The Effects of Processing Steps on γ-Oryzanol Retention in Rice Bran Added Bagels and Doughnuts

Abstract

Rice bran is a rich, natural source of γ-oryzanol, which has been reported to possess important health-promoting properties. The goal of this study was to incorporate this healthy ingredient into bakery products, and the effects of processing techniques on the retention of γ-oryzanol were investigated. Doughnuts and bagels were prepared with 10% rice bran added to high-protein formula flour. The products were sampled at various intervals during processing. Total γ-oryzanol was extracted and analyzed using high performance liquid chromatography. Sensory attributes were measured for the control and supplemented bakery products. The results showed that the total γ-oryzanol content decreased by 22% and 12% in doughnuts and bagels, respectively. The manufacturing steps causing significant losses (P < 0.05) of γ-oryzanol were the following: proofing ( _ 19.2%) in doughnut processing and boiling ( _ 10%) in bagel production. Substitution of 10% rice bran significantly (P < 0.05) increased the darkness of the products. Sensory evaluation results indicated that doughnuts and bagels with 10% rice bran were considered more acceptable than the control (P < 0.05).