Preparation process of extruded recombinant rice capable of rapidly rehydrating

Abstract

The preparation process comprises the following steps: mixing rice starch and rice protein, adding 9% of konjac glucomannan, and uniformly mixing again; the rotating speed of screws is 75-150 rpm, the temperature of an area III of the extruder is 80-130 DEG C, the temperature of an area IV of the extruder is 70-120 DEG C, the feeding amount is 900-1900 g / h, and the moisture content of a mixture is 20-50%; and spraying, cooling and pre-freezing the extrudate, and drying to obtain the rapidly rehydrated extruded recombinant rice. The extruded recombined rice is moderate in hardness and viscosity, the rehydration time is less than 5 minutes, the rice does not need to be cooked in a pot, and the use is convenient. According to the method, KGM is added, and spraying and pre-freezing treatment is combined, so that the rehydration time of the recombinant rice is greatly shortened, the eating quality is improved, and better eating experience is achieved.

Description

Technical Field

[0001] The invention relates to a preparation process of rapidly rehydrated extruded reconstituted rice, belonging to the technical field of rice processing. Background Art

[0002] Extruded recombinant rice, also known as engineered rice, nutritious rice, artificial rice, composite rice, etc., is a rice product similar to ordinary rice that is made from starch as the main raw material and is made through material conditioning, extrusion recombinant rice, granulation, drying and other processes. Compared with natural rice, extruded recombinant rice has advantages in quality, nutrition, convenience and sustainability.

[0003] In the current food market, convenience has become an important consideration for many consumers when choosing ready-to-eat products, and rehydration time is an important indicator for measuring the convenience of ready-to-eat products. Most instant rice on the market is in line with this trend, and widely adopts the rehydration method of heating with heating packs to meet consumers' needs for quick meals. The rehydration time of this type of product is mostly concentrated between 12-15 minutes. Compared with traditional products that require steaming, the rehydration time is significantly shortened, making extruded reconstituted rice free from dependence on traditional cooking tools.

[0004] Extruded recombinant rice continues to attract consumers who pursue convenient, efficient and healthy eating, as it does not require complicated cooking tools and can be enjoyed anytime and anywhere, becoming an indispensable convenient food choice.

[0005] After searching, the patent application with publication number CN117814438A discloses a recombinant rice and a preparation method thereof. The method uses rice flour and edible starch as raw materials, adopts vacuum screw extrusion granulation, and adds amylase during the production process. The recombinant rice obtained by the method is more resistant to cooking and has a better taste than ordinary rice. However, the recombinant rice obtained by the method still needs to be cooked in a pot when used, which lacks convenience in use. Therefore, it is necessary to develop a more convenient and fast rehydration recombinant rice preparation process. Summary of the invention

[0006] In order to solve the above technical problems and further enhance the advantages of the extruded recombinant rice being fast and convenient, the present invention provides a preparation process of the extruded recombinant rice which can be quickly rehydrated and convenient.

[0007] The technical solution adopted by the present invention is:

[0008] A preparation process for rapidly rehydrated extruded reconstituted rice comprises the following steps:

[0009] (1) rice starch and rice protein mix in a mass ratio of 85-95:15-5, take the total amount of rice starch and rice protein as a benchmark, add 1-10% konjac glucomannan in the mixture, mix again to obtain a mixture;

[0010] (2) pelletizing the mixture through a twin-screw extruder, with a screw speed of 75-150 rpm and a feed rate of 900-1900 g / h, controlling the temperature of zone III of the twin-screw extruder to 80° C.-130° C. and the temperature of zone IV to 70° C.-120° C., with the temperature of zone III being 10° C. higher than the temperature of zone IV, and the moisture content of the mixture being 20-50%;

[0011] (3) pre-freezing the extrudate after granulation, the pre-freezing temperature being -18°C to -50°C;

[0012] (4) drying the pre-frozen reconstituted rice to obtain extruded reconstituted rice that can be quickly rehydrated.

[0013] Preferably, the mass ratio of rice starch to rice protein is 92:8; the added amount of konjac glucomannan is 9%;

[0014] Preferably, the screw speed is 120 rpm; the feed rate is 1100 g / h; and the moisture content of the mixture is 37%.

[0015] Preferably, the temperatures of zone III and zone IV of the twin-screw extruder are 130°C and 120°C respectively; a liquid spraying device is provided at the outlet of the twin-screw extruder, and the temperature of the sprayed liquid is 0°C-50°C.

[0016] The moisture content of the recombinant rice after drying is 2%-12%.

[0017] Beneficial effects of the present invention:

[0018] (1) The preparation process of the rapidly rehydrated extruded recombinant rice of the present invention includes process parameters such as the temperature of the III zone and IV zone of the screw extruder, the screw speed, the feed rate, the moisture content, the KGM addition amount, etc., which are all determined through experiments to obtain the optimal conditions of the preparation process. The extruded recombinant rice obtained under this process has a rehydration time of less than 5 minutes, which is much lower than that of existing products, does not need to be steamed in a pot, and is convenient to use.

[0019] (2) The present invention adds KGM to the raw materials and simultaneously uses a flushing and pre-freezing process for the extruded material, so that the obtained product has a short rehydration time, an increased water absorption index, moderate hardness and viscosity, and significantly improved product quality.

[0020] (3) The addition of KGM in the present invention can significantly shorten the rehydration time of extruded recombinant rice, while giving it better appearance structure, palatability and taste. The shower pre-freezing treatment can further shorten the rehydration time of extruded recombinant rice, and on this basis reduce its hardness, improve its palatability, and do not affect the smell, appearance structure, taste and cold rice texture of the recombinant rice. Therefore, the present invention not only greatly shortens the rehydration time of extruded recombinant rice by adding KGM and combining the shower pre-freezing treatment, but also significantly improves its edible quality, so that the extruded recombinant rice product has a better eating experience on the basis of convenience. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Effect of temperatures in zones III and IV of the screw extruder on the rehydration time of reconstituted rice;

[0022] Figure 2 The effect of screw speed on the rehydration time of extruded reconstituted rice;

[0023] Figure 3 Effect of feed amount on rehydration time of extruded reconstituted rice;

[0024] Figure 4 Effect of moisture content of mixed materials on rehydration time of extruded reconstituted rice;

[0025] Figure 5 Effect of KGM addition in raw materials on rehydration time of extruded reconstituted rice. DETAILED DESCRIPTION

[0026] The technical solution of the present invention is further described in detail below in conjunction with specific embodiments.

[0027] Example 1 A preparation process for rapidly rehydrated extruded reconstituted rice

[0028] (1) adding rice starch and rice protein in a ratio of 92:8 (w / w, dry basis) into a blender and mixing them uniformly to obtain a mixed powder; then adding 9% konjac glucomannan (KGM) relative to the weight of the mixed powder and stirring them uniformly again;

[0029] (2) adding the mixture to a twin-screw extruder for extrusion granulation, controlling the temperature of zone III and zone IV of the extruder to be 130° C. and 120° C., the screw speed to be 120 rpm, the feed rate to be 1100 g / h, and the moisture content of the mixture to be 37%;

[0030] A liquid spraying device is provided near the extruder outlet and the cutter to control the temperature of the sprayed liquid at 4°C-30°C to continuously cool the extrudate to prevent the extrudate from sticking to the cutter; the extrudate is then pre-frozen at a temperature of -18°C to -50°C;

[0031] (4) Drying the pre-frozen recombinant rice to a moisture content of 2%-12%, thereby obtaining the extruded recombinant rice that can be quickly rehydrated.

[0032] The rehydration time of the obtained extruded recombinant rice was 182.00s±2.27s.

[0033] Example 2: Determination of process parameters for the rapid rehydration and extrusion of reconstituted rice of the present invention

[0034] The optimal rehydration time was used as the standard for evaluating the rapidly rehydrated extruded reconstituted rice, and the effects of five factors on the product, including the temperature of zones III and IV of the twin-screw extruder, screw speed, feed rate, moisture content and KGM addition, were studied.

[0035] 2.1 Determination of the optimal temperature of zone III and zone IV of twin-screw extruder

[0036] The temperatures of Zone III and Zone IV of the twin-screw extruder were set to 6 gradients: 80°C and 70°C, 90°C and 80°C, 100°C and 90°C, 110°C and 100°C, 120°C and 110°C, and 130°C and 120°C, respectively, and six groups of experiments were carried out; other parameters of each group of experiments such as screw speed of 90rpm, feed rate of 1300g / h, moisture content of the mixture of 32%, and KGM addition of 5% were the same, and the raw materials and process were the same as in Example 1.

[0037] The rehydration time of the extruded recombinant rice obtained from six groups of experiments at different temperatures in zones III and IV was measured. Figure 1 shown.

[0038] It can be seen that with the increase of temperature in zones III and IV, the rehydration time of the extruded recombinant rice shows a trend of first decreasing and then increasing. The lowest rehydration time occurs when the temperatures in zones III and IV are 120°C and 110°C, respectively.

[0039] 2.2 Determination of the optimal screw speed for extruding recombined rice

[0040] The screw speed of the twin-screw extruder was set to 6 gradients: 75rpm, 90rpm, 105rpm, 120rpm, 135rpm, and 150rpm, and six groups of experiments were carried out. Other parameters of each group of experiments, such as feed rate of 1300g / h, moisture content of the mixture of 32%, temperatures of zone III and zone IV of 90°C and 80°C respectively, and KGM addition amount of 5%, were the same, and the raw materials and process were the same as in Example 1.

[0041] The rehydration time of reconstituted rice was measured under six different screw speed conditions. The results are as follows: Figure 2 shown.

[0042] It can be seen that as the screw speed increases, the rehydration time of the reconstituted rice shows a downward trend in the process of the screw speed increasing from 75 rpm to 120 rpm. When the screw speed is further increased to 150 rpm, the rehydration time does not change significantly, so the screw speed is selected as 120 rpm.

[0043] 2.3 Determination of the optimal feeding amount for extruded recombinant rice

[0044] The feeding rate of the twin-screw extruder was set to 6 gradients of 900 g / h, 1100 g / h, 1300 g / h, 1500 g / h, 1700 g / h, and 1900 g / h, and six groups of experiments were carried out. Other parameters of each group of experiments, such as screw speed of 90 rpm, moisture content of the mixture of 32%, temperatures of zone III and zone IV of 90°C and 80°C respectively, and KGM addition amount of 5%, were the same, and the raw materials and process were the same as in Example 1.

[0045] Finally, the rehydration time was measured under different feeding conditions. The results are as follows: Figure 3 shown.

[0046] It can be seen that with the increase of feed amount, the rehydration time of extruded reconstituted rice first decreases and then increases. The feed amount when the rehydration time reaches the lowest point is 1100g / h. Therefore, the optimal feed amount selected is 1100g / h.

[0047] 2.4 Determination of the optimal moisture content of extruded reconstituted rice

[0048] The moisture content of the mixture in the twin-screw extruder affects the extruded recombinant rice. The moisture content of the mixture is set to 22%, 28%, 32%, 37%, 40%, and 43% in a total of 6 gradients. Six groups of experiments are carried out. Other parameters of each group of experiments such as screw speed of 90rpm, feed rate of 1300g / h, temperatures of zone III and zone IV of 90°C and 80°C respectively, and KGM addition of 5% are the same, and the raw materials and process are the same as in Example 1.

[0049] The rehydration time of the six groups of reconstituted rice was measured. The results are as follows: Figure 4 It can be seen that as the moisture content of the mixture increases, the rehydration time of the extruded reconstituted rice shows a trend of first increasing, then decreasing, and then increasing. When the moisture content is 40%, the rehydration time is the shortest.

[0050] 2.5 Determination of the optimal amount of KGM added to extruded recombinant rice

[0051] The KGM addition amount was set to 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, and 10%, with a total of 10 gradients, and 10 groups of experiments were carried out. The screw speed of each group of experiments was 90 rpm, the feed rate was 1300 g / h, the moisture content was 32%, the temperatures of zone III and zone IV were 90°C and 80°C, respectively, and the raw materials and processes were the same as in Example 1.

[0052] The rehydration time of 10 groups of recombinant rice was measured respectively. Figure 5 The results showed that as the amount of KGM added increased from 1% to 8%, the rehydration time showed a downward trend; when the amount of KGM added continued to increase to 10%, the rehydration time remained basically unchanged. Therefore, the optimal rehydration time was selected when the amount of KGM added was 8%.

[0053] 2.6 Determination of the optimal preparation process conditions for extruded recombinant rice

[0054] Based on the single factor experiments in 2.1-2.6 above, L 16 (5 4 )Orthogonal experiment.

[0055] The experimental method remained consistent, and the experimental parameters were changed. The temperatures of zone III and zone IV of the twin-screw extruder were set to 100°C and 90°C, 110°C and 100°C, 120°C and 110°C, 130°C and 120°C, respectively; the screw speeds were 105rpm, 120rpm, 135rpm, 150rpm, respectively; the feed rates were 900g / h, 1100g / h, 1300g / h, 1500g / h, respectively; the moisture contents were 32%, 37%, 40%, 43%, respectively; the KGM addition amounts were 6%, 7%, 8%, 9%, respectively (Table 1), and the optimal process parameters for rapid rehydration and extrusion of reconstituted rice were determined.

[0056] The results of orthogonal experiments showed that the optimal parameter combination was A2B4C2D2E4. Therefore, the optimal process parameters for rapid rehydration and extrusion of reconstituted rice were determined as follows: extruder zone III and IV temperatures of 130°C and 120°C, screw speed of 120 rpm, feed rate of 1100 g / h, moisture content of 37%, and KGM addition of 9%.

[0057] Table 1 Orthogonal experimental factor level table of extruded recombinant rice

[0058]

[0059] Comparative Example 1 Preparation of extruded recombinant rice without adding KGM

[0060] The preparation method is basically the same as that in Example 1, except that KGM is not added to the raw materials. The amounts of other raw materials and the process are the same as those in Example 1 and will not be described in detail.

[0061] Comparative Example 2 Preparation of extruded recombinant rice without rinsing and pre-freezing

[0062] The preparation method is basically the same as that in Example 1, except that the rinsing and pre-freezing steps are not provided in the process, and the amounts of other raw materials and processes are the same as those in Example 1, which will not be described in detail.

[0063] Product Performance Analysis

[0064] The extruded recombinant rice of Example 1 and the two comparative examples were analyzed from the aspects of color, rehydration time, water absorption index, water solubility index, density, radial expansion ratio, cooking loss, texture characteristics, sensory evaluation, etc.

[0065] (1) Color analysis

[0066] As can be seen from Table 2, the recombinant rice of the present invention has lower brightness, deeper red hue, and no significant change in yellow hue compared with Comparative Example 1 (without KGM addition); compared with Comparative Example 2 (without pre-freezing by showering), the recombinant rice of the present invention has higher brightness, and weaker red and yellow hues.

[0067] Table 2 Color of three kinds of recombinant rice

[0068]

[0069] Among them, L* represents brightness, a* represents red-green hue, and b* represents yellow-blue hue. Different lowercase letters in the same column indicate significant differences (P<0.05).

[0070] (2) Rehydration time, water absorption index and water solubility index

[0071] As shown in Table 3, the extruded recombinant rice of the present invention has a shorter rehydration time, an increased water absorption index, and a decreased water solubility index compared with Comparative Example 1 (without KGM addition); compared with Comparative Example 2 (without pre-freezing by showering), the rehydration time of the recombinant rice of the present invention is significantly shortened, and there is no significant change in the water absorption index and water solubility index of the two.

[0072] Table 3 Rehydration time, water absorption index, and water solubility index of three types of recombinant rice

[0073]

[0074] (3) Density, radial expansion ratio, and cooking loss

[0075] As can be seen from Table 4, the density and cooking loss of the recombinant rice of the present invention are lower than those of Comparative Example 1 (without adding KGM), and the radial expansion ratio is higher than that of Comparative Example 1; compared with Comparative Example 2 (without rinsing and pre-freezing), the density, radial expansion ratio and cooking loss of the extruded recombinant rice of the present invention do not change significantly.

[0076] Table 4 Density, radial expansion ratio and cooking loss of three types of extruded recombinant rice

[0077]

[0078] (4) Texture characteristics

[0079] As can be seen from Table 5, the hardness and viscosity of the recombinant rice of the present invention are higher than those of the comparative example 1 (without KGM), and the elasticity is not as good as that of the extruded recombinant rice without KGM. Compared with the comparative example 2 (without pre-freezing by showering), the hardness of the extruded recombinant rice of the present invention decreases, and the viscosity and elasticity do not change significantly.

[0080] Table 5 Texture characteristics of three types of extruded recombinant rice

[0081]

[0082] (5) Sensory evaluation

[0083] The recombinant rice of the present invention was subjected to a sensory evaluation, and the sensory evaluation scoring standard was based on Appendix B of GB / T 15682-2008 Grain and Oil Inspection Paddy Rice, Rice Cooking and Edible Quality Sensory Evaluation Method.

[0084] The sensory evaluation results are shown in Table 6. It can be seen from Table 6 that the appearance structure, palatability and cold rice texture of the recombinant rice of the present invention are significantly better than those of Comparative Example 1 (without adding KGM), and there is no significant difference in smell and taste compared with Comparative Example 1; compared with Comparative Example 2 (without rinsing and pre-freezing), there is no significant difference in smell, appearance structure, taste and cold rice texture, while the palatability is significantly higher than that of Comparative Example 2 (without rinsing and pre-freezing).

[0085] Table 6 Comparison of sensory evaluation of three types of extruded recombinant rice

[0086]

[0087] It can be seen that the addition of KGM in the present invention can significantly shorten the rehydration time of extruded recombinant rice, while giving it better appearance, palatability and taste. The pre-freezing treatment can further shorten the rehydration time of extruded recombinant rice, reduce its hardness on this basis, improve its palatability, and has no effect on the smell, appearance structure, taste and cold rice texture of the recombinant rice.

Claims

1. A process for preparing rapidly rehydrated extruded reconstituted rice, characterized in that: The following steps are involved: (1) rice starch and rice protein mix in a mass ratio of 85-95:15-5, take the total amount of rice starch and rice protein as a benchmark, add 1-10% konjac glucomannan in the mixture, mix again to obtain a mixture; (2) pelletizing the mixture through a twin-screw extruder, with a screw speed of 75-150 rpm and a feed rate of 900-1900 g / h, controlling the temperature of zone III of the twin-screw extruder to 80° C.-130° C. and the temperature of zone IV to 70° C.-120° C., with the temperature of zone III being 10° C. higher than the temperature of zone IV, and the moisture content of the mixture being 20-50%; (3) pre-freezing the extrudate after granulation, the pre-freezing temperature being -18°C to -50°C; (4) drying the pre-frozen reconstituted rice to obtain extruded reconstituted rice that can be quickly rehydrated.

2. The preparation process according to claim 1, characterized in that: The mass ratio of the rice starch to the rice protein is 92:

8.

3. The preparation process according to claim 1, characterized in that: The added amount of the konjac glucomannan is 9%.

4. The preparation process according to claim 1, characterized in that: The screw speed is 120 rpm.

5. The preparation process according to claim 1, characterized in that: The feeding amount is 1100 g / h.

6. The preparation process according to claim 1, characterized in that: The moisture content of the mixture was 37%.

7. The preparation process according to claim 1, characterized in that: The temperatures of zone III and zone IV of the twin-screw extruder are 130° C. and 120° C. respectively.

8. The preparation process according to claim 1, characterized in that: The outlet of the twin-screw extruder is provided with a liquid spraying device, and the temperature of the sprayed liquid is 0°C-50°C.

9. The preparation process according to claim 1, characterized in that: The moisture content of the recombinant rice after drying is 2%-12%.

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