Abstract/Summary

Moringa oleifera (MO) is a plant species of Indian subcontinent. Its pods contain kernels, which upon maturation consists of up to 35% protein and 41% oil (w/w). This oil is extractable using solvents such as hexane, but this is generally not looked upon favourably due to safety and environmental concerns. This thesis explores the use of aqueous enzymatic extraction (AEE) as an alternative, which involves incubating a mixture of MO kernels, water and enzymes under controlled conditions. Given that the oil globules are predominantly surrounded by proteins and cellulose, the enzymes used in this study were protease and cellulase. Centrifugation of the incubated mixture resulted in four distinct layers: free oil at the top, followed by an oil-in-water cream emulsion, an aqueous phase, and a residual solid meal at the bottom. The highest oil recovered in the free layer at the top following AEE was approximately 73% (w/w), measured in relation to the use of hexane. Another disadvantage of AEE in relation to organic solvent extraction is that a significant part of oil released from the cell ends up in the emulsified layer. Therefore, high pressure processing (HPP) pre-treatment was applied to the kernels prior to AEE, which resulted in increase in free oil quantity and a reduction in emulsion layer thickness. It is hypothesized that HPP modifies the MO protein structure into a form that lowers its emulsifying ability. The use of HPP considerably simplifies downstream oil separation steps. Storage tests showed that enzymatic extraction resulted in MO oil having better oxidative stability than the hexane-extracted oil. The MO oil also contained up to 75% oleic acid and high tocopherol contents, which contributed to its enhanced oxidative stability.