EFFECTS OF DRYING TECHNIQUES ON PHENOLICS CONTENT AND ANTIOXIDANT ACTIVITY OF WATER-SOLUBLE PALM FRUIT EXTRACT

Water-Soluble Palm Fruit Extract (WSPFE) is produced from the vegetation liquor of palm oil milling.It comprises water-soluble phenolic acids including protocatechuic acid (PCA), p-hydroxybenzoic acid (p-HBA) and three isomers of caffeoyl-shikimic acid .WSPFE has been shown to exhibit a range of bioactive properties both in vitro and in vivo.The present study investigated the effects of freeze and spray drying, on the phenolic content, antioxidant capacity, organoleptic properties, hygroscopicity and moisture content of WSPFE.To quantify the concentrations of PCA, p-HBA and 3-O-CSA within WSPFE, an isocratic HPLC-UV method was developed and validated.The HPLC method employed a mobile phase system consisting of 20% methanol and 80% water, with a flow rate of 0.8 mL min -1 , a running time of 40 min and UV detection at 280 nm.Comparative analysis revealed that freeze drying maintained a marginally higher retention of phenolic compounds.Spray drying resulted in WSPFE with lower hygroscopicity and moisture content.Spray drying showed a slightly higher concentration of PCA (23 0.3 g mL -1 ) compared to freeze drying (22 0.1 g mL -1 ).No significant differences were found in the concentrations of p-HBA acid and 3-O-CSA between freeze drying and spray drying.