Effect of some heat treatments on chemical composition and oil characteristics of sesame seeds (sesamum indicum l.)

Proximate chemical compositions of black and white sesame seeds (Sesamum indicum L.) were determined. The chemical properties after heat treatment of white seeds at 60 80ºC for (10 15 min) as compared to their raw counterparts were determined. Bioactive components of sesame oils, namely, lignans, tocopherols and total phenols were determined in raw black and white seeds then determined in white seeds after heating. Results indicated that the black and white sesame seeds contained high proportions of oil (52.82 and 56.24 %) and protein (20.14 and 20.91%), respectively. Sesame seeds were found to be good sources of minerals, where calcium exhibited the highest value among the other determined minerals in black seeds (0.97%) and (1.08%) in white seeds. Both Iron and Zinc were present in almost equal amounts in both seeds (372 230.6 mg/ kg) in white seeds and (340 289.4 mg/ kg) in black seeds, respectively. Palmitic and linoleic acids were the predominate fatty acids in sesame oil as measured by GC. After heating, the saturated fatty acids were increased while the unsaturated fatty acids were decreased. Lecithin and carob seeds powder were added to white tehina at different levels to delay the separation process of oil that might take place in tehina paste. Results showed that by adding carob seeds powder at (15 20%) significantly delayed separation time up to 45 60 days, respectively.