Use of viscozyme L for pre-treatment of coconut prior to extraction by screw press

Abstract

The effect of moisture content of coconut crushes and enzyme treatment prior to extraction by screw press on the yield and qualities of virgin coconut oil was investigated in this study. Results showed that the screw pressing efficiency was higher for coconut crushes with low moisture content. The highest yield of extracted oil (14%) was obtained when using coconut crushes containing moisture content of 15%. The optimum concentration of Viscozyme L for pretreatment before oil compression was 0.4% (w/w). The lightness (L*), redness (a*), yellowness (b*), specific gravity, refractive index, moisture content, peroxide value, acid value, iodine number and saponification number of the oil compressed from grated coconut with and without enzymatic pre-treatment were not significantly different (p > 0.05). However the viscosity of oil from enzymatic pretreated coconut meat (45.66 ± 0.10 cP) was significantly lower (p = 0.05) than those from non-pretreated coconut meat (47.12 ± 0.05 cP). The changes in quality of the oil kept in glass or PET bottles during storage at room temperature (30 ± 2°C) for 28 days were studied. It was found that moisture content of oil did not change (p > 0.05), while L*, peroxide value, acid value and sensory quality in terms of clearness increased but a*, b* and sensorial quality in term of coconut odour decreased during storage. An accelerated shelf life study of coconut oil at 55oC and 65oC indicated that the predicted shelf life of coconut oil stored at 30oC was 57 days.