EFFECT OF FERMENTATION ON IN VITRO PROTEIN DIGESTIBILITY, PROTEIN FRACTIONS AND AMINO ACIDS COMPOSITION OF MAIZE (ZEA MAYSLINNAUS) CULTIVARS

Two maize cultivars Hudeiba 1 and Mugtama 45 were used to study the effect of natural fermentation on maize protein quality. Maize flour was fermented for 32 h samples were withdrawn at 8 h intervals. The pH drop was from 5.7 to 3.8 at the end of the fermentation period. The in vitro protein digestibility was enhanced by fermentation to a level of 18.2% for Hudeiba 1 and 18.4% for Mugtama 45 after 24 h fermentation for both. Fermentation caused a significant improvement in protein fractions by causing significant increase in globulin plus albumin for Hudeiba 1 (19.4%) and for Mugtama 45 (20.9%). The amino acids composition of maize is characterized by low lysine and tryptophan content. Samples with high globulin plus albumin were of better quality in relation to lysine content. The lysine content was improved from 1.8 to 2.3 g/100g protein for Hudeiba 1 and from 1.9 to 2.6 g/100g protein for Mugtama 45.