基于纳米尺度研究香蕉花多酚-β乳球蛋白纳米颗粒抑制食品中AGEs形成的理论基础

Advanced glycation end products (AGEs) formed in intermediate moisture foods containing high protein are a risk factor for the human health. Inhibition of AGEs formation has been considered to play a significant important role in the improvement of food safety. Our previous studies indicated that improved stability of polyphenols and their inhibitory activity against AGEs in foods. However, effect of adding polyphenols on food quality is still the main problems in their applications for inhibiting AGEs in the real food systems. In this proposal, different sizes of multi-ligand complex nanaoparticles which contain protein and polyphenols will be prepared and evaluated. The surface effect of nanoparticle on performance characteristics and AGEs inhibitory activity will be conducted to determine the optimum dimensions of nanoparticle. The objectives of this study include the mechanism of interaction between beta-lactoglobulin and banana flower polyphenols (such as, ferulaic acid, vanillic acid and quercetin) and release characteristics of the nanoparticles. Intermediate moisture protein rich food will be used as a food model to monitor antiglycosylation mechanism and property of the nanoparticles in inhibiting AGEs formation in different food processing and storage conditions. The AGEs inhibition mechanism and performance characteristics of banana flower polyphenols nanoparticles will be examined by different non-enzymatic glycosylation reactions and key enzymatic reaction systems related to sugar hydrolyzation as well. This study can significantly promote the development of low AGEs of intermediate moisture protein rich foods and the utilization of post-harvest byproduct banana flowers.

高蛋白中间水分食品中晚期糖基化终末产物（AGEs）对人体健康存在风险，有效控制AGEs的形成，对提升食品安全水平具有重要意义。前期研究发现：提高多酚在食品中的稳定性和AGEs抑制活性、降低其对食品品质影响是多酚抑制食品中AGEs形成亟待解决的关键问题。本项目将制备不同纳米尺度的香蕉花多酚单体（阿魏酸、香草酸和槲皮素）和β-乳球蛋白多配体复合物纳米颗粒，考察其表面效应对纳米颗粒性能的影响，确定最佳纳米颗粒尺度，阐明香蕉花多酚和β-乳球蛋白纳米颗粒形成及多酚释放机制，在明确纳米颗粒结构和性能基础上，对比纳米颗粒和未包埋香蕉花多酚对高蛋白中间水分营养棒的品质及AGEs形成作用效果，结合已建立体外非酶糖基化反应不同阶段模型和AGEs形成关键酶反应体系，揭示纳米颗粒抑制食品AGEs形成的作用机制。本项目将为食品中AGEs的控制提供理论参考，也为香蕉花废弃物的综合利用开辟途径。

高蛋白中间水分食品中晚期糖基化终末产物（AGEs）对人体健康存在风险，有效控制AGEs的形成，对提升食品安全水平具有重要意义。本项目以β-乳球蛋白B（β-LG B）为载体，以阿魏酸(FA)、槲皮素(QT)和香草酸(VA)为配体，建立蛋白-三配体复合物，揭示了配体与蛋白的结合机制及其AGEs抑制活性。结果表明：FA、QT和VA与β-LG B在氢键和范德华力的作用下发生了静态结合，FA结合位点为β-桶的间隙附近的结合位点，QT与α-螺旋和β-桶形成的疏水袋结合，VA与β-桶内的配体结合位点结合，分别有9个(FA)、8个(QT)和7个(VA)氨基酸残基参与了结合。FA和QT的结合导致β-乳球蛋白B上部分的α-螺旋转变为β-折叠，VA的结合导致β-乳球蛋白B上部分的β-转角和无规则卷曲转变为β-折叠。复合物对牛血清白蛋白(BSA)-果糖、BSA-丙酮醛、精氨酸-丙酮醛模型中AGEs的抑制率分别为119.50%、68.30%、92.86%。. FA、QT和VA与热处理的β-LG B结合形成三配体复合物，通过乳化-蒸发法在可获得粒径分布稳定的纳米颗粒，粒径由亚微米级（100~200nm）降至纳米级（<100nm）。纳米颗粒中FA，QT，VA负载率分别为86.78%，75.00%，86.40%，高于三配体复合物的负载率60.11%，37.09%，68.93%，且纳米颗粒稳定性更强。8 %多酚蛋白纳米颗粒可以破坏绿霉菌丝的细胞壁，使其菌丝细胞涨破，降低了果实的失重率和发病率，提高了福橙果肉的过氧化物酶、过氧化氢酶、苯丙氨酸解氨酶、多酚氧化酶、β-1,3葡聚糖酶和几丁质酶活性，增强了福橙对绿霉病的抗病性。因此，多酚蛋白纳米颗粒作为福橙保鲜抑菌剂，能够有效抑制福橙绿霉病。. 此外，从10种亲水胶体中筛选出壳聚糖、黄原胶和海藻酸，采用蛋白非酶糖基化模型等阐明了其AGEs抑制机理：抑制了蛋白的氧化，消耗了早期糖基化反应的底物，通过清除二羰基化合物（丙酮醛、乙二醛等）。在蛋糕模型中证实了亲水胶体能提高蛋糕的水分含量，延缓蛋糕的老化，降低了蛋糕中荧光AGEs、结合态和游离态CML、CEL含量，同时抑制了蛋白的氧化。可见，焙烤食品中添加亲水胶体可有效降低其AGEs的生成。