Simple tests for differentiating raw-old and new and steamed rice in a mixture.

Bhashyam, M. K. and Meera, M. S. and Hirannaiah, B. V. and Ali, S. Z. (2002) Simple tests for differentiating raw-old and new and steamed rice in a mixture. Journal of Food Science and Technology, 39 (6). pp. 654-656.

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Abstract

When cooked, freshly harvested rice yields a product that is pasty, loses solids in excess cooking water and shows little swelling in comparison to cooked aged rice. A process for steaming (or curing) fresh rice has been developed to hasten the rice ageing process. Accidental or intentional mixing of new rice with old rice affects cooking quality. In this study, 3 tests were developed to determine the extent of rice admixture for quality control purposes. 5 varieties of freshly harvested rice (var. Jaya, Early Sona, Basmati, IR64 and Sonamasuri) and aged, new and steamed samples of a commercially available variety (var. Bangara Theegalu) were treated by cooking (boiling), tested for TBA values or incubated in alpha-amylase solution. Cooking resulted in the new rice showing longitudinal splitting or disintegration, while old rice remained intact. Reaction with TBA formed a dark reddish brown coloured complex with oxidized fat arising out of autooxidation during ageing. Incubation in alpha-amylase solution hydrolysed the gelatinized starch, which was seen in higher proportion in steamed rice than in raw rice and gave a dark reddish orange colour, upon addition of dinitrosalicylic acid. It is suggested that these tests may be useful for rice quality control.

Item Type:	Article
Uncontrolled Keywords:	Amylases; Boiling; Old rice; Raw rice; Differentiation
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:	Somashekar K.S
Date Deposited:	15 Jun 2011 11:20
Last Modified:	15 Jun 2011 11:20
URI:	http://ir.cftri.res.in/id/eprint/7586

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