The enzyme lipase is a hydrolase which brings about the hydrolysis reaction fo triglycerides or fats into fatty acid and glycerol. Fatty acids produced by the hydrolysis of lipids are weak organic acids with nonpolar alkyl group and a polar carboxylic acid (-COOH) group. When vegetable oils and bile are hydrolyzed at a pH 7.0 in the presence of the lipase, there woud be liberation of fatty acid as one of the products. This fatty acid would turn the solution acidic, there by decreasing the pH of the solution. So, after the reaction pH is expected to decrease.
