Fatty acids, tocopherols, phenolics and the antimicrobial effect of Sclerocarya birrea kernels with different harvesting dates

Abstract

Oil extracted from the kernel of Sclerocarya birrea with different harvesting dates was studied in terms of the oil content, fatty acids, tocopherols, phenolic compounds and antimicrobial activity. A quantitative increase in the oil content was observed to reach 63.0% at the end of the last harvesting date. The percentage of total fatty acids had altered and palmitic acid content was found to be 16.8% at the first date of harvesting and dropping for the rest of the dates to reach 14.6% by the end of the harvesting process. In the same manner, stearic acid was found to be 15.2% at the first date and this dropped dramatically to reach 8.8% by the end of the harvesting, while oleic and linoleic acids increased from 58.9 and 4.3% to 67.3 and 5.9%, respectively. Alpha and gamma tocopherols decreased rapidly, whereas the δ-tocopherol and δ-tocotrienol were 4.8 and 4.9 mg/100 g, respectively at the beginning and had disappeared completely by the last harvesting date. Total phenolic and flavonoid content increased continuously through the different harvesting dates. Sclerocarya birrea kernel oil was effective in inhibiting the growth of three out of four bacterial strains tested. This inhibitory effect was less than that of the control. © 2009 AOCS.