Characterization of enzyme-assisted cold-pressed cottonseed oil

Physicochemical properties of enzyme-assisted cold-pressed oils from seeds of cotton (Gossypium hirsutum), using five commercial enzymes (Phytezyme, Allzyme, Natuzyme, Kemzyme and Feedzyme), were compared with those of the control (without enzyme) and solvent-extracted oils. Enzyme-extracted cottonseed oil yield ranged from 9.70 to 12.89%, which was significantly (P < 0.05) higher than that of the control (8.50%). No significant (P > 0.05) variation in the protein, fiber and ash contents was observed in all extracted oilseed residues. The saponification value, unsaponifiable matter, free fatty acid content, specific extinctions at 232 and 270 nm, and peroxide and p-anisidine values of the enzyme-extracted oils were lower than those of solvent-extracted oils but comparable with those of the control. The fatty acid composition of the control, enzyme- and solvent-extracted cottonseed oils revealed no significant (P > 0.05) variation with regard to the constituent fatty acid contents. However, the enzyme-extracted oils had relatively lower levels of stearic acid. When compared with the control, the α-tocopherol content was high in the Phytezyme-, Natuzyme- and Feedzyme-extracted oils; nevertheless, it was comparable with those in solvent-extracted oils. The level of γ-tocopherol in enzyme-extracted oils was comparable with the control, but generally higher than that in the solvent-extracted oils. Enzyme-assisted cold pressing is very effective in enhancing the oil yield, with better quality of end-use products and involves lower capital investment than that of solvent extraction. Commercial enzymes were used in this study and the proposed enzyme-assisted extraction method will be beneficial for the local vegetable oilseed extraction sector and may offer valuable by-products for food and feed applications.