Low-gi rhizoma polygonati recombined rice and preparation method thereof

Abstract

The application discloses low-GI rhizoma polygonati recombined rice and a preparation method thereof, and belongs to the technical field of food deep processing. The rhizoma polygonati recombined rice is prepared by uniformly mixing 700-900 parts of rice powder, 100-300 parts of modified corn starch, 5-60 parts of rhizoma polygonati powder and 2-6 parts of monoglyceride, and then applying the functional effect of rhizoma polygonati to edible products by using a Chinese double-screw extruder. The rhizoma polygonati recombined rice has better functions and taste compared with the commercially available recombined rice, the palatability and edible quality of the rhizoma polygonati recombined rice product are optimized and improved, the taste of the product is close to that of normal rice, and the acceptance of the consumer group is increased. In addition, in-vitro digestion tests prove that the rhizoma polygonati recombined rice product is a low-GI food, and is suitable for long-term consumption of type Ⅱ diabetes patients.

Description

Technical Field

[0001] This invention relates to the field of food deep processing technology, specifically to a low-GI Polygonatum recombinant rice and its preparation method. Background Technology

[0002] In recent years, low-GI diets have remained a hot topic in nutritional prevention and treatment of chronic diseases. After consuming low-GI foods, blood sugar levels rise relatively slowly, and the feeling of fullness is enhanced, which helps control weight. Studies have found that cooked rice is a high-GI food. Therefore, the development of a low-GI rice product is highly in line with market and societal needs.

[0003] Polygonatum has a diverse chemical composition. The main chemical components isolated from it currently include polysaccharides, anthraquinones, steroidal saponins, and flavonoids. Polygonatum exhibits a wide range of pharmacological activities, including hypoglycemic, antioxidant, immunomodulatory, memory-enhancing, and antibacterial / anti-inflammatory effects, making it highly valuable both medicinally and nutritionally. As a plant used for both food and medicine, Polygonatum is suitable for processing into various products and has significant development potential and broad application prospects in the food, nutrition, health, and medical industries.

[0004] Reconstituted rice is generally made from starch as the main matrix, blended with various nutrients or nutrient-rich plant powders such as konjac flour, oats, chickpeas, and buckwheat. Small amounts of quality improvers such as monoglycerides or sucrose fatty acid esters are added, and the mixture is then extruded and granulated using a twin-screw extruder. Compared to regular rice, reconstituted rice has significant advantages in increasing the added value of raw materials, nutritional fortification, cost control, and flexibility in application scenarios. However, the palatability and eating quality of reconstituted rice products still need continuous optimization and improvement to approximate the taste of regular rice and increase consumer acceptance. CN2022115137703.5 discloses a high-protein, low-glycemic-fat recombinant rice and its preparation method. It is formed by extruding and granulating a mixture of rice flour, whey protein powder, whole grain powder, food-medicine homology powder, bean powder, potato powder, dietary fiber, and resistant starch. The prepared recombinant rice does not feature improved taste or quality and does not demonstrate the benefits of high protein and low glycemic-fat. CN202210904203.8 discloses a zero-additive, low-GI nutritional recombinant rice and its preparation method. The recombinant rice, made from wet-heat treated brown rice flour and microwave-treated potato flour, improves cooking quality to some extent without the addition of food additives, but does not significantly enhance the taste. Similarly, CN202211055268.6 discloses a solid-state fermented barley bran extruded recombinant rice with blood sugar regulating function and its preparation method, which focuses only on functional nutritional characteristics and neglects taste. Summary of the Invention

[0005] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0006] In view of the problems existing in the above and / or prior art, the present invention is proposed.

[0007] Therefore, the purpose of this invention is to overcome the shortcomings of the prior art and provide a low-GI Polygonatum recombinant rice and its preparation method.

[0008] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a low-GI Polygonatum recombinant rice and its preparation method.

[0009] Impurities were removed from Polygonatum, the soil was washed, soaked, dried, pulverized, and then sieved to obtain Polygonatum powder.

[0010] Corn starch was dispersed in an acetic acid / sodium acetate buffer solution to form a suspension. The suspension was gelatinized in a boiling water bath, cooled, and then transglucosidase was added. The mixture was heated and stirred to inactivate the enzyme. Ethanol was added and the mixture was centrifuged. The precipitate was freeze-dried, ground, sieved, and collected to obtain modified corn starch.

[0011] Rice flour, modified corn starch, polygonatum powder, and monoglycerides are mixed evenly and then poured into the feed inlet of an extruder. The water injection volume and twin-screw extruder parameters are set. After collecting the reconstituted rice particles at the extruder outlet, they are dried and polished to obtain the low-GI polygonatum reconstituted rice.

[0012] In a preferred embodiment of the preparation method described in this invention, the weight proportions of the rice flour, modified corn starch, polygonatum powder, and monoglyceride are as follows:

[0013]

[0014] As a preferred embodiment of the preparation method described in this invention, the soaking time for the Polygonatum sibiricum powder is 10-30 min, and the drying conditions are 50-55°C in an oven for 8-12 h.

[0015] As a preferred embodiment of the preparation method described in this invention, the Polygonatum sibiricum powder is pulverized and then passed through an 80-mesh sieve.

[0016] In a preferred embodiment of the preparation method described in this invention, the acetic acid / sodium acetate buffer solution has a pH of 5.1 and a concentration of 0.2 mol / L.

[0017] As a preferred embodiment of the preparation method described in this invention, the suspension has a mass fraction of 10%, a gelatinization time of 30 min, a cooling temperature of 50 °C, a transglucosidase activity of 1650 U / g, a heating temperature of 60 °C, a stirring time of 4–8 h, an enzyme inactivation condition of boiling water for 10 min, and an ethanol mass fraction of 70%.

[0018] In a preferred embodiment of the preparation method described in this invention, the freeze-drying temperature is -55°C.

[0019] As a preferred embodiment of the preparation method described in this invention, the precipitate is ground and then passed through an 80-mesh sieve.

[0020] As a preferred embodiment of the preparation method of the present invention, the recombinant Polygonatum rice is placed in a drying oven for heating treatment, wherein the heating temperature is 45-55°C, the treatment time is 8-12 hours, and the product moisture content is dried to 12%-15%.

[0021] As a preferred embodiment of the preparation method described in this invention, the parameters of the twin-screw extruder are as follows: 7 temperature zones: Zone 1 40℃, Zone 2 70℃, Zone 3 80℃~150℃, Zone 4 80℃~150℃, Zone 5 80℃~150℃, Zone 6 70℃, Zone 7 60℃; screw speed 160~240r / min; feeding speed 15kg / h~45kg / h; and rotary cutting blade frequency 25~35Hz.

[0022] Another objective of this invention is to overcome the shortcomings of the prior art and provide a low-GI Polygonatum recombinant rice.

[0023] Another objective of this invention is to overcome the shortcomings of the prior art and provide an application of low-GI Polygonatum recombinant rice in the deep processing of food.

[0024] Beneficial effects of this invention:

[0025] This invention produces Polygonatum functional recombinant rice by adding appropriate proportions of rice flour, modified corn starch, and Polygonatum powder using a Chinese twin-screw extrusion machine. This process is not only simple and efficient but also combines functionality and taste. Compared to commercially available recombinant rice, it has better sensory acceptance and a lower in vitro glycemic index than commercially available japonica rice, indica rice, and commercially available recombinant rice. It can be used as a low-GI food for long-term consumption by patients with type II diabetes. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0027] Figure 1 Image of the Polygonatum recombinant rice product from Example 1;

[0028] Figure 2 This is a graph showing the starch hydrolysis rate of different products in Example 4 of the present invention. Detailed Implementation

[0029] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0030] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0031] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0032] Example 1

[0033] This embodiment provides a method for preparing high-quality low-GI Polygonatum recombinant rice, the main steps of which are:

[0034] S1. Preparation of raw material powder:

[0035] (1) Preparation of Polygonatum powder: Remove impurities from Polygonatum and wash it. Soak it in clean water at room temperature for 20 minutes. After soaking, dry it in an oven. Pulverize the dried Polygonatum and pass it through an 80-mesh sieve to obtain Polygonatum powder.

[0036] (2) Preparation of modified corn starch powder: 100g of corn starch was dispersed in an acetate / sodium acetate buffer (0.2mol / L) at pH 5.1 to prepare a 10% suspension, and the suspension was gelatinized in a boiling water bath for 30 minutes. The gelatinized starch paste was cooled to about 50°C in cold water, and 16.5g of 100,000 U / g transglucosidase was added to the cooled starch paste. The mixture was then reacted and stirred continuously at 60°C for 6 hours. The enzyme reaction was stopped in boiling water for 10 minutes. After adding 70% ethanol, the suspension was centrifuged, and the precipitate was collected to obtain the enzyme-modified starch. Finally, the starch sample was freeze-dried at -55°C for 48 hours. The freeze-dried starch was ground and passed through an 80-mesh sieve to obtain modified corn starch.

[0037] S2. Proportioning and mixing of raw material powders: Take 850 parts rice flour, 150 parts modified corn starch, 10-50 parts Polygonatum powder and 2 parts monoglyceride and mix them evenly;

[0038] S3. Preparation of Polygonatum recombinant rice: The uniformly mixed raw material powder is poured into the feed inlet of the extruder. The water injection amount is set so that the moisture content of the material is 23%. The feeding speed of the twin-screw extruder is fixed at 32 kg / h. The temperatures of zones one, two, six, and seven are fixed at 40℃, 70℃, 70℃, and 60℃, respectively. Zones three, four, and five (hereinafter referred to as heating zones) are the main heating zone parameters at 90℃, 110℃, and 130℃. The screw speed is 160, 200, and 240 r / min. The blade cutting speed is adjusted according to the actual situation to obtain a shape similar to natural rice. The recombinant rice from the outlet is collected and placed in a 45℃ electric heating forced-air drying oven and dried until the product moisture content is about 13%. After polishing, Polygonatum recombinant rice is obtained.

[0039] Since different extrusion parameters affect the glycemic index and quality characteristics of extruded recombinant rice products, this example presents a series of recombinant rice products prepared under different extrusion conditions (heating zone temperature, screw speed) and different amounts of Polygonatum sibiricum powder. Table 1 shows the specific conditions used to prepare different recombinant rice samples.

[0040] Table 1 Preparation conditions of each recombinant rice sample

[0041]

[0042] Example 2

[0043] Sensory evaluation of Polygonatum recombinant rice:

[0044] The sensory evaluation method involved selecting 10 graduate students majoring in food science. After providing them with preliminary sensory training, they formed a sensory evaluation group to conduct sensory evaluations on the 13 types of Polygonatum recombinant rice in Example 1 to obtain Polygonatum recombinant rice with high sensory acceptance. The sensory scoring criteria were based on GB / T 15682-2008 and Fu Xi's method, with some modifications. The specific sensory scoring criteria are shown in Table 2.

[0045] Table 2 Sensory Evaluation Criteria for Recombinant Polygonatum Rice

[0046]

[0047] The sensory evaluation results of the 13 Polygonatum recombinant rice samples in Example 1 are shown in Table 3 below (the scores are the average of 10 evaluators).

[0048] Table 3 Sensory score results of the rice samples in Example 1

[0049] Sample number odor Appearance taste taste Sensory rating 1 15.6 24.3 15.6 14.3 69.8 2 17.7 23.3 18.7 18.2 77.9 3 16.2 20.4 14.7 17.4 68.7 4 14.4 22.8 17.3 13.2 67.7 5 15.4 20.1 16.4 14.7 66.6 6 14.6 21.7 15.6 12.9 64.8 7 17.8 24.7 20.2 18.3 81 8 14.5 19.2 13.9 15.8 63.4 9 15.7 19.9 18.7 16.6 70.9 10 15.6 16.4 15.9 12.9 60.8 11 16.7 20.5 18.1 17.2 72.5 12 17.4 23.3 18.1 16.2 75 13 16.2 22.3 16.2 17.3 72

[0050] Example 3

[0051] The Polygonatum recombinant rice varieties No. 2, 7, and 12 in Example 1 were used as the experimental groups, while Comparative Examples 1 to 3 were commercially available japonica rice, commercially available indica rice, and commercially available recombinant rice, respectively.

[0052] The edible quality, texture characteristics, and cooking characteristics of the three types of Polygonatum recombinant rice in Example 1 and the commercially available products in Comparative Examples 1 to 3 were determined.

[0053] Determination of textural properties: Weigh 10g of sample rice into a clean aluminum rice steamer, add 12g of deionized water, shake slightly, and then steam in a preheated rice cooker for 30 minutes. After 10 minutes, remove the reconstituted rice sample, and then take three grains of rice from the same location and place them on the stage of the texture analyzer for measurement. Each sample is measured in parallel five times. The maximum and minimum values ​​are removed, and the average of the remaining three sets of data is taken. Record the hardness, elasticity, stickiness, and chewiness of the sample rice. The measurement settings are as follows: the speed before, during, and after the test are 2mm / s, 1mm / s, and 2mm / s, respectively; the compression deformation rate is 70%; the probe is P36 / R; and the trigger force is 5g.

[0054] Determination of cooking characteristics:

[0055] (1) Determination of water absorption index

[0056] The sample was crushed and passed through an 80-mesh sieve. 0.5g of the sample was added to a pre-weighed centrifuge tube, followed by 10ml of water. The tube was then placed in a 25℃ water bath for 25 minutes, with shaking every 5 minutes. The tube was then centrifuged at 4000 rpm for 15 minutes to separate the supernatant and precipitate. The supernatant was removed, and the centrifuge tube and sample were weighed after water absorption. The weight of the centrifuge tube was subtracted from the weight of the sample, and the result was divided by the weight of the sample to obtain the water absorption index (g / g) of the target sample. Each sample was measured three times.

[0057] Determination of cooking loss rate

[0058] The method of Liu Chang et al. was modified as follows: 5g of sample rice (accurate to 0.0001g) was weighed and placed in a 100mL beaker. 50mL of deionized water was added, and the mixture was boiled in a water bath for 20min. The rice water in the beaker was then poured into a pre-weighed beaker and dried at 105℃ until constant weight. The determination was repeated 3 times, and the average value was taken. The formula for calculating the cooking loss rate is Equation (1).

[0059]

[0060] In formula (1), m1 is the sample mass, g; m2 is the mass of the constant weight beaker, g; and m3 is the total mass of the beaker and rice water after drying, g.

[0061] The results of the food quality test are shown in Table 4.

[0062] Table 4. Texture and cooking properties of rice samples from different samples

[0063]

[0064]

[0065] Example 4

[0066] In vitro simulated digestion test:

[0067] Based on the method of Zheng et al. and Dai Jiao, with appropriate modifications, the in vitro simulated digestion characteristics of six samples were determined. The specific operation was as follows: Rice samples containing 6.8g of total starch were mixed with distilled water to a total weight of 170.0g in a beaker and stirred at 180rpm for 20min at 37℃ to separate the rice grains. Simulated gastric digestion stage: 19ml (pH=1.2) of simulated gastric juice and 91.2mg of pepsin were added, and the mixture was shaken in a constant temperature water bath at 37℃ for 30min. At 0 and 30min, 0.5ml of the digestive solution was removed and 95% ethanol was added to inactivate the enzymes. Simulated intestinal digestion stage: 23ml (pH=6.8) of simulated intestinal juice, 92.0mg of trypsin, 6.9mg of invertase, and 59.8μl of amyloglucosidase were added. At 0min, 20min, 40min, 60min, 80min, 100min, 120min, and 180min, 0.5ml of the digestive solution was removed and 95% ethanol was added to inactivate the enzymes. Samples from the above time periods were centrifuged at 5000 r / min for 10 min. 0.1 ml of the supernatant was collected and added to 0.5 ml of invertase / amylase solution, along with 0.1875 mg of invertase and 0.1625 μl of amylase. The mixture was incubated at 37℃ for 10 min. The absorbance was measured at 510 nm using the GOPOD method to determine the glucose content. RDS, SDS, and RS were calculated using the following formulas.

[0068] RDS(%) = [M1 / 6.8] × 100 (2)

[0069] SDS(%)=[(M2-M1) / 6.8]×100 (3)

[0070] RS(%)=[(6.8-M1-M2) / 6.8] × 100 (4)

[0071] Where RDS—rapidly digestible starch content (%); SDS—slowly digestible starch content (%); RS—resistant starch content (%);

[0072] M1 and M2 represent the starch content at 20 and 120 min, respectively. The hydrolysis index (HI) is expressed as the percentage ratio of the area under the curve of the cooked sample to the area under the curve of the glucose standard. The glycemic index (eGI) is calculated using formula (5). The results are shown in Table 5.

[0073] eGI=0.549×HI+39.71 (5)

[0074] Table 5 Comparison of in vitro simulated digestion of different rice samples

[0075]

[0076]

[0077] Experimental results showed that the eGI of the four recombinant rice varieties was lower than that of commercially available japonica and indica rice. In particular, the in vitro glycemic index of the 2, 7, and 12 Polygonatum recombinant rice varieties in Example 1 was all below 55, indicating that the prepared Polygonatum recombinant rice is a low glycemic index food.

[0078] Depend on Figure 2 It is clear that the in vitro starch hydrolysis curves of the three commercially available products and the three types of Polygonatum recombinant rice showed a basically consistent trend during simulated digestion. The starch hydrolysis rate was fastest in the first 25 minutes, then began to decrease, and stabilized after 80 minutes. Compared to commercially available ordinary rice and one type of commercially available recombinant rice, Figure 2 The starch hydrolysis rates of the three types of Polygonatum recombinant rice were significantly lower, possibly due to higher resistant starch (RS) content in all three products. Low starch hydrolysis rates suggest potential for production as products with a lower glycemic index.

[0079] Comparative Example 1

[0080] Take 850 parts of rice flour, 170 parts of modified corn starch, 10 parts of Polygonatum sibiricum powder and 2 parts of monoglyceride and mix them evenly. All other conditions are the same as in Example 1 to prepare recombinant rice.

[0081] Comparative Example 2

[0082] Take 850 parts of rice flour, 160 parts of modified corn starch, 20 parts of Polygonatum sibiricum powder and 2 parts of monoglyceride and mix them evenly. All other conditions are the same as in Example 1 to prepare recombinant rice.

[0083] Comparative Example 3

[0084] Take 850 parts of rice flour, 140 parts of modified corn starch, 40 parts of Polygonatum sibiricum powder and 2 parts of monoglyceride and mix them evenly. All other conditions are the same as in Example 1 to prepare recombinant rice.

[0085] Table 6

[0086]

[0087] Table 7

[0088]

[0089] The difference between this comparative example and Example 1 is that the ratio of rice flour modified corn starch and polygonatum powder is adjusted, while the remaining steps and processes are the same as in Example 1.

[0090] As shown in Table 6, the changes in modified corn starch and Polygonatum powder may affect the digestibility of starch in reconstituted rice, making it more difficult for gastric acid and digestive enzymes to break down the reconstituted rice. This leads to a slower release rate of starch in the small intestine, thus delaying glucose release and consequently altering the in vitro glycemic index of the reconstituted rice. Specifically, the in vitro glycemic index of sample rice 7 was significantly different and lower than that of Comparative Examples 1 and 2; however, there was no significant difference compared to Comparative Example 3. However, Table 7 shows that sample rice 7 had higher sensory acceptability than Comparative Example 3. This may be because the higher content of Polygonatum powder in the reconstituted rice affected the product's taste and texture. Therefore, considering all factors, sample rice 7 in Example 1 combines both functionality and taste compared to the comparative examples.

Claims

1. A method for preparing low-GI Polygonatum recombinant rice, characterized in that: include, S1. Preparation of raw material powder: (1) Preparation of Polygonatum powder: Remove impurities from Polygonatum and wash it. Soak it in clean water at room temperature for 20 minutes. After soaking, dry it in an oven. Crush the dried Polygonatum and pass it through an 80-mesh sieve to obtain Polygonatum powder. (2) Preparation of modified corn starch: 100g of corn starch was dispersed in 0.2 mol / L acetate / sodium acetate buffer solution at pH 5.1 to prepare a 10% suspension, and the suspension was gelatinized in a boiling water bath for 30 minutes; the gelatinized starch paste was cooled to 50°C in cold water, and 16.5g of 100,000 U / g transglucosidase was added to the cooled starch paste. The mixture was then reacted and stirred continuously at 60°C for 6 hours. The enzyme reaction was stopped in boiling water for 10 minutes, 70% ethanol was added, and the suspension was centrifuged. The precipitate was then collected to obtain the enzyme-modified starch; finally, the starch sample was freeze-dried at -55°C for 48 hours. The freeze-dried starch was ground and passed through an 80-mesh sieve to obtain modified corn starch. S2. Proportioning and mixing of raw material powders: Take 850 parts rice flour, 150 parts modified corn starch, 30 parts Polygonatum powder and 2 parts monoglyceride and mix them evenly; S3. Preparation of Polygonatum recombinant rice by extrusion: The uniformly mixed raw material powder is poured into the feed inlet of the extruder. The water injection amount is set so that the moisture content of the material is 23%. The feeding speed of the twin-screw extruder is fixed at 32 kg / h. The temperatures of zones one, two, six, and seven are fixed at 40℃, 70℃, 70℃, and 60℃, respectively. Zones three, four, and five are the main heating temperature zones with a parameter of 110℃. The screw speed is 200 r / min. The blade cutting speed is adjusted according to the actual situation to obtain a shape similar to natural rice. The recombinant rice from the outlet is collected and placed in a 45℃ electric heating forced-air drying oven and dried until the product moisture content is 13%. After polishing, Polygonatum recombinant rice is obtained.

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