Preparation method and application of freeze-dried instant rice composite additive

Abstract

The invention discloses a preparation method of a freeze-dried instant rice composite additive, which is characterized by comprising the following preparation steps: step (1), soaking washed raw material rice in trehalose solutions with different concentrations, and continuously stirring in a constant-temperature water bath state to obtain raw material rice treated by the trehalose solutions with different concentrations, the preparation method comprises the following steps: (1) washing raw material rice, then cooking, dipping and braising rice, and then carrying out vacuum freeze drying, and (2) soaking the washed raw material rice in glutaminase solutions with different concentrations. The rehydration performance and sensory quality of the freeze-dried rice are researched by compounding trehalose, glutaminase and beta-amylase additives in different proportions; the compound ratio of trehalose, glutaminase and beta-amylase compound additives with better sensory quality is selected by selecting the compound ratio of the trehalose, glutaminase and beta-amylase compound additives with better sensory quality, so that the freeze-dried rice with better sensory quality can be prepared, the components are green and safe, the operation is simple, and the effect is better when the compound additives are applied to the freeze-dried rice.

Description

Technical Field

[0001] The invention relates to the technical field of composite additives, in particular to a preparation method of a freeze-dried instant rice composite additive and application thereof. Background Art

[0002] Rice has a fresh, sweet taste and high nutritional value. As an indispensable staple food, it has entered the market with huge market potential. In today's fast-paced world, the development of freeze-dried instant rice can continuously shorten people's cooking time, greatly enrich rice products, and increase the added value of rice processing. During the vacuum freeze-drying production and processing of freeze-dried instant rice, the taste quality and rehydration characteristics of the freeze-dried instant rice will deteriorate due to the aging and regeneration of starch. In order to maintain the rehydration characteristics and sensory quality of freeze-dried instant rice, certain measures need to be taken to treat the freeze-dried instant rice. A single additive is usually used on the market to improve this adverse effect.

[0003] However, the improvement effect of a single additive used in freeze-dried instant rice is usually poor. Therefore, it is necessary to provide a preparation method and application of a composite additive to process freeze-dried instant rice in a more efficient, safe and simple manner to improve the rehydration properties of freeze-dried instant rice. Summary of the invention

[0004] The present invention provides a preparation method of a composite additive for freeze-dried instant rice and an application thereof, which can effectively solve the problem in the above background technology that the improvement effect of a single additive used for freeze-dried instant rice is usually poor.

[0005] To achieve the above object, the present invention provides the following technical solution: a method for preparing a freeze-dried instant rice composite additive, comprising the following preparation steps:

[0006] Step (1), soaking the washed raw rice in trehalose solutions of different concentrations, stirring continuously in a constant temperature water bath to obtain raw rice treated with trehalose solutions of different concentrations, then steaming, soaking and stewing the rice and then vacuum freeze-drying it;

[0007] Step (2), soaking the washed raw rice in glutaminase solutions of different concentrations, stirring continuously in a constant temperature water bath to obtain raw rice treated with glutaminase solutions of different concentrations, then steaming, soaking and stewing the rice and then vacuum freeze-drying it;

[0008] Step (3), soaking the washed raw rice in β-amylase solutions of different concentrations, stirring continuously in a constant temperature water bath, obtaining raw rice treated with β-amylase solutions of different concentrations, and then steaming, soaking and stewing the rice and then vacuum freeze-drying it;

[0009] Step (4), soaking the washed raw rice in a composite additive solution mixed in different concentration ratios, stirring continuously in a constant temperature water bath state, obtaining raw rice treated with the composite additive solution mixed in different concentration ratios, then steaming, soaking and stewing the rice, and then vacuum freeze-drying;

[0010] The composite additive solution is a combination of trehalose, glutaminase and beta-amylase.

[0011] According to the above technical solution, in step (1), the concentration of the trehalose aqueous solution is 0.5-2.5%;

[0012] The temperature of the constant temperature water bath is 30-50℃;

[0013] The stirring time is 70-90 minutes;

[0014] The stirring rate is 2000-2800 rpm;

[0015] The ratio of rice to solution is 1:1-1:1.5.

[0016] According to the above technical solution, in step (2), the concentration of the glutaminase aqueous solution is 0.5-2.5%;

[0017] The temperature of the constant temperature water bath is 30-50℃;

[0018] The stirring time is 70-90 minutes;

[0019] The stirring rate is 2000-2800 rpm;

[0020] The ratio of rice to solution is 1:1-1:1.5.

[0021] According to the above technical solution, in step (3), the concentration of the β-amylase aqueous solution is 0.4-2.0%;

[0022] The temperature of the constant temperature water bath is 30-50℃;

[0023] The stirring time is 70-90 minutes;

[0024] The stirring rate is 2000-2800 rpm;

[0025] The ratio of rice to solution is 1:1-1:1.5.

[0026] According to the above technical solution, in step (4), the Box-Behken Design (BBD) design method is used to optimize the addition ratio of three additives (trehalose, glutaminase, β-amylase) at different concentrations;

[0027] The additives are a combination of trehalose, glutaminase and β-amylase;

[0028] The temperature of the constant temperature water bath is 30-50℃;

[0029] The stirring time is 70-90 minutes;

[0030] The stirring rate is 2000-2800 rpm;

[0031] The ratio of rice to solution is 1:1-1:1.5.

[0032] According to the above technical solution, the composite additive is used in freeze-dried instant rice to improve the rehydration performance and taste quality.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] 1. The composite additive of the present invention contains only trehalose, glutaminase and β-amylase, all of which are food raw materials, without chemical additives, and has safe ingredients and is green and environmentally friendly.

[0035] 2. The preparation method of the composite additive of the present invention is simple and easy to operate, and after the freeze-dried rice is soaked, no other processing operations are required during the refrigerated storage of the freeze-dried rice.

[0036] 3. The composite additive of the present invention is based on the excellent properties of β-amylase. The rice is treated with a combination of trehalose, glutaminase and β-amylase. The synergistic effect between the components enables the composite additive to well improve the sensory quality of the freeze-dried rice after rehydration, thereby solving the problem of quality degradation of the rice after freeze-drying and rehydration.

[0037] 4. The present invention utilizes β-amylase to fundamentally solve the problem of poor sensory quality of freeze-dried rice after rehydration due to aging and regeneration of starch in the rice, further improves the quality maintenance effect of the composite additive on the freeze-dried rice, and more effectively improves the sensory quality of the freeze-dried rice after rehydration.

[0038] 5. Among the various materials of the composite additive of the present invention, there is no substance with a strong odor, and it will not affect the flavor of the freeze-dried rice.

[0039] In summary, by studying the effects of different proportions of trehalose, glutaminase and β-amylase additives on the rehydration performance and sensory quality of freeze-dried rice, the composite proportion of trehalose, glutaminase and β-amylase composite additives with better sensory quality was selected, so that freeze-dried rice with better sensory quality can be prepared, and the ingredients are green and safe, the operation is simple, and the application effect in freeze-dried rice is better. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention.

[0041] In the attached picture:

[0042] Figure 1 This is a graph showing the effect of different concentrations of trehalose on the quality of freeze-dried instant rice;

[0043] Figure 2 is a graph showing the effect of different concentrations of glutaminase on the quality of freeze-dried instant rice;

[0044] Figure 3 is a graph showing the effect of different concentrations of β-amylase on the quality of freeze-dried instant rice;

[0045] Figure 4 is a schematic diagram of the response surface of the interaction between trehalose and glutaminase with sensory scores as responses in the present invention;

[0046] Figure 5 is a contour plot of the interaction between trehalose and glutaminase in response to sensory scores of the present invention;

[0047] Figure 6 is a schematic diagram of the response surface of the interaction between trehalose and β-amylase with sensory scores as responses in the present invention;

[0048] Figure 7 is a contour map of the interaction between trehalose and β-amylase in response to sensory scores of the present invention;

[0049] Figure 8 is a schematic diagram of the response surface of the interaction between glutaminase and β-amylase with sensory scores as responses in the present invention;

[0050] Fig. 9 is a contour plot of the interaction between glutaminase and β-amylase in response to sensory scores of the present invention;

[0051] Fig.10 It is a diagram of the preparation steps of the composite additive of the present invention. DETAILED DESCRIPTION

[0052] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0053] Embodiment 1:

[0054] like Fig.10 As shown, in this embodiment, fresh rice is soaked with additives according to the following steps:

[0055] (1) After washing away dirt on the surface of five portions of Northeastern polished rice (500 g) with purified water, the rice was added into 600 mL of trehalose aqueous solution with concentrations of 0.5%, 1.0%, 1.5%, 2.0% and 2.5%, respectively, and stirred at 2000 rpm for 80 min in a constant temperature water bath at 40°C;

[0056] (2) The rice that has been fully soaked and stirred is steamed and soaked for 20 minutes. After the steaming is completed, the rice is simmered for 3 minutes, and then taken out and vacuum-frozen and dried (pre-freezing temperature is -20°C, time is 4 hours; freeze-drying temperature is -55°C, time is 24 hours; vacuum degree is maintained at about 5Pa) and then vacuum-packed to obtain the finished product.

[0057] Embodiment 2:

[0058] like Fig.10 As shown, in this embodiment, fresh rice is soaked with additives according to the following steps:

[0059] (1) After rinsing the dirt off the surface of five portions of Northeastern polished rice (500 g) with purified water, the rice was added into 600 mL of glutaminase aqueous solution with concentrations of 0.5%, 1.0%, 1.5%, 2.0% and 2.5%, respectively, and stirred at 2000 rpm for 80 min in a constant temperature water bath at 40° C.;

[0060] (2) The rice that has been fully soaked and stirred is steamed and soaked for 20 minutes. After the steaming is completed, the rice is simmered for 3 minutes, and then taken out and vacuum-frozen and dried (pre-freezing temperature is -20°C, time is 4 hours; freeze-drying temperature is -55°C, time is 24 hours; vacuum degree is maintained at about 5Pa) and then vacuum-packed to obtain the finished product.

[0061] Embodiment 3:

[0062] like Fig.10 As shown, in this embodiment, fresh rice is soaked with additives according to the following steps:

[0063] (1) After rinsing the dirt off the surface of five portions of Northeastern polished rice (500 g) with purified water, the rice was added into 600 mL of β-amylase aqueous solution with concentrations of 0.4%, 0.8%, 1.2%, 1.6% and 2.0%, respectively, and stirred at 2000 rpm for 80 min in a constant temperature water bath at 40°C;

[0064] (2) The rice that has been fully soaked and stirred is steamed and soaked for 20 minutes. After the steaming is completed, the rice is simmered for 3 minutes, and then taken out and vacuum-frozen and dried (pre-freezing temperature is -20°C, time is 4 hours; freeze-drying temperature is -55°C, time is 24 hours; vacuum degree is maintained at about 5Pa) and then vacuum-packed to obtain the finished product.

[0065] Embodiment 4:

[0066] like Fig.10 As shown, in this embodiment, fresh rice is soaked with additives according to the following steps:

[0067] (1) After rinsing the dirt on the surface of 17 portions of 500 g Northeastern polished rice with purified water, the rice was added to the composite additive aqueous solution with different proportions and concentrations as shown in Table 2, and stirred at 2000 rpm for 80 min in a constant temperature water bath at 40° C.;

[0068] (2) The rice that has been fully soaked and stirred is steamed and soaked for 20 minutes. After the steaming is completed, the rice is simmered for 3 minutes, and then taken out and vacuum-frozen and dried (pre-freezing temperature is -20°C, time is 4 hours; freeze-drying temperature is -55°C, time is 24 hours; vacuum degree is maintained at about 5Pa) and then vacuum-packed to obtain the finished product.

[0069] Comparative Example 1:

[0070] In this comparative example, after using pure water to rinse off the dirt on the surface of 500g Northeastern polished rice, it is not soaked in any additives and is directly vacuum freeze-dried (pre-freezing temperature is -20°C, time is 4h; freeze-drying temperature is -55°C, time is 24h; vacuum degree is maintained at 5Pa) and then vacuum-packed to obtain the finished product. The Northeastern polished rice in this comparative example is counted as the control group.

[0071] Comparative Example 2:

[0072] (1) In this comparative example, 500 g of Northeastern polished rice was rinsed clean of dirt on its surface with purified water, and then added to a mixed solution of trehalose concentration of 2.0%, glutaminase concentration of 1.0% and β-amylase concentration of 0.8%, and stirred at 2000 rpm in a constant temperature water bath at 40°C for 80 min;

[0073] (2) The rice that has been fully soaked and stirred is steamed and soaked for 20 minutes. After the steaming is completed, the rice is simmered for 3 minutes, and then taken out and vacuum-frozen and dried (pre-freezing temperature is -20°C, time is 4 hours; freeze-drying temperature is -55°C, time is 24 hours; vacuum degree is maintained at 5Pa) and then vacuum-packed to obtain the finished product.

[0074] After the rice of the embodiment and the comparative example is processed, the freeze-dried rice is put into a fresh-keeping bag and vacuum-packed, and stored at 4° C. for 24 hours, and the quality of the processed samples is tested and analyzed.

[0075] 100 g of the finished freeze-dried rice was placed in a clean beaker, 150 mL of 100°C hot water was added, and the mixture was placed in a 100°C water bath for 15 min. During the period, the mixture was stirred continuously with a spoon to ensure that all the rice grains were fully rehydrated. The rehydrated freeze-dried rice was sensory evaluated by 10 sensory judges according to the standards in Table 1, and the sensory score results were averaged in points.

[0076] The sensory quality of the freeze-dried rice after rehydration in Example 1 and Comparative Example 1 was evaluated using the standards in Table 1. The results are as follows: Figure 1-3 shown.

[0077] Weigh 10 g of freeze-dried rice and place it in a beaker filled with boiling water. Then place it in a constant temperature water bath at 100°C. Take a grain of rice and place it on a glass plate every 1 min to observe whether there is a white core in the rice grain. After the white core appears, measure it every 10 s until it disappears. The recorded time at this time is the rehydration time of the freeze-dried rice, in minutes.

[0078] like Figure 1 As shown, by comparing the sensory scores of Comparative Example 1 with those of Example 1, it can be seen that the sensory score of the freeze-dried rice after rehydration in Comparative Example 1 is the lowest, indicating that the appropriate concentration of trehalose treatment can effectively improve the sensory quality of the freeze-dried rice after rehydration; however, as the concentration continues to increase, the trehalose treatment will instead reduce the sensory quality of the freeze-dried rice after rehydration. When the trehalose concentration is 2.0%, the sensory score of the freeze-dried rice after rehydration is the highest, reaching 13, indicating that the optimal concentration of trehalose treatment of rice is 2.0%.

[0079] like Figure 2 As shown, the rehydration time of the freeze-dried rice treated with glutaminase decreases continuously with the increase of glutaminase concentration, among which the rehydration time of the freeze-dried rice treated with 2.5% glutaminase is the shortest, and the rehydration time of the freeze-dried rice in Comparative Example 1 is the longest, indicating that glutaminase treatment of rice can effectively reduce the rehydration time of freeze-dried rice.

[0080] like Figure 2 As shown, by comparing the sensory scores of Comparative Example 1 and Example 2, it can be seen that the sensory score of the freeze-dried rice after rehydration in Comparative Example 1 is the lowest, indicating that the appropriate concentration of glutaminase treatment can effectively improve the sensory quality of the freeze-dried rice after rehydration; but as the concentration continues to increase, the glutaminase treatment will instead reduce the sensory quality of the freeze-dried rice after rehydration. When the glutaminase concentration is 1.5%, the sensory score of the freeze-dried rice after rehydration is the highest, indicating that the optimal concentration of glutaminase treatment of rice is 1.5%.

[0081] like Figure 3 As shown, the rehydration time of the freeze-dried rice treated with β-amylase decreases continuously with the increase of β-amylase concentration, among which the rehydration time of the freeze-dried rice treated with 2.5% β-amylase is the shortest, and the rehydration time of the freeze-dried rice in Comparative Example 1 is the longest, indicating that β-amylase treatment of rice can effectively reduce the rehydration time of freeze-dried rice.

[0082] like Figure 3As shown, by comparing the sensory scores of Comparative Example 1 and Example 3, it can be seen that the sensory score of the freeze-dried rice after rehydration in Comparative Example 1 is the lowest, indicating that the appropriate concentration of β-amylase treatment can effectively improve the sensory quality of the freeze-dried rice after rehydration. When the β-amylase concentration is 1.2%, the sensory score of the freeze-dried rice after rehydration is the highest, indicating that the optimal concentration of β-amylase for treating rice is 1.2%.

[0083] The BBD experimental design composite model was selected to conduct a response surface analysis experiment with three factors and three levels, with a total of 17 test points (5 center points). Trehalose (A), glutaminase (B) and β-amylase (C) were used as independent variables, and sensory score (Y) was used as the response value. The response surface experiment was conducted using Design Expert 8.0.6 software. The response surface experimental design and results are shown in Figure 2. Figure 4-9 As shown, the response surface results were subjected to multiple regression fitting analysis, and the analysis results are shown in Table 3.

[0084] Design Expert 8.0.6 software was used to perform multiple regression fitting on the experimental model. The multiple regression equations of sensory score (Y) and trehalose (A), glutaminase (B) and β-amylase (C) were as follows:

[0085] Y=14.80+0.13A++0.00B+0.13C-0.50AB-0.25AC-0.50BC-2.53A 2 -

[0086] 0.78B 2 -2.52C 2

[0087] As shown in Table 3, in the regression model of the sensory score of freeze-dried rice rehydration, the P value is <0.01, indicating that the regression equation of the model is extremely significant and statistically significant.

[0088] The lack-of-fit item is 0.7510>0.05, indicating that the lack-of-fit item is not significant and there is no lack-of-fit factor;

[0089] The multiple correlation coefficient R of the model 2 =0.9838, Corrected correlation coefficient Adj R 2 =0.9630, indicating that the model fits the actual situation well, the experimental error is small, and the prediction accuracy of the sensory score of freeze-dried rice after rehydration is high.

[0090] In the regression model, the quadratic term A 2 , B 2 , C 2 Very significant (P<0.01);

[0091] The interaction terms AB and BC were significant (P<0.05);

[0092] The test results show that there is no simple linear relationship between the test factors and the response values.

[0093] Due to the aging and recovery of starch in rice, freeze-dried rice is prone to problems such as long rehydration time and poor rehydration effect. At the same time, starch aging and recovery will also cause the quality of freeze-dried rice to decrease after rehydration, resulting in poor taste and unpopularity among consumers. Therefore, sensory score is one of the important indicators for evaluating the rehydration quality of freeze-dried rice and has important practical significance.

[0094] The response surface diagram and contour diagram of the interaction between the two factors affecting the sensory score of freeze-dried rice after rehydration are shown in the figure. Figure 4-9 shown.

[0095] Depend on Figure 4-9 It can be seen that the contours of glutaminase (B) and β-amylase (C) are elliptical, and the response surface is relatively steep, indicating that the interaction between BC is significant;

[0096] The contour lines of trehalose (A) and glutaminase (B) are circular, and the response surface is steeper, indicating that the interaction between AB also has a significant effect on the sensory quality of freeze-dried rice after rehydration, and their interaction has a greater effect on the sensory quality of freeze-dried rice after rehydration.

[0097] The response surface plot can evaluate the impact of the interaction of experimental factors on the response value to determine the optimal level range.

[0098] The steeper the slope of the response surface, the more sensitive the response value is to changes in conditions. Conversely, the flatter the slope of the response surface, the less likely it is that changes in treatment conditions will affect the size of the response value.

[0099] After fitting and optimizing the regression equation of the optimal process parameters for the sensory quality of freeze-dried rice rehydrated under different additive solution treatment conditions using Design Expert 8.0.6 software, the optimal addition ratio of composite additives (trehalose, glutaminase and β-amylase) to treat freeze-dried rice was obtained as 2.0% trehalose, 1.0% glutaminase and 0.8% β-amylase.

[0100] According to the treatment method of comparative example 2, the sensory score of the freeze-dried rice treated under this condition reached 15 after rehydration, which is almost twice that of the control group. The effect was good after the treatment under the optimized conditions.

[0101] Table 1 Sensory scoring standards for freeze-dried rice

[0102]

[0103] Table 2 Response surface analysis design and results of the effects of composite additives on sensory scores of freeze-dried instant rice

[0104]

[0105] Table 3 Analysis of variance of regression equation with sensory scores as response

[0106]

[0107]

[0108] Finally, it should be noted that the above description is only a preferred example of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a freeze-dried instant rice composite additive, characterized in that: The method comprises the following preparation steps: Step (1), soaking the washed raw rice in trehalose solutions of different concentrations, stirring continuously in a constant temperature water bath to obtain raw rice treated with trehalose solutions of different concentrations, then steaming, soaking and stewing the rice and then vacuum freeze-drying it; Step (2), soaking the washed raw rice in glutaminase solutions of different concentrations, stirring continuously in a constant temperature water bath to obtain raw rice treated with glutaminase solutions of different concentrations, then steaming, soaking and stewing the rice and then vacuum freeze-drying it; Step (3), soaking the washed raw rice in β-amylase solutions of different concentrations, stirring continuously in a constant temperature water bath, obtaining raw rice treated with β-amylase solutions of different concentrations, and then steaming, soaking and stewing the rice and then vacuum freeze-drying it; Step (4), soaking the washed raw rice in a composite additive solution mixed in different concentration ratios, stirring continuously in a constant temperature water bath state, obtaining raw rice treated with the composite additive solution mixed in different concentration ratios, then steaming, soaking and stewing the rice, and then vacuum freeze-drying; The composite additive solution is a combination of trehalose, glutaminase and beta-amylase.

2. The method for preparing a freeze-dried instant rice composite additive according to claim 1, characterized in that: In the step (1), the concentration of the trehalose aqueous solution is 0.5-2.5%; The temperature of the constant temperature water bath is 30-50℃; The stirring time is 70-90 minutes; The stirring rate is 2000-2800 rpm; The ratio of rice to solution is 1:1-1:1.

5.

3. The method for preparing a freeze-dried instant rice composite additive according to claim 1, characterized in that: In the step (2), the concentration of the glutaminase aqueous solution is 0.5-2.5%; The temperature of the constant temperature water bath is 30-50℃; The stirring time is 70-90 minutes; The stirring rate is 2000-2800 rpm; The ratio of rice to solution is 1:1-1:1.

5.

4. The method for preparing a freeze-dried instant rice composite additive according to claim 1, characterized in that: In the step (3), the concentration of the β-amylase aqueous solution is 0.4-2.0%; The temperature of the constant temperature water bath is 30-50℃; The stirring time is 70-90 minutes; The stirring rate is 2000-2800 rpm; The ratio of rice to solution is 1:1-1:1.

5.

5. The method for preparing a freeze-dried instant rice composite additive according to claim 1, characterized in that: In the step (4), the Box-Behken Design (BBD) method is used to optimize the addition ratios of the three additives at different concentrations; The additives are a combination of trehalose, glutaminase and β-amylase; The temperature of the constant temperature water bath is 30-50℃; The stirring time is 70-90 minutes; The stirring rate is 2000-2800 rpm; The ratio of rice to solution is 1:1-1:1.

5.

6. Application of the composite additive prepared by the method for preparing a composite additive for freeze-dried instant rice according to any one of claims 1 to 5, characterized in that: The composite additives are used in freeze-dried instant rice to improve its rehydration performance and taste quality.

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