Lactose fatty acid esters are high-value-added derivatives of lactose and represent a class of biodegradable, nonionic, low-molecular-weight surfactants (emulsifiers) that have considerable potential in the food, cosmetic, and pharmaceutical industries. Certain lactose esters have also garnered attention for their biological activities. In this work, we detail syntheses of a homologous series of 6′-O-acyllactose esters of varying alkyl chain length (from 6 to 18 carbons) and report on their activities as surfactants as well as their antimicrobial and cytotoxic properties. The structure−property profiles established in this work revealed that while the medium-chain esters displayed excellent emulsifying properties and moderate antimicrobial activities, their longer chain congeners exhibited the highest cytotoxicities. As such, we have established that certain 6′-O-acyllactose esters are superior to their sucrose-derived and commercially exploited counterparts. These results will serve as a useful guide for the development of lactose esters as, inter alia, emulsifiers in the food industry.

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.

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Long-chain fatty acid mono- and higher-order esters of sucrose are important chemicals, often produced at kilotonne scales, due to their wide range of commercial applications, including as food emulsifiers. While the monoester content of commercial sucrose stearate ester products range up to 75% (in S-1670), this can be further increased to >99% when enzymatic techniques are deployed for product preparation. Although the emulsifying properties of sucrose stearate ester-containing products (such as S-1670) are well-defined, formulations with monoester contents greater than 75% have never been prepared and evaluated. In this study, three sucrose stearate samples with an 80, 85, or 90% monoester content (samples 1–3, respectively) were prepared and the influence of these on their digestive, emulsifying, and rheological properties was studied. The results show that emulsions stabilized by S-1670 (75%) and sample 1 (80%) exhibited the best digestive behavior in a gastrointestinal behavior model, recording 69 and 78% free fatty acid release, respectively. Counterintuitively, an inverted V-shaped profile was observed when the monoester content, which ranged from 75–99%, was plotted as a function of emulsifying properties. These results should serve as an important guide for the development of new sucrose ester products in the food industry.