美拉德反应提升鲜味肽鲜味强度作用机理研究

Umami peptide plays an important role in delicious food and its umami intensity could be enhanced by Maillard reaction. Based on our previous results, the influence of different kinds of reducing sugar and reaction parameters on the change rule of umami peptide from Maillard reaction products was discussed to reveal the relationship between the umami intensity changes of umami peptide and reaction degree during Maillard reaction. Series of key umami substances (peptides and glycopeptides) were isolated and purified from Maillard reaction products using ultrafiltration, Gel filtration chromatography and reversed-phase high performance liquid chromatography. Then their chemical structures were identified by MALDI-TOF-MS and NMR. Based on above studies, different umami peptides and glycopeptides were synthesized to investigate the correlation between the structure and activity, in order to clarify their taste mechanisms. The umami-enhancing mechanism by Maillard reaction also be investigated by labling C, N and O of precursor umami peptide and reducing sugar and detecting their reaction path during Maillard reaction. The results will be favor of enhancing umami intensity for umami peptides or protein hydrolysates.

鲜味肽是食品中重要的呈味成分，研究发现美拉德反应可明显提升花生粕酶解物鲜味肽的鲜味强度。本项目将在已有研究结果的基础上，首次以花生粕酶解物鲜味肽为研究对象，探讨不同种类还原糖及反应参数对美拉德反应产物鲜味强度的变化规律，揭示美拉德反应过程中鲜味肽的鲜味强度变化规律与美拉德反应条件的内在关系；应用膜分离，凝胶过滤色谱、反相高效液相色谱等技术分离纯化系列关键鲜味物质（肽或糖肽类物质），并采用基质辅助激光解析电离飞行时间质谱和核磁共振谱仪鉴定其结构；在此基础上研究鲜味肽/糖肽的一级结构、空间构象与呈味特性之间的内在联系，明晰鲜味肽/糖肽的呈味机理；最后通过同位素标记美拉德反应前体物鲜味肽和还原糖中N、C、O元素，结合稳定同位素比例质谱仪追踪检测还原糖和肽在美拉德反应过程中的反应途径，明晰美拉德反应提升鲜味肽鲜味强度的作用机理，为定向提升鲜味肽或蛋白酶解产物的鲜味强度提供理论和方法指导。

美拉德反应是食品加工过程中广泛存在的一种非酶褐变反应，在食品的风味与色泽的形成中具有重要的作用，常被用来制备具有特定风味的食品。本项目采用乙醇分级分离花生鲜味肽，并系统研究美拉德反应对花生鲜味肽的呈味特性影响规律。项目研究结果表明：（1）不同浓度乙醇溶液提取会改变花生呈味肽的氨基酸组成、肽分子量分布，从而来改变其呈味特性。主要肽段分布在1000-3000Da的60%-组分由于含有较高的鲜味氨基酸和水溶性氨基酸，较低疏水性氨基酸而呈现出较强鲜味特性。（2）优化获得花生鲜味肽的美拉德反应增鲜工艺：花生鲜味肽浓度为10%、木糖浓度为0.57%、系统pH值为6.5在94℃下反应70 min可显著增鲜花生鲜味肽的鲜味强度和饱满感。（3）结合系列分离技术（膜分离、凝胶过滤和高效液相色谱）高效分离纯化美拉德反应产物中鲜味物质，并采用超高效液相色谱——四极杆串联飞行时间质谱（UPLC/Q-TOF-MS）鉴定出54种鲜味肽，通过氨基酸系列分析比对，发现54种鲜味肽均来源于花生蛋白氨基酸肽段或衍生物。本项目研究为阐明美拉德反应增鲜作用机制提供了物质基础，对提高调味品质量具有重大的理论意义。项目发表SCI收录论文7篇，EI收录2篇，申请中国发明专利3件，其中授权1件。