Carboxylic acid ester hydrolysis rate constants for food and beverage aroma compounds

Aroma compounds in the Flavornet database were screened for potentially hydrolysable carboxylic acid ester functionalities. Of 738 aroma compounds listed in this database, 140 molecules contain carboxylic acid ester groups that may be amenable to hydrolysis in various food and beverage products. Acid‐ (kA) and base‐ (kB) catalysed and neutral (kN) hydrolysis rate constants in pure water at 25°C were calculated for these aroma compounds. Where available, good agreement between theoretical and experimental hydrolytic half‐lives was obtained at various pH values. Wide ranges and broad frequency distributions for kA, kB, and kN are expected among the various hydrolyzable aroma compounds, with calculated kA ranging from 3.7 × 10‐8 to 4.7 × 10‐4 M‐1 s‐1, calculated kB ranging from 4.3 × 10‐4 to 43 M‐1 s‐1, and calculated kN ranging from 4.2 × 10‐17 to 7.6 × 10‐9 M‐1 s‐1. The resulting hydrolytic half‐lives also range widely, from 10 days to 370 years at pH 2.8, 18 days to 4,900 years at pH 4.0, 1.8 days to 470 years at pH 7.0, and 26 minutes to 5.1 years at pH 9.0. The findings illustrate the importance of considering abiotic hydrolysis and matrix pH when modelling the evolution of sensory characteristics for foods and beverages with carboxylic acid ester based aroma compounds.