Abstract

Polyglycerol ester is considered an excellent kind of food emulsifier. The aim of the current study was to synthesize polyglycerol fatty acid esters (PGFEs) with different-sized long-chain fatty acids (i.e. long-carbon fatty acid polyglycerol esters, L-PGFEs; medium-carbon fatty acid polyglycerol esters, M-PGFEs; and short-carbon fatty acid polyglycerol esters, S-PGFEs), using Lipozyme 435 as a catalyst in a solvent-free system. Thereafter, the physicochemical properties of the newly synthesized PGFEs and their potential applications as food emulsifiers were investigated. The maximum esterification efficiencies of L-PGFEs, M-PGFEs, and S-PGFEs were 69.37, 67.34, and 71.68%, respectively, at the optimum conditions: a reaction temperature of 84.48 °C, a reaction time of 6 h, a molar ratio of polyglycerol to fatty acid of 1.35:1, and 1.41 wt % enzyme usage (based on the total substrate mass). A high-performance liquid chromatograph equipped with an evaporative light-scattering detector (HPLC-ELSD) and an electrospray-ionization mass spectrometer (ESI-MS) were employed to identify the synthesized products. The results demonstrated that the main components of these PGFEs were dimeric glycerides (68.3%), triglycerides (13.13%), and a small amount of tetraglycerides (3.18%). The properties of the PGFEs were characterized by physical and chemical methods. Compared with M-PGFEs and S-PGFEs, L-PGFEs had the best physicochemical properties without any obvious odor. Further, the emulsion capabilities of these different long-chain PGFEs were evaluated via examining the particle sizes and storage stabilities and comparing them with those of glycerin monostearate (GMS). The results showed that the emulsions prepared with L-PGFEs had the best stability and the smallest particle sizes (16.8 nm) compared with those of M-PGFEs, S-PGFEs, and GMS, and they were not prone to oil-droplet coalescence or the separation of oil and water. From the current study, the newly synthesized PGFEs with long-chain fatty acids showed the best advantages as a food emulsifier compared with M-PGFEs, S-PGFEs, and even glycerin monostearate.

Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call