Direct Effect of cashew Nut Scarification Associated with Powdery Mildew in the Processing Industry

Abstract

Cashew powdery mildew disease can reduce on field yield by 100% depending on flowers’ susceptibility. Surviving flowers may still produce nuts that are severely damaged. The impact of this, post-harvest, damage to the processing industry is unknown. Therefore the objective of this experiment was to assess the effect of powdery mildew nut scarification on biometric and industrial processing variables: nut size, weight, nut count, outturn, cutting and peeling time and finally analyze the financial implication of the effect. Thus, raw cashew nuts were randomly sampled and categorized in to five disease score levels (treatments). Ten nuts (replicates) were used for each disease category. Length, thickness, width and weight were measured. Furthermore, from each disease level, two sets of nuts were established. One set for nut count and outturn assessment by cutting test. The other set, for steam boiling, cutting, peeling and other processes quantitatively assessed. A completely randomized experimental design was followed for data analysis. The summary effect was assessed as relative loss in percentage to non diseased nuts. The relative maximum loss due to powdery mildew attack was 41.2% for nut length, 42.9% for nut width, 31.3% for nut thickness and 50% for nut weight. The disease severity increased relative nut count (18.9%) and reduced the total percentage of kernels (20.3%), outturn (21.1%), the industrial yield of white wholes (88.1%), amount of peels (27.6%) and the outturn and nut count based projected income by 9.6%.  Three disease based nut categories are proposed for processing improvements. Nut scarification effect on kernel deterioration, seed germination and others is under investigation.