Food Safety Key Laboratory of Zhejiang Province, School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310018, People's Republic of China.
Food Safety Key Laboratory of Zhejiang Province, School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310018, People's Republic of China.
Food Res Int. 2023 Apr;166:112608. doi: 10.1016/j.foodres.2023.112608. Epub 2023 Feb 17.
Liposomes have been received much attention during the past decades as bioactive compounds carriers in food field. However, the application of liposomes is extremely limited by the structural instability during processing such as freeze-drying. In addition, the protection mechanism of lyoprotectant for liposomes during freeze-drying remains controversial. In this study, lactose, fructooligosaccharide, inulin and sucrose were used as lyoprotectants for liposomes and the physicochemical properties, structural stability and freeze-drying protection mechanism were explored. The addition of oligosaccharides could significantly suppress the changes in size and zeta potential, and the amorphous state of liposomes was negligible changed from XRD. The T of the four oligosaccharides, especially for sucrose (69.50 °C) and lactose (95.67 °C), revealed the freeze-dried liposomes had formed vitrification matrix, which could prevent liposomes from fusion via increasing the viscosity and reducing membrane mobility. The decrease in T of sucrose (147.67 °C) and lactose (181.67 °C), and the changes in functional group of phospholipid and hygroscopic capacity of lyophilized liposomes indicated oligosaccharides replaced water molecules to interact with phospholipids by hydrogen bonds. It can be concluded that the protection mechanism of sucrose and lactose as lyoprotectant was attributed to the combination of vitrification theory and water replacement hypothesis, while the water replacement hypothesis was dominated by fructooligosaccharide and inulin.
在过去的几十年中，脂质体作为食品领域中生物活性化合物的载体受到了广泛关注。然而，脂质体的应用受到其在加工过程中结构不稳定的限制，例如冷冻干燥。此外，冷冻干燥过程中保护剂对脂质体的保护机制仍存在争议。在本研究中，乳糖、果寡糖、菊粉和蔗糖被用作脂质体的保护剂，探讨了其物理化学性质、结构稳定性和冷冻干燥保护机制。寡糖的添加可以显著抑制脂质体粒径和 zeta 电位的变化，并且从 XRD 来看，脂质体的无定形状态几乎没有变化。四种寡糖的 T 值，尤其是蔗糖（69.50°C）和乳糖（95.67°C），表明冷冻干燥的脂质体形成了玻璃化基质，可以通过增加粘度和降低膜流动性来防止脂质体融合。蔗糖（147.67°C）和乳糖（181.67°C）的 T 值降低，以及冻干脂质体的磷脂官能团变化和吸湿性的变化表明，寡糖通过氢键与磷脂相互作用取代水分子。可以得出结论，蔗糖和乳糖作为保护剂的保护机制归因于玻璃化理论和水置换假说的结合，而水置换假说则由果寡糖和菊粉主导。
