Investigating the Impact of Active Poy(3-Hydroxybutyrate-Co-3-Hydroxyvalerate Films on the Nutritional Quality of Minimally Processed Apples

Abstract

The aim of the study was to study the effect of an active film, a blend of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) with a derivative of ferulic acid known as bis-O-dihydroferuloyl-1,4-butanediol (BDF), on the quality decay kinetic of minimally processed apples stored for 10 days at 4°C. Molecular modelling studies were conducted to explore the interaction between polyphenol oxidase (PPO) and BDF molecule, with the aim of understanding the mechanism of inhibition. The apple slices packed in different treatments exhibited an increase in PPO activity; however, the control treatments showed a significantly faster rate of PPO activity (p < 0.05). Almost 50% of the ascorbic acid content degraded in the control samples (4.95–4.97 mg/100 g fresh weight (FW)) at d-7 compared with the samples packaged in BDF-releasing films (5.81–6.1 mg/100 g FW) in which the degradation was only 30%. Using molecular modelling, it was observed that BDF (−6.3 kcal/mol) exhibited a stronger interaction with PPO than catechol (−4.5 kcal/mol) in the met and oxy states. BDF-releasing films showed superior preservative potential over the control as BDF competitively inhibits the PPO active site due to π–π stacking between the aromatic cycle of the BDF molecule and the PHE259 and hydrogen bonding with the active site.

Keywords: ferulic acid derivative, apple, PPO activity, active film, kinetics