Effect of phenolic compounds and hydroxyl content on the physicochemical properties of pine nut oil Pickering emulsions

Abstract

BACKGROUND For decades, pine nut oil Pickering emulsions have been stabilized using a covalent composite of two phenolic chemicals (tannic acid, TA; and gallic acid, GA) and whey protein isolate (WPI) following alkali treatment. Based on covalent composite particles being excellent sources of high‐quality stabilizers, this research explored the influence of phenolic addition and hydroxyl content on stability, rheological parameters and characterization of Pickering emulsions. RESULTS Tannic acid was more effective in reducing the average particle size of the emulsion, which decreased from 479.4 ± 2.1 nm without addition to between 187.6 ± 5.9 and 368.2 ± 16.8 nm (P < 0.05). The potential values of all the emulsions were between −30 and −50 mV (except for the gallic acid addition of 2.5 g kg−1). When the phenolic addition was 7.5 g kg−1, emulsions demonstrated the best emulsification ability. Pickering emulsion stabilized by WPI‐TA and WPI‐GA particles were successfully generated, according to confocal laser scanning microscopy. Rheological results showed that the increase of phenolic addition contributed to larger elastic modulus (G′), viscosity modulus (G″) and viscosity of emulsions, which was beneficial to the stability of emulsions. CONCLUSION Both phenolic compounds significantly improved the physicochemical stability of the emulsions (P < 0.05) and their oxidative stability. Covalently crosslinking phenolic compounds to proteins is a better method to prepare stable emulsions. It is more prominent that TA shows a more significant improvement in emulsion stability due to the number of hydroxyl groups it can provide. This research might serve as a theoretical foundation for enhancing the quality of pine nut oil‐related products. © 2022 Society of Chemical Industry.

Novel Insight into Pickering Emulsion and Colloidal Particle Network Construction of Basil Extract for Enhancing Antioxidant and UV-B-Induced Antiaging Activities

“…50 Therefore, the presence of hydrophobic and hydrophilic parts makes the phenolic compound act as a surface-active agent. 49 While phenolic compounds have been prepared in Pickering emulsions, most studies were carried out by adding other solid particles as costabilizers, such as starch, 51 zein protein, 52,53 or whey protein, 54 and only a few studies employed phenolic solid particles as the main stabilizer. 55 We proposed a Pickering emulsion green formulation of the basil extract using the emollient formulation.…”