Sebben Damien A, MacWilliams Stephanie V, Yu Long, Spicer Patrick T, Bulone Vincent, Krasowska Marta, Beattie David A
Future Industries Institute, UniSA STEM, Mawson Lakes Campus, University of South Australia, Mawson Lakes, SA 5095, Australia.
School of Agriculture, Food and Wine, The University of Adelaide, Adelaide, SA 5064, Australia.
Foods. 2021 Dec 23;11(1):34. doi: 10.3390/foods11010034.
Water-in-oil-in-water (W/O/W) emulsions (double emulsions) have often been used for the encapsulation of bioactive compounds such as anthocyanins. Instability of both anthocyanins and double emulsions creates a need for a tailored composition of the aqueous phase. In this work, double emulsions with a gelled internal water phase were produced and monitored over a 20-day storage period. The effect of the electrolyte phase composition (varying electrolyte components, including adipic acid, citric acid, and varying concentration of potassium chloride (KCl)) on anthocyanin and double emulsion stability was analysed using colour analysis, droplet sizing, and emulsion rheology. The effect of electrolytes on colour retention was shown to differ between the primary W/O emulsion and the secondary W/O/W emulsion. Furthermore, droplet size analysis and emulsion rheology highlighted significant differences in the stability and structural behaviour of the emulsions as a function of electrolyte composition. In terms of colour retention and emulsion stability, a citrate-buffered system performed best. The results of this study highlight the importance of strict control of aqueous phase constituents to prevent anthocyanin degradation and maximise double emulsion stability. Additional experiments analysed the effect of pectin chemistry on the anthocyanin colour retention and leakage, finding no conclusive difference between the unmodified and amidated pectin.
水包油包水（W/O/W）乳液（双重乳液）常被用于封装生物活性化合物，如花青素。花青素和双重乳液的不稳定性使得需要对水相进行定制化组成。在这项工作中，制备了内部水相呈凝胶状的双重乳液，并在20天的储存期内进行监测。使用颜色分析、液滴尺寸测量和乳液流变学分析了电解质相组成（不同的电解质成分，包括己二酸、柠檬酸以及不同浓度的氯化钾（KCl））对花青素和双重乳液稳定性的影响。结果表明，电解质对颜色保留的影响在初级W/O乳液和次级W/O/W乳液之间存在差异。此外，液滴尺寸分析和乳液流变学突出了乳液的稳定性和结构行为随电解质组成的显著差异。就颜色保留和乳液稳定性而言，柠檬酸盐缓冲体系表现最佳。本研究结果强调了严格控制水相成分以防止花青素降解并最大化双重乳液稳定性的重要性。额外的实验分析了果胶化学性质对花青素颜色保留和渗漏的影响，发现未改性果胶和酰胺化果胶之间没有确凿差异。
