Volatile medium-chain lactones function as taste modifiers, kokumi substances, by activating the calcium-sensing receptor in the oral cavity
Seiji Kitajima, Ryusei Goda, JUN NITTA, Yutaka Maruyama, Toshihito Seki, Motonaka Kuroda
Abstract
Lactones are common volatile flavor compounds found in fruits and animal meat, and exert taste-modifying effects. We herein first investigated whether lactones, such as δ-decalactone (DDL), function as taste modifiers and then attempted to elucidate the underlying mechanisms. The results obtained showed that DDL significantly enhanced the fatty orosensation in pork broth under olfactory deprivation. Moreover, the Ca 2+ mobilization assay showed that DDL activated the calcium-sensing receptor (CaSR), a receptor for taste-modifying kokumi substances. The activation of CaSR modulates taste-related koku perception described such as mouthfulness, complexity, and continuity. Further investigations revealed that several medium-chain γ- and δ- lactones with C9–11 and the terpen lactone dihydroactinidiolide (DHAD) with C11 activated CaSR in a concentration-dependent manner. We also found that DDL functioned as a positive allosteric modulator of CaSR, similar to γ-EVG. This taste-enhancing effect of DDL was significantly attenuated by the co-addition of the CaSR antagonist NPS-2143. Collectively, the present results strongly suggest that several medium-chain volatile lactones with C9–11 and DHAD function as taste modifiers by activating CaSR in the oral cavity.