Effect of Ethanol Extract of Rice Bran as an Antioxidant on the Flavour of Stored Buffaloes’milk Ghee

Abstract

Rice bran ethanol extract (RBEE) was used as a natural antioxidant at two concentrations (0.02% and 0.05% w/w) being added to buffaloes milk ghee. Butylated hydroxytoluene (BHT), the chemical antioxidant was also used at the concentration of 0.02 % w/w. Samples treated with natural (RBEE) and chemical (BHT) antioxidants were stored for 12 months at room temperature. The development of the flavour in the samples was estimated using Reichert-Meissl (RM), Polenske (PV) values, saponification number (SN) and Iodine value (IV). The fatty acid composition of the stored samples as well as thiobarbituric acid test (TBA) and peroxide value (POV) were also detected. Sensory score was carried out on all stored samples. Results revealed that the short chain fatty acid content of the control and RBEE (0.02% w/w) treated samples decreased with an associated decrease in RM, PV and SN. The IV and unsaturated fatty acid content also decreased with an increase in the saturated fatty acids. The TBA and POV were in agreement with the sensory score. The flavour deterioration was more evident as the values of TBA and POV increased. Concerning the samples treated with RBEE (0.05% w/w) and BHT (0.02% w/w), the addition of the RBEE succeeded to give similar results obtained by the addition of BHT at 0.02% w/w.