In the interest of promoting the consumption of whole grains, the chemical constituents (moisture, protein, ash, and fat) and biofunctional components (dietary fiber and γ‐oryzanol) were determined in six varieties of brown rice (five japonica and one indica) that are preferred in the form of polished rice by consumers in Taiwan. The results showed significant differences (P < 0.05) in the chemical compositions of the samples for all the measured parameters. The Koshihikari variety had the highest contents of protein and crude ash. Crop year showed significant effects on the moisture content and partly on the protein, ash, and fat contents. The total dietary fiber content of the tested rice ranged between 5.1 and 10.0%, with Kaohsiung 145 having the highest content (P < 0.05). In all varieties, the content of insoluble dietary fiber was greater than that of soluble dietary fiber. The content (mg/100 g) of γ‐oryzanol ranged from 17.9 to 29.2 for the 2009 crop and from 24.5 to 41.3 for the 2010 crop. It showed that γ‐oryzanol was affected by crop year and variety. The japonica types had significantly higher γ‐oryzanol content (P < 0.05) than the indica type. Taikeng 9 and Tainan 11 had greater γ‐oryzanol content than the other rice varieties.

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).