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Title: Rice bran stabilization by improved internal and external heating methods

Miscellaneous ·
OSTI ID:5473863

Rice bran stabilization was conducted by internal (microwave), external (oven drying and steam retorting) heating and non-heating ({sup 60}Co irradiation) treatments to improve currently used methods. Two commercial rice varieties cultivated in Louisiana, one long grain (Lemont) and a medium grain (Nato), were milled to collect bran samples. The bran was analyzed for its proximate composition and various physical and thermal characteristics. The rice bran stabilized by four methods was packed in brown paper bags and stored in an extremely unfavorable environment (33 {plus minus} 2{degree}C, 75 {plus minus} 5% relative humidity) to test the efficacy of each of the four stabilization methods. Bran treated by microwave heating was found to be very stable. At the end of the four week storage period, free fatty acids (FFA) increased only from 4.0% to 4.9% in long grain bran and 4.6% to 6.2% in medium grain bran, while in untreated bran it increased from 4.0% to 68% and 4.6% to 56.8%, respectively. Bran stabilized by microwave heating was as well as steam retorted bran in terms of FFA and better in color and nutrition. Oven dried bran was found to be unstable at high temperature and under high humidity conditions, and so was the bran stabilized by irradiation. Heat transfer efficiency analysis revealed that microwave heating is superior to either external heating methods for bran stabilization. Multiple regression analysis indicated that the initial moisture content, weight of the rice bran and microwave heating time are three important variables for the inactivation of bran peroxidase and lipase. Given the microwave heating strength constant, optimum stabilization effect was obtained with 21% initial moisture content in rice bran.

Research Organization:
Louisiana State Univ. and Agricultural and Mechanical Coll., Baton Rouge, LA (United States)
OSTI ID:
5473863
Resource Relation:
Other Information: Thesis (Ph. D.)
Country of Publication:
United States
Language:
English