Degradation kinetics of total anthocyanins and formation of polymeric color in blueberry hydrothermodynamic (HTD) processing

Abstract

Anthocyanin degradation and formation of polymeric color of blueberry puree in novel hydrothermodynamic (HTD) processing was studied. Anthocyanin degradation was non-significant in the range of temperatures from 2.5 to 80 °C, becoming significant above 80 °C (p < 0.05). Analysis of kinetic data indicated a first-order reaction for the degradation of blueberry anthocyanins with energy of activation 66.37 kJ/mol and half-lives (t1/2) of 346.6, 187.3, 123.8, 80.6 and 38.7 min at temperatures of 70, 80, 87.5, 95 and 105 °C respectively. Polymeric color formation followed zero-order kinetics, progressively increasing with temperature. Polyphenol oxidase (PPO) and peroxidase (POD) were completely deactivated at 80 °C, which can be the reason of better shelf-life stability (t1/2 = 533.2 and 216.6 days at 4 and 20 °C, respectively). The beneficial aspect of technology on anthocyanin degradation and storage stability could be attributed to unique combination of temperature-pressure regimes of HTD processing.