DIN EN ISO 6647-2:2015-09

This part of ISO 6647 is a test method for determining the quality of rice. It specifies a simplified routine method for determination of the amylose content of milled, non-parboiled rice in the range from 1 % to 30 %. Rice samples for which the amylose content has been determined by the reference method size exclusion chromatography (SEC) are used as standards to generate the calibration curve. The use of standards calibrated by SEC is an approach to determine the true amylose content and decreases the conversion errors of the present standard. Rice is ground to a very fine flour to break up the endosperm structure in order to aid complete dispersion and gelatinisation. A test portion is dispersed in sodium hydroxide solution, and then an aliquot is mixed with iodine solution. The absorbance, at 620 nm or 720 nm of the colour complex formed, is then determined using a spectrophotometer. The amylose content of the sample is then read from a calibration graph, which is prepared using rice samples with known amylose content, determined using the reference method (see ISO 6647-1). Rice samples with certified amylose content according to ISO 6647-1 are used as standards. The committee responsible for this standard is NA 057-05-06 AA "Getreide und Getreideerzeugnisse" ("Cereals and cereal products") at DIN.