EFFECT OF DRYING CONDITIONS AND EXTRACTION SOLVENTS ON TOTAL PHENOLIC COMPOUNDS AND ANTIOXIDANT PROPERTIES OF MANGO SEED KERNEL EXTRACTS

Abstract

Mango seeds are a by-product of fruit factories that have low economic value. But, its high phenolic content makes it to be important source of natural antioxidants. The effect of drying methods (sun-drying and oven-drying at 50 oC) and extraction solvents (chloroform / methanol mixture (2:1, v/v), 80% ethanol and water) on total phenolics andantioxidant properties of mango seed kernel extracts (MSKE) were studied. Results showed that the combination of oven-drying and chloroform / methanol mixture (2:1, v/v) extraction was the most effective recovery method in relation to the yield of gained dried matter (15.17%), and quantity of extracted total phenolics per gram of extractable dry matter (102.5 mg). Antioxidant properties expressed as antioxidant index calculated from the ratio of induction period (time taken in hours to reach a peroxide value of 5 during storage at 80±2oC) of buffalo ghee sample treated with 5% (w/v) of MSKE concentrated liquid obtained from using oven-dried mango seed kernel and chloroform / methanol mixture extraction to induction period of control sample was 4.52, compared to 3.23 when 0.02% BHT was used. Using HPLC, nine phenolic compounds identified in oven-dried mango seed kernel extract resulted from chloroform / methanol mixture extraction method were qurecetin, catechin, vanillin, coumarin, tannin, rutin and cinammic, ferulic, and gallic, acids. It could be concluded that mango seed kernel powder can serve as potential source of natural antioxidants for application in food products due to their marked antioxidant properties. Mango seeds are a by-product of fruit factories that have low economic value. But, its high phenolic content makes it to be important source of natural antioxidants. The effect of drying methods (sun-drying and oven-drying at 50 oC) and extraction solvents (chloroform / methanol mixture (2:1, v/v), 80% ethanol and water) on total phenolics andantioxidant properties of mango seed kernel extracts (MSKE) were studied. Results showed that the combination of oven-drying and chloroform / methanol mixture (2:1, v/v) extraction was the most effective recovery method in relation to the yield of gained dried matter (15.17%), and quantity of extracted total phenolics per gram of extractable dry matter (102.5 mg). Antioxidant properties expressed as antioxidant index calculated from the ratio of induction period (time taken in hours to reach a peroxide value of 5 during storage at 80±2oC) of buffalo ghee sample treated with 5% (w/v) of MSKE concentrated liquid obtained from using oven-dried mango seed kernel and chloroform / methanol mixture extraction to induction period of control sample was 4.52, compared to 3.23 when 0.02% BHT was used. Using HPLC, nine phenolic compounds identified in oven-dried mango seed kernel extract resulted from chloroform / methanol mixture extraction method were qurecetin, catechin, vanillin, coumarin, tannin, rutin and cinammic, ferulic, and gallic, acids. It could be concluded that mango seed kernel powder can serve as potential source of natural antioxidants for application in food products due to their marked antioxidant properties.