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

• Effect of HTD processing on thermal degradation of anthocyanins was non-significant at temperatures from 2.5 to 80 °​C.
• Energy of activation in HTD processing in the range of 70–105 °C was 66.37 kJ/mol.
• HTD completely deactivated polyphenol oxidase (PPO) and peroxidase (POD) at 80 °C.
• Energy of activation in storage of HTD processed blueberry puree in the range 4–25 °C was 24.40–29.98 kJ/mol.

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.