CN116076572A - Bagged normal-temperature yoghourt and preparation method thereof - Google Patents

Abstract

The invention provides normal-temperature yoghourt, which comprises 68-73 parts of concentrated milk, 17.7-22.6 parts of concentrated water, 6.5-8 parts of sugar, 1.2-1.8 parts of starch, 0.5-0.65 part of pectin and 0.0015-0.005 part of leavening agent according to weight parts. The normal-temperature yoghourt is prepared by adopting a secondary batching and secondary sterilization preparation mode. The normal temperature yoghurt obtained by the preparation method has fine and stable tissue state, thick texture and natural flavor; the normal temperature yoghourt product which is packaged by a self-standing bag, contains only one food additive, has stable taste and smooth state, does not separate out whey and has the shelf life of 6 months is produced by being matched with the existing equipment.

Description

Bagged normal-temperature yoghourt and preparation method thereof

Technical Field

The invention relates to the technical field of dairy product production and processing, in particular to self-standing bagged normal-temperature yoghurt and a preparation method thereof.

Background

The yoghurt has unique flavor and taste and rich nutritional value, and is deeply favored by consumers. At present, domestic yogurt products are mainly classified into low-temperature yogurt and normal-temperature yogurt. The low-temperature yoghourt sold in the market at present has rich taste, multiple packages and comprehensive nutrition, and greatly meets the various demands of consumers. The low-temperature yoghourt contains active lactobacillus, but has short shelf life, and the shelf life of the low-temperature yoghourt sold in the market at present is lower than 30 days; meanwhile, in order to ensure the taste, texture, effective viable count and the like of the yoghurt within the shelf life, the yoghurt is required to be refrigerated at low temperature in the aspects of transportation, storage and sales. The requirements of shorter shelf life, strict cold chain guarantee and the like greatly limit the sales radius of the low-temperature yoghourt. The normal temperature yoghourt which is rising in recent years not only effectively solves the difficult point of low temperature yoghourt, but also has the advantages of taste and nutrition which are comparable with those of low temperature yoghourt, and is close to the milk drinking habit of people in China, and the like, so that the normal temperature yoghourt is accepted by the market.

The current normal temperature yoghurt processing process generally adopts primary or secondary ingredients, and the primary or secondary ingredients are directly sterilized and filled or the secondary ingredients are filled and sterilized after fermentation. At present, the commercial normal-temperature yoghourt adopts a sterile filling process of sterilizing and then filling, the process has high requirements on filling conditions and equipment, new equipment or improved equipment is needed, the production cost of enterprises is increased, and a threshold exists for common medium-sized and small enterprises. The invention adopts a secondary batching and secondary sterilizing process, does not need new equipment investment, and can realize the mass production of normal-temperature yoghurt.

Meanwhile, the package form of the normal-temperature yoghourt sold in the market at present mainly comprises a brick package and a PET bottle, and the package form is far smaller than low Wen Suannai. The normal temperature yoghurt is subjected to sterilization heat treatment, and certain types and amounts of food additives are added in the processing process in order to effectively protect the texture of the yoghurt and the stability of protein in the heat treatment process. The number of food additives in the conventional commercial normal-temperature yoghurt ingredients is large, most of the food additives are 3-6, the ingredients of the ingredients are complex, and meanwhile, the conventional normal-temperature yoghurt ingredients are contrary to the cleaning labels pursued by current consumers.

Disclosure of Invention

The invention aims to provide normal-temperature yoghourt which is made by adopting a secondary batching and secondary sterilization manufacturing mode and has a concise label. The normal temperature yoghurt obtained by the preparation method has fine and stable tissue state, thick texture and natural flavor; the normal temperature yoghourt product which is packaged by a self-standing bag, contains only one food additive, has stable taste and smooth state, does not separate out whey and has the shelf life of 6 months is produced by being matched with the existing equipment.

In order to achieve the above purpose, the present invention adopts the following technical scheme:

the normal temperature yoghurt comprises 68-73 parts of concentrated milk, 17.7-22.6 parts of concentrated water, 6.5-8 parts of sugar, 1.2-1.8 parts of starch, 0.5-0.65 part of pectin and 0.0015-0.005 part of starter.

Preferably, the concentrated milk is derived from raw cow milk accepted according to GB19301 standard, and is obtained by a concentrating process, wherein the concentrated milk has a protein content of 4.2-4.4% and a fat content of 4.7-5.0%, and the concentrated water is water trapped during the concentrating of the milk.

Preferably, the sugar is one or a combination of two of white granulated sugar and crystalline fructose.

Preferably, the starch is a physical starch.

Preferably, the pectin is a high ester pectin.

Preferably, the starter is one or more of streptococcus thermophilus, lactobacillus bulgaricus, lactococcus lactis subspecies lactis, bifidobacterium lactis, lactobacillus acidophilus, lactobacillus rhamnosus and lactobacillus plantarum, and is mainly characterized by low post-acidification at the normal temperature of 25 ℃.

Lactobacillus bulgaricus and streptococcus thermophilus are probiotics of lactic acid bacteria and are also important microorganisms in the intestinal tract of the human body. The selection of the strain and the preparation of the starter not only affect the product quality of the yoghurt and the fermented milk beverage, but also directly affect the yield and the economic benefit of the yoghurt and the fermented milk beverage. Meanwhile, the Lactobacillus bulgaricus and the Streptococcus thermophilus have reciprocal symbiotic action, and different fermentation performances can be exerted by combining different lactobacillus.

A preparation method of self-standing bagged normal-temperature yoghourt,

the method comprises the following steps:

(1) Pretreatment of raw milk: the raw milk accepted according to GB19301 standard is subjected to filtration, centrifugation and standardized pasteurization in sequence, cooled to 2-6 ℃ and stored for standby;

(2) Concentrating milk: concentrating the raw milk pretreated in the step (1) by concentrating equipment, wherein the protein index in the concentrated milk is 4.2-4.4%;

(3) And (3) sterilization and fermentation: sequentially homogenizing and sterilizing the material obtained by the treatment in the step (2), wherein pasteurization is adopted for sterilization, and the minimum chemical, physical and sensory changes are generated while pathogenic microorganisms in the material are effectively killed, the strength is 85-95 ℃ and the time is 5-20 min, and a ferment is added after sterilization, wherein the fermentation temperature is 41-44 ℃;

(4) Terminating fermentation: after the fermentation acidity of the yoghourt obtained in the step (3) reaches 98-115 ℃, demulsification and tank turning are carried out, and the temperature is reduced to 20-25 ℃;

(5) And (3) secondary batching: heating the part of concentrated water treated in the step (2) to 65-75 ℃, and adding high-ester pectin and sugar. Shearing at a high speed for 15min, cooling the pectin solution to 35-45 ℃, adding the pectin solution into the yoghurt in the step (4), and stirring for 10min;

(6) Adding starch: heating the part of concentrated water treated in the step (2) to 35-40 ℃, adding starch, and shearing for 5min. Adding the starch solution into the yoghurt in the step (5), and stirring for 15min to obtain a yoghurt semi-finished product;

(7) Primary temperature rise: heating the semi-finished yoghurt product obtained in the step (6) to 50-60 ℃, and homogenizing again under 15-20 Mpa;

(8) And (3) secondary temperature rise: carrying out secondary heating on the material obtained in the step (7), and heating to 65-70 ℃; the temperature of the material can ensure that starch is partially gelatinized to increase the viscosity of the yoghurt, can effectively inhibit the proliferation of partial microorganisms in the yoghurt conveying process, and can avoid the easy deformation of the self-standing bag package caused by heating. According to the package design, the net content range of the self-standing pouch yoghurt product is 80-300 g/pouch;

(9) And (3) filling: and (3) filling the yoghourt finished product obtained in the step (8), wherein the filling environment is clean, filling nitrogen into the package after filling, replacing air, and finally completing cap screwing and sealing. The air replacement in the step can inhibit the oxidation of the yoghourt in the shelf life, prolong the shelf life and reduce the package deformation caused by pressure difference in the sterilization process.

(10) Basket loading and sterilization: and (3) placing the self-standing bagged yoghurt obtained in the step (9) in a basket, and placing the self-standing bagged yoghurt in a sterilizing kettle for shower pasteurization at a sterilizing temperature of 75-85 ℃ for 25-40 min.

Preferably, the method comprises the following steps:

(1) Pretreatment of raw milk: sequentially filtering raw milk accepted according to GB19301 standard, centrifuging, performing standardized pasteurization treatment, cooling to 4deg.C, and storing;

(2) Concentrating milk: concentrating the raw milk pretreated in the step (1) by concentrating equipment, wherein the protein index in the concentrated milk is 4.3% and the fat index is 4.8%;

(3) And (3) sterilization and fermentation: sequentially homogenizing and sterilizing the material obtained by the treatment in the step (2), wherein the sterilization mainly refers to pasteurization, and the minimum chemical, physical and sensory changes are generated while pathogenic microorganisms in the material are effectively killed, the pasteurization strength is 95 ℃, the time is 5min, the fermentation agent is added, and the fermentation temperature is 42.5 ℃;

(4) Terminating fermentation: after the fermentation acidity of the yoghourt obtained in the step (3) reaches 110 ℃, demulsification and tank turning are carried out, and the temperature is reduced to 20-25 ℃;

(5) And (3) secondary batching: heating the part of concentrated water treated in the step (2) to 70 ℃, and adding high-ester pectin and sugar. Shearing at high speed for 15min, cooling the pectin solution to 40 ℃, adding the pectin solution into the yoghurt in the step (4), and stirring for 10min;

(6) Adding starch: heating part of the concentrated water treated in the step (2) to 38 ℃, adding starch, and shearing for 5min; adding the starch solution into the yoghurt in the step (5), and stirring for 15min to obtain a yoghurt semi-finished product;

(7) Primary temperature rise: heating the semi-finished yoghurt product obtained in the step (6) to 53 ℃, and homogenizing again under the pressure of 18Mpa;

(8) And (3) secondary temperature rise: carrying out secondary heating on the material obtained in the step (7), and heating to 68 ℃; the temperature of the material can ensure that starch is partially gelatinized to increase the viscosity of the yoghurt, can effectively inhibit the proliferation of partial microorganisms in the yoghurt conveying process, and can avoid the easy deformation of the self-standing bag package caused by heating. According to the package design, the net content range of the self-standing pouch yoghurt product is 80-300 g/pouch;

(9) And (3) filling: and (3) filling the yoghourt finished product obtained in the step (8), wherein the filling environment is clean, filling nitrogen into the package after filling, replacing air, and finally completing cap screwing and sealing. The air replacement in the step can inhibit the oxidation of the yoghourt in the shelf life, prolong the shelf life and reduce the package deformation caused by pressure difference in the sterilization process.

(10) Basket loading and sterilization: and (3) placing the self-standing bagged yoghurt obtained in the step (9) in a basket, and placing the self-standing bagged yoghurt in a sterilizing kettle for shower pasteurization at a sterilizing temperature of 81 ℃ for 35min.

In the process of filling the self-standing bagged yoghurt into a basket, the stacking mode is mainly a horizontal stacking mode, so that the contact surface in the sterilization process is increased, and the sterilization effect is ensured to be better; under the same sterilization condition, the thermal deformation degree of the horizontal stacking is lower than that of the vertical stacking sterilization package, so that the opening of the included angle of the bottom of the self-supporting bag in the heat treatment process is effectively reduced, and the hidden danger of product quality caused by the damage of the packaging material is greatly avoided. The number of the self-standing bagged yoghurt sterilization stacking layers is 1-6, and 3-5 stacking sterilization is preferred.

The viscosity of the yoghourt product produced by the method and the operation is 2500-4500 cps (25 ℃), the yoghourt within the viscosity range is smooth and fine, the drinking process is convenient, the taste is moderate, and the yoghourt is suitable for consumer groups of all ages.

Advantageous effects

1. The invention adopts only one food additive to produce normal temperature yoghourt, has simple ingredients, ensures that the product label is cleaner, and meets the consumption requirement of current consumers.

2. The secondary batching and secondary sterilization process is adopted, so that the problem that common medium and small enterprises do not have aseptic filling equipment to produce normal-temperature yoghourt is solved.

3. The self-standing bag is adopted for packaging, so that the packaging mode of the normal-temperature yoghourt is enriched, the portable drinking experience is brought, the productivity of the self-standing bag filling equipment is improved, one filling equipment is realized, and the normal-low-temperature yoghourt is produced in a switching mode.

4. The preparation method, the sterilization mode and the stacking mode of the self-standing bag packaging product can produce the normal-temperature yoghourt with stable quality, smooth taste, low thermal deformation degree of the packaging material and less packaging wrinkles.

Detailed Description

Example 1

The normal temperature yoghurt comprises 68 parts of concentrated milk, 17.7 parts of concentrated water, 6.5 parts of sugar, 1.2 parts of starch, 0.5 part of pectin and 0.0015 part of starter.

In the invention, the concentrated milk adopted by the self-standing bagged normal-temperature yoghourt is derived from raw milk accepted according to GB19301 standard, and is obtained through a concentration process, wherein the index of the concentrated milk is that the protein content is preferably 4.2%, and the fat content is preferably 4.7%. According to the index of the concentrated milk, the protein content of the concentrated milk is preferably 4.3%, the fat content is 4.8%, and the addition amount of the concentrated water is 70%, wherein the adopted concentrated water is water cut off when the concentrated milk is concentrated, and the addition amount of the concentrated water is preferably 17.7%, and the addition amount of the concentrated water is preferably 20.1%.

In the present invention, the sugar used is one or a combination of two of white sugar and crystalline fructose as a sweetener, and the sugar content is 6.5%, preferably 8%.

In the invention, the adopted starch is physical starch, and the raw materials are not particularly limited, and belong to conventional commercial physical starch. The starch is added in an amount of 1.2%, preferably 1.3%.

In the invention, the pectin is high-ester pectin, and the raw materials are not particularly limited, and belong to conventional commercial pectin. Pectin is added at 0.5%, preferably at 0.6%.

In the invention, the starter is used as a starter which is weakly acidified at the normal temperature of 25 ℃, and belongs to starter conventionally used in the industry, and one or more of streptococcus thermophilus, lactobacillus bulgaricus, lactococcus lactis subspecies lactis, bifidobacterium lactis, lactobacillus acidophilus, lactobacillus rhamnosus and lactobacillus plantarum are preferred. More preferably Streptococcus thermophilus and Lactobacillus bulgaricus, and the addition amount is 0.003%.

A self-standing bagged normal-temperature yoghourt and a preparation method thereof are provided, and the specific method is as follows:

(1) Pretreatment of raw milk: raw milk accepted according to GB19301 standard is filtered, centrifuged, standardized and pasteurized, cooled to 2 ℃ and stored.

(2) Concentrating milk: concentrating the raw milk pretreated in the step (1) by using equipment, wherein the protein index in the concentrated milk is 4.3%, and the fat index is 4.8%. The concentrated water obtained in the concentration process is subjected to pasteurization treatment and is cooled to 2 ℃ for storage.

(3) And (3) sterilization and fermentation: homogenizing, sterilizing and adding a fermenting agent into the concentrated milk obtained by the treatment in the step (2), wherein the fermentation temperature is 43 ℃.

(4) The fermentation was terminated. And (3) after the acidity of the fermented yoghourt obtained in the step (3) reaches 105 ℃, demulsification and tank turning are carried out, and the temperature is reduced to 25 ℃.

(5) And (3) secondary batching: heating the part of concentrated water treated in the step (2) to 75 ℃, and adding high-ester pectin and white granulated sugar. Shearing at high speed for 15min, cooling the pectin solution to 40 ℃, adding the pectin solution into the yoghurt in the step (4), and stirring for 10min.

(6) Adding starch: heating the part of concentrated water treated in the step (2) to 40 ℃, adding starch, and shearing for 5min. Adding the starch solution into the yoghurt in the step (5), and stirring for 15min to obtain a yoghurt semi-finished product.

(7) Primary temperature rise: and (3) heating the semi-finished yoghurt product obtained in the step (6) to 55 ℃ and homogenizing the yoghurt at 17Mpa.

(8) And (3) secondary temperature rise: and (3) heating the material obtained in the step (7) to 68 ℃ again, and filling. The temperature of the material can ensure that starch is partially gelatinized to increase the viscosity of the yoghurt, can effectively inhibit the proliferation of partial microorganisms in the yoghurt conveying process, and can avoid the easy deformation of the self-standing bag package caused by heating. The net content of the self-standing pouch yoghurt product ranges from 200 g/pouch according to the packaging design.

(9) And (3) filling: and (3) filling the yoghourt finished product obtained in the step (8), wherein the filling environment is clean, filling nitrogen into the package after filling, replacing air, and finally completing cap screwing and sealing. The air replacement in the step can inhibit oxidation of the yoghurt, prolong the shelf life, and reduce package deformation caused by pressure difference in the sterilization process.

(10) Basket loading and sterilization: and (3) placing the self-standing bagged yoghurt obtained in the step (9) in a basket, and placing the self-standing bagged yoghurt in a sterilizing kettle for shower pasteurization. Sterilizing at 80deg.C for 25min. In the process of filling the self-standing bagged yoghurt into a basket, the stacking mode is mainly a horizontal stacking mode, so that the contact surface in the sterilization process is increased, and the sterilization effect is ensured to be better; under the same sterilization condition, the thermal deformation degree of the horizontal stacking is lower than that of the vertical stacking sterilization package, so that the opening of the included angle of the bottom of the self-supporting bag in the heat treatment process is effectively reduced, and the hidden danger of product quality caused by the damage of the packaging material is greatly avoided. The number of the self-standing bagged yoghurt sterilization stacking layers is 1-6, and 5 stacking sterilization is preferred.

The yogurt produced by the method and the operation has the viscosity of 3200cps (25 ℃), the yogurt within the viscosity range is smooth and fine, the drinking process is convenient, the mouthfeel is moderate, and the yogurt is suitable for consumer groups of all ages.

Example 2

The normal temperature yoghurt comprises 73 parts of concentrated milk, 22.6 parts of concentrated water, 8 parts of sugar, 1.8 parts of starch, 0.65 part of pectin and 0.005 part of starter.

In the invention, the concentrated milk adopted by the self-standing bagged normal-temperature yoghourt is derived from raw milk accepted according to GB19301 standard, and is obtained through a concentration process, wherein the index of the concentrated milk is that the protein content is preferably 4.4%, and the fat content is preferably 5.0%. According to the index of the concentrated milk, the protein content of the concentrated milk is preferably 4.3 percent, the fat content is preferably 4.8 percent, and the addition amount is preferably 70 percent. The concentrated water used is water which is cut off when the milk is concentrated, and the addition amount of the concentrated water is 22.6%, preferably 20.9%.

In the present invention, the sugar is white sugar, crystalline fructose, or a combination of both, and the amount of the sugar added is 8%, preferably 6.8%.

In the invention, the adopted starch is physical starch, and the raw materials are not particularly limited, and belong to conventional commercial physical starch. The starch is added in an amount of 1.8%, preferably 1.7%.

In the invention, the pectin is high-ester pectin, and the raw materials are not particularly limited, and belong to conventional commercial pectin. Pectin is added at 0.65%, preferably at 0.6%.

In the invention, the starter is used as a starter which is weakly acidified at the normal temperature of 25 ℃, and belongs to starter conventionally used in the industry, and one or more of streptococcus thermophilus, lactobacillus bulgaricus, lactococcus lactis subspecies lactis, bifidobacterium lactis, lactobacillus acidophilus, lactobacillus rhamnosus and lactobacillus plantarum are preferred. More preferably Streptococcus thermophilus and Lactobacillus bulgaricus, and the addition amount is 0.003%.

The invention also provides a self-standing bagged normal-temperature yoghourt and a preparation method thereof, wherein the specific method comprises the following steps:

(1) Pretreatment of raw milk: raw milk accepted according to GB19301 standard is filtered, centrifuged, standardized and pasteurized, cooled to 6 ℃ and stored.

(2) Concentrating milk: concentrating the raw milk pretreated in the step (1) by using equipment, wherein the protein index in the concentrated milk is 4.3%, and the fat index is 4.8%. The concentrated water obtained in the concentration process is subjected to pasteurization treatment and is cooled to 6 ℃ for storage.

(3) And (3) sterilization and fermentation: homogenizing, sterilizing and adding a fermenting agent into the concentrated milk obtained by the treatment in the step (2), wherein the fermentation temperature is 43 ℃.

(4) The fermentation was terminated. And (3) after the acidity of the fermented yoghourt obtained in the step (3) reaches 105 ℃, demulsification and tank turning are carried out, and the temperature is reduced to 25 ℃.

(5) And (3) secondary batching: heating the part of concentrated water treated in the step (2) to 75 ℃, and adding high-ester pectin and white granulated sugar. Shearing at high speed for 15min, cooling the pectin solution to 40 ℃, adding the pectin solution into the yoghurt in the step (4), and stirring for 10min.

(6) Adding starch: heating the part of concentrated water treated in the step (2) to 40 ℃, adding starch, and shearing for 5min. Adding the starch solution into the yoghurt in the step (5), and stirring for 15min to obtain a yoghurt semi-finished product.

(7) Primary temperature rise: and (3) heating the semi-finished yoghurt product obtained in the step (6) to 55 ℃ and homogenizing the yoghurt at 17Mpa.

(8) And (3) secondary temperature rise: and (3) heating the material obtained in the step (7) to 68 ℃ again, and filling. The temperature of the material can ensure that starch is partially gelatinized to increase the viscosity of the yoghurt, can effectively inhibit the proliferation of partial microorganisms in the yoghurt conveying process, and can avoid the easy deformation of the self-standing bag package caused by heating. The net content of the self-standing pouch yoghurt product ranges from 200 g/pouch according to the packaging design.

(9) And (3) filling, namely filling the yoghourt finished product obtained in the step (8) into a clean environment, filling nitrogen into the package after filling, replacing air, and finally completing cap screwing and sealing. The air replacement in the step can inhibit oxidation of the yoghurt, prolong the shelf life, and reduce package deformation caused by pressure difference in the sterilization process.

(10) Basket loading and sterilization: and (3) placing the self-standing bagged yoghurt obtained in the step (9) in a basket, and placing the self-standing bagged yoghurt in a sterilizing kettle for shower pasteurization. Sterilizing at 80deg.C for 25min. In the process of filling the self-standing bagged yoghurt into a basket, the stacking mode is mainly a horizontal stacking mode, so that the contact surface in the sterilization process is increased, and the sterilization effect is ensured to be better; under the same sterilization condition, the thermal deformation degree of the horizontal stacking is lower than that of the vertical stacking sterilization package, so that the opening of the included angle of the bottom of the self-supporting bag in the heat treatment process is effectively reduced, and the hidden danger of product quality caused by the damage of the packaging material is greatly avoided. The number of the self-standing bagged yoghurt sterilization stacking layers is 1-6, and 5 stacking sterilization is preferred.

TABLE 1

As is clear from table 1, the proportions of concentrated milk, concentrated water, sugar, starch and pectin completely determine the quality and mouthfeel of the yogurt, and the finished products produced by the present invention, which are shown in examples 1 to 2 above, were obtained.

TABLE 2

Note that: the sample temperature at the time of viscosity detection was 25 ℃.

According to the viscosity data in table 2, it can be seen that increasing the secondary temperature rise is beneficial to partial gelatinization of starch in the scheme, and properly increasing the viscosity of the yogurt, so that the yogurt can be more matched with the production speed of the filling equipment, and the production efficiency and quality are ensured, but the viscosity of the product is lower at this time, a secondary sterilization process is required, the viscosity recovery of the finished product is ensured, and meanwhile, the viscosity fluctuation in shelf life is 20%.

TABLE 3 Table 3

The results in Table 3 show that the way the products are placed (stacked) during the secondary sterilization process is relevant for the product packaging. The method has the advantages that the selected placement (stacking) mode and stacking layer number are better, the attractive appearance of the product package is effectively ensured, and meanwhile, the quality safety and the optimal labor efficiency of the product are ensured.

TABLE 4 Table 4

From table 4, the comparison results: as can be seen from the analysis of the sensory and evaluation dimensions of the product, the product prepared by the invention

	Overall evaluation	Smoothness degree of smoothness	Sweetness and acidity	Feeling of roughness	Thickness of thick thickness	Shelf life of the beverage
							The invention is that	5.0	4.0	3.3	1.0	3.0	6 months of
Existing technology	3.1	3.5	3.8	3.8	3.8	2-4 months

The normal temperature yoghourt product has various indexes superior to the prior art. Through the secondary batching and secondary sterilization process, the unique fermented milk flavor of the yoghourt can be maintained, the smoothness of the yoghourt is improved, the crunchy feeling of the yoghourt is reduced, the drinking experience of the yoghourt is improved, and the shelf life of the yoghourt is prolonged.

The above description is merely of preferred embodiments of the present invention, and the scope of the present invention is not limited to the above embodiments, but all equivalent modifications or variations according to the present disclosure will be within the scope of the claims.

Claims (8)

1. A normal temperature yoghurt, which is characterized in that: the normal temperature yoghurt comprises 68 to 73 parts of concentrated milk, 17.7 to 22.6 parts of concentrated water, 6.5 to 8 parts of sugar, 1.2 to 1.8 parts of starch, 0.5 to 0.65 part of pectin and 0.0015 to 0.005 part of leavening agent according to weight parts.

2. A yoghurt as claimed in claim 1, wherein: the index of the concentrated milk is that the protein content is 4.2-4.4%, the fat content is 4.7-5.0%, and the concentrated water is water which is cut off when the milk is concentrated.

3. A yoghurt as claimed in claim 1, wherein: the sugar is one or the combination of two of white granulated sugar and crystalline fructose.

4. A yoghurt as claimed in claim 1, wherein: the starch is physical starch.

5. A yoghurt as claimed in claim 1, wherein: the pectin is high ester pectin.

6. A yoghurt as claimed in claim 1, wherein: the starter is one or more of streptococcus thermophilus, lactobacillus bulgaricus, lactococcus lactis subspecies lactis, bifidobacterium lactis, lactobacillus acidophilus, lactobacillus rhamnosus and lactobacillus plantarum.

7. A preparation method of self-standing bagged normal-temperature yoghourt is characterized by comprising the following steps of: the method comprises the following steps:

(1) Pretreatment of raw milk: sequentially filtering, centrifuging and carrying out standardized pasteurization on raw milk, cooling to 2-6 ℃ and storing for later use;

(2) Concentrating milk: concentrating the raw milk pretreated in the step (1) by concentrating equipment, wherein the protein index in the concentrated milk is 4.2-4.4%;

(3) And (3) sterilization and fermentation: sequentially homogenizing and sterilizing the material obtained by the treatment in the step (2), wherein pasteurization is adopted for sterilization, the pasteurization strength is 85-95 ℃, the time is 5-20 min, a ferment is added after sterilization, and the fermentation temperature is 41-44 ℃;

(4) Terminating fermentation: after the fermentation acidity of the yoghourt obtained in the step (3) reaches 98-115 ℃, demulsification and tank turning are carried out, and the temperature is reduced to 20-25 ℃;

(5) And (3) secondary batching: heating the part of concentrated water treated in the step (2) to 65-75 ℃, and adding high-ester pectin and sugar. Shearing at a high speed for 15min, cooling the pectin solution to 35-45 ℃, adding the pectin solution into the yoghurt in the step (4), and stirring for 10min;

(6) Adding starch: heating the part of concentrated water treated in the step (2) to 35-40 ℃, adding starch, and shearing for 5min. Adding the starch solution into the yoghurt in the step (5), and stirring for 15min to obtain a yoghurt semi-finished product;

(7) Primary temperature rise: heating the semi-finished yoghurt product obtained in the step (6) to 50-60 ℃, and homogenizing again under 15-20 Mpa;

(8) And (3) secondary temperature rise: carrying out secondary heating on the material obtained in the step (7), and heating to 65-70 ℃; the temperature of the material can ensure that starch is partially gelatinized to increase the viscosity of the yoghurt, can effectively inhibit the proliferation of partial microorganisms in the yoghurt conveying process, and can avoid the easy deformation of the self-standing bag package caused by heating. According to the package design, the net content range of the self-standing pouch yoghurt product is 80-300 g/pouch;

(9) And (3) filling: filling the yogurt finished product obtained in the step (8), wherein the filling environment is clean, filling nitrogen into the package after filling, replacing air, and finally completing cap screwing and sealing;

(10) Basket loading and sterilization: and (3) placing the self-standing bagged yoghurt obtained in the step (9) in a basket, and placing the self-standing bagged yoghurt in a sterilizing kettle for shower pasteurization at a sterilizing temperature of 75-85 ℃ for 25-40 min.

8. The method for preparing the free-standing bagged normal-temperature yoghourt according to claim 7, wherein the method comprises the following steps of: the method comprises the following steps:

(1) Pretreatment of raw milk: sequentially filtering raw milk, centrifuging, sterilizing with standardized pasteurizer, cooling to 4deg.C, and storing;

(2) Concentrating milk: concentrating the raw milk pretreated in the step (1) by concentrating equipment, wherein the protein index in the concentrated milk is 4.3% and the fat index is 4.8%;

(3) And (3) sterilization and fermentation: sequentially homogenizing and sterilizing the material obtained by the treatment in the step (2), wherein the sterilization mainly refers to pasteurization, the pasteurization strength is 95 ℃, the time is 5min, the ferment is added, and the fermentation temperature is 42.5 ℃;

(4) Terminating fermentation: after the fermentation acidity of the yoghourt obtained in the step (3) reaches 110 ℃, demulsification and tank turning are carried out, and the temperature is reduced to 20-25 ℃;

(5) And (3) secondary batching: heating the part of concentrated water treated in the step (2) to 70 ℃, and adding high-ester pectin and sugar. Shearing at high speed for 15min, cooling the pectin solution to 40 ℃, adding the pectin solution into the yoghurt in the step (4), and stirring for 10min;

(6) Adding starch: heating part of the concentrated water treated in the step (2) to 38 ℃, adding starch, and shearing for 5min; adding the starch solution into the yoghurt in the step (5), and stirring for 15min to obtain a yoghurt semi-finished product;

(7) Primary temperature rise: heating the semi-finished yoghurt product obtained in the step (6) to 53 ℃, and homogenizing again under the pressure of 18Mpa;

(8) And (3) secondary temperature rise: carrying out secondary heating on the material obtained in the step (7), and heating to 68 ℃; the temperature of the material can ensure that starch is partially gelatinized to increase the viscosity of the yoghurt, can effectively inhibit the proliferation of partial microorganisms in the yoghurt conveying process, and can avoid the easy deformation of the self-standing bag package caused by heating. According to the package design, the net content range of the self-standing pouch yoghurt product is 80-300 g/pouch;

(9) And (3) filling: filling the yogurt finished product obtained in the step (8), wherein the filling environment is clean, filling nitrogen into the package after filling, replacing air, and finally completing cap screwing and sealing;

(10) Basket loading and sterilization: and (3) placing the self-standing bagged yoghurt obtained in the step (9) in a basket, and placing the self-standing bagged yoghurt in a sterilizing kettle for shower pasteurization at a sterilizing temperature of 81 ℃ for 35min.