Rice cake capable of regulating postprandial blood sugar and inhibiting starch aging and preparation method of rice cake

Abstract

The invention discloses a rice cake capable of regulating postprandial blood sugar and inhibiting starch aging, and belongs to the field of food processing and preservation. The rice cake is prepared from the following raw materials in parts by mass: 100 to 300 parts of polished round-grained rice flour, 100 to 200 parts of glutinous rice flour, 5 to 30 parts of pre-gelatinized corn starch, 5 to 30 parts of wheat type B starch granules and 100 to 300 parts of water. The pre-gelatinized corn starch-wheat type B starch composite preservative prepared by mixing the pre-gelatinized starch and the wheat type B starch in proportion can effectively inhibit hardness increase caused by starch aging and retrogradation in the storage process of the rice cake and avoid taste deterioration. Meanwhile, by adding the composite starch, the digestibility rate of the rice cake is remarkably reduced, and the metabolic regulation characteristic similar to that of low glycemic index food is endowed to the product. The characteristic of a cleaning label formed by natural components of the rice highly conforms to the development trend of healthy food, and the rice is especially suitable for functional rice product development of people needing to control postprandial blood sugar fluctuation.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of food processing, and particularly relates to a rice cake with the functions of regulating postprandial blood glucose and inhibiting starch aging and a preparation method thereof. BACKGROUND

[0002] As a traditional rice product, rice cake is favored by consumers due to its unique soft and glutinous texture. However, during storage at room temperature or in a cold storage, starch molecules in the rice cake will undergo irreversible aging denaturation through recrystallization (retrogradation), resulting in a significant increase in hardness and deterioration in taste. This phenomenon usually occurs within 3-5 days of storage, which seriously restricts the shelf life and eating experience of the product and has become a long-standing technical bottleneck in the industry. Although the addition of exogenous additives helps to improve the storage performance of the rice cake and inhibit starch aging, the requirements for food additives in the production of rice cake are extremely strict, and the only additive currently allowed for use is epsilon-polylysine hydrochloride.

[0003] Pre-gelatinized starch is usually used as a binder to improve the taste and storage performance of food. For example, patent CN105124426A discloses a stuffed rice cake and a preparation method thereof, which improves the quality and internal structure of the rice cake by adding denatured starch (pre-gelatinized starch) and prolongs the shelf life. Although pre-gelatinized starch can improve the quality of rice cake to some extent, on the one hand, its improvement of the quality of rice cake is limited, and excessive addition will result in high adhesion and decreased chewing resilience of the rice cake, and on the other hand, pre-gelatinized starch forms rapidly digestible starch due to high depolymerization, which significantly increases the glycemic index after being ingested by the human body and increases the risk of metabolic diseases such as diabetes.

[0004] Therefore, there is an urgent need to develop a rice cake formula that can effectively improve the texture characteristics of rice cake, prolong its shelf life, and also has a hypoglycemic effect. SUMMARY

[0005] In view of the above problems, the present application aims to provide a rice cake with the functions of regulating postprandial blood glucose and inhibiting starch aging and a preparation method thereof, so as to solve the problems of hardness increase and high glycemic index due to starch retrogradation during storage of existing rice cakes. The hardness of the rice cake prepared by the present application is lower than that of rice cakes without pre-gelatinized starch and wheat B-type starch, has a lower starch digestion rate, and significantly reduces the aging and retrogradation of starch during storage, which can effectively improve the storage quality of rice cake and reduce the deterioration of taste.

[0006] In order to achieve the above object, the present application provides a rice cake with the functions of regulating postprandial blood glucose and inhibiting starch aging, which comprises 100-300 parts of japonica rice powder, 100-200 parts of waxy rice powder, 5-30 parts of pregelatinized starch, 5-30 parts of wheat B-type starch granules and 100-300 parts of water.

[0007] In one embodiment of the present application, the rice cake comprises 200-300 parts of japonica rice powder, 150-200 parts of waxy rice powder, 10-20 parts of pregelatinized starch, 10-20 parts of wheat B-type starch granules and 200-300 parts of water.

[0008] In one embodiment of the present application, the rice cake comprises 300 parts of japonica rice powder, 200 parts of waxy rice powder, 15 parts of pregelatinized starch, 15 parts of wheat B-type starch granules and 260 parts of water.

[0009] In one embodiment of the present application, the pregelatinized starch comprises at least one of pregelatinized corn starch, pregelatinized rice starch, pregelatinized cassava starch and pregelatinized waxy rice powder.

[0010] The present application also provides a preparation method of the rice cake with the functions of regulating postprandial blood glucose and inhibiting starch aging, which comprises the following steps: uniformly mixing japonica rice powder, waxy rice powder, pregelatinized starch, wheat B-type starch and water, stirring, extending and pressing to form a rice cake dough, and then steaming the dough to be cooked.

[0011] In one embodiment of the present application, the preparation method of the pregelatinized starch is as follows: adding 500-800 mL of ultrapure water into a beaker, adding 25-50 g of starch, ultrasonically treating for 5 min, water-bathing in a water bath to make the liquid temperature in the beaker reach 50 DEG C for 5 min, then increasing the temperature to 65 DEG C for 5 min, then increasing the temperature to 80 DEG C for 5 min, then taking out, rapidly cooling with liquid nitrogen, and freeze-drying with a freeze dryer.

[0012] In one embodiment of the present application, the extraction and purification method of the B-type starch granules is as follows: mixing wheat flour and water to form a smooth dough, repeatedly kneading and washing the dough with water until the washing water is clear and transparent; sieving the starch milk obtained by washing the dough, standing and centrifuging, scraping off the gray impurities on the surface of the obtained precipitate, washing the obtained starch with anhydrous ethanol, removing the ethanol by vacuum filtration, and freeze-drying to obtain wheat B-type starch.

[0013] In one embodiment of the present application, the specific method for extracting and purifying B-type starch granules is as follows: 500-700 g of wheat flour is poured into a mixing bowl, followed by the slow addition of 300-350 mL of distilled water, and thoroughly mixed until the surface of the dough is smooth. Subsequently, the mixed dough is placed in a fermentation box with a constant temperature of 30 DEG C and a relative humidity of 80%, and allowed to ferment for 30 min. This process helps to strengthen the gluten network structure, thereby allowing better separation of starch from gluten protein in the subsequent process. After the dough fermentation is completed, the weight of the flour is 8-10 times the amount of distilled water, and the dough is repeatedly kneaded and washed. Until the washing water is clear and transparent, indicating that the starch in the dough has been basically separated. The obtained starch milk is filtered twice through a 120 mesh sieve to effectively remove impurities such as bran. After the screening is completed, the starch milk is allowed to stand at room temperature for 8 h, and then centrifuged at a centrifugal force of 3000 g for 15 min. After centrifugation, the supernatant is carefully poured off, and the surface gray impurities are carefully scraped off. An appropriate amount of distilled water is added to the remaining precipitate to prepare a dilute starch milk, which is again centrifuged, and the supernatant is discarded and the upper impurities are scraped off. This step is repeated three times. Then, the precipitate is resuspended with distilled water, allowed to stand for 2 h, and the supernatant is collected. The remaining precipitate is treated in the same way, and the cycle is repeated five times. After the above treatment, the supernatant mainly contains B starch, and the entire supernatant is collected and centrifuged at a centrifugal force of 4000 g for 15 min. The supernatant is discarded, and the upper gray impurities are scraped off. The lower precipitate is B starch. The obtained B starch granules are washed with three times the volume of anhydrous ethanol, and the excess ethanol is removed by vacuum filtration. Finally, the separated B starch granules are freeze-dried, ground into powder, sieved through a 100 mesh sieve, and the obtained starch can be used for subsequent experiments.

[0014] The present application also discloses a rice cake preservative for regulating postprandial blood glucose and inhibiting starch aging, which comprises pregelatinized starch and wheat B-type starch, and the mass ratio of the pregelatinized starch to the wheat B-type starch in the rice cake preservative is 1:2-2:1.

[0015] The present application also discloses the application of the above rice cake preservative in low GI food.

[0016] Beneficial effects:

[0017] (1) The present application can effectively improve the storage performance of rice cakes, improve product quality, and reduce the digestibility of starch in rice cakes by adding pregelatinized starch and wheat B-type starch to the raw materials of rice cakes. And the added corn starch and wheat starch are well known to the public, are natural ingredients, have high safety, and will not change the original taste of rice cakes.

[0018] (2) The pre-gelatinized starch and wheat B-type starch are compounded in a certain ratio, and then added to rice cake products, which can effectively reduce the cooking loss rate and hardness of the rice cake, and effectively increase the content of resistant starch in the rice cake, and reduce the digestibility of the rice cake. The single pre-gelatinized starch and wheat B-type starch have limited effect on reducing the cooking loss rate and hardness, and the addition of single pre-gelatinized starch increases the content of resistant starch, which shows that the pre-gelatinized starch and wheat B-type starch in the application are synergistically combined to improve the quality of rice cake and reduce blood sugar.

[0019] (3) The pre-gelatinized corn starch-wheat B-type starch composite preservative prepared by mixing pre-gelatinized starch and wheat B-type starch in a certain ratio can effectively inhibit the increase in hardness of starch products caused by starch aging and retrogradation during storage, and avoid deterioration of taste. At the same time, the addition of the composite preservative significantly reduces the digestibility rate of rice cake, and gives the product similar metabolic regulation characteristics of low glycemic index food. The "clean label" characteristics of natural ingredients are highly consistent with the development trend of healthy food, and are especially suitable for the development of functional rice products for people who need to control postprandial blood glucose fluctuations. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 The hardness change of rice cake during storage in Example 2, Comparative Example 1, Comparative Example 3 and Comparative Example 6. DETAILED DESCRIPTION

[0021] The application will be described in detail below with reference to the drawings and examples. In the following description, many specific details are set forth in order to provide a thorough understanding of the application, but the application can also be implemented in other ways different from those described herein, and those skilled in the art can make similar generalizations without departing from the scope of the application. Therefore, the application is not limited to the specific examples disclosed below.

[0022] The preparation method of pre-gelatinized corn starch involved in the examples and comparative examples of the application is as follows:

[0023] 500 mL of ultrapure water was added to a beaker, and then 25 g of corn starch was added. After ultrasonic treatment for 5 min, the liquid in the beaker was water-bathed in a water bath to reach 50 DEG C for 5 min, then the temperature was raised to 65 DEG C for 5 min, then the temperature was raised to 80 DEG C for 5 min, then it was taken out and rapidly cooled with liquid nitrogen, and then freeze-dried with a freeze dryer.

[0024] The preparation and purification method of wheat B-type starch granules involved in the examples and comparative examples of the application is as follows:

[0025] Put 500g wheat flour into a mixing bowl, then slowly add 300mL distilled water, mix well until the dough surface is smooth. Then, put the mixed dough into a proofing box with constant temperature of 30℃ and relative humidity of 80%, and proof for 30min. This process helps to strengthen the gluten network structure, so that the subsequent separation of starch and gluten protein is better. After the dough is proofed, use 8-10 times the weight of the flour distilled water to repeatedly knead and wash it. Until the washing water is clear and transparent, indicating that the starch in the dough has been basically separated. The obtained starch milk is filtered through a 120 mesh sieve twice to effectively remove impurities such as bran. After screening is completed, the starch milk is placed at room temperature for 8h, then centrifuged at 3000g for 15min. After centrifugation, carefully pour off the supernatant, and carefully remove the surface gray impurities. Add an appropriate amount of distilled water to the remaining precipitate to prepare a dilute starch milk, and repeat the centrifugation and discarding of the supernatant and removing the upper impurities. This step is repeated three times. Then, resuspend the precipitate with distilled water, stand for 2h, and collect the supernatant; the remaining precipitate is treated in the same way, and the cycle is repeated five times. After the above treatment, the supernatant mainly contains B starch, and the collected supernatant is centrifuged at 4000g for 15min, the supernatant is discarded, and the upper gray impurities are scraped off. The lower precipitate is B starch. The obtained B starch particles are washed with three times the volume of anhydrous ethanol, and the excess ethanol is removed by vacuum filtration. Finally, the separated B starch particles are freeze-dried, ground into powder, sieved through a 100 mesh sieve, and the obtained starch can be used for subsequent experiments.

[0026] Example 1

[0027] A rice cake with the functions of regulating postprandial blood glucose and inhibiting starch aging, comprising the following raw materials in mass fraction: 300 parts of japonica rice flour, 200 parts of waxy rice flour, 10 parts of pregelatinized corn starch, 10 parts of wheat B-type starch particles, and 260 parts of water.

[0028] The preparation method comprises the following steps:

[0029] Stir 300 parts of japonica rice flour, 200 parts of waxy rice flour, 10 parts of pregelatinized corn starch, 10 parts of wheat B-type starch particles, and 260 parts of water to form a dough; extrude the dough into a shape, steam it to cook, and then seal and package it.

[0030] Example 2

[0031] A rice cake with the functions of regulating postprandial blood glucose and inhibiting starch aging, comprising the following raw materials in mass fraction: 300 parts of japonica rice flour, 200 parts of waxy rice flour, 15 parts of pregelatinized corn starch, 15 parts of wheat B-type starch particles, and 260 parts of water.

[0032] The preparation method comprises the following steps:

[0033] 300 parts of japonica rice flour, 200 parts of waxy rice flour, 15 parts of pre-gelatinized corn starch, 15 parts of wheat B-type starch granules, 260 parts of water are stirred to form a dough; the dough is extruded into a shape, sealed and packaged after steaming.

[0034] Example 3

[0035] A rice cake with the functions of regulating postprandial blood glucose and inhibiting starch aging, comprising the following raw materials in mass fraction: 300 parts of japonica rice flour, 200 parts of waxy rice flour, 20 parts of pre-gelatinized corn starch, 20 parts of wheat B-type starch granules, and 260 parts of water.

[0036] The preparation method comprises the following steps:

[0037] 300 parts of japonica rice flour, 200 parts of waxy rice flour, 20 parts of pre-gelatinized corn starch, 20 parts of wheat B-type starch granules, and 260 parts of water are stirred to form a dough; the dough is extruded into a shape, sealed and packaged after steaming.

[0038] Example 4

[0039] A rice cake with the functions of regulating postprandial blood glucose and inhibiting starch aging, comprising the following raw materials in mass fraction: 300 parts of japonica rice flour, 200 parts of waxy rice flour, 20 parts of pre-gelatinized corn starch, 10 parts of wheat B-type starch granules, and 260 parts of water.

[0040] The preparation method comprises the following steps:

[0041] 300 parts of japonica rice flour, 200 parts of waxy rice flour, 20 parts of pre-gelatinized corn starch, 10 parts of wheat B-type starch granules, and 260 parts of water are stirred to form a dough; the dough is extruded into a shape, sealed and packaged after steaming.

[0042] Example 5

[0043] A rice cake with the functions of regulating postprandial blood glucose and inhibiting starch aging, comprising the following raw materials in mass fraction: 300 parts of japonica rice flour, 200 parts of waxy rice flour, 10 parts of pre-gelatinized corn starch, 20 parts of wheat B-type starch granules, and 260 parts of water.

[0044] The preparation method comprises the following steps:

[0045] 300 parts of japonica rice flour, 200 parts of waxy rice flour, 10 parts of pre-gelatinized corn starch, 20 parts of wheat B-type starch granules, and 260 parts of water are stirred to form a dough; the dough is extruded into a shape, sealed and packaged after steaming.

[0046] Comparative Example 1

[0047] A rice cake, comprising the following raw materials in mass fraction: 300 parts of japonica rice flour, 200 parts of waxy rice flour, and 260 parts of water.

[0048] The preparation method comprises the following steps:

[0049] 300 parts of japonica rice powder, 200 parts of waxy rice powder, and 260 parts of water are mixed and stirred to form a dough; the dough is extruded into a shape, sealed and packaged after steaming.

[0050] Comparative Example 2

[0051] A pregelatinized corn starch rice cake comprises the following raw materials in mass parts: 300 parts of japonica rice powder, 200 parts of waxy rice powder, 10 parts of pregelatinized corn starch, and 260 parts of water.

[0052] The preparation method comprises the following steps:

[0053] 300 parts of japonica rice powder, 200 parts of waxy rice powder, 10 parts of pregelatinized corn starch, and 260 parts of water are mixed and stirred to form a dough; the dough is extruded into a shape, sealed and packaged after steaming.

[0054] Comparative Example 3

[0055] A pregelatinized corn starch rice cake comprises the following raw materials in mass parts: 300 parts of japonica rice powder, 200 parts of waxy rice powder, 15 parts of pregelatinized corn starch, and 260 parts of water.

[0056] The preparation method comprises the following steps:

[0057] 300 parts of japonica rice powder, 200 parts of waxy rice powder, 15 parts of pregelatinized corn starch, and 260 parts of water are mixed and stirred to form a dough; the dough is extruded into a shape, sealed and packaged after steaming.

[0058] Comparative Example 4

[0059] A pregelatinized corn starch rice cake comprises the following raw materials in mass parts: 300 parts of japonica rice powder, 200 parts of waxy rice powder, 20 parts of pregelatinized corn starch, and 260 parts of water.

[0060] The preparation method comprises the following steps:

[0061] 300 parts of japonica rice powder, 200 parts of waxy rice powder, 20 parts of pregelatinized corn starch, and 260 parts of water are mixed and stirred to form a dough; the dough is extruded into a shape, sealed and packaged after steaming.

[0062] Comparative Example 5

[0063] A wheat B-type starch rice cake comprises the following raw materials in mass parts: 300 parts of japonica rice powder, 200 parts of waxy rice powder, 10 parts of wheat B-type starch, and 260 parts of water.

[0064] The preparation method comprises the following steps:

[0065] 300 parts of japonica rice flour, 200 parts of waxy rice flour, 10 parts of wheat B-type starch, 260 parts of water are mixed and stirred to form a dough; the dough is extruded into a shape, sealed and packaged after steaming and cooking.

[0066] Comparative Example 6

[0067] A wheat B-type starch rice cake, comprising the following mass fractions of raw materials: 300 parts of japonica rice flour, 200 parts of waxy rice flour, 15 parts of wheat B-type starch, 260 parts of water.

[0068] The preparation method comprises the following steps:

[0069] 300 parts of japonica rice flour, 200 parts of waxy rice flour, 15 parts of wheat B-type starch, 260 parts of water are mixed and stirred to form a dough; the dough is extruded into a shape, sealed and packaged after steaming and cooking.

[0070] Comparative Example 7

[0071] A wheat B-type starch rice cake, comprising the following mass fractions of raw materials: 300 parts of japonica rice flour, 200 parts of waxy rice flour, 20 parts of wheat B-type starch, 260 parts of water.

[0072] The preparation method comprises the following steps:

[0073] 300 parts of japonica rice flour, 200 parts of waxy rice flour, 20 parts of wheat B-type starch, 260 parts of water are mixed and stirred to form a dough; the dough is extruded into a shape, sealed and packaged after steaming and cooking.

[0074] Comparative Example 8

[0075] A rice cake with the functions of regulating postprandial blood glucose and inhibiting starch aging, comprising the following mass fractions of raw materials: 300 parts of japonica rice flour, 200 parts of waxy rice flour, 5 parts of pregelatinized corn starch, 20 parts of wheat B-type starch granules, 260 parts of water.

[0076] The preparation method comprises the following steps:

[0077] 300 parts of japonica rice flour, 200 parts of waxy rice flour, 5 parts of pregelatinized corn starch, 20 parts of wheat B-type starch granules, 260 parts of water are mixed and stirred to form a dough; the dough is extruded into a shape, sealed and packaged after steaming and cooking.

[0078] Comparative Example 9

[0079] A rice cake with the functions of regulating postprandial blood glucose and inhibiting starch aging, comprising the following mass fractions of raw materials: 300 parts of japonica rice flour, 200 parts of waxy rice flour, 20 parts of pregelatinized corn starch, 5 parts of wheat B-type starch granules, 260 parts of water.

[0080] The preparation method comprises the following steps:

[0081] 300 parts of japonica rice flour, 200 parts of waxy rice flour, 20 parts of pregelatinized corn starch, 5 parts of wheat B-type starch granules, 260 parts of water are stirred to form a dough; the dough is extruded into a shape, sealed and packaged after steaming and cooking.

[0082] Table 1: Raw material ratio table of examples 1-5 and comparative examples 1-9

[0083] Examples Sushi rice flour (parts) Waxy rice flour (parts) Water (parts) Pre-gelatinized corn starch (parts) Wheat type B starch (parts) Example 1 300 200 260 10 10 Example 2 300 200 260 15 15 Example 3 300 200 260 20 20 Example 4 300 200 260 10 20 Example 5 300 200 260 20 10 Comparative Example 1 300 200 260 0 0 Comparative Example 2 300 200 260 10 0 Comparative Example 3 300 200 260 15 0 Comparative Example 4 300 200 260 20 0 Comparative Example 5 300 200 260 0 10 Comparative Example 6 300 200 260 0 15 Comparative Example 7 300 200 260 0 20 Comparative Example 8 300 200 260 5 20 Comparative Example 9 300 200 260 20 5

[0084] Test results of rice cake performance

[0085] 30 parts of rice cakes prepared in the examples and comparative examples are respectively placed in 500 parts of water and boiled under a slightly boiling condition, and the cooking loss rate of the rice cakes is determined according to the standard AACC66-50 method; the hardness of the rice cakes is measured using a texture analyzer. The results are shown in Table 2. The smaller the cooking loss rate and the smaller the hardness represent the better texture quality of the rice cakes.

[0086] Table 2: Performance test of rice cakes prepared in examples and comparative examples

[0087]

[0088]

[0089] As can be seen from the above table, both the pregelatinized corn starch and the wheat B-type starch can significantly reduce the loss and hardness of the rice cakes during cooking. By adding the pregelatinized corn starch and the wheat B-type starch into the rice cakes in proportion, the cooking loss and hardness of the examples are significantly lower than those of the comparative examples. This may be due to the strong gelation of the pregelatinized starch and the mutual adhesion between the starch and the wheat B-type starch in the presence of water under heating, so that the cooking loss of the rice cakes is significantly reduced. And after adding the pregelatinized corn starch and the wheat B-type starch, the hardness of the rice cakes is significantly reduced, which can improve the taste of the rice cakes.

[0090] According to the experimental data of examples and comparative examples 8-9, it can be seen that the addition ratio of the pregelatinized starch and the wheat B-type starch also has a great influence on the cooking loss and hardness of the rice cakes. Specifically, when the amount of the pregelatinized starch added exceeds 15 parts, adding a small amount of the wheat B-type starch not only cannot continue to reduce the cooking loss and hardness, but also will increase them. Similarly, if the amount of the pregelatinized starch added is small, it also cannot significantly reduce the cooking loss and hardness.

[0091] Test results of rice cake taste and flavor

[0092] After the rice cakes of the examples and the comparative examples were cooked for the best cooking time, the rice cakes were immediately taken out, placed in bowls respectively, tasted, and the sensory evaluation team evaluated the taste, texture, shape, color and the like of the rice cakes in four aspects, the sensory evaluation scoring standards were shown in Table 3, and the sum of the average scores of the rice cakes of each example and the comparative example in the above four aspects was calculated as the sensory evaluation score of the example and the comparative example, and the results were shown in Table 4.

[0093] Table 3 Sensory evaluation scoring standards of rice cakes

[0094]

[0095]

[0096] Table 4 Sensory evaluation of rice cakes of examples and comparative examples

[0097] Sensory score Example 1 97.06 ± 0.57 a ]] Example 2 98.25 ± 0.7 a ]] Example 3 97.45 ± 0.58 a ]] Example 4 97.12 ± 0.56 a <!-- 7 -->]]> Example 5 97.34 ± 0.36 a ]] Comparative Example 1 79.37 ± 0.85 h ]] Comparative Example 2 85.48 ± 0.3 f ]] Comparative Example 3 87.16 ± 0.27 d ]] Comparative Example 4 87.72 ± 0.74 d ]] Comparative Example 5 86.37 ± 0.27 e ]] Comparative Example 6 82.95 ± 0.17 g ]] Comparative Example 7 89.23 ± 0.08 c ]] Comparative Example 8 90.24 ± 0.31 b ]] Comparative Example 9 90.34 ± 0.53 b ]]

[0098] It can be known from the comparison of the data of examples 1-5 and comparative examples 1-9 that the rice cakes prepared by the examples have better taste.

[0099] Test results of digestibility of rice cakes

[0100] 0.2 g (dry weight of powder) of the sample to be tested was accurately weighed, 5 glass beads were added, 5 mL of acetic acid-sodium acetate buffer solution (0.2 mol / L, pH 5.2) was added, and gelatinization was carried out at 90°C for 30 min. After the acetic acid-sodium acetate buffer solution (10 mL) was added and stirred uniformly, it was placed in a 37°C water bath for 10 min. Then 1 mL of saccharifying enzyme (15 U / mL) and 9 mL of α-amylase (290 U / mL) (both were incubated at 37°C for 10 min) were added, and digestion was carried out in a 37°C constant temperature water bath shaker. The reaction time was accurately recorded, and 1 mL of the reaction solution was taken at 0 min, 20 min and 120 min respectively. 2 mL of anhydrous ethanol was added to inactivate the enzyme, and centrifuged at 3000 r / min for 10 min. 1 mL of the supernatant was taken, DNS reagent was added, and colorimetry was carried out at 540 nm. The glucose content produced was determined. The specific calculation formulas of rapidly digestible starch (RDS), slowly digestible starch (SDS) and resistant starch (RS) are as follows:

[0101] Rapidly digestible starch (RDS) = (G20-FG) x 0.9 / TS x 100%

[0102] Slowly digestible starch (SDS) = (G120-G20) x 0.9 / TS x 100%

[0103] Resistant starch (RS) = [TS-(RDS+SDS)] / TS x 100%

[0104] G20: glucose content (mg) produced after 20 min of amylase hydrolysis

[0105] G120: glucose content (mg) produced after 120 min of amylase hydrolysis

[0106] FG: free glucose content (mg) contained in the sample without amylase hydrolysis

[0107] TS: total starch content

[0108] It should be noted that the lower the digestibility of fast digestible starch represents the more resistant to digestion. The results are shown in Table 5.

[0109] Table 5: Digestibility of rice cake of examples and comparative examples (%)

[0110]

[0111]

[0112] The results show that from the above table, the fast digestible starch digestibility of the rice cake of the examples is lower than that of the comparative examples, and the slow digestible starch and resistant starch are higher than those of the comparative examples. The starch digestion core of low GI food is to release glucose slowly, which depends on the dominant role of slow digestion and resistant starch. It is shown that the pre-gelatinized corn starch-wheat B-type starch rice cake can be used as a low GI food.

[0113] Test results of hardness of rice cake during storage

[0114] The rice cake samples of Example 2 and Comparative Examples 1, 3 and 5 after storage were boiled in boiling water for 6 min, and the hardness of the samples was determined by TA-XT plus texture analyzer with p / 36R probe in TPA mode. Each sample was compressed twice at a speed of 1 mm / s, and the deformation level was set to 50% of the original sample. The results are shown in Table 6, the lower the hardness, the better the effect. Figure 1

[0115] Through the hardness and sensory evaluation of Table 2 and Table 4, the best mass fraction of pre-gelatinized corn starch-wheat B-type starch (15 parts of pre-gelatinized corn starch and 15 parts of wheat B-type starch) was selected for storage experiment. The rice cakes in Example 2 and Comparative Examples 1, 3 and 6 were stored at 25°C. It was found by the texture meter that under the same storage time, the hardness of the rice cake of the example was significantly reduced, which could slow down the increase of the hardness of the rice cake during storage. (Under the same storage days, different letters represent significant differences.)

[0116] ​The above examples are not intended to limit the scope of the present application, nor are the described steps intended to limit the order in which they are performed. Modifications apparent to one skilled in the art in light of the above teachings are intended to fall within the scope of the claims.

Claims

1. A rice cake having the function of regulating postprandial blood sugar and inhibiting starch aging, characterized in that: The rice cake comprises 100-300 parts by weight of japonica rice powder, 100-200 parts by weight of glutinous rice powder, 5-30 parts by weight of pregelatinized starch, 5-30 parts by weight of wheat B-type starch granules, and 100-300 parts by weight of water.

2. The rice cake according to claim 1, characterized by, The rice cake comprises 200-300 parts by weight of japonica rice powder, 150-200 parts by weight of glutinous rice powder, 10-20 parts by weight of pregelatinized starch, 10-20 parts by weight of wheat B-type starch granules, and 200-300 parts by weight of water.

3. The rice cake according to claim 1, characterized by, The rice cake comprises 300 parts by weight of japonica rice powder, 200 parts by weight of glutinous rice powder, 15 parts by weight of pregelatinized starch, 15 parts by weight of wheat B-type starch granules, and 260 parts by weight of water.

4. The rice cake according to claim 1, wherein The pregelatinized starch comprises at least one of pregelatinized corn starch, pregelatinized rice starch, pregelatinized tapioca starch, and pregelatinized glutinous rice powder.

5. The rice cake according to claim 1, wherein The pregelatinized starch is prepared by adding 500-800 mL of ultrapure water into a beaker, adding 25-50 g of starch, ultrasonically treating for 5 min, water-bathing in a water bath to make the liquid in the beaker reach 50 ℃ for 5 min, then increasing the temperature to 65 ℃ for 5 min, and then increasing the temperature to 80 ℃ for 5 min, and then quickly cooling with liquid nitrogen, and freeze-drying.

6. The rice cake according to claim 1, wherein The wheat B-type starch granules are extracted and purified by mixing wheat flour with water to form a smooth dough, repeatedly kneading and washing the dough with water until the washing water is clear and transparent, sieving the starch milk obtained by washing the dough, centrifuging and removing the gray impurities on the surface of the obtained precipitate, washing the obtained starch with anhydrous ethanol, vacuum filtering to remove the ethanol, and freeze-drying to obtain the wheat B-type starch.

7. A method for preparing the rice cake according to any one of claims 1 to 6, characterized by, The method comprises the following steps: uniformly mixing the japonica rice powder, the glutinous rice powder, the pregelatinized starch, the wheat B-type starch, and the water, stirring, and then extending and pressing to form a rice cake dough, and then steaming the rice cake dough to be cooked.

8. A rice cake preservative for regulating postprandial blood glucose and inhibiting starch retrogradation, characterized by comprising the compound according to claim 1. The rice cake preservative comprises pregelatinized starch and wheat B-type starch, and the mass ratio of the pregelatinized starch to the wheat B-type starch in the rice cake preservative is 1:2-2:

1.

9. Use of the rice cake preservative of claim 8 in low GI food.

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