The effect of pre-treatment methods on the yield and taste of cashew kernels (Anacardium occidentale L.)

Abstract

Pre-treatment methods that cashew nuts (Anacardium occidentale L.) are subjected to before shelling are crucial in influencing the yield of whole kernels and the aftertaste. In this work, raw cashew nuts were subjected to different times of steaming, boiling, and roasting as pre-treatment methods and their effect on yield and panellists’ preference for taste followed by spectrophotometric determination of residual cashew nut shell liquid (CNSL) on kernels were assessed. After initial comparison of kernels obtained from similarly pre-treated samples, the samples boiled for 15 min, steamed for 30 min, and conditioned before roasting were selected. Further analysis showed no significant differences in the yield of all grades of cashew kernels from cashew nuts steamed for 30 min (71%) and that boiled for 15 min (69%). The sample conditioned before roasting, had a significantly lower whole kernel recovery (51%) but significantly higher percentage yield for halves (37%) than the steamed (19%) and boiled samples (21%).Panellists preferred the sample boiled for 15 min as having the least after-taste, followed by the sample steamed for 30 min, with the sample conditioned before roasting being least preferred. Spectrophotometric results of residual CNSL on kernels were 25, 54, and 71 ppm, respectively for samples boiled for 15 min, steamed for 30 min, and the one conditioned before roasting, buttressing the sensory evaluation results. Key words: Cashew nuts, steaming, boiling, roasting, spectrophotometric determination.