Shelf-life of roasted cashew nuts as affected by relative humidity, thickness of polythene packaging material and duration of storage.

Abstract

The effect of relative humidity, thickness of polythene packaging material and duration of storage on the shelf life of roasted cashew was determined to provide information for packaged roasted cashew nuts marketers. For this study, split plot in Randomized Complete Block Design was used with a total number of 180 observations (3 relative humidity x 4 polythene thicknesses x 5 duration levels of storage x 3 replications) each for moisture content, microbial count and quality index, which were measured using standard procedures. The initial mean moisture content, total fungal counts and percentage quality index of the nuts were found to be 1.17%db, 30CFU/g and 100% respectively, which were all deemed appropriate in comparison with the set acceptable storage mo isture content of 5 .8%db, tolerable fungal levels of 10 3 and 10 4 /g and acceptable percentage quality index of 45% for roasted cashew nuts which did not exceed its shelf-life and still deemed fit for human consumption. The results of the study indicates that relative humidity, polythene thickness and duration of storage have a highly significant effect (P≤0.01) on moisture content and quality index while for the microbial count, polythene thickness and duration of storage has significant effect (P≤0.05) with relative humidity showing non-significance. For all le vels of relative humidity and polythen e thickness, moisture content and microbial count increased with increase in duration of storage while quality index decreased with increase in duration of storage. As the polythene thickness increased at constant storage duration, the moisture content decreased. The moisture content of all the samples increased with increase in duration of storage at constant polythene thickness level. As the thickness of the polythene packaging material increased, the amount of moisture absorbed over time (in days) decreases; the total fugal growth decreases, and the percentage quality index increases. It is recommended that for the packaged roasted cashew nuts industry for poverty alleviation, the most favourable polythene thickness of 0.95mm should be used. The best storage relative humidity was determined in the study to be 47.2% under which conditions, storage period should not exceed 14 days for best quality and value for money.