Extraction of Phenolic Compounds from Wheat Bran using Ohmic Heating

Abstract

Phenolic compounds have been extracted from Iraqi local wheat bran by using ohmic heating at temperature of 80 ^oC by using different values of the electric field intensity are 14, 20, 44 Vcm^-1 and has been compared with the traditional method. The results showed that the required times to reach 80 ^oC were 6, 10, 20 and 30 min. at using electric field intensity of 14, 20, 44 Vcm^-1 respectively. The electric field intensity had a significant effect on the electric resistance, electric conductivity, heating rate and power. Phenolic compounds quantity has been evaluated in extracts by using Folin-Ciocateau method, where the treatment extract (20 Vcm^-1) was superior in content of phenolic compounds and anti-oxidative activity over the rest of treatments. The dialysis technology was used to fractionate the treatment extract (20 Vcm^-1). It has been shown that compounds with low molecular weight compounds (less than 1000) are responsible for the anti-oxidation activity degree is greater than the high molecular weight (more than 1000). The treatment extract (20 Vcm^-1) has proven its capability to hinder the self-oxidation of olive oil at the concentration of (0.25%) for a 25 day storage period.

Keywords: antioxidant, ohmic heating, wheat bran, Phenolic compounds