Identification and improvement of volatile profiles of Allomyrina dichotoma larvae by fermentation with lactic acid bacteria

The larva of Allomyrina dichotoma is an edible insect that is widely consumed in Asia. A. dichotoma larvae are reported to be beneficial to human health. They have a high nutritional value, so consumer demand is increasing. However, A. dichotoma larvae have a unique off-flavor that adversely affects consumer preference. In this study, HS-SPME/GC-MS was used to identify the unique volatile profiles and potential off-flavor volatiles in A. dichotoma larvae. Also, fermentation process of A. dichotoma larvae with various lactic acid bacteria was applied to improve their safety and overall flavor. As a result, a total of 36 volatiles were identified from A. dichotoma larvae. Lactic acid fermentation showed a decrease in indole, pyrazines, 1-octen-3-ol, and 3-octanol and an increase of propanol, ethanol, and acetone. These changes in volatiles may improve overall flavor of the larvae by reducing a fecal, roasted, earthy, mushroom, and animal odors and by enhancing sweet or bitter flavors. The volatile profiles of A. dichotoma larvae provide useful information for further studies focusing on reducing their off-flavor.