谷朊粉发酵液中鲜味肽的分离、鉴定与呈味分析

鲜味是五种基本味感之一,它在人们选择食品中扮演了越来越重要的角色,肽是氨基酸组成的混合物,具有多种味道,是主要的呈味物质,利用蛋白酶解可以获得具有较强鲜味的肽段。本实验采用感官评价结合超滤(UF)、凝胶层析(GPC)和反相高效液相色谱(RP-HPLC)等技术从以盐酸脱酰胺面筋蛋白为原料的发酵液中分离纯化得到一种鲜味肽,同时采用MALDI-TOF-MS串联质谱鉴定该鲜味肽的氨基酸序列及其分子质量;目标定向固相合成鉴别出的鲜味肽,并测定了其鲜味阈值及鲜味相乘效应。结果发现:该鲜味肽的氨基酸序列为Asp-Cys-Gly(DCG),分子质量为293.15 Da,固相合成该鲜味肽后采用滋味稀释法评价发现该鲜味肽的鲜味阈值为100 mg/m L,是MSG阈值的1/3,该鲜味肽对浓度为200 mg/L的I+G溶液具有鲜味增强作用,对MSG没有鲜味增强作用。

Isolation, Purification, Identification, and Sensory Evaluation of Umami Peptide in Wheat Gluten Fermentation Broth

Umami is one of five basic tastes, which has been playing an increasingly important role in the selection of food products. Peptides are primary tastants composed of amino acids with several tastes. Peptides with significant umami taste could be produced through proteolysis. An umami peptide was isolated and purified from wheat gluten fermentation broth by ultra-filtration (UF), gel filtration chromatography (GPC), reverse phase high-performance liquid chromatography (RP-HPLC), and sensory evaluation. The sequence and molecular weight of the umami peptide were identified by matrix-assisted laser desorption/ionization- time-of-flight - mass spectrometry (MALDI-TOF-MS). The identified peptide was synthesized and taste dilution analysis (TDA) was conducted to evaluate taste characteristics of the peptide. The umami peptide was identified to be Asp-Cys-Gly (DCG) and the molecular weight was 293.15 Da. TDA results showed that the umami taste threshold of the peptide was 100 mg/mL, which was one third of MSG. DCG can enhance the umami taste of I+G at a concentration of 200 mg/L, but no similar effect was found with MSG.