Comparative Study of Nutrient Composition and Retention of Raw and Cooked Imported and Local Rice (Oryza sativa) Varieties

Abstract

Background: Cereals and grains constitute major sources of nutrients worldwide. Rice is a major staple in many household in Nigeria. However majority of people prefer imported rice to locally grown rice though it is costlier. Knowledge about nutrient composition of locally-grown rice can promote its acceptability and consumption among Nigerians. This study was carried out to determine the nutrient composition and nutrient retention of raw and cooked imported and local rice varieties.  Materials and Methods: Imported (Aroso) and local varieties (Ofada and Abakaliki) rice were purchased from Bodija market in Ibadan, Oyo state, Nigeria. The three samples were divided into two portions each. One portion each was used as raw samples while the second portion of each sample of rice was cooked for 40 minutes at 100°C. The cooked samples were then homogenised using the warring blender. The resultant six rice samples were analyzed using AOAC (2005) methods. Results and Discussion: An 100 g portion of raw rice samples contained between 10.97-11.36 g moisture, 6.98-8.28 g protein, 0.84-1.24 g crude fibre, 0.94-1.19 g ash, 77.51-79.46 g carbohydrates, 17.81-19.31 g amylose, 5.57-9.69 mg sodium, 113.07-118.75 mg potassium, 4.54-7.34 mg iron, 221.4-238.75 µg folate, and yielded 366.75 - 371.50 kcalories of energy. Ofada rice was highest in all the macro and micronutrients, followed by Abakaliki rice and imported rice, which was highest in gross energy. Cooking resulted in significant reduction in all the nutrients studied (p<0.05), but the reduction was less pronounced in the two local rice samples. Conclusion and Recommendation: The local varieties of rice were nutritious and compared favourably well with the imported rice. Cooking caused significant reduction in the level of antinutrients in the samples. Consumption of local rice varieties is recommended as means of promoting dietary diversity.