Factors Affecting Amylose Analysis in Rice Samples by Iodine Binding Method
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Abstract
Factors affecting the error of amylose analysis in rice samples by iodine binding method were studied in order to establish a standard amylose analysis in rice samples for laboratories in Thailand. A comparison between an international standard method, ISO 6647: 2015 and rice department standard method, TAS 4004-2017 from the Ministry of Agriculture and Cooperatives (Thailand) was studied. The results showed that the main factor that caused large error in amylose analysis was the use of pure amylose standards instead of cultivated rice flour standards in constructing the calibration curve. The calibration curve constructed with cultivated rice flour standards was linearly followed the equation y = 0.0161x - 0.0046 with R2 0.9980. The precision within-day was 2.6 and 1.7 %RSD (n = 5) at amylose 12 and 29 %, respectively. The precision between-day was 5.3 and 3.1 %RSD (n = 10) at amylose 12 and 29 %, respectively. The accuracy of the method was validated with rice flour certified reference material BCR-467. The Student’s t-test showed that there was no significant difference in the result at 95 % confidence level. This method was used to analyze amylose in 26 rice samples with various cultivars.
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