COMPARATIVE ASSESSMENT OF QUALITY ATTRIBUTES OF WET- AND DRY-MILLED MAIZE-BASED ‘MASA’

Abstract

The comparative assessment of quality attributes of maize-based ‘masa’ obtained from wet- and dry- milling processes was carried out. Three maize varieties (BR9943 DMR-SR-W, TZPB-SR- W and DMR-LSR-Y) obtained from International Institute of Agriculture Research and Training (IAR&T) was used for the study while other materials (Saccharomyces cerevesiae, Trona, vegetable oil, sugar and salt) were obtained from a neighborhood market (Oja Oba, Akure, Nigeria). The maize varieties were respectively used to prepare ‘masa’ samples (using dry- and wet-milling processes) which were then subjected to various analyses. The results obtained revealed that the pH of flour (6.4-6.5), pH of batter after fermentation (4.1-4.5), total titratable acidity (TTA) of flour (0.20-0.22g/l), TTA of batter after fermentation (0.27-0.30g/l), water absorption capacity of flour (47.6- 50%) and oil absorption capacity of flour (74.1-76.9%); all were being influenced by maize varieties. The pasting properties of flour meant for ‘masa’ production were also influenced by maize varieties reflected in the pasting factors including peak viscosity (358-514 cP), trough (300-426 cP), final viscosity (719-1131 cP), setback (419-705 cP) and pasting temperature (90°-92.05°C). The proximate composition of ‘masa’ was observed to be influenced by both the maize varieties and production methods. ‘Masa’ obtained through wet- milling process had protein content of 6.43-6.68 g/100g while that from dry-milling process was 6.47-6.70 g/100g. Similarly, the ash content of wet-milled ‘masa’ was 1.07-1.49 g/100g while that from dry-milling was 1.91-1.98 g/100g. The same trend of significant influence of both the maize varieties and production methods on ‘masa’ quality attributes was observed for the mineral composition and colour characteristics of the traditional food product. The estimated glycemic index (eGI), in-vitro starch digestibility (IVSD) and oiliness index of ‘masa’ samples were also influenced by maize varieties and production techniques adopted. The eGI, IVSD, and oiliness index of wet-milled ‘masa’ were 46.08-46.38%, 61.21-67.18 mg/g and 25.1-28.26 cm 2 respectively, while those of dry-milled ‘masa’ were 46.08-46.17%, 52.30-56.65 mg/g and 29.66- 34.6 cm 2 , respectively. There were variations in the microbial quality of the traditional food product after 24 hours. The bacterial count of wet-milled ‘masa’ (3.0 x 10 3 - 1.4 x 10 4 CFU/ml) was higher than those of dry-milled ‘masa’ (1.0 x 10 3 - 9.0 x 10 3 CFU/ml) after 24 hours of storage. However, the fungal count of wet-milled ‘masa’ (3.8 x 10 4 – 4.5 x 10 4 CFU/ml) was lower than those of dry-milled samples (3.0 x 10 4 – 8.6 x10 4 CFU/ml) after 24 hours of storage. The sensory quality rating of ‘masa’ samples showed that the traditional food product from wet-milling process was generally rated higher with the range of 6.8 to 7.1 than those from dry-milling process which has a range of 6.10 to 6.53. ‘Masa’ from wet-milled DMR-LSR-Y was rated the highest in terms of appearance, taste, aroma and overall acceptability with values of 7.73, 7.00, 7.03, 7.00 and 7.10 respectively. The second rated ‘masa’ sample was also from wet-milled BR9943-DMR-SR-W which was rated the highest in terms of texture and second rated in terms of appearance, taste, aroma and overall acceptability. It may be concluded that the quality attributes of maize-based ‘masa’ is a function of maize composition used and production technique adopted and ‘masa’ from wet-milled was generally rated in overall acceptability than the dry-milled.