Modified-atmosphere Packaging of Blueberry Fruit: Effect of Temperature on Package O2 and CO2

Abstract

Highbush blueberry (Vaccinium corymbosum L. `Bluecrop') fruit sealed in low-density polyethylene packages were incubated at 0, 5, 10, 15, 20, or 25C until O 2 and CO 2 levels in the package reached a steady state. A range of steady-state O 2 partial pressures (1 to 18 kPa) was created by placing a range of fruit weights within packages having a constant surface area and film thickness. The steady-state O 2 partial pressure in packages containing the same weight of fruit decreased as temperature increased, indicating the respiratory rate rose more rapidly (i.e., had a greater sensitivity to temperature) than O 2 transmission through the film. Steady-state O 2 and CO 2 partial pressures were used to calculate rates of O 2 uptake. CO 2 Production. and the respiratory quotient (RO). The effects of temperature and 0 2 partial pressure on O 2 uptake and CO 2 production and the RQ were characte∼zed. The steady-state O, partial pressure at which the fruit began to exhibit anaerobic CO 2 production (the RQ breakpoint) increased with increasing temperature, which implies that blueberry fruit can be stored at lower O 2 partial pressures when stored at lower temperatures.