PROPERTIES OF ROSELLE SEEDS (Hibiscus sabdauriffa L.) AS A NEW SOURCE OF OIL

Abstract

Physico-chemical properties of roselle seed and its oil as affected by extraction method were investigated. The obtained results revealed that moisture, ether extract, crude protein, crude fiber, ash and carbohydrate contents of roselle seed were 8.38%, 22.24%, 26.25%, 16.22%, 5.61% and 21.30%, respectively. The most predominant minerals in whole roselle seed were K, Na, Mg and Ca. The results indicated that the major essential amino acids present in roselle seed were leucine, lysine and phenylalanine. The lowest limiting amino acid in roselle seed was tryptophan (0.34 g/16 gN). Also, the results of lipid classes indicated roselle seed oil contained a moderate amounts of sterols (3.17% and 3.40% in oil extracted by petroleum ether and cold pressing) and sterol esters (2.84% and 2.23%, respectively). GLC analysis of both fatty acids and unsaponifiable matters composition of roselle seed oil indicated that oil has a high ratio of unsaturated fatty acids per saturated fatty acids and contained a high amount of -sitosterol and a moderate amounts of campesterol and stigmasterol. Linoleic, oleic and palmitic acids were the major fatty acid constituents in crude oil. Petroleum ether extraction was the better method to extract the oil from the seed comparing to cold pressing due to high yield and quality of the extracted oil. Therefore, roselle seed oil could be used as an edible oil based on its physical and chemical properties.