African Journal of Biotechnology Vol. 6 (8), pp. 1016-1020, 16 April 2007   

ISSN 1684–5315 © 2007 Academic Journals        

Full Length Research Paper

Effect of cooking and soaking on physical characteristics, nutrient composition and sensory evaluation of indigenous and foreign rice varieties in Nigeria

Osaretin Albert T.  Ebuehi¹* and Abosede Christiana Oyewole²

¹Institute of Sustainable Livelihoods, Vaal University of Technology, Private Bag X021, Vanderbijlpark 1900, South Africa.

²Department of Biochemistry, College of Medicine, University of Lagos, PMB 12003, Lagos, Nigeria.

*Corresponding author email: ebuehi@yahoo.com

Accepted 13 November, 2006

The objective of this study is to ascertain the effect of cooking and soaking on the physical characteristics, nutrient composition and sensory evaluation of indigenous ‘ofada’ rice and foreign ‘aroso’ rice varieties in Nigeria. The two rice varieties were freshly purchased in the raw state, soaked in water and cooked. The physical characteristics, such as, length, width, weight, colour, purity, breakage, cooking time, dispersability and swelling capacity of the raw rice varieties were determined. The raw, soaked and cooked rice varieties were oven dried as 60°C for 4 h and milled to attain uniform surface area.  The proximate composition and some minerals of the raw, soaked and cooked rice varieties and the sensory evaluation of the cooked rice were determined. Ofada and aroso rice varieties were brown and creamy in colour, respectively. There were significant (p<0.01) differences in the purity, breakage, cooking time, swelling capacity and weight of the whole grain, but with no difference in the length and width.  The raw, cooked and soaked ofada rice contain more protein, fat, and fibre than in aroso rice, but with no change in carbohydrate content .There were no significant (p>0.01) differences in the levels of minerals; Ca, Fe, Mg and P, in raw, cooked and soaked ofada and aroso rice. Sensory evaluation showed that cooked aroso rice was generally preferred, in terms of colour, aroma, taste, texture and overall acceptability.

Key words: Rice varieties, ‘Ofada’, ‘Aroso’, nutrients, sensory properties, Nigeria.