Otimização da hidrólise enzimática do óleo residual de fritura catalisadapor combi-lipases

Abstract

Oils and fats are the so-called fatty materials of plant and animal origin and belong to the group of lipids. Vegetable oils represent one of the main products extracted from plants, with approximately 2/3 being used in food products, thus making an integral part of the human diet. The use of soybean oil in frying for food preparation is often used in restaurants, bakeries, households and in the food industry. During the frying process, when the oil is subjected to high temperatures for long periods, several degrading changes can occur: it can hydrolyze or/and oxidize, resulting in the formation of undesirable products. Consequently, it results in the accumulation of residual oils and effluent formation, which leads to the improper disposal of these residues, causing possible harmful damage to fauna, flora and water bodies. However, there is a growing concern about adopting actions to reduce, reuse and recycle waste generated by oil resulting from frying to preserve the environment and especially water resources. Therefore, the technique of experimental design of mixtures using different sources of lipases in the enzymatic hydrolysis of triglycerides, becomes a biotechnological alternative in the treatment of residual frying oil. Therefore, the present work aimed to optimize the hydrolysis reaction of residual frying oil catalyzed by commercial combi-lipases: Porcine Pancreas (LPP), Rhizopus oryzae (LRO) and Burkolderia cepacia (LBC), using different concentrations (g) and proportions of activity units (U/g), in order to determine the conditions that favor the highest conversion to fatty acids. Initially, the determination of the enzymatic activity of the lipases LPP, LBC and LRO was carried out, whose objective was to quantify the unit of activity (U/g) of each enzyme. Ten experiments were carried out with different concentrations (g) and proportion of activity units (U/g), and in experiments 1 to 3, lipases were used freely. In experiments 4 to 6, two lipases with the same amount of activity units (1000 U/g) were used. Experiment 7, which represents the central point, used a 1/3 ratio of 2000 U/g for each enzyme. In experiments 8 to 10, the three lipases were used in the proportions 2/3, 1/3 and 1/3. During the tests carried out, it can be observed that experiment 10 showed very promising results, reaching a percentage of hydrolysis of 96.22% and a conversion to free fatty acids (FFA) of 1730.12 mMol/L in 8 h of reaction, whose results were superior to the central point (experiment 7) which used 1/3 (2000 U/g) reaching 42.8% hydrolysis and 759.411 mMol/L of FFA.