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

ABSTRACT

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.