Comparative Assessment of Some Physicochemical Properties of Different Sesame Varieties and Oil Yield, Ethiopia

Abstract

The proximate composition and physico chemical properties of released and improved Ethiopian sesame oil seed crops were evaluated. The results of statistical analyses showed significant variations in proximate composition values and physico chemical characteristics of sesame oil seed crops. The analysis of variance indicated that moisture content was ranged between 4.4% to 4.8%, total ash (4.70% to 8.72%), crude protein content (14.44% to 21.51%), crude fat /oil (44.40% to 50.84%) and carbohydrate was ranged between (16.23% to 29.46%). Maturity stage and storage conditions are the major factors for moisture contents. The lower moisture values indicated that there is low vulnerable for oil spoilage the so-called rancidity. Total ash values are the indication of inorganic elements that are present in food as minerals. From the ash values, comparatively Tate has a better mineral value as compared with others. Serkamo sesame variety has a better protein value while the minimum (14.44%) was recorded at Adi. This may due to the reason that protein values have direct correlation with agronomic practices. The oil contents of seed crops were significantly different; this may be due to genetic difference. The carbohydrate values have significant difference among varieties. These variations may be bringing form the concept that oil crops mostly have a better oil values, thus subtractions of carbohydrate from the proximate values have a significant effect on the carbohydrate’s values. On the other hand, the oil characterization of seed crops indicated that the range of saponification value was between (184.47 to 199.60 mgKOH/g), specific gravity (0.85 to 0.90), thousand seed weight (2.72 to 3.63 g), free fatty acid value (7.63 to 16.67%), ester value (151.32 to 182.90) and acid value (15.18 to 33.15 KOH/g). The physico chemical parameters of sesame oil seed crops were significantly different among varieties. This variation mainly exists due to genetic variabilities among the seed crops. From these ten different sesame varieties, Abasena with its lowest saponification value and high free fatty acid value indicated that the oil from this variety is regarded non-edible oil. Lower acid value indicated the oil stability against peroxidation. Abasena with its higher acid value indicated that the oil is not suitable for cooking as compared with the remain sesame varieties.