JP2015055548A - Method of evaluating rice starch characteristic based on gelatinization and viscosity characteristics - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of simply and promptly evaluating functionality-related rice starch characteristics such as an indigestible starch content at low cost with high accuracy by using gelatinization and viscosity characteristics.SOLUTION: Rice starch characteristics are evaluated by a multiple regression analysis using gelatinization and viscosity characteristic values of rice powder or rice starch as explanatory variables. The rice starch characteristics include an indigestible starch content, a sugar chain fraction content of a glucose polymerization degree 10 or 22, an amylose content, and an amylopectin chain length distribution. As the explanatory variables of the multiple regression analysis, one type or two or more types of characteristic values selected from among a group consisting of a gelatinization start temperature, a highest viscosity, a lowest viscosity, a final viscosity, a breakdown, a setback, a consistency, a new gelatinization temperature are used.

Description

  The present invention evaluates rice starch characteristics such as resistant starch content and sugar chain fraction content closely related to resistant starch based on the gelatinized viscosity characteristics of rice starch easily and quickly with high accuracy. Regarding the method.

  In recent years, Japan has become a society with a declining birthrate and an aging society, and it is necessary to promote health maintenance and disease prevention with a diet rich in functional ingredients.

  Rice with a high amylose content of starch and rice with a long amylopectin chain are indigestible, have a slow increase in blood sugar after meals, and are expected to prevent the onset of diabetes (Non-Patent Documents 1 and 2). It is extremely important to develop a technology that can easily and quickly measure the content of resistant starch and related sugar chain fractions in various rice.

  Conventionally, the amylopectin chain length distribution of rice starch has been measured by high performance liquid chromatography after debranching with isoamylase (Non-patent Document 3).

  Igarashi et al. Reported that the amylose molecular weight distribution and amylopectin chain length distribution of rice starch analyzed by fluorescence-labeled gel filtration affect the gelatinization characteristics and taste of rice starch (Non-Patent Document 4).

  In addition, Igarashi et al. Show that the amylopectin unit chain length distribution of glutinous rice analyzed by fluorescence-labeled gel filtration strongly affects the curability of rice bran (Non-patent Document 5) and the iodometric color absorption of 400-900 nm rice starch. From the curve, the ratio of the two peak areas on the low wavelength side and the high wavelength side with 600 nm as a boundary is obtained, and it has been reported that this ratio is useful as an aging index of rice starch (Non-Patent Document 6).

  Although these conventional measurement methods provide accurate measurement values such as amylopectin chain length distribution, they do not measure the resistant starch content that is expected to prevent disease in rice starch. Is a costly method because it requires expensive equipment such as a high performance liquid chromatograph, and it is simple, quick, low cost and highly resistant to starch in the fields of breeding selection and food processing. In order to evaluate the sugar chain fraction content closely related to the content or resistant starch content, a new measurement method was required.

  Moreover, Otsubo et al. Filed a patent (Patent Document 1) as a gelatinization characteristic measuring device for displaying food property values of cereals.

  However, although the invention described in Patent Document 1 uses an estimation formula with gelatinization characteristics as a variable, the object of estimation is food physical properties such as rice physical properties in rice and raw noodle hardness in wheat. However, it did not estimate the content of indigestible starch or the content of sugar chain fraction closely related to indigestible starch.

Japanese Patent No. 3908227

Kenichi Otsubo, Sumiko Nakamura, Kazunori Utsunomiya, Yasunobu Masuda, Keisuke Tsuji: Efforts to prevent and commercialize hard rice and diabetes. Food industry, 53 (14), 46-51, 2010. Ken’ichi Ohtsubo, Sumiko Nakamura, Keisuke Tsuji, Kazunori Utsunomiya, Yasunobu Masuda, Mineo Hasegawa: Possibility of diabetes prevention by high-amylose rice.Rice studies, present and future, Sankyosyuppan Inc., pp.109-115, 2012. Masako Asaoka, Kazutoshi Okuno, Yasumi Sugimoto, Masahiro Yano, Takeshi Omura, and Hidetsugu Fuwa: Structure and properties of endosperm starch and wated soluble polysaccharides from sugary mutant of rice, Starch, 37, 364-366 (11), 1985. Toshinari Igarashi, Isao Hanashiro, and Yasuhito Takeda: Molecular structures and some properties of rice starches from Hokkaido cultivars.J. Applied Glycoscience, 55, 5-12, 2008. Toshinari Igarashi, Masafumi Kinoshita, Hideki Kanda, Tomoko Nakamori, and Toshimi Kusume: Evaluation of hardness of waxy rice cake based on the amylopectin chain-length distribution.J. Applied Glycoscience, 55, 13-19, 2008. Toshinari Igarashi: Molecular structure and properties of Hokkaido rice starch. Hokkaido Agricultural Experiment Station Report, 127, 12-19, 2010.

  It is an object of the present invention to provide a method for evaluating rice starch characteristics related to functionality such as resistant starch content easily, quickly, at low cost, and with high accuracy by gelatinization viscosity characteristics.

  As a result of diligent research to solve the above problems, the present inventors analyzed rice flour or rice starch samples, and applied the analytical values to the estimation formula to obtain the resistant starch content or resistant starch content. The present inventors have found that the sugar chain fraction content closely related can be estimated easily, quickly, at low cost and with high accuracy, and have arrived at the present invention.

  That is, the rice starch characteristic evaluation method of the present invention is characterized in that the rice starch characteristic is evaluated by multiple regression analysis using rice flour or the gelatinized viscosity characteristic value of rice starch as an explanatory variable.

  Moreover, the rice starch characteristic is characterized by the indigestible starch content.

  Moreover, the rice starch characteristic is the content of sugar chain fraction having a polymerization degree of glucose of 10 or a polymerization degree of 22.

  The rice starch characteristic is characterized by amylose content.

  Moreover, the rice starch characteristic is characterized by the chain length distribution of amylopectin.

  In addition, as an explanatory variable for multiple regression analysis, one of the gelatinization viscosity characteristic values among the gelatinization start temperature, maximum viscosity, minimum viscosity, final viscosity, breakdown, setback, consistency, and new gelatinization temperature. It is characterized by using a kind or two or more kinds.

  Moreover, the estimation formula of the content of the sugar chain fraction having a polymerization degree of 10 is characterized by the following formula.

  Further, the estimation formula for the content of the sugar chain fraction having a degree of polymerization of 22 is the following formula.

  Moreover, the estimation formula of the resistant starch content is the following formula.

  Moreover, the estimation formula of the resistant starch content is the following formula.

  Moreover, the estimation formula of the resistant starch content is the following formula.

  Moreover, the estimation formula of the resistant starch content is the following formula.

  The amylose content estimation formula is characterized by the following formula.

  According to the present invention, the content of indigestible starch in rice that is expected to have functions such as prevention of diabetes and prevention of obesity by slowing the increase in postprandial blood glucose of a person, only a gelatinization viscosity measuring device is required. By measuring the gelatinization viscosity of rice flour or rice starch to be evaluated, it can be easily and quickly evaluated at low cost.

  Further, according to the present invention, it is possible to estimate the content of sugar chain fraction having a polymerization degree of 10 or a polymerization degree of 22 by measuring gelatinization viscosity of rice flour or rice starch, and the possibility of functionality of the rice sample. Can be estimated.

  In addition to the conventional amylose content, information on the structure of amylopectin can also be obtained by simple gelatinization viscosity measurement, so that the quality characteristics of the sample rice can be estimated to some extent.

It is a graph which shows the amylose content of various sample rice. It is a graph which shows the resistant starch content of various sample rice. It is an estimation formula of amylose content by multiple regression analysis using gelatinization viscosity characteristics as a variable. It is an estimation formula of resistant starch (RS) content by gelatinization viscosity characteristic. It is the estimation formula (the 2) of indigestible starch (RS) content by gelatinization viscosity characteristic. It is an estimation formula of sugar chain fraction content by gelatinization viscosity characteristics. It is an estimation formula of resistant starch by amylopectin short chain and gelatinization characteristic value. It is an estimation formula of resistant starch content with the new gelatinization temperature as a variable.

  The present invention simply and quickly evaluates starch properties such as resistant starch content and sugar chain fraction content closely related to resistant starch based on the gelatinization viscosity characteristics of rice flour or rice starch. Related to technology.

  The rice flour in the present invention refers to general Japanese rice or Indian rice, newly cultivated new trait rice, and brown rice or milled rice of amylopectin long-chain rice. It is a powder that has been pulverized by using a pulverizer or an airflow pulverizer.

  The rice starch in the present invention is a product obtained by defatting and deproteinizing a polished rice sample, which is obtained by removing protein with a dilute alkali at a low temperature and subsequently defatted with ethanol and acetone. The protein may be deproteinized by heating, or degreased by hot butanol or hexane.

  The gelatinization viscosity characteristics in the present invention are obtained by using rice flour or rice starch as a sample, and a general rotation such as a rapid visco analyzer (RVA) manufactured by Foss Japan, an amylograph manufactured by Brabender, a trace viscograph, and a rheometer manufactured by Anton Paar. Suspend a sample in water or other dispersion medium using a viscometer, and increase, hold, or decrease the temperature while stirring, and detect the viscosity of the solution or suspension as a rotational resistance value Pasting start temperature, maximum viscosity, minimum viscosity, final viscosity or breakdown (difference between maximum viscosity and minimum viscosity), setback (difference between final viscosity and maximum viscosity), consistency (final viscosity and minimum viscosity) Parameters such as viscosity difference), new gelatinization temperature (gelatinization temperature of sample rice-gelatinization temperature of glutinous rice) / amylose content of sample rice) And refers to the property to be expressed.

  The multiple regression analysis in the present invention is to predict one objective variable with a plurality of explanatory variables, and is a kind of multivariate analysis. Which explanatory variable influences the objective variable to what extent. I can know. For example, when there are three independent variables, the multiple regression equation is as follows. The coefficient applied to each independent variable is called “partial regression coefficient”. The suitability of the model is expressed as a coefficient of determination (the square of the multiple correlation coefficient) and can be tested by analysis of variance.

  The starch characteristic in the present invention refers to a functional characteristic of starch, for example, a physiological characteristic such as digestion and absorption after feeding, and a physical characteristic such as viscosity characteristic of gelatinized starch.

  The indigestible starch in the present invention refers to a starch that is difficult to digest and absorb to the human stomach and small intestine after feeding, and when starch molecules are mutually cross-linked by a covalent bond or chemically modified. In the case of crystallization by hydrogen bonding, when starch molecules are structurally covered with other materials, gelatinized starch is aged, etc. It also refers to starch that has been reported to have an intestinal effect.

  The sugar chain fraction in the present invention refers to a glucose polymer formed by partial decomposition of amylose or amylopectin constituting starch by amylase or isoamylase, and using a technique such as gel filtration chromatography, Separation and fractionation by molecular weight can be performed.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example, this invention is not limited to these Examples at all.

(Measurement of resistant starch content of sample rice)
2 g of the polished rice was suspended in 10 mL of 0.1% sodium hydroxide and deproteinized by shaking at 4 ° C. for 3 hours. After light centrifugation, the precipitate was washed three times with pure water, twice with 99% ethanol, then washed with acetone and air-dried to obtain a sample starch.

  FIG. 1 shows the results of taking a starch sample having a dry matter weight of 100 mg in a test tube and measuring the amylose content by an iodometric colorimetric method.

  Moreover, the result of having measured the indigestible starch content using the same sample and using a resistant starch measurement kit manufactured by Megazyme is as shown in FIG. 2, such as EM174, Kaori Koshinono, Hokuriku Flour 243, etc. Showed a high value.

(Quantification of sugar chain fractions with different chain lengths)
4 mg of the starch sample prepared in Example 1 was suspended in 1.6 mL of distilled water, the starch was gelatinized at 100 ° C., and 16 μL of 1M acetate buffer pH 3.5 was added to adjust the pH to 3.5. 0.67 μL (0.03 U / mg) was added and reacted at 45 ° C. for 15 hours to debranch the 1,6-glucoside bond of starch. Subsequently, the enzyme was inactivated by heating at 100 ° C. for 10 minutes, cooled in water, and used as a dry sample with a centrifugal concentrator (Tomy CC-105).

  To this sample, 111 μL of dimethyl sulfoxide was added and dissolved by heating. To this, 89 μL of distilled water and 200 μL of 2-aminopyridine were added and mixed well, and incubated at 60 ° C. for 1 hour in the dark. Thereafter, 200 μL of sodium cyanoborohydride was added and incubated for 24 hours to prepare a sample for HPLC. Next, this sample was filtered through a membrane filter (manufactured by Millipore, pore size 0.2 μm), and 20 μL of the filtrate was injected into HPLC manufactured by JASCO Corporation for analysis. The column was connected with SHODEXOHPAKSB-803HQ and SHODEXOHPAKSB-802.5 and detected with a fluorescence detector LP2020. The measurement results of the sugar chain fraction of the rice sample starch are shown in Table 1.

(Measurement of gelatinization viscosity characteristics of rice starch)
25 mL of pure water was added to 3 g of dried rice starch, and the viscosity characteristics were measured under the following measurement conditions. That is, after stirring at 50 ° C. for 1 minute, the temperature was raised from 50 ° C. to 93 ° C. over 4 minutes, stirred at 93 ° C. for 7 minutes, cooled from 93 ° C. to 50 ° C. for 4 minutes, and stirred at 50 ° C. for 3 minutes. The viscosity was measured. The difference between the highest viscosity and the lowest viscosity was taken as breakdown, the difference between the final viscosity and the lowest viscosity was taken as consistency, and the difference between the highest viscosity and the final viscosity was taken as setback.

  Table 2 shows the gelatinization characteristic values of 32 types of starch by RVA. In the highest viscosity, super hard rice Hokuriku flour No. 243, high amylose rice Koshi no Kaori, Koshika Koshi, good-tasting rice yumepirika etc. show high values, and super hard rice EM10, EM145, glutinous rice It showed a low value. These results are presumed to be due to the influence of starch properties of amylose and amylopectin without being affected by each enzyme activity and protein and lipid because of the gelatinization property test using starch.

  Moreover, in the gelatinization start temperature, super hard rice showed a very high value, followed by high amylose rice scent and super hybrid rice of Japan-India hybrid. In addition, in the breakdown, super hard rice other than Hokuriku Flour No. 243 showed a very low value, while Indica rice and Japan-India mixed rice also showed a low value, but the scent of high amylose rice has a high value. Indicated. Good-tasting rice and general-purpose rice showed almost high values. Next, the final viscosity and consistency values, which are indicators of aging, are high in Indian type Yumeji, ultra-hard rice, followed by Hoshiyutaka, Carnaroli, and high amylose rice in Japan-India hybrid rice. Kaori showed a high value.

  Table 3 shows the results of a correlation analysis t-test of gelatinization characteristic values, amylose content, and resistant starch content of starch. The highest correlation value with the resistant starch content was the gelatinization start temperature, followed by a significant difference in the risk factor of 1% for the lowest viscosity and the final viscosity.

(Estimation of amylose content of rice starch)
The results of multiple regression analysis with the gelatinization characteristic values of 17 varieties (Table 2) as explanatory variables and the objective variable as the amylose content (FIG. 1), as shown in FIG. The estimation formula using the tenancy and the consistency / breakdown is shown, the multiple correlation coefficient is 0.9504, and as shown in FIG. 3B, as a result of testing the 14 unknown samples using this formula, The multiple correlation coefficient was 0.8343, and it was revealed that this is an extremely applicable estimation formula.

(Estimation of resistant starch content of rice starch)
As shown in FIG. 4A, the gelatinization characteristic values (Table 2) of 13 varieties are used as explanatory variables, the objective variable is the resistant starch content (FIG. 2), and multiple regression analysis is performed. As a result, gelatinization starts. An estimation formula using temperature and minimum viscosity was shown. In this calibration curve, the multiple correlation coefficient is 0.8679, and as shown in FIG. 4B, in the test of 12 unknown samples, the multiple correlation coefficient is 0.8338. However, it showed a very high correlation and was found to be an estimation formula with wide applicability.

(Estimation of resistant starch content of rice starch-2)
As shown in FIG. 5A, the gelatinization characteristic values (Table 2) of 13 varieties were used as explanatory variables, the objective variable was set as the indigestible starch content (FIG. 2), and as a result of the multiple regression analysis, gelatinization was started. An estimation formula using temperature and consistency and consistency / breakdown was presented. The multiple correlation coefficient of this calibration curve is 0.871. Next, as shown in FIG. 5B, in the test of 10 unknown samples, the multiple correlation coefficient is 0.500. However, it showed a high correlation and was found to be an estimation formula with wide applicability.

(Preparation formula of sugar chain fraction content based on gelatinization viscosity measurement results)
Next, the results of the correlation analysis of the chain length distribution in Table 1 and the analysis values of the gelatinization characteristic values in Table 2, the amylose content, and the resistant starch content are shown as the relationship between the amylopectin chain length distribution and the gelatinization characteristic values. As shown in Table 4. From DP7 to DP16 (content of sugar chain fraction from polymerization degree 7 to polymerization degree 16) is amylose content, and from DP17 to DP18 (content of sugar chain fraction from polymerization degree 17 to polymerization degree 18) is breakdown DP19 (content of sugar chain fraction with a polymerization degree of 19) is the minimum viscosity, DP20 (content of sugar chain fraction with a polymerization degree of 20) is the final viscosity, and DP21 (content of sugar chain fraction with a polymerization degree of 21). ) Is the minimum viscosity, amylose content, DP22 to DP24 (content of sugar chain fraction from polymerization degree 22 to polymerization degree 24) is amylose content, DP25 (content of sugar chain fraction of polymerization degree 25) is Consis Tensy / breakdown and DP26 to DP30 (content of sugar chain fraction from polymerization degree 26 to polymerization degree 30) showed the highest correlation with amylose content. As for the correlation with the RS content, a negative correlation is shown with a 1% risk in the short chain from DP7 to DP14 (degree of polymerization 7 to degree 14), DP21 to DP23 (degree of polymerization 21 to degree 23) On the long chain side, a positive correlation was shown with a risk factor of 5%.

  Next, in A and B of FIG. 6, the gelatinization characteristic values of 10 varieties are used as explanatory variables, the objective variables are A: DP10 (content of sugar chain fraction having a polymerization degree of 10), and B: DP22 (polymerization degree of 22 As a result of multiple regression analysis, the estimation formula using final viscosity, gelatinization start temperature, consistency / breakdown, and consistency was shown. The multiple correlation coefficients of this estimation formula were A: 0.9597 and B: 0.9922, and it was possible to create an estimation formula with a high correlation coefficient.

(Estimated formula for resistant starch content based on gelatinization viscosity measurement results -Part 3-)
As a result of multiple regression analysis using the resistant starch content as an objective variable and the amylopectin short-chain fraction and gelatinization characteristic values of 9 rice varieties as explanatory variables, an estimation formula as shown in FIG. 7 was obtained. . The lowest viscosity was selected as the gelatinization characteristic value. The multiple correlation coefficient of this estimation formula was 0.9057, and it was possible to create an estimation formula with a high correlation coefficient.

(Estimation formula of resistant starch content using new gelatinization temperature as a variable -Part 4)
As a result of multiple regression analysis using the resistant starch content as an objective variable and the amylopectin short-chain fraction and gelatinization characteristic values of 9 rice varieties as explanatory variables, an estimation formula as shown in FIG. 8 was obtained. . A new gelatinization temperature was selected as the gelatinization characteristic value. The new gelatinization temperature refers to a value obtained by subtracting the gelatinization temperature of glutinous rice from the gelatinization temperature of the sample rice and dividing the value by the amylose content of the sample rice. The coefficient of determination of this estimation formula (the square of the multiple correlation coefficient) is 0.8110, which makes it possible to create an estimation formula with a high correlation coefficient.

Claims (13)

A method for evaluating rice starch characteristics, characterized by evaluating rice starch characteristics by multiple regression analysis using rice flour or gelatinized viscosity characteristic values of rice starch as explanatory variables. 2. The method for evaluating rice starch characteristics according to claim 1, wherein the rice starch characteristics are indigestible starch content. The method for evaluating rice starch characteristics according to claim 1, wherein the rice starch characteristics are the content of a sugar chain fraction having a polymerization degree of glucose of 10 or a polymerization degree of 22. The method for evaluating rice starch characteristics according to claim 1, wherein the rice starch characteristics are amylose content. 2. The method for evaluating rice starch characteristics according to claim 1, wherein the rice starch characteristics are amylopectin chain length distribution. As an explanatory variable for multiple regression analysis, one of the pasting viscosity characteristic values of pasting start temperature, maximum viscosity, minimum viscosity, final viscosity, breakdown, setback, consistency, new pasting temperature or Two or more types are used, The evaluation method of the rice starch characteristic in any one of Claims 1-5 characterized by the above-mentioned. The estimation formula for the content of sugar chain fraction with a degree of polymerization of 10 is
The method for evaluating rice starch characteristics according to claim 3, wherein: The estimation formula for the content of the sugar chain fraction with a degree of polymerization of 22 is
The method for evaluating rice starch characteristics according to claim 3, wherein: The estimation formula for resistant starch content is
The method for evaluating rice starch characteristics according to claim 2, wherein: The estimation formula for resistant starch content is
The method for evaluating rice starch characteristics according to claim 2, wherein: The estimation formula for resistant starch content is
The method for evaluating rice starch characteristics according to claim 2, wherein: The estimation formula for resistant starch content is
The method for evaluating rice starch characteristics according to claim 2, wherein: The estimation formula for amylose content is
The method for evaluating characteristics of rice starch according to claim 4, wherein: