Thermal degradation of starch in parboiled rice

Mahanta, C. L. and Bhattacharya, K. R. (1989) Thermal degradation of starch in parboiled rice. Starch/Staerke, 41 (3). pp. 91-94. ISSN 0038-9056

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Abstract

Raw and variously parboiled (conventional parboiling, dry-heat parboiling, pressure parboiling) Intan rice (intermediate-amylose var.) starch was fractionated in Sepharose CL-2B column into a larger-molecule (Fr I) and a smaller-molecule (Fr II) fraction. Amount of Fr I decreased and that of Fr II increased in parboiled as compared with raw rice, extent of change increased with increasing severity of processing. Proportion of polysaccharide and `amylose' in Fr I decreased from 70 and 40% of total, resp., in raw rice to 16% for both in parboiled rice prepared by 3 kg/cm-2 gauge steam pressure. Simultaneously, the lambdamax of its iodine complex increased from 570 to 588 nm in Fr I and decreased from 635 to 620 nm in Fr II. The change was marginal or low after steaming at ambient pressure or after sand roasting. Data show that thermal degradation of starch must be considered as another contributor, in addition to starch gelatinization and reassociation, to the peculiar properties of parboiled rice.

Item Type:	Article
Uncontrolled Keywords:	STARCHES-SPECIFIC; rice starch, parboiling & thermal degradation of; BOILING-; DECOMPOSITION-; THERMAL-PROCESSES; RICE-; parboiling & thermal degradation of rice starch
Subjects:	600 Technology > 08 Food technology > 25 Sugar/Starch/Confectionery 600 Technology > 08 Food technology > 21 Cereals > 01 Rice
Divisions:	Grain Science and Technology
Depositing User:	Food Sci. & Technol. Information Services
Date Deposited:	05 Jul 2008 08:41
Last Modified:	22 Dec 2016 10:37
URI:	http://ir.cftri.res.in/id/eprint/1922

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