Cultivar Comparison on Tocopherols, Tocotrienols, and Antioxidant Compounds in Rice Bran

Abstract

The rice bran, a by-product of rice milling process, is well known for various functional components, such as tocopherol, tocotrienol, γ-oryzanol, carrying antioxidant activities. This study was conducted to investigate the antioxidant components and antioxidant activities in rice bran of different Korean rice cultivars. The 8 isomers of vitamin E, γ-oryzanol, flavonoids, and polyphenolics in rice bran from 16 Korean premium and high quality rice cultivars were quantified. DPPH and ABTS radical scavenging activities and reducing power of the ethanol extracts of rice bran were measured. 'Hopum' showed the highest total vitamin E content, 221.47 µg/g among the cultivars, and 'Hanseol' showed the lowest content. The rice bran showed different compositions of α-, β-, γ-, δ-tocopherol and tocotrienol among rice cultivars. The antioxidant contents were also different by cultivar; the γ-oryzanol contents ranged from 1.99 mg/g (Unkwang) to 4.30 mg/g (Chilbo), the polyphenol contents ranged from 427.22 mg gallic acid eq./100 g (Odaebyeo) to 775.80 mg gallic acid eq./100 g (Hopum). 'Hopum' also had the highest DPPH and ABTS free radical scavenging activities, 9.82% and 187.5 AEAC mg/100 g, respectively. In vitro, the rice bran extracts from 'Hopum' had significantly higher antioxidant activities than that of other cultivars.

Comparative Analysis of the Nutritional Components and Antioxidant Activities of Different Brassica juncea Cultivars

“…The pretreatments of the samples for the analysis of sinigrin in BJD and BJJ were carried out by modifying the method of Kim et al [ 25 ]. First, 20 g of freeze-dried BJD and BJJ and 400 mL 80% ethanol was added, and the mixture was refluxed for 2 h at 70 °C, concentrated under reduced pressure and lyophilized.…”