Effect of solid state fermentation on the physico-chemical, functional and textural properties of nixtamalized maize

Abstract

Spontaneous lactic acid fermentation is an important process in cereal processing. It is applied to develop and enhance taste and flavour, modify texture and improve the microbial safety of foods. When applied with nixtamalization to maize, it is expected to further improve the functionality, improve nutritional quality and provide an alternative maize-based ingredient. This study was carried out to determine the extent to which fermentation could influence the physico-chemical, functional and textural properties of nixtamalized maize. A 2 x 3 x 3 factorial experimental design with fermentation medium (water, coconut water), fermentation time (0, 24, 48 hours) and blends composition (0:100, 50:50, 100:0 steeped:nixtamalized maize) was performed. The blends were fermented for the specific times and analysed for pH, titratable acidity, water absorption, colour and texture. Traditional maize dough facilitated the fermentation process by acting as a starter culture to produce lower pH and higher acidity in the steeped:nixtamalized maize blends. The fermentation time significantly (p<0.05) influenced the pH, titratable acidity, water absorption capacity, colour and texture of the samples. The pH of all the blends decreased from 6.24 to 4.22 with a corresponding increase in titratable acidity from 0.009 to 0.036 g Lactic/100g sample during fermentation. There was however no significant (p<0.05) difference in the effect of fermentation medium on these indices. The samples with a higher percentage of nixtamalized maize had a deeper yellow colour, that is lower L - value (lightness) and higher b-values (yellowness) than the non- nixtamalized maize and this increased further with fermentation. The texture of the blends of steeped - nixtamalized maize generally decreased with increasing fermentation time for all samples fermented in water as well as in coconut water, however, the texture of the blends of steeped: nixtamalized maize for samples fermented in coconut water had relatively higher but comparable textural values. Maize can therefore be nixtamalized and fermented using both water and coconut water to effectively produce adequate souring or acids resulting in improved physicochemical, functional and textural quality characteristics required for the processing of traditional fermented maize products. Copyright © 2006 The Berkeley Electronic Press. All rights reserved.