3.2.4 Effect of Temperature
The effects of reaction temperature on hydrolysis of PFAD and vitamin E concentration are shown in Table 3.4. Data from the optimization result (water content of 70% w/w, reaction time of 5hr, and lipase concentration of 10% w/w) was maintained to study this effect on extent of PFAD hydrolysis. FFA levels gradually increased when the reaction temperature increased to 65. Vitamin E extracted also increased significantly from an initial value of 4.35% at 50 to 7.09% at 65. Between 65 to 70, the FFA content attained high values (93.88% and 93.04% respectively) and these temperature values signified the optimum temperature for the lipase hydrolytic activity. Increase in temperature up to 70 may be responsible for the increase the FFA content and vitamin E content extracted, both in the product, by shifting the equilibrium of the reaction to favour a faster hydrolysis. However, vitamin E concentration extracted from the PFAD decreased significantly when was temperature increased. High temperatures (>70) might have oxidized the tocols thereby reducing the output of the reaction and recovery. Furthermore, elevated temperature may have inactivated the lipase which yielded reduced contents of FFA and vitamin E even though the lipase has been immobilized.
Table 3.3 Changes in percentages of free fatty acid (FFA) and vitamin E extracted as a function of reaction temperature.