Preparation, characterization and stability of water-in-oil Pickering emulsions stabilized by acylated EGCG derivatives
Zhaojuan Shi, Hanxu Ma, Chao Tang, Tingting Zhu, Qingmei Zeng, Chuanxun Yuan, Risheng Jin
Abstract
Excessive intake of trans and saturated fatty acids from solid fats contributes to the development of chronic diseases. Food-grade water-in-oil (W/O) emulsions for the replacement of trans and saturated fat products, delivery of active compounds and microreactors remain to be further explored. Camellia oil-based W/O Pickering emulsions were prepared using acylated EGCG derivatives with various carbon chain lengths, including EGCG myristate (MYR-E), EGCG palmitate (PAL-E), and EGCG stearate (STEA-E). The acylated EGCG derivatives exhibited a contact angle of 90–100° with water droplets and could theoretically be used as Pickering emulsion stabilizers. The acylated EGCG derivatives were dissolved in the oil phase as needle-like crystals, which stabilized the emulsion against aggregation by adsorption at the oil-water interface. Pickering emulsions developed with STEA-E (PE-STEA) maintained higher stability after three freeze-thaw cycles, with a creaming index (CI) of 0% at oil-water volume ratios greater than 4:6. PE-STEA with varying oil-water volume ratios were stable at room temperature and 4 °C after long-time storage, with a maximum CI of only 1.39%. This study could provide new perspectives on the application of acylated EGCG derivatives and broaden the application of surfactant-free W/O Pickering emulsions in the food industry.