Respiratory Rate and Quality Changes in Fresh‐Cut Pears as Affected by Superatmospheric Oxygen

Abstract

Changes in the respiration rate of fresh-cut "Flor de Invierno" pears stored under superatmospheric oxygen concentrations were studied and compared to those observed under traditional modified atmosphere packaging conditions. Changes in package headspace O(2) and CO(2) concentrations throughout storage were curve-fitted to nonlinear equations, calculating respiration rates by combining the derivatives of the equations and the gas permeations throughout storage. Moreover, relationships between respiratory activity and quality parameters of fresh-cut Flor de Invierno pears dipped into an antioxidant solution (0.75% N-acetylcysteine and 0.75% glutathione) were assessed. CO(2) production of fresh-cut Flor de Invierno pears stored under 70 kPa O(2) atmospheres was successfully estimated with the proposed mathematical procedure. This method also proved to describe well CO(2) production rates of fresh-cut pears stored under initial 2.5 kPa O(2)+ 7 kPa CO(2) or 21 kPa O(2). In addition, a modification of Michaelis-Menten enzyme kinetics was adequate to describe the changes in estimated CO(2) production due to fermentative processes occurring under low oxygen concentrations. Superatmospheric O(2) concentrations seem to promote oxidative processes, which result into a dramatical modification of some quality attributes of fresh-cut pears.

Use of Weibull distribution for describing kinetics of antioxidant potential changes in fresh-cut watermelon

“…In fresh-cut watermelon stored at 15-20°C, substantial vitamin C degradation could be related to high CO 2 accumulation in these packages (Table 1). High CO 2 production rates appeared to have negative effect on vitamin C content of fresh-cut fruits (Agar et al, 1997;Oms-Oliu et al, 2007;Odriozola-Serrano et al, 2008). High CO 2 partial pressures in the fruit could result in oxidative damage (Tudela et al, 2002), which could be overcome by the oxidation of ascorbic acid catalyzed by ascorbate peroxidase (Pinto et al, 2001).…”

The use of packaging techniques to maintain freshness in fresh‐cut fruits and vegetables: a review

“…Day (2001) reported that high O 2 atmospheres did not result in a further decrease in ascorbic acid contents in prepared lettuce. However, it has been shown that the vitamin C content in fresh‐cut pears packaged under 70 kPa O 2 is rapidly lost in comparison with a 2.5 kPa O 2 + 7 kPa CO 2 atmosphere (Oms‐Oliu et al. , 2007b).…”

Marketability of ready-to-eat cactus pear as affected by temperature and modified atmosphere

“…Generally, the beneficial effect of MA can be attributed to a decrease of the overall metabolic activity of plant tissues. However, if O 2 partial pressure in MA decreases below the fermentation threshold limit, the tissue will initiate anaerobic respiration, with the corresponding production of off-flavours and off-odours that limit marketability (Oms-Oliu et al 2007b).…”