不同温度胁迫条件下太平洋牡蛎挥发性化合物的变化

Changes in Volatile Compounds in Pacific Oysters under Different Temperature Stress Conditions

摘要:

为探究温度胁迫后太平洋牡蛎挥发性成分的变化，该研究采用感官评定、气相色谱-离子迁移谱（Gas Chromatography-Ion Mobility Spectroscopy，GC-IMS）、气相色谱-质谱联用（Gas Chromatography-Mass Spectrometer，GC-MS）结合多元统计分析的方法，对不同温度胁迫条件（12、22、32 ℃）的太平洋牡蛎挥发性成分进行了检测，同时测定了其存活率以及脂肪酸含量的变化。结果显示，胁迫6 d后，低温12 ℃组的存活率达到97.90%，n-3型多不饱和脂肪酸（Polyunsaturated Fatty Acid，PUFA）含量升高。感官评定、GC-IMS以及GC-MS结果显示辛醛等鱼腥味醛类成分含量下降，而呈紫罗兰气味的(E,Z)-2,6-壬二烯醛升至12.15%，提供了愉悦的气味。高温32 ℃胁迫后存活率降至26.00%，n-3 PUFA含量下降从46.07%下降至39.59%，同时饱和醛等腥味醛类含量显著上升，加重了太平洋牡蛎的腥味，导致牡蛎的品质严重下降。最后通过统计分析筛选6种关键成分：己醛、辛醛、(E,Z)-2,6-壬二烯醛、(E)-2-壬烯醛、(E,E)-2,4-庚二烯醛以及3-辛酮。温度对太平洋牡蛎的存活率、n-3 PUFA含量及挥发性成分有较大影响，该研究为提升太平洋牡蛎品质提供了有益参考。

Abstract:

The changes in volatile components in Pacific oysters under temperature stress were investigated using multiple methods, including sensory evaluation, gas chromatography-ion mobility spectroscopy (GC-IMS), gas chromatography-mass spectrometry (GC-MS), and multivariate statistical analysis. The analysis was conducted under different temperature stress conditions (12, 22, and 32 ℃). Concurrently, survival rate and fatty acid content of Pacific oysters were determined. After 6 days of stress, the 12 ℃ group exhibited a 97.90% survival rate, accompanied by an increase in n-3 polyunsaturated fatty acid (PUFA) content. Sensory evaluation, GC-IMS, and GC-MS results indicated a decrease in the content of aldehydes associated with fishy flavor, including octanal, and an increase in the content of (E,Z)-2,6-nonadienal (12.15%), which associated with fruity flavor, providing a pleasant odor to Pacific oysters. In contrast, exposure to high temperature stress at 32 ℃ resulted in a decrease in survival rate to 26.00%, accompanied by a decrease in n-3 PUFA content from 46.07% to 39.59%. Concurrently, there was a considerable increase in the content of aldehydes associated with fishy flavor, such as saturated aldehydes, intensifying the fishy smell of Pacific oysters and resulting in a notable deterioration in quality. In other words, high temperature stress caused a serious decline in oyster quality. Statistical analysis revealed significant differences in six key volatile components: octanal, hexanal, (E,Z)-2,6-nonadienal, (E)-2-nonenal, (E,E)-2,4-heptadienal, and 3-octanone. The survival rate, n-3 PUFA content, and volatile component composition of Pacific oysters were remarkably influenced by temperature stress. This study provides a valuable reference for enhancing the quality of Pacific oysters.