STUDIES OF OIL FROM COWPEA (VIGNA UNGUICULATA (L.) WALP.) CULTIVARS COMMONLY GROWN IN PAKISTAN

Abstract

The physiochemical properties and fatty acid (FA) composition of oil from seeds of 4 cowpea cultivars viz., Elite, CP1, White Star and SA dandy, commonly grown in Pakistan, were investigated. Oil contents ranged from 2.71-2.96% with triacylglycerols being present in highest amount. Iodine values were found highest in CP1 while SA dandy and CP1 excelled in saponification values and acid values, respectively. Despite variations unsaturated fatty acids were observed as being present in higher concentration in all cultivars. Among sterols, stigmasterol was present in highest amount followed by β-sitosterol and campesterol. Among tocopherols, a-, and β- tocopherols were observed as being present in highest and lowest concentrations, respectively. Results from most of the parameters revealed not significant (p≤0.05) differences among the cultivars. The results showed that campestrol positively correlated with stigmasterol, D5- avenasterol, D7-avenasterol, and have high negative (-0.9) correlation with b-sitosterol. However, campesterol (sterol) has only negative correlation with α-tocopherol, while have positive correlations with β-tocopherol, γ-tocopherol and δ-tocopherol. But stigmasterol has negative correlations with α-tocopherol (-0.7; high), β-tocopherol (-0.3, low) and δ-tocopherol (-0.2, low) while have low positive (+0.4) with γ-tocopherol. b-sitosterol also depicted similar correlations with different tocopherols. All cowpea cultivars appeared to be suitable as nutritional oil source of comparable quality.