Functional recombinant rice with low glycemic index and preparation method thereof

Abstract

The invention belongs to the technical field of food processing, discloses functional low-glycemic-index recombinant rice and a preparation method thereof, and particularly discloses recombinant rice which is prepared from functional ingredients, an emulsifier, rice flour and resistant starch. The recombinant rice is round and full in appearance, low in cooking loss rate, good in chewing taste quality and close to natural rice in texture property, in-vitro starch digestion tests prove that the recombinant rice can obviously delay starch hydrolysis and delay glucose release, the in-vitro glycemic index is as low as 45, and the recombinant rice is suitable for being eaten by people with hyperglycemia for a long time, can obviously reduce the glycemic index, and can be used as a health-care food for people with hyperglycemia. The cooking loss rate of the cooked recombinant rice is 1t; 5%.

Description

Technical Field

[0001] The invention belongs to the technical field of food processing, and in particular relates to functional low glycemic index reconstituted rice and a preparation method thereof. Background Art

[0002] The glycemic index (GI) is the ratio of the blood sugar-raising effect of a certain food to the blood sugar-raising effect of a standard food. It usually reflects how much a food can cause the body's blood sugar to rise. Foods with a GI value below 55 are low-GI foods, foods with a GI value between 55 and 70 are medium-GI foods, and foods with a GI value above 70 are high-GI foods. Compared with high-GI foods, low-GI foods are more conducive to stabilizing blood sugar, and can also enhance satiety, help control weight, reduce digestive burden, and prevent diabetes.

[0003] Rice is the daily staple food of Chinese residents. Studies have found that cooked rice is a high GI food. Ordinary rice is easy to gelatinize and hydrolyze during cooking, resulting in the GI of related products reaching 80-90, which is not suitable as a food for people with high blood sugar and high blood sugar. Therefore, low GI recombinant rice has attracted much attention as a substitute staple food for patients with high blood sugar. At present, recombinant rice is restricted by many factors during processing: first, the appearance of recombinant rice after extrusion is quite different from that of natural rice. Since the molding of recombinant rice is closely related to the material formula, feed moisture, barrel temperature, screw speed, etc., low GI recombinant rice is currently mainly prepared by mixing resistant starch and various grains. However, the introduction of dietary fiber and protein in the material will cause the recombinant rice to be not round enough and have sharp edges and corners. After drying, the surface of the rice grains will crack and burst. Recombinant rice with a good appearance cannot be obtained by simply adjusting the extrusion parameters. Second, there are differences in the texture characteristics of recombinant rice and natural rice. After recombinant rice (especially low-GI recombinant rice from whole grains) is cooked, the rice absorbs too much water and expands, causing the rice grain structure to collapse. There are problems such as high cooking loss rate, sticking into lumps after cooling, and poor taste (poor elasticity and chewiness). At present, the taste of extruded recombinant rice is still somewhat different from that of ordinary rice. While reducing the GI value of recombinant rice, we should also consider improving its edible quality. Summary of the invention

[0004] The present invention aims to provide a method for preparing reconstituted rice with high rehydration property and low glycemic index. The method comprises the following steps: rationally compounding several components such as rice flour, resistant starch, mulberry leaf extract, diglyceride, soybean polysaccharide, monoglyceride, etc., and carrying out a specific extrusion granulation process to obtain a functional reconstituted rice with low glycemic index. Compared with reconstituted rice made from coarse grains, the reconstituted rice has better sensory quality, a texture characteristic closer to that of natural rice, and a flavor and a taste more in line with consumers' expectations of natural rice. The in vitro starch digestion test shows that the reconstituted rice can significantly delay starch hydrolysis, and the in vitro glycemic index is as low as 45, so the rice is suitable for long-term consumption by people with high blood sugar.

[0005] The first aspect of the present invention aims to provide a recombinant rice.

[0006] The purpose of the second aspect of the present invention is to provide a method for preparing the recombinant rice of the first aspect of the present invention.

[0007] The third aspect of the present invention aims to provide a product.

[0008] In order to achieve the above object, the technical solution adopted by the present invention is:

[0009] A first aspect of the present invention provides a recombinant rice, wherein the raw materials of the recombinant rice include functional ingredients, an emulsifier, rice flour and resistant starch.

[0010] In some embodiments of the present invention, the functional ingredients include at least one of mulberry leaf extract, diglyceride, quinoa powder, oat powder, barley powder, chickpea powder, Poria powder, konjac powder, dietary fiber, whey protein, resistant dextrin, white kidney bean extract, oat β-glucan, corn flour, purple sweet potato powder, inulin, polydextrose, soy protein isolate, and pea protein.

[0011] In some embodiments of the present invention, the functional ingredient includes mulberry leaf extract and / or diglyceride.

[0012] In some embodiments of the present invention, the emulsifier includes at least one of monoglycosides, soybean polysaccharides, sucrose esters, sorbitol lipids, soybean lecithin, monolaurin, propylene glycol fatty acid esters, carrageenan, xanthan gum, guar gum, pectin, konjac gum, gum arabic, and citrus pectin.

[0013] In some embodiments of the present invention, the emulsifier includes monoglycosides and / or soybean polysaccharides.

[0014] In some embodiments of the present invention, the usage amount of the functional ingredient is 0.75% to 7.75% of the total mass of the recombinant rice raw material.

[0015] In some embodiments of the present invention, the usage amount of the functional ingredient is 5.75% to 7.75% of the total mass of the recombinant rice raw material.

[0016] In some embodiments of the present invention, the usage amount of the mulberry leaf extract is 0% to 0.80% of the total mass of the recombinant rice raw material.

[0017] In some embodiments of the present invention, the usage amount of the mulberry leaf extract is 0.70% to 0.80% of the total mass of the recombinant rice raw material.

[0018] In some embodiments of the present invention, the usage amount of the diglyceride is 0% to 7% of the total mass of the recombinant rice raw material.

[0019] In some embodiments of the present invention, the diglyceride is used in an amount of 5% to 7% of the total mass of the recombinant rice raw material.

[0020] In some embodiments of the present invention, the usage amount of the emulsifier is 1% to 3% of the total mass of the recombinant rice raw material.

[0021] In some embodiments of the present invention, the amount of the emulsifier used is 2% to 3% of the total mass of the recombinant rice raw material.

[0022] In some embodiments of the present invention, the usage amount of the monoglyceride is 0.9% to 1.2% of the total mass of the recombinant rice raw material.

[0023] In some embodiments of the present invention, the usage amount of the monoglyceride is 1% to 1.1% of the total mass of the recombinant rice raw material.

[0024] In some embodiments of the present invention, the soybean polysaccharide is used in an amount of 0% to 2% of the total mass of the recombinant rice raw material.

[0025] In some embodiments of the present invention, the usage amount of the monoglyceride is 1% to 2% of the total mass of the recombinant rice raw material.

[0026] In some embodiments of the present invention, the mass ratio of the rice flour to the resistant starch is 2.8-3.2:1.

[0027] In some embodiments of the present invention, the mass ratio of the rice flour to the resistant starch is 3:1.

[0028] In some embodiments of the present invention, the rice flour includes japonica rice flour.

[0029] In some embodiments of the present invention, the rice flour is japonica rice flour.

[0030] In some embodiments of the present invention, the resistant starch may be resistant starch modified by physical, chemical or biological means, or may be starch that is naturally resistant to digestion, such as resistant starch naturally present in crops such as potatoes, bananas and corn.

[0031] The second aspect of the present invention provides a method for preparing the recombinant rice of the first aspect of the present invention, comprising the following steps:

[0032] The functional component and the emulsifier are mixed, dissolved, and emulsified to obtain a nanoemulsion;

[0033] The nanoemulsion is mixed with rice flour and resistant starch, the water content is adjusted to obtain a mixed material, and the mixed material is extruded to obtain reconstituted rice; or

[0034] The preparation method comprises the following steps:

[0035] Functional ingredients, emulsifiers, rice flour and resistant starch are mixed, and the water content is adjusted to obtain a mixed material, which is extruded to obtain reconstituted rice.

[0036] In some embodiments of the present invention, the emulsification condition is 60-61 MPa for 4-5 times.

[0037] In some embodiments of the present invention, the water content of the mixed material is 8.25wt% to 19wt%.

[0038] In some embodiments of the present invention, the water content of the mixed material is 8.25wt% to 12.25wt%.

[0039] In some embodiments of the present invention, a twin-screw extruder is used to process the mixed material, wherein the feed rate of the twin-screw extruder is 5.5-5.8 kg / h, the screw speed is 158-162 rpm, and the cutter speed is 1298-1302.

[0040] In some embodiments of the present invention, the feeding rate of the twin-screw extruder is 5.5 kg / h, the screw speed is 160 rpm, and the cutter speed is 1300 rpm.

[0041] In some embodiments of the present invention, the temperature of the extrusion conveying zone of the twin-screw extruder is 58°C to 62°C, the temperature of the pregelatinization zone is 108°C to 112°C, the temperature of the gelatinization shear zone is 98°C to 102°C, the temperature of the melting zone is 58°C to 62°C, and the temperature of the die molding zone is 58°C to 62°C.

[0042] In some embodiments of the present invention, the temperature of the extrusion conveying zone of the twin-screw extruder is 60°C, the temperature of the pregelatinization zone is 110°C, the temperature of the gelatinization shear zone is 100°C, the temperature of the melting zone is 60°C, and the temperature of the die molding zone is 60°C.

[0043] In some embodiments of the present invention, the extruded recombinant rice is dried, and the drying method can be a currently commonly used drying method, such as hot air drying (57-62° C.) and vacuum drying.

[0044] In some embodiments of the present invention, the recombinant rice is dried to a moisture content of 9% to 10%.

[0045] Diacylglycerol (DG, DAG) is a structural lipid in which a fatty acid in a class of triglycerides (TAG) is replaced with a hydroxyl group through bioenzyme technology. Diacylglycerol is a trace component of natural plant oils and fats and an endogenous intermediate product of fat metabolism in the body. Dietary DAG has the effects of reducing visceral fat, inhibiting weight gain, and lowering blood lipids and blood sugar. The present invention increases the dispersion area of ​​diacylglycerol by emulsifying diacylglycerol, thereby making it better in contact with starch, and better forming oil-starch inclusion complexes during the thermal process of twin-screw extrusion, thereby slowing down the digestion of starch.

[0046] Mulberry leaf extract, especially mulberry leaf extract containing amino sugar components represented by 1-deoxynojirimycin (DNJ), can inhibit α-glycosidase, reduce the decomposition of short-chain carbohydrates into monosaccharides such as glucose, thereby reducing the GI value of food. However, the water solubility of mulberry leaf amino sugar components represented by DNJ is very good. If they are directly added to flour or rice flour to make food that needs to be cooked in water, such as dumplings, wontons, noodles, rice noodles, etc., the amino sugar components will be lost due to dissolution. This not only causes a waste of active ingredients, but also cannot effectively reduce the GI value of such food, and cannot achieve blood sugar control for the edible population. In the present invention, soybean polysaccharides and monoglycosides are used to emulsify mulberry leaf extract and diglyceride, and water-in-oil diglyceride emulsion droplets are formed. The formation of soybean polysaccharide-mulberry leaf extract nanocomplexes can effectively reduce the loss of mulberry leaf amino sugar components during rice cooking.

[0047] Soybean polysaccharides are water-soluble polysaccharides composed of galactose, arabinose, galactose acid, rhamnose, trehalose, xylose and glucose molecules connected by 1,4-glycosidic bonds and 1,6-glycosidic bonds, also known as soluble soybean dietary fiber. They can be used as anti-caking agents to prevent rice and flour from sticking together, inhibit starch retrogradation, improve product texture, promote water absorption, and synergize with emulsifiers to help rice taste moist and fragrant without being greasy.

[0048] The calories produced by resistant starch are only about half of those produced by sugars, and can be used to control appetite and balance macronutrients, thereby achieving weight control. Resistant starch has a lower glycemic index and insulin response, and can delay the rise in blood sugar after meals, especially for type 2 diabetics, and effectively control diabetes.

[0049] The present invention uses mulberry leaf extract and diglyceride as functional raw materials for blood sugar and blood lipid, uses monoglycosides and soybean polysaccharides to nano-encapsulate diglyceride, and combines rice flour and resistant starch to obtain recombinant rice through extrusion and drying steps, thereby improving the appearance, cooking loss rate and edible quality of the recombinant rice. At the same time, the formation of the soybean polysaccharide-mulberry leaf extract complex and the nano-encapsulation of diglyceride and the formation of diglyceride-starch inclusion complex during the extrusion process can effectively reduce the GI value of the recombinant rice, thereby obtaining functional low-GI recombinant rice.

[0050] The third aspect of the present invention provides a product, comprising the recombinant rice according to the first aspect of the present invention or the recombinant rice prepared by the preparation method of the second aspect of the present invention.

[0051] In some embodiments of the invention, the product includes a product that helps maintain healthy blood sugar levels.

[0052] In some embodiments of the present invention, the product includes food, medicine or health care product.

[0053] The beneficial effects of the present invention are:

[0054] The recombinant rice provided by the present invention has a rounded appearance, a low cooking loss rate, a good chewing texture quality, and a texture property close to that of natural rice. An in vitro starch digestion test confirms that the recombinant rice can significantly delay starch hydrolysis and glucose release, and the in vitro glycemic index is as low as 45, so the rice is suitable for long-term consumption by people with high blood sugar levels and can significantly reduce the glycemic index. The cooking loss rate of the cooked recombinant rice is less than 5%. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 The in vitro digestion glucose release curve of the recombinant rice prepared in each embodiment or comparative example of the present invention is shown.

[0056] Figure 2 The following are photos of the recombinant rice prepared in various embodiments or comparative examples of the present invention and cooked recombinant rice.

[0057] Figure 3 The scanning electron micrographs of the recombinant rice prepared in various embodiments or comparative examples of the present invention are shown in FIG. 1 , wherein the scale bar is 20 μm. DETAILED DESCRIPTION

[0058] The present invention is further described in detail below through specific examples.

[0059] It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0060] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0061] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0062] In the examples, mulberry leaf extract was purchased from Huangshan Hualuyuan Biotechnology Co., Ltd., the water extract of mulberry leaves, GSMFL01 type; japonica rice flour was purchased from Yihai Kerry Golden Dragon Fish Cereals and Oils Food Co., Ltd., Jinyuanbao selected long-grain fragrant rice, first grade; resistant starch was purchased from Roquette Trading (Shanghai) Co., Ltd., high-amylose corn starch, N470 type; soybean polysaccharide was purchased from Wei Bo Food Co., Ltd., Quanzhou City, Fujian Province.

[0063] Example 1

[0064] A method for preparing functional low glycemic index recombinant rice comprises the following steps:

[0065] (1) 1 part by weight of monoglyceride and 0.75 part by weight of mulberry leaf extract are dissolved in 18.25 parts by weight of water, and the mixture is added to 80 parts by weight of a mixture of glutinous rice flour and resistant starch in a ratio of 3:1, thereby obtaining a mixture having a water content of 18.25 wt%, 1 wt% of monoglyceride, 0.75 wt% of mulberry leaf extract and 80 wt% of the mixture.

[0066] (2) The mixed material is extruded and molded using a twin-screw extruder, wherein the feeding rate of the twin-screw extruder is 5.5 kg / h, the screw speed is 160 rpm, and the cutting machine speed is 1300 rpm. The temperature of the extrusion conveying zone of the twin-screw extruder is 60° C., the temperature of the pre-gelatinization zone is 110° C., the temperature of the gelatinization shearing zone is 100° C., the temperature of the melting zone is 60° C., and the temperature of the die molding zone is 60° C. The extruded product is heat-dried at 60° C. to a moisture content of 10%, thereby obtaining functional low glycemic index recombinant rice.

[0067] Example 2

[0068] A method for preparing functional low glycemic index recombinant rice comprises the following steps:

[0069] (1) 1 part by weight of soybean polysaccharide, 1 part by weight of monoglyceride and 0.75 part by weight of mulberry leaf extract are added to 12.25 parts by weight of water and mixed and dissolved, 5 parts by weight of diglyceride are added and dispersed at high speed for 30 minutes, homogenized and emulsified 4 times at 60 MPa, and then added to 80 parts by weight of a mixture of glutinous rice flour and resistant starch in a ratio of 3:1, to obtain a mixture containing 12.25 wt% of water, 1 wt% of monoglyceride, 0.75 wt% of mulberry leaf extract, 5 wt% of diglyceride, 1 wt% of soybean polysaccharide and 80 wt% of the mixture.

[0070] (2) The mixed material is extruded and molded using a twin-screw extruder, wherein the feeding rate of the twin-screw extruder is 5.5 kg / h, the screw speed is 160 rpm, and the cutting machine speed is 1300 rpm. The temperature of the extrusion conveying zone of the twin-screw extruder is 60° C., the temperature of the pre-gelatinization zone is 110° C., the temperature of the gelatinization shearing zone is 100° C., the temperature of the melting zone is 60° C., and the temperature of the die molding zone is 60° C. The extruded product is heat-dried at 60° C. to a moisture content of 10%, thereby obtaining functional low glycemic index recombinant rice.

[0071] Example 3

[0072] A method for preparing functional low glycemic index recombinant rice comprises the following steps:

[0073] (1) 2 parts by weight of soybean polysaccharide, 1 part by weight of monoglyceride and 0.75 parts by weight of mulberry leaf extract are added to 8.25 parts by weight of water and mixed and dissolved, 8 parts by weight of diglyceride are added and dispersed at high speed for 30 minutes, homogenized and emulsified 4 times at 60 MPa, and then added to 80 parts by weight of a mixture of glutinous rice flour and resistant starch mixed in a ratio of 3:1, to obtain a mixed material having a water content of 8.25 wt%, 1 wt% of monoglyceride, 0.75 wt% of mulberry leaf extract, 2 wt% of soybean polysaccharide, 8 wt% of diglyceride and 80 wt% of the mixture.

[0074] (2) The mixed material is extruded and molded using a twin-screw extruder, wherein the feeding rate of the twin-screw extruder is 5.5 kg / h, the screw speed is 160 rpm, and the cutting machine speed is 1300 rpm. The temperature of the extrusion conveying zone of the twin-screw extruder is 60° C., the temperature of the pre-gelatinization zone is 110° C., the temperature of the gelatinization shearing zone is 100° C., the temperature of the melting zone is 60° C., and the temperature of the die molding zone is 60° C. The extruded product is heat-dried at 60° C. to a moisture content of 10%, thereby obtaining functional low glycemic index recombinant rice.

[0075] Example 4

[0076] A method for preparing recombinant rice comprises the following steps:

[0077] (1) 1 part by weight of soybean polysaccharide and 1 part by weight of monoglyceride are added to 13 parts by weight of water and mixed and dissolved, 5 parts by weight of diglyceride are added and dispersed at high speed for 30 minutes, and then added to 80 parts by weight of a mixture of glutinous rice flour and resistant starch uniformly mixed in a ratio of 3:1, so as to obtain a mixed material having a water content of 13 wt%, 1 wt% of monoglyceride, 5 wt% of diglyceride, 1 wt% of soybean polysaccharide and 80 wt% of the mixture.

[0078] (2) The mixed material is extruded by a twin-screw extruder, wherein the feeding rate of the twin-screw extruder is 5.5 kg / h, the screw speed is 160 rpm, and the cutting machine speed is 1300 rpm. The temperature of the extrusion conveying zone of the twin-screw extruder is 60° C., the temperature of the pre-gelatinization zone is 110° C., the temperature of the gelatinization shearing zone is 100° C., the temperature of the melting zone is 60° C., and the temperature of the die head molding zone is 60° C. The extruded product is heat-dried at 60° C. to a moisture content of 10%, thereby obtaining recombinant rice.

[0079] Comparative Example 1

[0080] Commercially available japonica rice was selected (purchased from Yihai Kerry Golden Dragon Fish Cereals, Oils and Foodstuffs Co., Ltd., Jinyuanbao specially selected long-grain fragrant rice, first grade).

[0081] Comparative Example 2

[0082] A method for preparing recombinant rice comprises the following steps:

[0083] (1) Dissolve 1 part by weight of monoglyceride in 19 parts by weight of water and disperse evenly, add 80 parts by weight of polished rice flour to obtain a mixed material having a water content of 19 parts by weight and a monoglyceride content of 1 part by weight.

[0084] (2) The mixed material is extruded by a twin-screw extruder, wherein the feeding rate of the twin-screw extruder is 5.5 kg / h, the screw speed is 160 rpm, and the cutting machine speed is 1300 rpm. The temperature of the extrusion conveying zone of the twin-screw extruder is 60° C., the temperature of the pre-gelatinization zone is 110° C., the temperature of the gelatinization shearing zone is 100° C., the temperature of the melting zone is 60° C., and the temperature of the die head molding zone is 60° C. The extruded product is heat-dried at 60° C. to a moisture content of 10%, thereby obtaining recombinant rice.

[0085] Effect Example

[0086] The cooking loss was determined by referring to the method of Lourembam et al. with slight adjustments, mainly as follows: 2.00 g (m0) of recombinant rice was placed in a centrifuge tube, 20 mL of distilled water was poured in, and the mixture was cooked for 10 min. All the rice soup was transferred to a plate (m1), and then dried in an oven at 105 °C until constant weight (m2). The cooking loss rate was calculated as follows:

[0087]

[0088] In vitro simulated digestion experiment:

[0089] The main steps of the in vitro simulated digestion experiment are as follows: simulate the digestion process of reconstituted rice after cooking through the two stages of the mouth, stomach and small intestine. First, take 2g of each sample (the rice prepared by Examples 1 to 4 and Comparative Examples 1 to 2 is placed in boiling water and cooked for 10 minutes at a ratio of 1:1 rice to water) and put it into a beaker and beat it up and down with a mortar rod for 15s. Then add 18mL of ultrapure water, adjust to pH 3.0, add 2mL of pepsin dissolved in 0.02mol / L HCl (digestive fluid enzyme activity 2000U / mL), and keep it at a constant temperature of 37°C for 30min under a 160r / min water bath shaker to simulate the human gastric digestion process. Subsequently, adjust the pH of the digestive fluid to neutral, add 4mL of acetate buffer (pH 6.0) and 1mL of mixed enzyme solution (pancreatin, 16U / mL; glucoamylase, 40U / mL), and continue to keep it at a constant temperature of 37°C for 2h under a 160r / min water bath shaker to simulate the intestinal digestion process. Sampling was performed at specific time points during the simulated digestion process. 0.1 mL of the sample was added to 0.4 mL of anhydrous ethanol and centrifuged (1500 g, 10 min, 25°C) to obtain the supernatant. The glucose content in the supernatant was determined using a D-glucose kit (Shanghai Megazyme Company; Catalog No.: K-GLUC).

[0090] According to the above glucose determination results, the digestion time (t)-glucose release (Ct) relationship curve was drawn, and the first-order kinetic equation was used to fit the curve as shown in formula (1), thereby obtaining the final glucose release (C∞), glucose release rate (k) and correlation coefficient (r2). The area under the curve (Area Under Cure, AUC) was integrated and compared with the AUC of the standard (white bread), the obtained ratio was the hydrolysis index (Hydrolysis Index, HI) of the sample, as shown in formula (2). Finally, the eGI was calculated according to formula (3):

[0091] Ct=C(1-e-kt)(1)

[0092] HI=-AUCsampte / AUCstandard(2)

[0093] eGI=0.862HI+8.189(3)

[0094] Simulate the force of people chewing food:

[0095] The texture characteristics of the recombinant rice obtained in the examples and comparative examples were measured using a texture analyzer to simulate the stress of people chewing food, mainly as follows: 35g of rice (the rice prepared in Examples 1 to 4 and Comparative Examples 1 to 2 was steamed by a conventional method) was weighed and put into a sample pre-pressing assembly, and 150g of water was used to press the rice for 1 minute, and the texture characteristics of the rice were measured using a texture analyzer to obtain the hardness and viscosity data of the rice. Seven parallel measurements were performed for each test, and the average value was taken.

[0096] Scanning electron microscopy:

[0097] The recombinant rice obtained in the example and the comparative example was subjected to scanning electron microscopy, and the main steps were as follows: the samples were cut at 1 / 3 and 2 / 3 of the long axis of the rice grains with a blade, the rice grains were adhered to a stage with double-sided tape with the broken surface of the rice grains facing upward, and then gold was directly sprayed on the rice grains. Finally, the cross-sections of each sample were photographed and observed using a scanning electron microscope.

[0098] Sensory evaluation:

[0099] The sensory evaluation standard refers to the national standard "GB / T 15682-2008 Cereal and Oil Inspection Paddy and Rice Steamed Edible Quality Sensory Evaluation Method" for sensory testing.

[0100] result:

[0101] The cooking properties of the recombinant rice samples of each embodiment and comparative embodiment are shown in Table 1. Comparative Example 1 (i.e., ordinary japonica rice) and Comparative Example 2 (i.e., blank recombinant rice, without the addition of ingredients such as soybean polysaccharides, mulberry leaf extract and resistant starch) have excellent cooking properties, but their eGI values ​​reach above 80. The cooking properties of the rice samples with the addition of ingredients such as resistant starch, mulberry leaf extract, soybean polysaccharides and diglycerides and Examples 1 to 4 are significantly lower than the former, but their eGI values ​​are significantly reduced, indicating that while the functional recombinant rice achieves a low GI, its cooking quality will be significantly reduced.

[0102] The water absorption rate and swelling rate of the recombinant rice prepared in Example 1 were the lowest, and the cooking loss rate was close to that of Comparative Example 1 (i.e., ordinary japonica rice), indicating that its cooking quality was poor. The water absorption rate and swelling rate of the recombinant rice in Examples 2, 3, and 4 were significantly improved and close to that of Comparative Example 2, and the cooking loss rate was significantly reduced, among which Examples 2 and 3 had better cooking quality. This indicates that the addition of resistant starch and mulberry leaf extract has a greater impact on the cooking quality of recombinant rice, while the addition of functional ingredients such as diglycerides and soybean polysaccharides can significantly reduce the degree of deterioration of its cooking quality.

[0103] Table 1 Cooking characteristics of samples in various embodiments

[0104]

[0105] The eGI value of Example 4 is significantly lower than that of Comparative Examples 1-2, and the eGI values ​​of the Example group are all lower than those of the Comparative Example group, indicating that the addition of resistant starch and mulberry leaf extract can significantly reduce the glycemic index of recombinant rice. Compared with Example 1, which also added resistant starch and mulberry leaf extract, the eGI of Examples 2 and 3 is reduced more, indicating that their functional ingredients can not only effectively improve the cooking characteristics of low GI recombinant rice, but also play a certain role in delaying glucose release in in vitro simulated digestion. The glucose release results of each Example or Comparative Example are shown in the figure. Figure 1 shown.

[0106] The texture characteristics of each embodiment are shown in Table 2. As can be seen from the table, the embodiment group has significantly reduced hardness and improved adhesion compared with comparative examples 1 and 2, and there is no significant difference in elasticity, resilience and cohesion. This shows that the recombinant rice with added functional ingredients is softer in taste than ordinary rice and blank recombinant rice, and the other tastes such as adhesion are similar. Among them, the adhesion of Example 1 is higher than that of the other groups, indicating that it is stickier to the teeth during chewing, and it is significantly improved after the addition of soybean polysaccharides and diglycerides. The results show that the functional recombinant rice is softer to chew than natural rice and blank recombinant rice while ensuring its functionality, and the other tastes are similar to blank recombinant rice and natural rice.

[0107] Table 2 Texture characteristics of various examples

[0108]

[0109] The sensory evaluation of each embodiment is shown in Table 3 and Figure 2 . It can be seen that the total sensory scores of Examples 1, 2, 3, and 4 are lower than those of Comparative Examples 1 and 2. This is mainly because the functional recombinant rice has a slightly special flavor due to its complex ingredients compared to ordinary rice and blank recombinant rice, resulting in a lower functional recombinant rice in the smell and taste scores. In addition, the functional recombinant rice is yellow, resulting in a color score that is significantly lower than that of ordinary rice and blank recombinant rice. In the gloss score, Example 2 is the best, with better gloss and morphology, and the other properties of Example 2 are close to those of Comparative Examples 1 and 2. Example 1 has the lowest overall score. The results show that when the functional recombinant rice with the addition of soybean polysaccharides and triglycerides and pre-emulsification treatment achieves the function of low glycemic index, its eating experience is close to that of ordinary recombinant rice, and the recombinant rice is more glossy on the surface and has a better morphology.

[0110] The results of scanning electron microscopy are as follows Figure 3As shown, the rice after cooking has a loose porous structure, among which the mesh of Comparative Example 1 is small and dense, while the mesh of Comparative Example 2 and Example 4 is large and loose after cooking. After adding resistant starch, mulberry leaf extract, monoglyceride and soybean polysaccharide, the mesh size of the recombinant rice after cooking gradually becomes uniform and dense, among which Examples 2 and 3 clearly show that the mesh is small and the structure is uniform, forming a stable starch gel network structure.

[0111] Table 3 Sensory evaluation table of each embodiment

[0112]

[0113] The embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the purpose of the present invention. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

Claims

1. A recombinant rice, characterized in that: The raw materials of the recombinant rice include functional ingredients, emulsifiers, rice flour and resistant starch.

2. The recombinant rice according to claim 1, characterized in that: The functional ingredients include at least one of mulberry leaf extract, diglyceride, whey protein, resistant dextrin, white kidney bean extract, oat beta-glucan, corn flour, purple potato flour, inulin, polydextrose, soy protein isolate, and pea protein.

3. The recombinant rice according to claim 1, characterized in that: The emulsifier includes at least one of monoglycosides, soybean polysaccharides, sucrose esters, sorbitol lipids, soybean lecithin, lauric acid monoglyceride, propylene glycol fatty acid esters, carrageenan, xanthan gum, guar gum, pectin, konjac gum, gum arabic, and citrus pectin.

4. The recombinant rice according to any one of claims 1 to 3, characterized in that The usage amount of the functional ingredient is 0.75% to 7.75% of the total mass of the recombinant rice raw material; and / or the usage amount of the emulsifier is 1% to 3% of the total mass of the recombinant rice raw material.

5. The recombinant rice according to claim 4, characterized in that: The mass ratio of the rice flour to the resistant starch is 2.8-3.2:

1.

6. The method for preparing the recombinant rice according to any one of claims 1 to 5, comprising the following steps: The functional component and the emulsifier are mixed, dissolved, and emulsified to obtain a nanoemulsion; The nanoemulsion is mixed with rice flour and resistant starch, the water content is adjusted to obtain a mixed material, and the mixed material is extruded to obtain reconstituted rice; or The preparation method comprises the following steps: Functional ingredients, emulsifiers, rice flour and resistant starch are mixed, and the water content is adjusted to obtain a mixed material, which is extruded to obtain reconstituted rice.

7. The preparation method according to claim 6, characterized in that: The emulsification condition is 60-61 MPa emulsification for 4-5 times; and or, the water content of the mixed material is 8.25wt%-19wt%.

8. The preparation method according to claim 6, characterized in that: The mixed material is processed by a twin-screw extruder, wherein the feeding amount of the twin-screw extruder is 5.5-5.8 kg / h, the screw speed is 158-162 rpm, and the cutting machine speed is 1298-1302 rpm.

9. The preparation method according to claim 8, characterized in that: The temperature of the extrusion conveying zone of the twin-screw extruder is 58°C to 62°C, the temperature of the pre-gelatinization zone is 108°C to 112°C, the temperature of the gelatinization shearing zone is 98°C to 102°C, the temperature of the melting zone is 58°C to 62°C, and the temperature of the die molding zone is 58°C to 62°C.

10. A product comprising the recombinant rice according to any one of claims 1 to 5, or the recombinant rice prepared by the preparation method according to any one of claims 6 to 9.

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