Thermal Stability of Manuka Honey Specific Ingredients and Heat Processing Applications in Cooking

Abstract

This study aimed to investigate the thermal stability of characteristic chemicals in manuka honey during high-temperature heating and propose a cooking method that suppresses the reduction of one antibacterial ingredient, methylglyoxal (MGO). MGO was significantly decreased to approximately 12% by heating at 150°C for 10 min, similar to candy preparation. 2'-methoxyacetophenone, a marker for manuka honey authenticity developed by the New Zealand Ministry for Primary Industries, was also significantly reduced when heated for 10 min. We also compared the stability of these chemicals at various temperatures for 10 min. MGO was identified as stable up to 90°C, but significantly reduced over 100°C. The presence of sugar and volatilization of MGO had little effect on MGO reduction. Our data suggest that heating processed foods containing manuka honey at a high temperature of 120°C or more were expected to significantly decrease MGO in the final product compared to the original quantity. Additionally, lowering the processing temperature and shortening the heating time may effectively suppress the reduction of MGO.