Phenolic compounds and antioxidant properties of arabinoxylan hydrolysates from defatted rice bran.

• Autores: Prachit Yuwang, Irina Sulaeva, Johannes Hell, Ute Henniges, Stefan Böhmdorfer, Thomas Rosenau, Benjamart Chitsomboon, Sunanta Tongta
• Localización: Journal of the science of food and agriculture, ISSN 0022-5142, Vol. 98, Nº 1, 2018, págs. 140-146
• Idioma: inglés
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• Resumen

  • Background: The water unextractable arabinoxylans (WUAX) contain beneficial phenolic compounds that can be used for food rather than for animal feed. The antioxidant activities of defatted rice bran obtained by xylanase-aided extraction is reported herein. The chemical and molecular characteristics of extracted fractions were investigated.; Results: The WUAX hydrolysate precipitated by 0-60% ethanol (F60), 60-90% ethanol (F6090), and more than 90% ethanol (F90) had decreased molar masses with increasing ethanol concentration. The fractions of interest, F60 and F6090, contained 75% arabinoxylans with ferulic acid as the major bound phenolic acid, followed by p-coumaric acid. According to chemical-based antioxidant assays F60 and F6090 exhibited higher diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and ferric iron reducing ability than F90 which contained minor contents of small sugars and free phenolic acids. In cell-based antioxidant assays, using the fluorescent 2',7'-dichlorofluorescein diacetate probe, all three fractions were potent intracellular scavengers.; Conclusion: The high molar mass of WUAX hydrolysates with high amount of bound phenolics contributes to the chemical-based antioxidant activity. All fractions of WUAX hydrolysates showed high potent intracellular scavenging activity regardless of molar mass, content and the component of bound phenolics. © 2017 Society of Chemical Industry.; © 2017 Society of Chemical Industry.