Evaluation of physicochemical properties, fatty acid composition and bioactivity of the cashew nut (Anacardium Occidentale L.) oil extracted by different methods

Abstract

The main purpose of this study was to evaluate the efficiency of different methods for cashew nut oil extraction and to investigate the storage stability and quality of the oil produced from different methods. In the present study, cashew nut kernel oil was extracted by 3 methods including cold-pressing, solvent method and enzyme assisted aqueous extraction (EAAE). The cold-pressing was conducted at pressure of 25 MPa and room temperature, using a custom-made device. The solvent extraction was done on Soxhlet apparatus for 6 h, using hexane as solvent. The EAAE was carried out with commercial enzyme Viscozyme Cassava C. The three methods were compared by the extraction yields and several indicators, such as specific gravity, free fatty acid (FFA), peroxide values (PV), total phenolic, total flavonoid content and fatty acid composition. The PVs, FFAs, TPC and the yields were significantly different among 3 methods but volatile compounds content, specific gravity and TFC were insignificantly different. The storage ability of the oils was investigated by following the change in FFA and values in a period of 45 days at 60 °C. The oil obtained by cold-pressing was most stable against oxidization and rancidity. It was concluded that the EAAE oil and solvent extraction oil are stable for at least 8 months at room temperature condition, while the cold-pressed oil is stable for 12 months. The oils were rich in un-saturated fatty acid, with more than 65% mono- and polyunsaturated fatty acid (MUFA and PUFA). Also, the fatty acid composition was not significantly different among the three methods. Key words: Cashew nut kernel oil, cold-pressing, enzyme assisted aqueous extraction, solvent extraction, storage stability.