3.2.2 Effect of Water Content
Table 3.2 reveals the changes in FFA content and concentration of vitamin E extracted from the reaction mixtures with different water contents. Following optimization result, the system was set up at reaction time of 5hr at 65\(\pm\)1 with lipase concentration of 10% w/w. PFAD was hydrolysed most effectively at water content of 70% v/w, and at this point FFA content in the resulting mixture was recorded as 93.94%, and vitamin E extracted from PFAD was 6.69%. In the system, lipase catalysis, hydrolysis and esterification were reactions that occurred simultaneously. Large amount of water was necessary to shift the equilibrium favouring hydrolysis reaction. However, the degree of hydrolysis decreased with more than 70% v/w of water. This phenomenon is attributed to low enzyme concentration in relation to available water phase as a result of large amount of water. Similar trend was observed in the study made by Chu et al. (2002). Levels of vitamin E extract also decreased significantly from 6.96% to 4.88%, when water content increased from 70 % v/w to 80% v/w.
Table 3.2 Changes in percentages of free fatty acid (FFA) and vitamin E extracted as a function of water content in the reaction mixture.