Yield of carotenoids, phenolic compounds and antioxidant capacity of extracts from Gac peel as affected by different solvents and extraction conditions

Gac fruit (Momordica cochinchinensis Spreng.) is a rich source of bioactive compounds especially carotenoids. Currently, only the aril of the Gac fruit is processed and the peel is discarded although it contains high levels of carotenoids and phenolic compounds, which could be extracted for commercial use. In the present study, solvent type, ratio of solvent to material, extraction time and temperature were investigated for the extraction yields of carotenoids and phenolic compounds, the antioxidant activity of the extract from Gac peel. Ethyl acetate extract showed the highest extraction yield of carotenoids, phenolics and ABTS antioxidant capacity. The highest levels of carotenoid yield and antioxidant capacity were obtained at 2 hours of extraction with the ratio of solvent to material of 20:1 (ml/g). Phenolic extraction yield reached the highest level after 2.5 hours of extraction and rose with the increase in extraction temperature while the highest extraction yield of carotenoids was obtained at 40 to 50C and declined at higher temperature. The extraction using ethyl acetate with the ratio of 20:1 (ml solvent/g Gac peel) for 2 hours at 50C is suggested for extraction of bioactives from Gac peel.