基于电子舌技术分析不同采收期紫菜的滋味特征

为科学评价不同采收期的紫菜在滋味方面的差异，采用电子舌技术分析了头水、二水、四水和六水条斑紫菜(Porphyra yezoensis)的滋味组成，同时，对不同采收期紫菜中游离氨基酸、呈味核苷酸等呈味物质的含量进行了测定。结果显示，紫菜滋味主要由鲜味、鲜味回味、咸味和苦味组成。头水、二水、四水和六水紫菜的鲜味强度依次减弱。二水紫菜的鲜味回味值最大，头水和四水紫菜的鲜味回味值接近，六水紫菜的鲜味回味值显著降低(P<0.05)。头水和二水紫菜的咸味强度接近，且显著高于后期采收紫菜的咸味值(P<0.05)。头水、二水紫菜的苦味值接近，四水紫菜的苦味值略低，六水紫菜的苦味值最低。不同采收期紫菜的呈味物质含量及其对滋味的贡献程度差异较大。头水、二水、四水和六水紫菜的游离氨基酸总量依次减少，4组样品之间存在显著差异(P<0.05)，对滋味贡献大的游离氨基酸主要是丙氨酸和谷氨酸。呈味核苷酸中肌苷酸(Inosine monophosphate，IMP)对滋味的贡献大。头水、二水、四水和六水紫菜的味精当量(Equivalent umami concentration，EUC)分别为223.89、222.13、118.54和47.19 g MSG/100 g，研究表明，前期采收的紫菜鲜味更加强烈。电子舌的检测数据与呈味物质含量的分析结果基本一致。

Taste Characteristic Analysis of Porphyra yezoensis During Different Harvest Periods: A Study Based on Electronic Tongue Technology

The aim of this study was to evaluate the taste characteristics of Porphyra yezoensis during different harvest periods. Electronic tongue (INSENT taste analysis system) was applied to characterize the taste of lavers. The contents of free amino acids and flavor nucleotides in the first, second, fourth, and sixth harvest of lavers were measured. The electronic tongue data showed that the taste of lavers mainly consisted of umami, aftertaste of umami, saltiness, and bitterness. The umami value decreased successively in the first, second, fourth, and sixth harvest of lavers. The intensity of aftertaste of umami was the greatest in the second harvest of lavers, followed by the first and fourth harvest, and was significantly decreased in the sixth harvest (P<0.05). The saltiness intensity was higher in the first and second harvest of lavers. The intensity of bitterness was similar between the first and second harvest of lavers. The bitterness value was significantly lower in the sixth harvest of lavers (P<0.05). The astringency value was small, and there was no significant difference among the four samples (P>0.05). The contents of taste compounds and their contributions to the flavor were significantly different among the four laver samples. The contents of total free amino acids in the first, second, fourth, and sixth harvest of lavers were 4291.54 mg/100 g, 3485.29 mg/100 g, 3277.98 mg/100 g, and 1148.12 mg/100 g, respectively. Alanine and glutamic acid made the biggest contribution to the flavor. The content of inosine monophosphate (IMP) was relatively high in all flavor nucleotides. The taste active values (TAV) of IMP in the first, second, fourth, and sixth harvest of lavers were 4.13, 4.56, 2.19, and 2.33, respectively. The equivalent umami concentrations (EUC) of the first, second, fourth, and sixth harvest of lavers were 223.89 g MSG/100 g, 222.13 g MSG/100 g, 118.54 g MSG/100 g, and 47.19 g MSG/100 g, respectively, which means the umami of the earlier harvest of lavers was more intense. The electronic tongue analysis results are consistent with the experimental data of the flavor substances measurements. Electronic tongue technology could be used as a quick method to evaluate the taste of lavers and other aquatic products.