USE OF PRINCIPAL COMPONENT ANALYSIS AND AGGLOMERATIVE HIERARCHY CLUSTERING TO STUDY THE RELATIONSHIP BETWEEN ALPHA AMYLASE AND STARCH DURING FERMENTATION OF OGI FROM MAIZE, SORGHUM AND ACHA

Abstract

Ogi, a popular breakfast cereal and weaning food in West Africa was produced from maize, acha and sorghum. Ogi was produced from the three cereals and the gruels obtained were subjected to fermentation. The total starch content and alpha amylase activity during the period of fermentation of the ogi slurries were evaluated using standard methods. Total starch content was determined at 0, 12, 24, 36 and 48 h and α-amylase activity was also determined at 10 ^oC, 20 ^oC, 30 ^oC, 40 ^oC at 0, 12, 24, 36 and 48 h. The outcome of the research showed that α-amylase activity increased with increase in temperature and was highest in maize ogi (1.507 – 4.458 E. U) while acha ogi (0.497 – 3.219 E. U) had the lowest α-amylase activity . The starch content decreased with increase in time of fermentation time and was highest in maize ogi while acha ogi had the lowest. This shows that the higher the temperature of fermentation and longer fermentation time can increase the breakdown of starch by α-amylase in ogi slurry. The result of the Principal component analysis (PCA) showed distinct similarity in maize and acha. Agglomerative hierarchical clustering grouped acha into two groups (groups one and two) but grouped all maize and sorghum ogi samples together into group three. Due to the low starch content and low α-amylase activity observed in acha, it could be utilized in the production of gluten-free ogi with low glycemic index especially for vulnerable groups.