Some physico-chemical properties of Moringa oleifera seed oil extracted using solvent and aqueous enzymatic methods

The physico-chemical properties of oil from Moringa oleifera seed were determined following extraction either with petroleum ether or 2% Neutrase 0.8L (a neutral bacterial protease from Bacillus amyloiquefaciens, Novozyme Bagsvaerd Denmark). The enzyme was chosen following a preliminary study conducted on the enzymatic extraction of M. oleifera seed oil using four commercial enzymes that showed Neutrase to be the best enzyme with the highest oil recovery value. The enzymes used were Termamyl 120L, Type L (α-Amylase), Neutrase ® 0.8L (Neutral protease), Celluclast ® 1.5 L FG (Cellulase) and Pectinex ® Ultra SP-L (Pectinase), all from Novozyme, Denmark. The fatty acid compositions of solvent and enzyme-extracted oil from M. oleifera seed were determined. Results showed that the solvent-extracted oil has 67.9% oleic acid compared to 70.0% in enzyme-extracted oil. Results obtained following analysis of extracted oil showed that the oil is highly unsaturated because of the high percentage of oleic acid. Apart from oleic acid, other prominent fatty acids were palmitic (7.8% and 6.8%), stearic (7.6% and 6.5%), and behenic (6.2% and 5.8%) acids for solvent and enzyme-extracted oils, respectively. It was liquid at room temperature and pale-yellow in colour (0.7R + 5.9Y and 0.7R + 3.0Y for solvent and enzyme-extracted oils, respectively). Electronic nose analysis showed that it had flavor similar to that of peanut oil. The melting points estimated by differential scanning calorimetry were found to be 19.0 and 18.9 °C for the solvent- and enzyme-extracted oils, respectively. The oil contains 36.7% triolein as the main triacylglycerol. The extraction methods were found to slightly influence the relative amounts of the fatty acids in the oil. The oils extracted using these two methods were found to differ in the percentage composition of their fatty acids. Quality attributes such as relative percent of oleic acid, total percentage of unsaturated fatty acids, iodine value, free fatty acid and unsaponifiable matter contents and the colour of the enzyme-extracted oil were better than those of the solvent-extracted oil.