疏水改性乳清分离蛋白-普鲁兰多糖复合气凝胶的制备及性能研究

曹庆龙; 吴浩; 高文婧; 雷桥

doi:10.13386/j.issn1002-0306.2021040023

疏水改性乳清分离蛋白-普鲁兰多糖复合气凝胶的制备及性能研究

Preparation and Properties of Hydrophobically Modified Whey Protein Isolate-Pullulan Composite Aerogel

摘要

摘要: 目的：对易吸湿的蛋白/多糖类气凝胶进行疏水改性并对其性能进行评估。方法：对乳清分离蛋（whey protein isolate，WPI）-普鲁兰多糖（pullulan，PUL）复合气凝胶进行低温等离子体处理，使其羟基充分暴露后，使用硅烷偶联剂进行表面接枝处理，获得具有疏水性能的复合气凝胶，并研究其吸湿性、疏水疏油性、抗压性能、热失重、精油装载与缓释性能等。结果：甲基三甲氧基硅烷（methyltrimethoxysilane，MTMS）改性后复合气凝胶的平衡吸湿率为（9.67%±0.323%），十八烷基三甲氧基硅烷（octadecyltrimethoxysilane，OTMS）改性后复合气凝胶平衡吸湿率为（9.34%±0.276%），相比为改性前（11.41%±0.506%）均明显降低；改性前，复合气凝胶水接触角为（40.14°±2.16°），油接触角为（28.07°±2.43°）；MTMS改性后水接触角为（82.10°±4.78°），油接触角为（56.14°±3.25°）；OTMS改性后水接触角为（85.21°±4.61°），油接触角为（74.63°±3.08°）；改性后疏水疏油性均有所提升，且OTMS改性处理效果更好。改性前复合气凝胶压缩模量（21.745±1.982）MPa，MTMS改性后（17.655±3.034）MPa，OTMS改性后（18.412±3.513）MPa。改性后抗压强度略有降低，但不影响正常使用。改性前复合气凝胶丁香精油的最大装载率为（254.26%±5.585%），MTMS疏水改性后丁香精油最大装载率（241.57%±5.214%），OTMS组则为（223.31%±4.436%）。丁香精油装载率有所下降但缓释性能均有所提升，且MTMS改性缓释效果更好。热稳定性方面均有所提升，且OTMS组热稳定性更好。结论：综上所述，硅烷接枝疏水改性处理可以显著提升复合气凝胶的疏水性并提高其亲油性。适用于油脂类活性物质的装载与缓释应用，拓宽了WPI-PUL复合气凝胶的应用领域。

Abstract: Objective: To modify hydrophobicity of protein/polysaccharide aerogels and evaluate their properties. Methods: The whey protein isolate(WPI)- pullulan(PUL) composite aerogels were treated by low temperature plasma treatment. After exposure to hydroxyl groups, silane coupling agents were used for surface grafting. Hydrophobic composite aerogels were obtained, and their hygroscopicity, hydrophobicity, oil content, compression resistance, thermal weightlessness, loading and slow release properties of essential oils were studied. Results: The equilibrium moisture absorption rate of the composite aerogel modified by methyltrimethoxy silane(methyltrimethoxysilane, MTMS) was (9.67%±0.323%), eighteen alkyl trimethoxy silane(octadecyltrimethoxysilane, OTMS) modified composite aerogel equilibrium moisture absorption rate of (9.34%±0.276%), compared with before modification(11.41%±0.506%). It was significantly reduced; Before modification, the contact angle of composite gas gel was (40.14°±2.16°), the oil contact angle was (28.07°±2.43°); The contact angle of water after MTMS modification was (82.10°±4.78°), the oil contact angle was (56.14°±3.25°); The contact angle of water after OTMS modification was (85.21°±4.61°), the oil contact angle was (74.63°±3.08°); The hydrophobic and oil drainage properties of the modified products were improved, and the effect of OTMS was better. Compression modulus of modified composite aerogel(21.745±1.982) MPa, (17.655±3.034) MPa after MTMS modification, (18.412±3.513) MPa after OTMS modification. The compressive strength of the modified material decreased slightly, but it did not affect the normal use. The maximum loading rate of the modified composite aerogel clove essential oil was (254.26%±5.585%), after MTMS hydrophobic modification, the maximum loading rate of clove essential oil was (241.57%±5.214%) and OTMS group (223.31%±4.436%). The loading rate of clove essential oil had decreased, but the sustained release property had been improved, and the MTMS modified slow-release effect was better. The thermal stability of OTMS group was better. Conclusion: Silane graft hydrophobic modification can significantly enhance the hydrophobicity and enhance the hydrophobicity of composite aerogels. It is suitable for loading and slow releasing applications of active oils, which widens the application field of WPI-PUL composite aerogels.