Sensory evaluation and physico-chemical analyses of super maize mealH.M. van Eck, M. Kinnear & H.L. de Kock*
Dept. of Food Science, University of Pretoria, South Africa
 riette.dekock up.ac.za
Maize meal is a staple for many South Africans. Seven super maize meal samples, incorporating different milling equipment and specifications, were obtained for this study. The objective was to determine what the effect of the milling variables would be on the sensory and physico-chemical quality of the maize meal. A trained descriptive sensory panel (n=10) profiled the sensory characteristics (appearance, aroma, texture, flavour and mouthfeel) of cooked maize porridges and the appearance of the uncooked maize meals. Physico-chemical measurements namely flour particle size, proximate analysis (ash, fat and moisture), colour measurements, total starch and enzyme-susceptible starch content were also determined. Principal component analysis using covariate matrices was used to obtain complete maps of the differences and similarities of the properties of the maize meal samples.
For the uncooked meal, significant differences (p<0.05) were found in the intensity of maize meal aroma, visual perception of coarseness, presence of both brown and yellow/white specks as well as the overall colour of the meal. For cooked maize porridge, significant differences were found in colour intensity, presence of brown specks, hardness, coarseness and extent of gritty residues left in mouth after swallowing.
The criteria for distinguishing the different samples were mainly texture-related. The distribution of maize particles of different sizes affected the visual perception of coarseness of uncooked maize meal and the mouthfeel of the cooked maize meal. Colour differences as evaluated by the sensory panel were well correlated with Hunter Lab whiteness index. Differences in fat and ash content as well as enzyme-susceptible starch content were significant. Principal component analysis revealed three groups of maize meal samples; those with more coarse particles and having a darker creamy colour, a group of samples that were less coarse and whiter and a third group of samples with properties between these extremes.
Key words: maize meal, texture, porridge, physico-chemical quality |
