A comparative study on free and bound phenolic acid content and their antioxidant activity in bran of rice (Oryza sativa L.) cultivars of Eastern Himalayan range

Abstract

In our study, seven most prevailing but unexplored indigenous rice cultivars of northeast India, situated in the Eastern Himalayan Range, were investigated for their phenolic acid profile, total phenolic content (TPC) and antioxidant capacities in free and bound phenolic extracts of their bran. HPLC studies showed the presence of ferulic, p-coumaric, sinapic, caffeic, chlorogenic and vanillic acids, with ferulic and p-coumaric acids being the dominant phenolic acids in the bound form. The lower EC 50 values of the bound extracts than the free extracts suggested the better radical scavenging activity of the bound extracts. Significant correlations were observed between TPC and phenolic acid content (HPLC-DAD) of bound extracts, and between Trolox equivalents antioxidant capacity (TEAC) and phenolic acid content (HPLC-DAD) of both free and bound extracts. The findings suggest that phenolic acids in the rice cultivars investigated were exclusively present in bound form and contribute significantly towards their antioxidant capacity.Free and bound phenolic acids in rice bran A. Begum et al.

A Comparison of the Chemical Composition, In Vitro Bioaccessibility and Antioxidant Activity of Phenolic Compounds from Rice Bran and Its Dietary Fibres

“…Conversely, ferulic acid and p -coumaric acid were the major bound monomeric phenolic compounds in DRB and IDFDRB, and they totally accounted for 72.1% and 74.1% of their total bound monomeric phenolics, respectively. Similar results were found in earlier studies on rice bran [ 17 , 18 ]. However, vanillic acid [ 34 , 35 ] and hydroxybenzonic acid [ 15 ] were reported to be the major bound monomeric phenolics together with the predominant ferulic acid in rice bran.…”

“…Simultaneous monitoring was set at 280 nm for the quantification of monomeric phenolics. Based on the previous reports [ 17 , 18 , 19 , 26 , 32 , 34 , 35 , 36 , 53 ], the phenolic compounds in the samples were identified by comparing their experimental retention times and UV spectral data with those of known authentic standards.…”

“…The chemical composition and antioxidant activities of phenolics in brown rice and rice bran [ 13 , 14 , 15 , 16 , 17 , 18 , 19 ] and the influences of processing treatment on those parameters [ 20 , 21 , 22 , 23 , 24 , 25 , 26 ] have been reported in previous studies. Even though the majority of the phenolic components are widely reported to bind to the fibre matrix of grains, little is known about the chemical composition and antioxidant activities of the phenolics in rice bran dietary fibre.…”

Effect of Wheat Bran on Dough Rheology and Final Quality of Chinese Steamed Bread

“…Thus, cereal bran can be a good source of DF, including arabinoxylan, b-glucan, cellulose, and lignin as major components (Elleuch et al 2011;Kiszonas et al 2015). Apart from DF, cereal bran is rich in protein, lipids, minerals, and B vitamins (Nordlund et al 2013;Begum et al 2015;Onipe et al 2015;Sobota et al 2015). Wheat bran has a high DF content and contains 44-50% fiber.…”

Exploiting Phenylpropanoid Derivatives to Enhance the Nutraceutical Values of Cereals and Legumes

“…The colorimetric methods include Folin-Ciocalteu assays (Singleton et al, 1999 ), Prussian blue tests (Graham, 1992 ), ferric ammonium citrate tests (International Organization for Standardization), and vanillin-HCl and butanol-HCl tests (Price et al, 1978 ; Watterson and Butler, 1983 ; Porter et al, 1986 ). These methods have been used for total phenol determination in barley ( Hordeum vulgare L.), common bean (Hart et al, 2015 ), rice ( Oryza sativa L.; Begum et al, 2015 ), sorghum (Beta et al, 1999 ; Waniska and Rooney, 2000 ; Dykes et al, 2005 ; Dlamini et al, 2007 ; Chiremba et al, 2012 ), soybean [ Glycine max (L.) Merr. ; Nikolova et al, 2014 ; Phommalath et al, 2014 ], einkorn wheat ( Triticum monococcum L.), and bread wheat ( Triticum aestivum L.; Fogarasi et al, 2015 ).…”