Modelling respiration in fresh-cut pineapple and prediction of gas permeability needs for optimal modified atmosphere packaging

This study investigated the effects of intrinsic factors (origin, physiological age and seasonality) and extrinsic factors (cut-size, blade-sharpness and dipping treatments) on respiration rate (RCO2RCO2) of fresh-cut pineapple chunks. A mathematical model for respiration rate based on exponential decay was developed that showed a gradual decrease in rate with time. The model parameters (Ri and Req, initial respiration rate and equilibrium respiration rate, respectively) were found useful to compare respiration rates for the factors studied. The average values were 8.52 ± 4.68 and 2.64 ± 0.68 ml/kg h for Ri and Req, respectively. Ri was affected to a greater extent by physiological age and origin than by season. Cut size had a considerable effect on Ri and Req, with larger cut pieces having the lowest Ri and Req of 5.9 and 2.7 ml/kg h, respectively. In contrast, smallest cut pieces had highest Ri (7 ml/kg h) and Req (3.2 ml/kg h). Cutting the fruit with a razor sharp blade versus a blunt blade decreased the Ri, while only caused a slight reduction in Req. The target O2 and CO2 transmission rate required for optimal modified atmosphere packaging were 7300–12,500 and 13,900–23,500 ml/m2 day atm covering variability in respiration rate due to intrinsic and extrinsic factors studied.

► Respiration rate declined over time and achieved an equilibrium value within 20 h.
► Respiration rate was affected more by physiological age and origin than by season.
► Smallest cut pieces and blunt blades resulted in highest respiration rates.
► Dipping increased respiration rate.
► Mathematical consideration of the implications of these respiration rates for packaging.