Optimization of the maize drying parameters, a strategy to increase maize shelf life.

Abstract

The shelf life of grains after harvest is greatly determined by its moisture content because the moisture in the grain has influence. on water activity of the grain and water activity has influence on lipid Oxidation, enzyme activity non-enzymatic browning. and microbial activity and also influences grain texture. After harvesting the maize grains must therefore be dried as soon as possible since wet grains attract insects and mould (Green et al. 2005). For drying to be effectively done, all the parameters that affect it need to be optimally controlled Such parameters include drying temperature, tine for drying; and fate or the drying air flow Variation of-such parameters affects the properties of the final dried maize grains and thus affecting its shelf life. The methodology of this research involved varying different drying parameters combinations in a number of maize samples during the drying process. The shelf life. properties such as moisture content,. mould action, and degree of' wrinkleless of the samples, as well as seed variability of the stored-maize samples were tested after a period of 1 0days and 20 days. A Graph of time against air temperature plotted ta clearly illustrate how time of maize grain drying varies at different airflow rates and drying air temperatures. Graphs of properties against temperature were plotted, to illustrate how the shelf life determining properties varies in samples dried at different drying parameter combination after given Storage time intervals. A graph of germinability against drying temperature-was also platted to determine the level of viability of the maize seeds when dried at different drying parameters. Results of shelf life were further analysed with reference to UNBS and FAC Quality Standards. With this, an objective function equation which minimizes the shelf. fife reducing parameters, P was formulated. The drying parameter combination that minimizes the shelf life reducing properties, P was considered the best that optimizes the maize drying parameters. From the study conducted on properties that reduce shelf life such as moisture content, degree of wrinkleless, and mould action; and seed viability of the dried maize grains after storage for a period of 20 days; shelf life. can be maximized when maize grains are dried at a temperature of 700C, and flow rate of-O.O.1 2m 3/s, and for a period of 120 minutes.