阅读说明：本技术 一种降低大米淀粉gi值的加工方法 (Processing method for reducing GI value of rice starch ) 是由 陈玲 曾茜茜 郑波 何海 李晓玺 于 2019-10-11 设计创作，主要内容包括：本发明公开了一种降低大米淀粉GI值的加工方法。所述方法包括以下步骤：(1)将20质量份大米淀粉和0.5～2质量份瓜尔豆胶或卡拉胶混合均匀,得到复配粉；(2)调节复配粉的水分含量,然后在80～90℃下挤压处理,将挤压所得产物在30～60℃下干燥8～24h,粉碎,过筛,得到GI值较低的大米淀粉-非淀粉多糖复合物。本发明综合了挤压处理,热风干燥和非淀粉多糖添加剂的优势,能将挤压淀粉的RS含量从14.5％增加到67.5％,PGI值从82.3降到61.8。(The invention discloses a processing method for reducing GI value of rice starch. The method comprises the following steps: (1) uniformly mixing 20 parts by mass of rice starch and 0.5-2 parts by mass of guar gum or carrageenan to obtain compound powder; (2) adjusting the water content of the compound powder, then carrying out extrusion treatment at 80-90 ℃, drying the product obtained by extrusion at 30-60 ℃ for 8-24 h, crushing, and sieving to obtain the rice starch-non-starch polysaccharide compound with a lower GI value. The invention combines the advantages of extrusion treatment, hot air drying and non-starch polysaccharide additive, can increase the RS content of the extruded starch from 14.5 percent to 67.5 percent, and reduce the PGI value from 82.3 to 61.8.)

1. A processing method for reducing the GI value of rice starch is characterized by comprising the following steps:

(1) uniformly mixing 20 parts by mass of rice starch and 0.5-2 parts by mass of guar gum or carrageenan to obtain compound powder;

(2) adjusting the water content of the compound powder, then carrying out extrusion treatment at 80-90 ℃, drying the product obtained by extrusion at 30-60 ℃ for 8-24 h, crushing, and sieving to obtain the rice starch-non-starch polysaccharide compound with a lower GI value.

2. The processing method for reducing the GI value of rice starch according to claim 1, wherein the rotation speed of the extrusion treatment in the step (2) is 150 to 250 r/min.

3. The processing method for reducing the GI value of the rice starch according to claim 1 or 2, wherein the moisture content of the compound powder in the step (2) is 40-45% by mass.

4. The processing method for reducing the GI value of rice starch according to claim 3, wherein the guar gum or carrageenan in the step (1) is added in an amount of 1-2 parts by mass.

5. The processing method for reducing the GI value of rice starch according to claim 3, wherein the temperature for the extrusion in the step (2) is 85-90 ℃.

6. The processing method for reducing the GI value of rice starch according to claim 3, wherein the drying temperature in the step (2) is 30-40 ℃ for 24 hours.

7. The processing method for reducing the GI value of rice starch according to claim 3, wherein the extrusion treatment of the step (2) is performed by using an extruder.

8. The processing method for reducing the GI value of rice starch according to claim 7, wherein the extrusion treatment of the step (2) is performed by using an extruder.

9. The processing method for reducing the GI value of rice starch according to claim 3, wherein the mesh number of the screen in the step (2) is 100-200 meshes.

Technical Field

The invention belongs to the technical field of food, and particularly relates to a processing method for reducing the GI value of rice starch.

Background

With the development of economy and the continuous improvement of living standard, the dietary nutrition composition and common clinical diseases of people are greatly changed. Starch, as one of three main nutritional components of food, accounts for a large proportion in human diet, not only can provide energy substances necessary for human survival, but also can regulate and control physiological functions of human body such as glycometabolism, lipid metabolism, intestinal microbial diversity and the like, thereby influencing human health. After entering human body, starch is hydrolyzed into glucose under the participation of various enzymes in digestive tract, and finally absorbed in small intestine to supply energy to human body. According to the difference of digestion rate in human body, starch can be divided into three types of fast digestion starch, slow digestion starch and anti-digestion starch, and most of the starch is fast digestion starch, which is easy to be digested and absorbed by human body to generate high blood sugar reaction, which is not in accordance with modern nutrition health concept. Therefore, the multi-scale structure of the starch is changed through different processing modes or physical modification, so that the digestion, absorption and metabolism of the starch in the gastrointestinal tract of a human body are regulated, and the nutrition function of the starch is improved, and the starch has important application value.

Glycemic Index (GI) and anti-digestive starch (RS) content are two important indicators characterizing starch digestion rate. Wherein the GI value may reflect the degree to which ingested food causes an increase in blood glucose in a human. High GI foods digest rapidly in the gastrointestinal tract and produce large amounts of glucose in a short time. While low GI foods are slowly digested and absorbed in the gastrointestinal tract, stay for a long time, and slowly produce glucose. It has been reported that chronic ingestion of low GI foods can reduce the incidence and prevalence of heart disease, diabetes and certain cancers (Hyun-JungChung, Dong-HoonShin, et al. in vitro stage diagnostic and diagnosed physiological index of chemically modified heart stages [ J ]. food research International,2008,6(41): 579-585). However, accurate measurement of GI values requires extensive zoological and anthropometric testing, which is time consuming and costly. In 1999, Englyst et al (K.Englyst, H.Englyst, ethyl.Rapid available glucose in foods: an in vitro measurement of which is reflected by a significant correlation between the glycemic response and Rapidly Available Glucose (RAG) found that the glycemic response in vivo can be reflected by measuring the amount of RAG in food in vitro. At present, this method is widely adopted at home and abroad. Related studies have also characterized the rate of starch digestion and absorption in humans by the predicted blood glucose concentration (PGI) measured in vitro digestion experiments. RS refers to the part of starch which can not be digested by small intestine but can be fermented in large intestine, RS has low digestion rate and can resist the degradation of digestive enzyme in small intestine.

At present, methods for modifying starch structure mainly include chemical methods, physical methods, biological methods and complex methods. Wherein the green and environment-friendly physical method is popular among people. In the physical modification method, the digestion rate of the starch can be changed by technologies such as high-pressure, normal-pressure cooking, extrusion and the like, so that the GI value of the starch is reduced. The extrusion technology is a physical modification technology integrating multiple unit operations of mixing, homogenizing, curing, forming and the like of materials, starch moves forwards along with the rotation of a screw rod and is simultaneously subjected to the comprehensive action of high pressure, high temperature and high shearing, and compared with other physical processing technologies, the extrusion technology has stronger acting force on the starch and has larger influence on the multi-scale structure of the starch.

After the starch is extruded, molecular chains are exposed, the starch is gelatinized and degraded, the starch digestion is often promoted by using the extrusion technology only, and the reduction degree of the starch digestion rate is limited. Many researchers have greatly improved the rate of starch digestion by adding hydrocolloids, flour, soy oil, etc. But with single or complex additives + extrusion techniques, there is limited modification of the starch structure.

Disclosure of Invention

In order to overcome the defects and shortcomings in the prior art, the invention aims to provide a processing method for reducing the GI value of rice starch. The method comprises adding non-starch polysaccharide (guar gum, carrageenan), squeezing, and hot air drying.

The purpose of the invention is realized by the following technical scheme:

a processing method for reducing GI value of rice starch comprises the following steps:

(1) uniformly mixing 20 parts by mass of rice starch and 0.5-2 parts by mass of guar gum or carrageenan to obtain compound powder;

(2) adjusting the water content of the compound powder, then carrying out extrusion treatment at 80-90 ℃, drying the product obtained by extrusion at 30-60 ℃ for 8-24 h, crushing, and sieving to obtain the rice starch-non-starch polysaccharide compound with a lower GI value.

The addition amount of the guar gum or the carrageenan in the step (1) is 1-2 parts by mass. The guar gum or the carrageenan is based on the dry basis of the rice starch in parts by mass.

The water content of the compound powder in the step (2) is 40-45% by mass.

The rotating speed of the extrusion treatment in the step (2) is 150-250 r/min. The extrusion treatment is carried out using an extruder, preferably an extruder, more preferably a micro-extruder.

And (3) extruding at 85-90 ℃.

And (3) drying at the temperature of 30-40 ℃ for 24 hours in the step (2).

The mesh number of the sieving in the step (2) is 100-200 meshes.

Compared with the prior art, the invention has the following advantages and beneficial effects:

(1) the invention integrates the advantages of extrusion treatment, low-temperature hot air drying and non-starch polysaccharide additive, overcomes the limitation of single technology, has obvious effects of non-starch polysaccharide, extrusion treatment and low-temperature hot air drying, and can increase the RS content of the extruded starch from 14.5% to 67.5% and reduce the PGI from 82.3 to 61.8.

(2) The invention applies the extrusion technology, is beneficial to the unique mechanical structure, and the sample can be subjected to the comprehensive actions of high pressure, high temperature, high shear and the like in the cavity, so that the starch gelatinization degree is higher, and the chain segment is more fully extended. The dissociated molecular chain is easy to be embedded and wound by the added guar gum and the carrageenan to form a compound.

(3) The invention applies hot air drying technology, on one hand, the sample can be dried, and on the other hand, the starch sample is easy to regenerate and rearrange to form ordered crystals under the environment of high moisture and medium and low temperature, so that the resistance of amylase is enhanced, and the blood sugar reaction is reduced.

(4) The guar gum and the carrageenan which are simple in branched structure are used, wherein the carrageenan has a more linear chain structure, and the GI value regulation and control capability of the extruded rice starch is stronger. The carrageenan can improve RC by 41.1-53 percent and reduce PGI by 14.4-19.2 percent, the guar gum can improve RC by 27.5-46.4 percent and reduce PGI by 18-20.5 percent, and pectin with a complex branch structure can improve RC by 38.1 percent and reduce PGI by 12 percent at most.

Drawings

FIG. 1 is an SEM image of an extruded rice starch sample of comparative example 1.

Fig. 2 is an SEM image of the extruded rice starch-guar gum complex of example 1.

Fig. 3 is an SEM image of the extruded rice starch-guar gum complex of example 2.

Fig. 4 is an SEM image of extruded rice starch-guar gum complex of example 3.

Fig. 5 is an SEM image of the extruded rice starch-guar gum complex of example 4.

Fig. 6 is an SEM image of extruded rice starch-carrageenan complex of example 5.

Fig. 7 is an SEM image of extruded rice starch-carrageenan complex of example 6.

Fig. 8 is an SEM image of extruded rice starch-carrageenan complex of example 7.

Fig. 9 is an SEM image of extruded rice starch-carrageenan complex of example 8.

FIG. 10 is an SEM photograph of the extruded rice starch-pectin composite of comparative example 6 with 0.5 parts pectin added.

FIG. 11 is an SEM image of an extruded rice starch-pectin complex (1 part pectin added) of comparative example 6.

Fig. 12 is an SEM image of the extruded rice starch-pectin complex (1.5 parts pectin added) of comparative example 6.

Fig. 13 is an SEM image of the extruded rice starch-pectin complex of comparative example 6 (2 parts pectin added).

FIG. 14 is a sample plot of a rice starch-non-starch polysaccharide blend prior to extrusion in comparative example 7.

FIG. 15 is a graph of a sample of extruded rice starch-non-starch polysaccharide complex of comparative example 7.

Detailed Description

The present invention will be described in further detail with reference to examples and drawings, but the embodiments of the present invention are not limited thereto.

The mesh number of the sieve in the application example and the comparative example is 100 meshes; the RDS, the SDS, the RS, the RC and the PGI are fast-digestion starch, slow-digestion starch, anti-digestion components and predicted blood glucose index respectively; the Pe, the Gg and the Cg are pectin, guar gum and carrageenan respectively; the parts are all parts by mass; the moisture content refers to mass content; the extrusion treatment was carried out using a micro-extruder (model Hakke MiniLab II, Thermo Fisher, Germany).

The digestion performance and the relative crystallinity, which are measured by XRD test method, are tested according to the conventional methods in the art.