Enzymatic Deglycosylation and Lipophilization of Soy Glycosides into Value-Added Compounds for Food and Cosmetic Applications

Abstract

Soybean is one of the most important crops worldwide, being placed ninth on the chart of the most cultivated species. Its high level of production correlates with a huge amount of waste produced. These residues could be of great interest due to the presence of high-value-added molecules, including some glycosides (i.e., daidzin, genistin, glycitin) widely studied for their potent antioxidant properties. Due to their low bioavailability and limited solubility in lipidic media, lipophilization strategies have recently gained momentum to improve daidzin, genistin, and glycitin applications as multifunctional additives in the food, pharmaceutical, and cosmetic sectors. In this context, starting from soybean glycosides, we followed two parallel approaches, i.e., hydrolysis to obtain the corresponding aglycones possessing a better pharmacokinetic profile and esterification of the sugar primary alcohol with short-chain fatty acids. First, homemade extremophilic glycosidase (HOR) from Halothermothrix orenii has been employed for the preparation of aglycones (molar conversion 96–99%) in both water and biphasic media (water/2,2,5,5-tetramethyloxolane 1:1). Subsequently, lipophilization reactions with butanoic, hexanoic, and octanoic acids have been carried out using commercially available immobilized lipase B from Candida antarctica (CaLB) under flow conditions to produce modified glycosides with better physicochemical properties to be implemented in cosmetic preparations. Noteworthily, compared to the batch methodology, compound 1 (6-O-octanoildaidzin) was obtained with a drastic reduction in reaction time (30 min vs 18 h) and a consequent 9-fold increase in specific reaction rates (0.15 vs 0.017 μmol/(min·g)).