Assessment of the quality of bran and bran oil produced from some Egyptian rice varieties

ABSTRACT

Rice [Oryza satlva L] is one of the leading food crops of the world, the staple food ofover half the world's population. Tha bran, which is an important byproduct obtainedduring rice milling, constitutes about 1/10 of the weight of the rice grain. Rice branis the outer brown layer including the rice germ that is removed during the millingprocess of brown grain. This milling byproduct is reported to be high in natural vitaminsand minerals, particularly vitamin E.The present study was conducted to determine the chemical composition of branand bran oil of 13 different rice varieties commonly produced in Egypt, to study theutilization of rice bran in [Dread production, and to assess the quality and acceptanceof the rice bran edible oil produced.Rice bran was produced from 13 Egyptian varieties of recently harvested rice as wellas from paddy rice stored for 1 year. The extracted bran was immediately stabilizedthen subjected to chemical analysis [such as moisture content, protein, fat,carbohydrates, fiber, and ash] as well as trace and heavy metals determination [P, K,Na, Ca, Fe, Zn, Cu, and Mg]. Bread was produced by adding Giza172 rice bran atthree different concentrations to wheat flour then subjected to chemical analysis,caloric content, and organoleptic examination. Bran oil was extracted from the differentvarieties of rice bran [recently harvested and stored] then subjected to chemicaland organoleptic examinations as well as vitamin E and oryzanol determination.The percentage of rice bran of newly harvested Egyptian rice was 11.68% and was'10.97% in stored rice. The analysis showed mean values of 5.91 and 5.53% formoisture, 14.60 and 14.40% for crude protein, 14.83 and 15.20% for fat, 44.77 and45.40% for carbohydrates, 6.55 and 7.06% for crude fiber, and 8.87 and 8.50% forash for newly harvested and stored rice bran, respectively. Bread containing 15% ricebran showed the highest score percentages for organoleptic quality compared withthe control [100% wheat flour]. Rice bran oil showed higher scores of taste, smell,appearance, and texture than corn oil and sunflower oil.Rice bran contains high nutritional components as well as phytochemicals such asvitamin E [i.e. tocopherols and tocotrienols] and the y-oryzanol fraction that havepositive effects on human health. Storage of paddy rice before milling resulted insignificant effect on all studied rice bran characters and rice bran oil characters underthe present investigation except crude protein and carbohydrates characters,Substitution of wheat flour with rice bran by 15% in bread production to fortify thebread with vitamin E and to reduce the amount of imported flour is recommended