Viability and Quality Changes in Brown Rice

Abstract

Viability and quality changes of brown rice are important to find out the appropriate approach of brown rice management in trade. Two experiments, (1) Survey on viability and qualities of brown rice in trade and (2) Longevity and quality changes of brown rice after harvest, were carried out in Pathum Thani Rice Research Center during 2002-2004. Viability of brown rice sampled from millers and exporters at the range of 0, 1-25, 26-50 and 80-100% were found at 5, 6, 12, 23 and 54%, respectively. Low amylose content, soft gel consistency and 1-2 aromatic level were found in all samples. Free fatty acid was 14.04-50.78 mg KOH/100 g starch. Aflatoxin B₁ of the samples were detected in the range of 0-11 ppb which were below maximum level against standard (20 ppb). Viability of KDML105 brown rice dropped to 48 and 26% within 3-month storage and dropped to 5 and 0% within 6-month storage in vacuum filling and normal package, respectively. Amylose content and gelatinization temperature did not change during 10-month storage. Free fatty acid increased with storage time. Brown rice stored in laminated plastic bag with vacuum filling was damage due to insect invasion within 8-month of storage whereas that in normal laminated plastic bag was damage within 4 months.