Cashewnut moisture relations

Abstract

AbstractInvestigations on the moisture relations of raw cashewnuts at tropical temperatures (about 27°) are described; a description is included of a laboratory method suitable for use as a reference method, which involves the use of toluene in a Dean & Stark distillation apparatus. This method was found to be reliable to within 0.3%.There was some evidence that differences in the moisture contents of these nuts stored under identical conditions may be partly due to differences in the kernel/shell weight ratio, and that this ratio is probably higher in small than in larger nuts. This might explain the slight tendency for the moisture content of heavy nuts to be greater than that of lighter nuts.Nuts stored in moving air took up moisture more rapidly and attained equilibrium moisture, content much faster than in apparently still air.It was found that at an equilibrium moisture content the shell moisture content could be used to predict the moisture contents of the whole nut and kernel.Above 75% R.H., cashewnuts at 27° became visibly invaded by microflora including members of the genera Aspergillus, Fusarium, Paecilomyces, Penicillium and Rhizopus. Sorption and desorption curves were produced, relating the ambient relative humidities to the corresponding equilibrium moisture contents of fresh nuts stored in apparently still air at 27°. From this relationship the maximum safe moisture content for raw cashewnuts was estimated to lie between 8.9 and 9.2%, being that in equilibrium with surrounding air at 70% R.H. and 27°.