Synthesis and characterization of a lactose-based biosurfactant by a novel nanodendritic catalyst and evaluating its efficacy as an emulsifier in a food emulsion system

Nonionic lactose fatty acid esters are a class of synthetic biosurfactants with various uses in the food, pharmaceutical, personal care, and cosmetic industries. The objective of this research was the preparation and full characterization of a series of novel metallic encapsulated magnetic core/dendrimer shell composites as catalysts (Co(II)/Mn(II) G(2.0)L(1/2)@SCMBNP) and their use in the chemo- and regioselective synthesis of a biosurfactant for the first time. Surface-active properties (such as contact angle (CA), surface tension (SFT), interfacial tension (IFT), critical micelle concentration (CMC), hydrophilic–lipophilic balance (HLB), foamability (FA) & foam stability (FS), emulsion ability (EmA) & emulsion stability (EmS), surface excess (Γ) and free energy of adsorption (ΔG) were also determined for all synthesized biosurfactants. In comparison to other works, these results suggested that the synthesized lactose fatty acid esters have potential application as synthetic emulsifiers featuring surface properties and are comparable with Ryoto sugar ester L-1695 (sucrose laurate) & Tween-20 (polysorbate 20) as industrial emulsifiers. The optimized conditions for biosurfactant syntheses are 8 days at 2 : 1 molar ratio of lactose sugar to lauric acid at 50 °C. Lactose ester as a biosurfactant exhibited a decrease of SFT & IFT and was able to stabilize a 20% soybean O/W emulsion. Furthermore, high conversion & yield, excellent chemo- and regioselectivity, and high operational stability over 5 runs were achieved for Co(II)/Mn(II)-G(2.0)L(1/2)@SCMBNP, indicating the suitable efficiency of the catalytic process.