SPECTROPHOTOMETRIC ANALYSIS OF ALPHA AMYLASE LEVELS AT STAGES IN THE RIPENING OF MUSA SPECIES

Alpha-amylases are starch degrading enzymes and their activities have been found to be the major change that occurs in the ripening of bananas and plantains. This study was designed to basically develop a simple spectrophotometric method to monitor some of the biochemical processes involved in the ripening of Giant horned plantain (Apantu), French horned plantain (Apem) and local banana (Abibifo mpua).The pericarp from five ripening stages was collected and alpha amylases were extracted with cold 0.025M sodium acetate buffer (pH 5.5) and used for the study. The protein concentration of Apem and Apantu as determined by Biuret method was highest at their yellow with large black patches stages respectively as 0.5399mg/mL and 1.0164mg/mL. This was however true for banana in the more green than yellow stage where the concentration was found to be 0.9148mg/mL. Test for enzyme activity at the various stages in ripening showed that α-amylase exhibited highest activity in the more yellow than green stage and lowered when the fruit is fully ripen. The α-amylase extracted had an approximate molecular weight of 90.1-114.8 kDa by SDS-PAGE and were seen in all  the ripening stages the of samples except the hard green stage (Banana), hard green stage (Apem) and more green than yellow stage (Apem).