Respiration Model for Fresh-Cut Products as a Function of Degree of Cutting

The Michaelis-Menten type respiration model for fresh-cut products was used to describe the effect of cutting, the respiration rates of four sizes of green pepper, eggplant and cucumber slices at different O-2 partial pressures, using a flow through system at 20 degrees C. The degree of cutting (D-value) was quantified by determining the surface area created through cutting per unit weight of the product. CO2 production decreased in response to decreasing O-2. In addition, increases in D-value resulted in increased respiration rates. The Michaelis-Menten type equation was fitted to each data set of different cutting sizes using nonlinear least squares method, and the parameters K-m and V-max were estimated. With an increase in D-value, K-m decreased and V-max increased, but at a higher range of D-value, both parameters approached constant values. The dependencies of both these parameters on D-value could be expressed by exponential equations. The extended Michaelis-Menten type respiration model provided a good prediction of respiration rate of fresh-cut products at any O-2 partial pressure and degree of cutting.