Changes in the composition of the pulp, alpha-amylase activity and titratable acidity during the controlled rotting of egusi fruits (Colocynthis citrullus l.) for the harvesting of the seeds

Abstract

The laboratory rotting of Egusi Fruits was completed in 120 hours. At this stage pulp became soft and the seeds were extracted easily with the fingers. The changes in the composition of the pulp, alpha-amylase activity and titratable acidity during the controlled rotting of egusi fruit (Colocynthis citrullus L.) for the harvesting of the seeds showed that moisture content (MC) increased from 82.04% at 0 hour of rotting to 85.00% at 120 hours of rotting. The Titratable acidity increased from 0.10mg lactic acid/g, wet matter (WM) at 0 hour to 0.70mg lactic acid/g, at 120 hours. The total carbohydrate (water soluble carbohydrate) decreased from 10.76% at 0 hour to 0.35% at 120 hour and the reducing sugars also decreased from 1.25mg/g (WM) at 0 hour to 0.25mg/g (WM) at 120 hours; the protein content increased from 0.39% at 0 hour to 4.38% at 96 hours and then fell to 1.14% at 120 hours. The alpha-amylase activity which was not detectable at 0 hour reached a peak of 0.80mg/g (WM) at 48 hours and then fell to 0.02mg/g at 120 hours. The crude fat decreased from 6.85% at 0 hour to 6.72% at 120 hours. The pH rose from 5.20 at 0 hour to 6.70 at 120 hours while the temperature rose from 28.00C at 0 hour to 300C at 120 hours. These changes resulted in the softening of the pulp and hence facilitating the easy removal of the seeds from the fruits with fingers.

KEYWORDS: Rotting, Egusi, Pulp, Composition, Alpha-amylase, titratable acidity.