Comparative study of grain quality characteristics of some selected traditional and improved rice varieties in Sri Lanka: a review

Abstract

Consumer acceptability and market demand in rice (Oryza sativa L.) are mainly determined by its grain quality. Therefore, the main aim of the present analytical review was to evaluate some selected traditional and improved rice varieties in Sri Lanka for their grain quality characteristics that include physical, physico-chemical, milling, cooking and eating and nutritional properties. Information from higher number of traditional varieties than that of improved varieties was used in the review as existing number of traditional varieties is about ten times higher than that of improved varieties in the country. Most of the traditional rice varieties are red with short to medium size grains having round and bold shape. Most of the improved rice varieties are white with long to medium-size grains having either round, bold, or internationally acceptable slender shapes. The total milling recoveries of both traditional and improved rice varieties are more or less similar and are in the range of 69-74%. Nutritional value of rice is influenced by genotype, soil and environmental condition under which the rice is grown as well as postharvest processing and storage condition and also degree of milling influences on the end-use nutritional quality. Both the cooking and eating quality and nutritional properties varied within traditional as well as within improved varieties. Total carbohydrate content of almost all of the improved rice varieties is higher except in the improved variety Bg 360 than that of the traditional varieties studied. Available data on grain protein, crude fat and crude fiber contents of traditional and improved rice varieties are significantly varying and inconsistent within and between traditional and improved rice varieties. The majority of the traditional and improved rice varieties belong to high amylose class, however, improved rice variety at 405 recorded the lowest amylose content and several traditional rice varieties recorded intermediate amylose content. Both traditional and improved rice varieties showed a similar swelling power. Though the swelling power of rice grains has shown a negative linear relationship with grain amylose content in general, a positive linear relationship between those two characteristics has been observed between improved and traditional rice varieties in Sri Lanka.