39D-8

S. K. SEFA-DEDEH, Department of Nutrition and Food Science, University of Ghana, Box LG 134, Legon, Accra, Ghana, B. Cornelius, and W. K. Amoa-Awuah, Food Research Institute, Accra, Ghana.

JUSTIFICATION Nixtamalization is a traditional process which improves the nutritional quality of corn. To provide a means of utilizing the nutritional benefits of nixtamalized corn and improve product acceptability, lactic acid fermentation was applied. It is important to establish the microbial profile of the fermented nixtamalized corn.

OBJECTIVE To study the microbial profile and establish the important lactobacilli of fermenting nixtamalized maize dough.

METHOD Two batches of cleaned whole corn were subjected to the process of nixtamalization, using two concentrations of lime (0.5 and 1.0%), milled, made into a dough (55% moisture) and fermented spontaneously for 72 hours. A control sample was prepared without alkaline treatment. pH and titratable acidity of the dough were measured. Aerobic mesophiles, lactic acid bacteria, yeasts and molds were enumerated on Plate Count Agar (PCA), deMan, Rogossa and Sharpe (MRS) Agar and Malt Extract Agar (MEA) respectively. The identity of lactobacilli present was established at the species level using API 50 CHL.

RESULTS The pH of all the fermenting systems decreased with fermentation time with concomitant increase in titratable acidity. Lactic acid bacteria (1.6 x 10⁹, 2.3 x⁹, 1.8 x 10⁹cfu/g), yeasts and molds (8.0 x 10⁷, 5.0 x 10⁵, 1.7 x 10⁵ cfu/g) were observed in the control and the two nixtamalized (0.5 and 1% lime) samples after 48 hours of fermentation. Lactobacilli identified in the fermenting nixtamalized maize dough were Lactobacillus plantarum, L. fermentum and L. cellobiosus as well as Pediococci spp.

SIGNIFICANCE

Nixtamalized corn though alkaline in nature can be subjected to spontaneous fermentation to produce a sour product. Lactobacillus plantarum, L. fermentum and L. cellobiosus as well as Pediococci spp. play important roles in the fermentation