ABSTRACT

This study was carried out to determine the effects of various drying methods on unripe plantain and its drying kinetics. The effects of commonly used drying methods which are sun, electric oven and solar drying), on the nutrient content of plantain (Musa paradisiaca) was investigated. This food crop was dried using these various drying methods and their nutritional composition determined. Analysis of the nutritional composition showed that these drying methods significantly lowered the moisture content from 58.70% w.b (fresh) to 7.55% w.b (Solar dried samples). Fibre, vitamin C, magnesium and potassium levels were retained more with open sun drying and least with solar drying while ash, CHO, vitamin A and Fe recorded highest with solar drying and least with open sun drying. It was observed that Magnesium increased with each drying method and could be due to absence of oxalate and phytate compounds in the fruit. Oven dried plantain slices had the highest (76.55%) retained protein than solar dried (65.88%) and open sun dried (50.75%). The proximate parameters of control (fresh) plantain slices are significantly (p = 5%) different from that of dried plantain for all the studied drying methods except iron (Fe). Comparing the composition of dried plantain slices with different method, no significant (p < 5%) difference was observed though their mean values differ. These results indicate that the effects of the various drying methods on the food samples were almost similar, with each drying method retaining the nutrients, without total loss of any nutrient; although, with some degree of loss to some nutrients. The goodness of fit was determined using the coefficient of determination (R2), reduced chi square (x2) and root mean square error (RMSE). Among the empirical drying models fitted and their statistical analysis for all the drying methods studied (Table 4.2), logarithmic model had the most satisfactory condition for describing the drying behaviour of plantain slices. Logarithmic model obtained the highest R2values and lowest 2 and RMSE values as 0.98, 0.0396 and 0.0 170 respectively (open sun drying), 0.97, 0.0492 and 0.0121 respectively (oven drying) and 0.99, 0.0344 and 0.0083 respectively (solar drying).