RO water after ultra-high temperature sterilization to 20-30°C.

(7) Ultrafiltration (UF) retentate treatment: the ultrafiltration retentate after ultrafiltration concentration is carried out as follows:

Immersion sterilization: 142±1℃/4s.

Vacuum degassing: vacuum degree -35～-80kPa.

Homogenization after sterilization: homogenization temperature 70-75°C, homogenization pressure 50/250±5bar.

Cooling: Cool the homogenized ultrafiltration retentate to 20-30°C.

(8) Preparation: Sample preparation was carried out according to the expected indicators of each component in Comparative Example 2 (ie, in terms of mass percentage, including 4.05% fat, 3.34% protein, 4.40% lactose, and 12.81% dry matter).

(9) Homogenization: Homogenize the prepared materials, the homogenization temperature is 50-55°C, and the homogenization pressure is 50/250bar.

Among them, the physical and chemical indicators of each process link are shown in Table 2.

Table 2

Comparative example 1

This comparative example provides a kind of preparation method of milk, specifically as follows:

(1) Raw milk: test the physical and chemical indicators of raw milk and record the storage temperature.

(2) Preheating: preheating the raw milk whose physical and chemical indicators have been tested to 50-55°C.

(3) Standardization:

Homogenization: Homogenize the above preheated raw milk to obtain homogenized milk, the homogenization temperature is 50-55°C, and the homogenization pressure is 30/180±5bar.

Pre-sterilization: The homogeneous milk is further pre-sterilized, and the pre-sterilization condition is 75-90°C/15s to obtain pasteurized milk.

Cooling: Cool the above-mentioned pre-sterilized pasteurized milk to 1-8°C.

(4) The pasteurized milk in the step (3) is further operated as follows:

Vacuum degassing: vacuum degree -35～-80kPa.

Homogenization: the homogenization temperature is 70-75°C, the homogenization pressure is 50/250±5bar, and semi-finished products are obtained.

Ultra-high temperature sterilization (indirect sterilization): the semi-finished product is subjected to ultra-high temperature sterilization, and the sterilization condition is 138±1°C/4s.

Cooling: Cool the semi-finished product after ultra-high temperature sterilization to 20-30°C.

Among them, the physical and chemical indicators of each process are shown in Table 3:

table 3

Comparative example 2

This comparative example provides a kind of preparation method of milk, specifically as follows:

(1) Raw milk: test the physical and chemical indicators of raw milk and record the storage temperature.

(2) Preheating: preheating the raw milk whose physical and chemical indicators have been tested to 50-55°C.

(3) Standardization:

Homogenization: Homogenize the above preheated raw milk to obtain homogenized milk, the homogenization temperature is 50-55°C, and the homogenization pressure is 30/180±5bar.

Pre-sterilization: The homogeneous milk is further pre-sterilized, and the pre-sterilization condition is 75-90°C/15s to obtain pasteurized milk.

Cooling: cooling the above-mentioned pre-sterilized pasteurized milk to 1-8°C to obtain a semi-finished product.

(4) The semi-finished product in the step (3) is further operated as follows:

Immersion sterilization: 142±1℃/4s.

Vacuum degassing: vacuum degree -35～-80kPa.

Homogenization after sterilization: homogenization temperature 70-75°C, homogenization pressure 50/250±5bar.

Cooling: Cool to 20-30°C.

Among them, the physical and chemical indicators of each process are shown in Table 4:

Table 4

performance measurement

The milk prepared by the above-mentioned embodiment 1-2 and comparative example 1-2 was tested for furosine and tasted, as follows:

1. Detection of furosine:

According to the standard "NY/T939-2016 Identification of Reconstituted Milk in Pasteurized Milk and UHT Sterilized Milk" issued by the Ministry of Agriculture of the People's Republic of China, the milk prepared in Example 1-2 and Comparative Example 1-2 was braned. amino acid detection, the specific detection results are shown in Table 5 and Figure 3:

table 5

Sample serial number Furosine content (mg/100g protein) Comparative example 1 375.7 Example 1 143.6 Comparative example 2 63.9 Example 2 35.1

Can obtain by table 5 furosine detection data: comparative example 1 furosine content (mg/100g protein) is 375.7, and embodiment 1 furosine content (mg/100g protein) is 143.6, and embodiment 1 sample compares Proportion 1 sample has reduced 62%; Comparative example 2 furosine content (mg/100g protein) is 63.9, embodiment 2 furosine content (mg/100g protein) is 35.1, embodiment 2 sample is compared to comparative example 2 The sample was reduced by 45%. The reason why the content of furosine in the sample of Example 1-2 is significantly lower than that of the sample of Comparative Example 1-2 lies in the step-by-step sterilization step, that is, the concentrated milk part and the lactose part are sterilized separately to avoid lactose and lactose. Amino acid undergoes Maillard reaction.

2. Tasting of mouthfeel: Taste the milk prepared in the above-mentioned embodiment 1-2 and comparative example 1-2, specifically as follows:

60 people were organized to taste. According to the evaluation method of the taste test, they liked it very much (5 points), liked it relatively (4 points), average, didn’t like it or not (3 points), didn’t like it very much (2 points), and didn’t like it at all (2 points). The five scores of dislike (1 point) and the number of people with different liking degrees are used to calculate the overall liking degree score of this type of product. Table 6 summarizes according to the liking degree of the overall evaluators.

Table 6

Note: I like it very much (no cooking smell), I like it a little bit (slight cooking smell), so-so, I can’t say whether I like it or not (it has a cooking smell but not serious), I don’t like it very much (it has a serious cooking smell), and I don’t like it at all Didn't like it (has a very severe cooking smell).

As can be seen from the above table, (1) comparative example 1 and embodiment 1 preference are respectively 73% and 88%, and embodiment 1 is 15% higher than comparative example 1 preference;

(2) comparative example 2 and embodiment 2 liking degree are respectively 76% and 93%; Embodiment 2 is 17% higher than comparative example 2 liking degree;

(3) According to the preference score, it can be obtained: Example 2>Example 1>Comparative Example 2>Comparative Example 1.

To sum up: the furosine and mouthfeel of the dairy products produced by sterilizing the protein and lactose parts separately and then combining these parts are significantly better than those obtained by sterilizing the protein and lactose components together.

The above are only preferred embodiments of the present invention. It should be noted that those skilled in the art may make various modifications, combinations, alterations or substitutions to the details and features of the present invention without departing from the spirit and essence of the present invention. These modifications, combinations, alterations or substitutions should also be understood to be included within the scope of protection of the present invention.

Claims (10)

1. A preparation method of milk without cooking flavor is characterized by comprising the following steps:

(1) And (3) ultrafiltration: ultrafiltering raw milk to obtain trapped fluid and penetrating fluid;

(2) And (3) sterilization: respectively sterilizing the trapped fluid and the first part of penetrating fluid;

(3) Blending: blending and homogenizing the sterilized trapped fluid and the sterilized penetrating fluid.

2. The method according to claim 1, further comprising performing reverse osmosis treatment on the remaining permeate to obtain reverse osmosis water between the step (2) and the step (3).

3. The method of claim 1, wherein the raw milk is skim milk.

4. The process according to claim 1, wherein the first permeate fraction in step (2) is 70% to 80% by volume of the total permeate.

5. The method according to claim 2, wherein the step of preparing in step (3) further comprises adding reverse osmosis water, preferably, the added reverse osmosis water is sterilized reverse osmosis water.

6. The method of claim 1, wherein the operating temperature of each step is maintained between 1-8 ℃, and the milk product is stored for no more than 6 hours in each step.

7. The method according to any one of claims 1 to 6, wherein the sterilization is ultra-high temperature sterilization selected from direct sterilization and indirect sterilization.

8. The preparation method according to claim 7, wherein the temperature of the indirect sterilization is 138 ± 1 ℃, and the sterilization time is 3-5s; the temperature of the direct sterilization is 142 +/-1 ℃, and the sterilization time is 3-5s.

9. The method of claim 1, wherein the ultrafiltration has a molecular weight cut-off of not less than 10000 daltons.

10. Non-steamed milk prepared by the preparation method according to any one of claims 1 to 9.

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