Antioxidant and physicochemical properties of oils extracted from cashew (Anacardium occidentale L.) Kernels
Emelike NJT, Akusu MO, Ujong AE
The effects of various processing methods such as hand cracking (HC), steam cooking (SC), oil roasting (OR) and dry roasting (DR) on the antioxidant and physicochemical properties of cashew kernel oil samples were investigated. Results revealed that OR produced the highest percentage of wholesome kernels (93.00%) while a gradual decrease was observed from DR (61.30%), SC (33.18%) to HC (10.00%) methods. Percentage yield of the oil samples from solvent extraction and screw press methods showed high values in the DR (44.10 and 32.81%) followed by OR (39.80 and 30.90%), HC 35.18% and 28.24% and SC (34.40% to 27.06%), respectively. Total phenolic (53.18mgGAE/g), total flavonoid (24.07mgRE/g) and total antioxidant capacity (12.50mgAAE/g) of the DR oil sample drastically reduced than other processing methods studied. Physicochemical analyses showed that peroxide values were 0.33, 0.43, 0.62 and 0.84meq/g for SC, HC, OR and DR, respectively with significant difference (P<0.05) in all the samples. Moisture, impurities and volatile matter (MIV) values decreased in the following order; 0.39% (SC), 0.33% (HC), 0.18% (OR) and finally 0.16% for DR sample. Flash (290oC) and smoke (218oC) points of the oil was highest in the OR and decreased to 273oC and 210oC in the DR sample, respectively. Processing methods showed no significant effect on the iodine and saponification values, specific gravity, melting and cloud points of the oil samples. Based on the values for antioxidant, physicochemical, wholesomeness and oil yield, the findings of this study has shown that DR and OR methods can be recommended at the industrial and domestic level for the processing of cashew kernel oil.