Enzymatic Preparation of a Homologous Series of Long-Chain 6‑O‑Acylglucose Esters and Their Evaluation as Emulsifiers

Sugar fatty acid esters are nonionic surfactants that are widely exploited in the food and cosmetics industries, as well as in the oral care and medical supply fields. Accordingly, new methods for their selective synthesis and the “tuning” of their emulsifying properties are of considerable interest. Herein we report simple and irreversible enzymatic esterifications of d-glucose with seven fatty acid vinyl esters. The foaming and emulsifying effects of the resulting 6-O-acylglucose esters were then evaluated. In accord with expectations, when the length of the alkyl side chain associated with the 6-O-acylglucose esters increases, then their hydrophilic–lipophilic balance (HLB) values decrease, while the stabilities of the derived emulsions improve. In order to maintain good foaming properties, alkyl side chains of at least 9 to 11 carbons in length are required. In the first such assays on 6-O-acylglucose esters, most of those described herein are shown to be nontoxic to the HepG2, MCF-7, LNacp, SW549, and LO-2 cell lines.