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Modified atmosphere packaging of sweet cherry (Prunus avium L., ev. ‘Sams’) fruit: metabolic responses to oxygen, carbon dioxide, and temperature

2002; Elsevier BV; Volume: 24; Issue: 3 Linguagem: Inglês

10.1016/s0925-5214(01)00192-2

1873-2356

Peter D. Petracek, Dennis W. Joles, Arman Shirazi, Arthur C. Cameron,

Nanocomposite Films for Food Packaging

The influence of O2, CO2 partial pressures (pO2pkg and pCO2pkg, respectively), and temperature on sweet cherry (Prunus avium L. cv. 'Sam') fruit respiration was examined in modified atmosphere (MA) packages. Ranges of pO2pkg and pCO2pkg were created by sealing 2–20 fruit in 76.6 μm (3 mil) low-density polyethylene (LDPE) packages stored at 0, 5, 10, 15, 20, or 25 °C. Steady-state pO2pkg and pCO2pkg were attained within 2 (25 °C) to 10 (0 °C) days. Respiration rates were calculated based on polymer film permeability, thickness, and surface area, steady-state pO2pkg and pCO2pkg, and packaged fruit mass. The Michaelis–Menten equation combined with Q10 was used to model steady-state O2 uptake as a function of temperature and pO2pkg. Estimated maximum respiration at 0 °C (rO2max,0), Q10, and k1/2 values for a combined model (0, 5, 10, 15, and 20 °C) were 36 nmol kg−1 s−1, 2.5, and 0.3 kPa O2, respectively. Estimated k1,2 values increased slightly from 0.3 kPa at 0 °C to 1.0 kPa at 25 °C. The fermentation induction point (FIP), as determined by a specific increase in respiratory quotient (RQ) and ethanol production, also increased from under 1 at 0 °C to over 4 kPa at 25 °C. Removing CO2 from the package did not influence pO2pkg, respiration rates or headspace levels of ethanol or acetaldehyde. Shelf life, as determined by visual appearance, principally decay incidence, was an inverse function of temperature, but was not related to package pO2pkg, pCO2pkg, or respiration rate. CO2 levels usually considered fungistatic (pCO2pkg over 10 kPa) were attained in LDPE packaging of sweet cherries only when fruit were anaerobic.