Estimate of respiration rate and physicochemical changes of fresh-cut apples stored under different temperatures

In this study, the influence of storage temperature and passive modified packaging (PMP) on the respiration rate and physicochemical properties of fresh-cut Gala apples (Malus domestica B.) was investigated. The samples were packed in flexible multilayer bags and stored at 2 degrees C, 5 degrees C, and 7 degrees C for eleven days. Respiration rate as a function of CO2 and O-2 concentrations was determined using gas chromatography. The inhibition parameters were estimated using a mathematical model based on Michaelis-Menten equation. The following physicochemical properties were evaluated: total soluble solids, pH, titratable acidity, and reducing sugars. At 2 degrees C, the maximum respiration rate was observed after 150 hours. At 5 degrees C and 7 degrees C the maximum respiration rates were observed after 100 and 50 hours of storage, respectively. The inhibition model results obtained showed a clear effect of CO2 on O-2 consumption. The soluble solids decreased, although not significantly, during storage at the three temperatures studied. Reducing sugars and titratable acidity decreased during storage and the pH increased. These results indicate that the respiration rate influenced the physicochemical properties.