Nutrient Composition of Selected Improved and Traditional Rice varieties (Oryza saliva L.)

Abstract

The rice market in Sri Lanka is currently dominant with selected improved rice varieties but the consumer trend is to use traditional varieties as the preventive measures of Non-communicable diseases which has been highly spread among all the societies. Despite these facts, the traditional varieties are not easily acquired by the majority of the population due to less availability and the high cost.Therefore, this study was conducted to determine the available portion of nutrients that could be acquired by the rice consumer after cooking each of the rice variety in the usual manner. Twenty five rice varieties including 12 traditional and 13 improved rice varieties were cultivated at Rice Research Station, Ambalanttoa during 2017 /18 maha season. Recommended cultural and processing practices were adapted. Each variety was husked to remove the outer husk with a rubber roll sheller and polished for 30 seconds to remove the bran partially. Rice was washed twice with distilled water before cooking in a rice cooker. Cooked rice was oven dried at 65 °C for 3 ½ hrs and ground in an electrical grinder to obtain fine powder. The powder was used to analyze different rice components such as proximate compositions (moisture, crude protein, crude fat, crude fiber, crude ash). This study reveals that partially polished rice even after washing twice with water has given a considerable amount of nutrients with significant readings.Highest to lowest values of crude protein %, crude fat%, crude ash %, crude fiber% and carbohydrate % ranged between 8.5 to 5.2, 2.57 to 0.9, 1.32 to 0.57, 0.13 to 0.086 and 92.9 to 89.2 respectively. An improved rice variety At 354 and a traditional variety Hera th banda gave the significantly (p $ 0.05) highest protein content of 8.50 % and 8.33 % respectively compared to other tested rice varieties. Carbohydrate has contributed to nearly 90 % of the total nutrients in dry basis having the highest value in Bg 380 (92.9 %) and lowest in Herath banda (89.2 %). Next to carbohydrate, protein contributes to the total nutrient composition varying between 5.2 ± 0.7 to 8.5± 0.4 %.There was no difference between pooled values of traditional and improved rice varieties for their protein or fat contents. Rath suwandel and Suduru samba had the highest fat %. However, ash percentage of traditional rice varieties was significantly higher than improved rice varieties. Beheth heenati recorded the highest mean crude ash content of 1.32 %. Negative correlation was found between the crude ash and carbohydrate contents (-0.4836), crude fat and carbohydrate contents (-0.4430) and crude protein and carbohydrate contents (-0.88).A positive correlation between fat and ash contents were found (0.63) but no correlation was reported between other components.There were no influences on nutritional attributes by grain pericarp colour or sizes and shapes of grains. Comparable nutrient values were found in red and white pericarp varieties.None of the varieties had all nutrients at significantly high levels. Nutrient availability is varieity dependent and high and low nutritional values are present either in improved or traditional varieites.