Starter culture and its preparation method

Abstract

The present invention provides a leavening agent and a preparation method thereof. The leavening agent includes yeast granules and a coating layer coated on the surface of the yeast granules, wherein the coating layer includes grease and modified starch. The main function of the grease in the coating layer of the present invention is to wrap the yeast and slow down the absorption of moisture by the yeast granules, and the modified starch in the coating layer can replace part of the yeast to absorb a small amount of moisture, so that it can not only relieve the degree of yeast inactivation due to water absorption, but also improve the solubility of starch in water, and then more easily release the yeast inside the embedding layer. Therefore, due to the characteristics of stable vitality, oxygen resistance and moisture absorption resistance of the above leavening agent, the shelf life of self-rising flour products can be further significantly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of the preparation of leavening agents, and more particularly, to a leavening agent and a preparation method thereof. Background Art

[0002] Self-rising flour is compounded from an expanding agent, dry yeast powder, flour, etc. Generally, high-activity dry yeast powder and an expanding agent are added to flour together, and consumers only need to add water, knead and stir to make baked products. However, since the water content of flour is higher than that of dry yeast, dry yeast absorbs the moisture in flour and becomes activated during storage, resulting in a decrease in fermentation power and a reduction in the number of viable bacteria. Since self-rising flour or premixed flour is generally not vacuum-packed, the special yeast for self-rising flour needs to maintain its activity without a too rapid decline in the non-vacuum state and in the presence of other ingredients. As the storage time of self-rising flour prolongs, the required fermentation time increases, and even the situation of non-fermentation may occur. Summary of the Invention

[0003] The main object of the present invention is to provide a leavening agent and a preparation method thereof to solve the problems of too rapid decline in the activity of self-rising flour and longer fermentation time in the prior art.

[0004] To achieve the above object, according to one aspect of the present invention, a leavening agent is provided, which includes yeast particles and a coating layer coated on the surface of the yeast particles, wherein the coating layer includes grease and modified starch.

[0005] Further, the mass of the coating layer is 5-30% of the mass of the yeast particles, preferably 10-20%, and preferably the mass ratio of grease to modified starch is 1:0.5-2, preferably 1:0.5-1.

[0006] Further, the water content of the yeast particles is less than 5%, preferably the particle size of the yeast particles is 0.45-0.8 mm, preferably the yeast particles are spherical or rod-shaped, preferably spherical.

[0007] Further, the melting point of the grease is above 30°C, preferably grease with a melting point of 35-50°C, and preferably the grease is selected from any one or more of palm oil, coconut oil or lard, preferably palm oil.

[0008] Further, the viscosity peak value of the modified starch is less than 1000 BU.

[0009] According to another aspect of the present invention, a preparation method of the foregoing leavening agent is provided, which includes: extruding and molding a yeast composition and then performing first drying to obtain yeast particles; coating a protective agent on the surface of the yeast particles and then performing second drying to form a leavening agent, wherein the protective agent includes grease, modified starch and water, and the yeast composition includes yeast and additives.

[0010] Furthermore, the mass ratio of the above-mentioned grease, modified starch and water is 1:0.5-2:3.5-7.

[0011] Furthermore, on a dry weight basis, the above yeast composition comprises: 987-994 parts by weight of yeast, 5-10 parts by weight of sorbitan monostearate, and 1-3 parts by weight of vitamin C.

[0012] Furthermore, in the above first drying, the water loss rate of the formed yeast granules is controlled at 0.7-1% / min. Preferably, during the drying process, the air temperature is 45-60 °C, the air volume is 60-100 m 3 / h, and preferably the time of the first drying is 1-1.5 h.

[0013] Furthermore, the above coating is spraying. Preferably, the temperature during the spraying process is controlled at 30-35 °C. Preferably, the weight gain rate of the yeast granules is controlled at 0.5-1.5% / 10 min. The weight gain of the yeast granules refers to the ratio of the increased mass of the yeast granules after coating to the mass of the yeast granules before coating.

[0014] Applying the technical solution of the present invention, the main function of the grease in the coating layer of the present invention is to wrap the yeast and slow down the absorption of water by the yeast granules. The modified starch in the coating layer can replace part of the yeast to absorb a small amount of water, so that it can not only relieve the degree of yeast inactivation due to water absorption, but also improve the solubility of starch in water, and then it is easier to release the yeast inside the embedding layer. Therefore, due to the characteristics of the above-mentioned leavening agent having stable activity, oxygen resistance and moisture absorption resistance, the shelf life of the self-rising flour product can be further significantly improved. Specific Embodiments

[0015] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the embodiments.

[0016] As analyzed in the background art of the present application, there are problems in the prior art that the activity of self-rising flour decreases too fast and the fermentation time is relatively long. To solve this problem, the present application provides a leavening agent and a preparation method thereof.

[0017] In a typical embodiment of the present application, a leavening agent is provided. The leavening agent comprises yeast granules and a coating layer coated on the surface of the yeast granules. Among them, the coating layer comprises grease and modified starch.

[0018] The main function of the grease in the coating layer of the present invention is to wrap the yeast and slow down the absorption of water by the yeast particles. The modified starch in the coating layer can replace part of the yeast to absorb a small amount of water, so that it can not only alleviate the degree of yeast inactivation due to water absorption, but also improve the solubility of starch in water, and then easily release the yeast inside the embedding layer. Therefore, due to the characteristics of stable vitality, oxygen resistance and moisture absorption resistance of the above-mentioned leavening agent, the shelf life of the self-rising flour product can be further significantly improved.

[0019] In addition, compared with the existing instant dry yeast, the yeast particles with a coating layer can be transported in a non-vacuum packaging state, and the quality requirements for the packaging material are lower than those of the existing instant dry yeast, which can reduce the packaging cost.

[0020] In an embodiment of the present application, the mass of the above-mentioned coating layer is 5-30% of the mass of the yeast particles, preferably 10-20%, and the preferred mass ratio of grease to modified starch is 1:0.5-2, preferably 1:0.5-1.

[0021] The grease in the coating layer has a water-blocking effect on the yeast particles, but the grease will also cause a certain degree of decrease in the solubility of the yeast during the application process. The coating layer itself has no fermentation activity. The preferred mass of the coating layer can not only give full play to its water-blocking effect on the yeast particles, but also will not cause a great impact on the overall fermentation activity of the leavening agent. The preferred mass ratio of grease to modified starch helps to balance the water-blocking property of the grease and the water-absorbing and solubilizing property of the modified starch, so as to optimize the performance of the leavening agent.

[0022] In an embodiment of the present application, the water content of the above-mentioned yeast particles is less than 5%, preferably the particle size of the yeast particles is 0.45-0.8 mm, preferably the yeast particles are spherical or rod-shaped, preferably spherical.

[0023] Compared with yeast particles of the same mass, the yeast particles with the preferred particle size and the preferred spherical shape help to minimize their specific surface area as much as possible, so that the contact area with the flour is smaller, and then greatly slow down the absorption rate of water in the environment during storage. The preferred water content of the above-mentioned yeast particles being less than 5% is beneficial to reducing the influence of water on its activity and helps to extend its shelf life.

[0024] Preferably, the melting point of the above-mentioned grease is above 30 °C, preferably the grease with a melting point of 35-50 °C, and the preferred grease is selected from any one or more of palm oil, coconut oil, lard, and butter, preferably palm oil, so as to help control the smell of the coating layer.

[0025] The modified starch is easy to gelatinize and has good film-forming property after gelatinization. Preferably, the peak viscosity of the above-mentioned modified starch is lower than 1000 BU, which helps to disperse the oil more evenly and can replace yeast to absorb water in the short term. At the same time, compared with oil, the modified starch is more soluble in water after fully absorbing water, which helps to improve the solubility of the leavening agent in water during the fermentation process.

[0026] In another typical embodiment of the present application, a preparation method of the above-mentioned leavening agent is provided. The preparation method includes: extruding and molding the yeast composition and then performing the first drying to obtain yeast particles; coating a protective agent on the surface of the yeast particles and performing the second drying to form a leavening agent, wherein the protective agent includes oil, modified starch and water, and the yeast composition includes yeast and additives.

[0027] Through the above preparation method, the components containing oil and modified starch are simultaneously coated on the surface of the yeast particles, so that the oil therein can be used to slow down the absorption of water by the yeast particles. The modified starch can replace part of the yeast to absorb a small amount of water, which can not only alleviate the degree of yeast inactivation due to water absorption, but also improve its solubility in water, and then release the internal yeast more quickly. Therefore, due to the characteristics of the above-mentioned leavening agent having stable activity, high temperature resistance, oxygen resistance and high humidity resistance, the shelf life of the self-rising flour product can be further significantly improved.

[0028] Preferably, the mass ratio of the above-mentioned oil, modified starch and water is 1:0.5 - 2:3.5 - 7, which helps the protective agent to be a uniform dispersion system and better achieve coating on the surface of the yeast particles.

[0029] In some embodiments of the present application, based on dry weight, preferably, the yeast composition after drying includes: 987 - 994 parts by weight of yeast, 5 - 10 parts by weight of sorbitan monostearate, and 1 - 3 parts by weight of vitamin C, which helps to obtain high-activity yeast particles.

[0030] The yeast in the above yeast composition is a high-sugar type yeast in GB / T 20886.1-2021 "Yeast for Food Processing", which will not be elaborated here.

[0031] In one embodiment of the present application, in the above first drying, the water loss rate of the formed yeast particles is controlled at 0.7 - 1% / min. Preferably, during the drying process, the air temperature is 45 - 60°C, the air volume is 60 - 100m 3 / h, and preferably the time of the first drying is 1 - 1.5h.

[0032] Control the above air temperature and air volume to slow down the water loss rate of yeast, so that the boiling time in the drying bed is longer. The impact between particles and between particles and the bed wall makes the surface of yeast denser, which slows down the water absorption to a certain extent. This is conducive to controlling the water loss rate during the drying process within the above range, improving the density of the yeast particle surface, and then reducing the water absorption rate of yeast particles from the environment. At the same time, the lower air temperature keeps the overall temperature of the yeast low, thus reducing the impact of the air temperature on the fermentation power of the yeast.

[0033] In an embodiment of the present application, the above coating is spraying. Preferably, the temperature during spraying is controlled at 30 - 35°C, and preferably the weight gain rate of yeast particles is controlled at 0.5 - 1.5% / 10min. The weight gain of yeast particles refers to the ratio of the increased mass of yeast particles after coating to the mass of yeast particles before coating.

[0034] Controlling the temperature during spraying within the above range and controlling the weight gain rate of yeast particles within the above range helps to shorten the contact time with air and improve the uniformity of the coating layer on the basis of ensuring uniform coating, thereby helping to reduce the damage to the yeast activity during the entire spraying process.

[0035] The beneficial effects of the present application will be further described below in conjunction with embodiments.

[0036] Example 1

[0037] Based on dry weight, 994 parts by weight of high-sugar yeast containing 65% water (high-sugar type yeast in GB / T 20886.1 - 2021 "Yeast for Food Processing"), 10 parts by weight of sorbitan monostearate, and 3 parts by weight of vitamin C are mixed evenly and then extruded through a 0.65 mm aperture sieve, transferred to a fluidized bed. Set the air temperature at 50°C and the air volume at 80 m 3 / h, and perform the first drying for 1 hour until the water content is lower than 5%. The water loss rate during this first drying process is controlled at 1% / min to obtain yeast particles with a particle size of 0.45 mm.

[0038] Weigh 30 g of oxidized film-forming starch ETX1073 (Hangzhou Xulang Biotechnology Co., Ltd.) and 30 g of palm oil, add water to 210 g, place it in a 70°C water bath, and stir at 3000 rpm for 45 minutes to obtain a protective agent for standby.

[0039] At 30°C, use the bottom spray coating process to coat 400 g of yeast particles, control the feeding pump speed at 1 r / min, and control the weight gain rate of yeast particles at 1.25% / 10min. After coating for 120 minutes, stop the feeding pump, raise the air temperature to 60°C, and ensure that the water content of the yeast particles is not higher than 5% to obtain a fermenting agent with a yeast weight gain of about 15%.

[0040] Example 2

[0041] The difference from Example 1 is that the mass of the modified starch is 20 g, the mass of the palm oil is 40 g, the water is 140 g, the weight gain rate of the yeast granules is controlled at 1.25% / 10 min, and a leavening agent with a yeast weight gain of about 15% is finally obtained.

[0042] Example 3

[0043] The difference from Example 1 is that the mass of the modified starch is 40 g, the mass of the palm oil is 20 g, the water is 140 g, the weight gain rate of the yeast granules is controlled at 1.25% / 10 min, and a leavening agent with a yeast weight gain of about 15% is finally obtained.

[0044] Example 4

[0045] The difference from Example 1 is that the mass of the modified starch is 10 g, the mass of the palm oil is 50 g, the water is 140 g, the weight gain rate of the yeast granules is controlled at 1.25% / 10 min, and a leavening agent with a yeast weight gain of about 15% is finally obtained.

[0046] Example 5

[0047] The difference from Example 1 is that the mass of the modified starch is 50 g, the mass of the palm oil is 10 g, the water is 140 g, the weight gain rate of the yeast granules is controlled at 1.25% / 10 min, and a leavening agent with a yeast weight gain of about 15% is finally obtained.

[0048] Example 6

[0049] The difference from Example 1 is that no palm oil is used and the oil is butter, and a leavening agent with a yeast weight gain of about 15% is finally obtained.

[0050] Example 7

[0051] The difference from Example 1 is that the modified starch is MIRA-MIST 662NG (Tate & Lyle Trading (Shanghai) Co., Ltd.), and a leavening agent with a yeast weight gain of about 15% is finally obtained.

[0052] Example 8

[0053] 987 parts of high-sugar-tolerant yeast containing 65% water (the same as in Example 1), 5 parts of sorbitan monostearate, and 2 parts of vitamin C are mixed evenly, then extruded and formed, rounded by a rounding machine, and then transferred to a fluidized bed. The particle size can be adjusted by the screen aperture to obtain yeast granules with a particle size of 0.5 mm, and a leavening agent with a yeast weight gain of about 15% is finally obtained.

[0054] Example 9

[0055] The difference from Example 8 is that the particle size of the yeast granules is 0.8 mm, and a leavening agent with a yeast weight gain of about 15% is finally obtained.

[0056] Example 10

[0057] The difference from Example 8 is that the particle size of the yeast granules is 0.3 mm, and a leavening agent with a yeast weight gain of about 15% is finally obtained.

[0058] Example 11

[0059] The difference from Example 1 is that the air temperature is 45 °C, the air volume is 60 m 3 / h, the time of the first drying is 1.5 h, the water loss rate during the first drying process is controlled at 0.7% / min, and a leavening agent with a yeast weight gain of about 15% is finally obtained.

[0060] Example 12

[0061] The difference from Example 1 is that the air temperature is 50 °C, the air volume is 70 m 3 / h, the time of the first drying is 1.3 h, the water loss rate during the first drying process is controlled at 0.8% / min, and a leavening agent with a yeast weight gain of about 15% is finally obtained.

[0062] Example 13

[0063] The difference from Example 1 is that the air temperature is 70 °C, the air volume is 120 m 3 / h, the time of the first drying is 0.5 h, the water loss rate during the first drying process is controlled at 1.2% / min, and a leavening agent with a yeast weight gain of about 15% is finally obtained.

[0064] Example 14

[0065] The difference from Example 1 is that the weight gain rate of the yeast granules is controlled at 0.5% / 10 min. After coating for 300 minutes, the feed pump is stopped, and the air temperature is increased to 60 °C to ensure that the water content of the yeast granules is not higher than 5%. Finally, a leavening agent with a yeast weight gain of about 15% is obtained.

[0066] Example 15

[0067] The difference from Example 1 is that the weight gain rate of the yeast granules is controlled at 1.5% / 10 min. After coating for 100 minutes, the feed pump is stopped, and the air temperature is increased to 60 °C to ensure that the water content of the yeast granules is not higher than 5%. Finally, a leavening agent with a yeast weight gain of about 15% is obtained.

[0068] Example 16

[0069] The difference from Example 1 is that the weight gain rate of the yeast granules is controlled at 1.7% / 10 min. After coating for 88 minutes, the feed pump is stopped, and the air temperature is increased to 60°C to ensure that the water content of the yeast granules is not higher than 5%. Finally, a leavening agent with a yeast weight gain of about 15% is obtained.

[0070] Example 17

[0071] The difference from Example 1 is that the mass of the modified starch is 20 g, the mass of the palm oil is 20 g, the water is 140 g, and the weight gain rate of the yeast granules is controlled at 1.25% / 10 min. Finally, a leavening agent with a yeast weight gain of about 10% is obtained.

[0072] Example 18

[0073] The difference from Example 1 is that the mass of the modified starch is 40 g, the mass of the palm oil is 40 g, the water is 280 g, and the weight gain rate of the yeast granules is controlled at 1.25% / 10 min. Finally, a leavening agent with a yeast weight gain of about 20% is obtained.

[0074] Example 19

[0075] The difference from Example 1 is that the mass of the modified starch is 10 g, the mass of the palm oil is 10 g, the water is 70 g, and the weight gain rate of the yeast granules is controlled at 1.25% / 10 min. Finally, a leavening agent with a yeast weight gain of about 5% is obtained.

[0076] Example 20

[0077] The difference from Example 1 is that the mass of the modified starch is 60 g, the mass of the palm oil is 60 g, the water is 420 g, and the weight gain rate of the yeast granules is controlled at 1.25% / 10 min. Finally, a leavening agent with a yeast weight gain of about 30% is obtained.

[0078] Comparative Example 1

[0079] The difference from Example 1 is that the yeast granules are not coated and directly used as a leavening agent.

[0080] 4.2 g of the samples of Examples 1 to 20 and Comparative Example 1 above were respectively mixed evenly with 280 g of flour (moisture content 12.98%), and the leavening power was measured for 1 hour. After standing for three months, the leavening power was measured again for 1 hour. The yeast leavening power method was detected according to the method of GB / T 20886.1-2021 "Yeast for food processing". The results are as follows.

[0081] Table 1

[0082]

[0083] As can be seen from the above description, the above embodiments of the present invention achieve the following technical effects:

[0084] The main function of the grease in the coating layer of the present invention is to wrap the yeast and slow down the absorption of water by the yeast particles. The modified starch in the coating layer can replace part of the yeast to absorb a small amount of water, so that it can not only alleviate the degree of yeast inactivation due to water absorption, but also improve the solubility of starch in water, and then more easily release the yeast inside the embedding layer. Therefore, due to the characteristics of stable vitality, oxygen resistance and moisture absorption resistance of the above leavening agent, the shelf life of the self-rising flour product can be further significantly improved.

[0085] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A leavening agent, characterized in that, The starter culture includes yeast granules and a coating layer coated on the surface of the yeast granules, wherein the coating layer includes oil and modified starch; The mass of the coating layer is 10-30% of the mass of the yeast granules; The preparation method of the starter culture includes: Extruding and molding the yeast composition and then performing first drying to obtain yeast granules; Coating a protective agent on the surface of the yeast granules and performing second drying to form the starter culture, wherein the protective agent includes oil, modified starch and water, and the mass ratio of the oil, the modified starch and the water is 1:0.5-2:3.5-7; the yeast composition includes yeast and additives; The weight gain rate of the yeast granules is controlled at 0.5-1.5% / 10 min, and the weight gain of the yeast granules refers to the ratio of the increased mass of the yeast granules after coating to the mass of the yeast granules before coating.

2. The starter culture according to claim 1, characterized in that, The mass of the coating layer is 10-20% of the mass of the yeast granules.

3. The starter culture according to claim 1 or 2, characterized in that, The water content of the yeast granules is less than 5%.

4. The starter culture according to claim 1 or 2, characterized in that, The particle size of the yeast granules is 0.45-0.8 mm.

5. The starter according to claim 1 or 2, characterized in that, The yeast granules are spherical or rod-shaped.

6. The starter culture according to claim 5, characterized in that, The yeast granules are spherical.

7. The starter according to claim 1 or 2, characterized in that, The melting point of the oil is above 30°C.

8. The starter according to claim 7, characterized in that, The melting point of the oil is 35-50°C.

9. The starter according to claim 1 or 2, characterized in that, The oil is selected from any one or more of palm oil, coconut oil, lard, and butter.

10. The starter according to claim 9, characterized in that, The oil is palm oil.

11. The starter culture according to claim 1 or 2, characterized in that, The peak viscosity of the modified starch is less than 1000 BU.

12. A method for preparing the starter culture according to any one of claims 1 to 11, characterized in that, The preparation method includes: Extruding and molding the yeast composition and then performing first drying to obtain yeast granules; Coating a protective agent on the surface of the yeast granules and performing second drying to form the starter culture, wherein the protective agent includes oil, modified starch and water, and the mass ratio of the oil, the modified starch and the water is 1:0.5-2:3.5-7; the yeast composition includes yeast and additives; The coating is spraying, the temperature during the spraying process is controlled at 30-35°C, the weight gain rate of the yeast granules is controlled at 0.5-1.5% / 10 min, and the weight gain of the yeast granules refers to the ratio of the increased mass of the yeast granules after coating to the mass of the yeast granules before coating.

13. The preparation method according to claim 12, characterized in that, Based on dry weight, the yeast composition includes: 987-994 parts by weight of yeast; 5-10 parts by weight of sorbitan monostearate; and 1-3 parts by weight of vitamin C.

14. The preparation method according to claim 12 or 13, characterized in that, In the first drying process, the water loss rate of the formed yeast granules is controlled at 0.7 - 1% / min. During the drying process, the air temperature is 45 - 60°C and the air volume is 60 - 100 m 3 / h.

15. The preparation method according to claim 12 or 13, characterized in that, The time of the first drying is 1-1.5 h.

Images