Molecular degradation of rice starch during processing to flakes

Rajni, Mujoo. and Ali, S. Z. (1999) Molecular degradation of rice starch during processing to flakes. Journal of the Science of Food and Agriculture, 79. pp. 941-949.

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Abstract

Roasting of the soaked paddy (roasting-parboiling) appeared to cause an increase in the proportion of the high-molecular-weight component of starch, separated in Fraction-I, probably due to retrogradation. The solubility of starch also decreased. Flaking of roasted-parboiled paddy in the traditional edge-runner Øaker did not cause any further appreciable change in the proportion of Fraction-I and Fraction-II. Flaking in the roller-Øaker unit, on the other hand, caused a decrease in the proportion of Fraction-I, indicating molecular breakdown of starch. The total starch solubility increased marginally in edge-runner Øakes but substantially in roller-Øaker Øakes. Fractionation of starch that was soluble in hot water showed that the major amount of amylose equivalent resided in this portion as revealed by a higher proportion of Fraction-II and a high lmax of the peak of this fraction. When retrogradation was induced in the Øakes under appropriate conditions of moisture and temperature, the content of the high-molecular-weight Fraction-I of total starch increased slightly in edge-runner Øakes but markedly in roller-Øaker Øakes, indicating an aggregation or reassociation of starch molecules or its fractions.

Item Type:	Article
Uncontrolled Keywords:	rice; starch; flaking; degradation; retrogradation
Subjects:	600 Technology > 08 Food technology > 21 Cereals > 01 Rice 600 Technology > 08 Food technology > 05 Processing and Engineering
Divisions:	Grain Science and Technology
Depositing User:	Food Sci. & Technol. Information Services
Date Deposited:	26 Jun 2008 03:49
Last Modified:	16 May 2012 09:21
URI:	http://ir.cftri.res.in/id/eprint/1755

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