Production of Linoleic Acid-rich Oil from Canola and Grapeseed Oils Using Enzymatic Interesterification Reactions with Microwave Irradiation as a Green Technique

This study evaluated the incorporation of linoleic acid (LA) into canola oil (CO) through enzymatic interesterification reactions aided by microwave irradiation and catalyzed by TL IM lipase enzyme (sn-1,3). To optimize the process and identify the best reaction conditions, an experimental design utilizing a central composite experiment was implemented to analyze the effects of time (1.5-3.5 h), the reactant ratio LA:CO (0.3:1) and temperature (50-75°C). The linoleic acid (LA) extract was obtained from grapeseeds through extraction and purification techniques. Under optimal conditions (73°C, 48 min and an LA:CO ratio of 1.2), a 69.80% incorporation of linoleic acid was achieved. Moreover, the reactant ratio emerged as the most crucial factor shaping the outcome of the reaction, underscoring its vital role in achieving optimal results. The quality analysis of the crude oil, obtained as a reaction product, revealed a variation in the saponification index (177.5 ± 0.7 mg KOH/g), with respect to the starting substrates, indicating modifications in its composition. This value is higher than the saponification index reported for canola oil (172.82 ± 1.92 mg KOH/g) but lower than that of grapeseed oil (184.56 ± 0.45 mg KOH/g). This variation may be attributed to differences in fatty acid composition; specifically, the crude oil contains a lower proportion of long-chain fatty acids compared to canola oil. This study emphasizes the potential of grapeseeds as a sustainable source of polyunsaturated fatty acids (PUFA). Additionally, the use of microwave irradiation has proven to be a viable alternative to traditional methods by reducing reaction times, minimizing energy consumption and increasing yield percentages. These advancements support green chemistry, the circular economy and the creation of value-added products that can benefit various industries.