基于主客观嗅觉评价结合挥发性成分分析优选美洲大蠊去腥矫臭炮制方法

Optimization of processing methods for deodorizing Periplaneta americana based on subjective and objective smell evaluation combined with analysis of volatile components

目的通过主客观评价结合分析挥发性成分变化,筛选美洲大蠊去腥矫臭的炮制方法,研究去腥矫臭作用机制。方法分别制备美洲大蠊生品、醋炙品、酒炙品与麸炒品,采用志愿者感官评价法结合电子鼻系统评价美洲大蠊生品与炮制品的腥臭气味差异,筛选较优炮制品种类。采用顶空-固相微萃取-气相-质谱联用(HS-SPME-GC-MS)结合相对气味活度值(ROAV)分析关键性腥臭气味成分,并采用面积归一化法结合多元统计分析方法分析生品与炮制品挥发性成分差异,探究炮制去腥矫臭的作用机制。结果志愿者评分结果显示生品、醋炙品、酒炙品与麸炒品的平均评分分别为3.38、1.25、2.88与3.04。电子鼻结果显示,醋炙品、酒炙品、麸炒品与生品间的欧式距离分别为7.34、3.77、1.60,但醋炙品的散点分布方向与酒炙品、麸炒品方向相反,提示可能作用机制有异。整合分析主客观评价数据,确定醋炙为最优去腥矫臭炮制方法。ROAV法确认美洲大蠊关键性腥臭气味成分为3-甲基丁醛、己醛、壬醛、庚醛、癸醛、苯乙醛、(E,E)-2,4-壬二烯醛、2-戊基呋喃、(+)-柠檬烯、肉豆蔻醛。挥发性成分的PCA结果显示,4种炮制品可被明显区分开,挥发性成分及含量存在差异。正交偏最小二乘判别分析(OPLS-DA)结果表明,生品与醋炙品中存在7个差异性成分,分别为己醛、棕榈酸、油酸、油酸乙酯、醋酸、棕榈酸乙酯、亚油酸乙酯,醋炙品含量较生品均有减少,其中关键性腥臭味成分己醛减少最为明显。结论醋炙为改善美洲大蠊腥臭气味的较优方法,其炮制机制是通过降低己醛等挥发性腥臭气味成分实现的。

Objective To screen a processing method suitable for deodorizing of Periplaneta americana(PA) through subjective and objective evaluation combined with changes in volatile components, and explore the mechanism of deodorization. Methods Raw, vinegar-processed, wine-processed, wheat bran-processed products of PA were prepared respectively. Volunteer sensory evaluation combined with electronic nose system was used to evaluate the odor difference between raw and processed products to screen a better processed product. HS-SPME-GC-MS and ROAV were used to analyze the key odorous components of PA. The peak area normalization method combined with multivariate statistical analysis were used to analyze the difference of volatile components between raw and processed products to explore the mechanism of processing. Results Volunteer scores showed that the average scores of raw, vinegar-processed, wine-processed, wheat bran-processed products were 3.38, 1.25, 2.88, and 3.04, respectively. The results of the electronic nose showed that the Euclidean distance between the raw and vinegar-processed, wine-processed, wheat bran-processed products were 7.34, 3.77 and 1.60, respectively, but the direction of scatter of vinegar-processed product was opposite to that of wine-processed product and wheat bran-processed product, suggesting that the mechanism of deodorization may be different. Vinegar processing was determined as the optimum method for deodorizing by comprehensive analysis of subjective and objective evaluation data. The key odor components of PA were 3-methyl butanal, hexanal, nonyl aldehyde, heptaldehyde, decyl aldehyde, phenyl acetaldehyde,(E,E)-2,4-nonadienal, 2-pentylfuran,(+)-limonene, and myristic aldehyde. The PCA result of volatile components showed that four kinds of processed products can be clearly distinguished, and there were differences in volatile components and content. There were seven differential chemical components between raw and vinegar-processed products, including hexanal, palmitic acid, oleic acid, acetic acid, ethyl oleate, ethyl palmitate, and ethyl linoleate. The content of vinegar-processed products was lower than that of raw products, especially the key odorous component hexanal. Conclusion The vinegar processing is a better method to improve the odor of PA, and its mechanism may be associated with reducing odorous components such as hexanal.