BIOCHEMICAL PROPERTIES OF MAIZE BRAN WITH SPECIAL REFERENCE TO DIFFERENT PHENOLIC ACIDS

Abstract

ABSTRACT Maize bran is a milling by-product having many nutritional and functional properties. Functional properties are attributed to the presence of some bioactive compounds. Among those, ferulic acid is a natural phenolic compound and abundantly present in maize bran. It has numerous advantages and generally has nutraceutical properties in many food products. In the current research, the nutritional & bioactive profiles of two different maize brans (PEARL-11and FSH-810) were explored with special reference to different phenolic acids. Moreover, the alkaline-hydrolysis method was used to extract ferulic acid from maize brans using NaOH and then extracted by precipitating with ethanol. The extraction method was optimized using two different concentrations (0.5 M NaOH and 1 M NaOH) at 40°C & 60°C, respectively, and was analyzed to evaluate the optimization effects on extraction yield. Furthermore, obtained extracts were analyzed by High-Performance Liquid Chromatography (HPLC). Results showed that maize bran (PEARL-11) contains higher dietary fiber, total phenolic and flavonoid contents as compared to FSH-810. Moreover, DPPH and FRAP contents ranged from 78 to 86% and 26.8 to 22.6 mg TE/100 g in FSH-810 and PEARL-11, respectively. HPLC results showed maximum amount of ferulic acid (3.89 ± 0.07 mg/g) in maize bran (PEARL-11) at these conditions (0.5 M NaOH concentration; 60°C hydrolysis temperature) whilst other phenolic acids such as diferulic and p-coumaric acid were 0.79 ± 0.012 and 0.42 ± 0.003 mg/g at 0.5 M NaOH concentration and 60°C hydrolysis temperature, respectively. Furthermore, the extraction yield of ferulic acid from maize bran (PEARL-11) of NaOH concentration (0.5) with hydrolysis temperature (60°C) was increased. Conclusively, it is observed that maize bran is the cheapest and naturally rich source of different phenolic acids (especially ferulic acid) among other cereal bran.