Differentiating volatile compounds in soy sauce that regulate the attractiveness of flesh flies (Parasarcophaga dux).

Soy sauce, renowned for its distinctive taste and aroma, has become one of the most popular condiments worldwide. However, its odor attracts the flesh fly Parasarcophaga dux for larviposition, posing a threat to product quality and safety. Here, gas chromatography-ion mobility spectrometry (GC-IMS) was employed to analyze the differential volatile compounds in nine types of soy sauce with varying degrees of attractiveness to P. dux. Notably, 12 differential volatile compounds elicited antennal responses. Furthermore, olfactometer bioassays revealed 6 of them induced behavioral reaction. 3-hydroxy-2-butanone, 2-propanol, butanal, and 2-methylpyrazine were attractive to female flies, while β-myrcene and δ-octalactone exhibited repellent effects. These findings suggest that key volatile compounds with attractive or repellent properties may regulate the differential preference of P. dux for various soy sauces. This study provides a theoretical foundation for preventing P. dux larviposition in soy sauce through formula adjustment and supports the development of the soy sauce industry.