方格星虫酶解物与不同糖Maillard反应特性及其产物特征风味变化

研究不同种类糖（葡萄糖、麦芽糖、木糖和阿拉伯胶）与方格星虫酶解物（enzymatic hydrolysate of Sipunculus nudus，SEH）在一定条件下（120 ℃、120 min）形成Maillard反应产物的吸光度（A420 nm和A294 nm）、pH值、色差、总/游离氨基酸和荧光强度变化，并结合电子鼻对不同反应产物的特征风味进行分析。结果表明，不同种类糖与SEH反应后，产物褐变度增大、黄色加深、亮度变暗、pH值减小；Maillard反应产物的17 种游离氨基酸和总氨基酸含量较SEH均降低，其中8 种苦味氨基酸含量显著降低，改善了酶解液的苦味；SEH与不同糖反应后的荧光强度显著降低且红移，其三级结构发生改变；且不同糖与SEH的反应程度表现为：木糖＞阿拉伯胶＞葡萄糖＞麦芽糖。电子鼻能够较好地区分SEH与不同糖形成的Maillard反应产物特征风味，发现线性判别分析法区分效果优于主成分分析方法，负荷加载分析显示2号和7号传感器在第1主成分上贡献率较大，6号和9号在第2主成分上贡献率较大，表明氨氧化物、甲烷、硫化氢类成分是区别SEH和Maillard反应产物的主要挥发性特征风味。因此，不同种类糖与酶解物Maillard反应特性及其产物特征风味不同，可根据工艺需求选择合适的糖基供体。

Comparative Physicochemical and Flavor Characteristics of Maillard Reaction Products Derived from Enzymatic Hydrolysate of Sipunculus nudus and Different Saccharides

Maillard reaction products (MRPs; 120 ℃, 120 min) derived from an enzymatic hydrolysate (SEH) of Sipunculus nudus and different saccharides (glucose, maltose, xylose and gum arabic) were characterized by measuring their absorbance at 420 nm and 294 nm, pH, color difference, total amino acid (TAA) composition, and free amino acid (FAA) composition and fluorescence intensity. Moreover, an electronic nose (E-nose) was used to analyze changes in their volatile flavor compounds. The results obtained suggested that SEH conjugated with saccharides showed a higher browning degree, a yellower color with darker lightness, and a lower pH value. Additionally, the contents of 17 FAAs and TAAs in MRPs were reduced, especially for 8 bitter amino acids, relative to SEH, which improved the bitterness of SEH. The fluorescence spectra revealed that the fluorescence intensity of MRPs was significantly reduced and a slight red-shift was observed as compared to SEH, leading to changes in the tertiary structure of SEH. On the basis of the above results, the reaction degree of SEH conjugated with different saccharides followed the declining order: xylose > gum arabic > glucose > maltose. E-nose could distinguish the flavor characteristics of SEH from those of MRPs better with linear discriminant analysis (LDA) than with principal composition analysis (PCA). Loadings analysis showed that sensors 2 and 7 contributed greatly to the first principal component, while sensors 6 and 9 to the second principal component, indicating that ammonia oxides, methane and sulfides were the main volatile flavor components that could discriminate between SEH and MRPs. In this study, we have found that the flavor and reaction characteristics of MRPs derived from SHE and different saccharides are different, suggesting that an appropriate saccharide can be chosen to meet technological demands.