Suitability of yellow maize as an alternative to white maize as an adjunct in lager beer brewing

Abstract

Yellow maize is used as a raw material in many food industries but its use as an adjunct in beer brewing has not received much attention. This study was carried out at Delta Beverages Southerton Plant, Harare, to determine the suitability of yellow maize as an adjunct in larger beer brewing in terms of proximate analysis of its milled grits and wort analysis. The proximate composition of the yellow maize milled grits was determined through analysis of moisture content, gelatinization temperature, fat/oil content, protein content, limit of extract and fermentability-alcohol content. The wort characterization of the yellow maize milled grits was done through analysis of wort gravity, starch presence and colour of cooked maize grits. Wort gravity (15.720 Plato) and colour of cooked maize grits of yellow maize was high compared to wort gravity (15.650 Plato) and colour of cooked maize grits of white maize. Yellow maize grits had a higher starch, content than white maize making it a better alternative since wort of a higher sugar content produces beer with a higher alcohol percentage. Protein content and moisture content of yellow maize (9% and 12%, respectively) were similar to those of white maize (8.46%, and 12.27%, respectively) and they were within acceptable ranges for lager beer manufacturing. Undesirable properties of yellow maize grits including high fat content, colour and gelatinization temperatures were recorded but they are insignificant since they can be managed during the brewing process. From the wort and proximate analysis done, yellow maize can substitute for white maize in lager beer brewing.