NONLINEAR ESTIMATION OF RESPIRATORY DYNAMICS OF FRESH‐CUT SPINACH (SPINACIA OLERACEA) BASED ON ENZYME KINETICS

Abstract

The respiratory behavior of fresh‐cut spinach under different temperatures and gas conditions was evaluated to develop an integrated respiration model taking into account the temperature dependence of enzyme kinetics parameters. The dependence of respiration rate on the O2 and CO2 concentrations has been described assuming the enzyme kinetics model for combined type of inhibition caused by CO2. The respiration model parameters under the specified environmental conditions of 10, 15, 20C and 75% relative humidity were estimated using non‐linear regression technique and were utilized to predict the rates of respiration for O2 consumption and CO2 evolution. Mixed type of inhibition was observed at all the temperatures, but changed from predominantly competitive at 10 and 15C to predominantly uncompetitive at 20C. The enzyme kinetics parameters were analyzed according to Arrhenius law, as well as simple linear and polynomial equations to determine relationships for describing their temperature dependence. The final integrated model encompassed the effect of headspace gaseous concentrations, CO2 inhibition, surrounding temperature, and can be utilized for respiratory and shelf‐life studies of different fruits and vegetables. PRACTICAL APPLICATIONS Fresh‐cut spinach leaves have an enormous market around the world owing to their high nutritive value. Shelf life and quality of fresh‐cut produce may be greatly reduced due to high rates of respiration. Traditional packaging, handling, storage and transportation techniques reduce the shelf life and various nutritional and phytochemical components of fresh‐cut produce. Temperature control and atmospheric modifications (low O2: 1–5% and high CO2: 5–10%) help to maintain produce quality by reducing respiration rate and enhance shelf‐life by minimizing the adverse effects of cutting in fruits and vegetables. This research has focused on determination of respiratory behavior of fresh‐cut spinach leaves at temperatures commonly encountered during transportation and retail distribution i.e., 10–15C. The results of the study show the potential of use of modified atmosphere packaging for packaging of fresh‐cut spinach leaves. Utilization of the results of this research would be of immense help in developing a user friendly program for simulating in‐pack gaseous conditions by varying the experimental parameters and in proper designing of modified atmosphere packages for storage and transportation to retail markets.

Respiration Rate Measurement and Chemical Kinetic Modelling for Mung Bean Sprouts

“…It indicated that the low temperature could effective resist respiration rates of mung bean sprouts. It appears to be in agreement with the observation of Kaur et al (Kaur et al 2011). The O 2 consumption rate of fresh-cut spinach decreased by 54.24% by decreasing the temperature from 20 to 10C.…”

“…It appears to be in agreement with the observation of Kaur et al (Kaur et al . ). The O 2 consumption rate of fresh‐cut spinach decreased by 54.24% by decreasing the temperature from 20 to 10C.…”

Respiratory dynamics of fresh baby corn (Zea mays L.) under modified atmospheres based on enzyme kinetics

“…The dependence of respiration rate on the headspace O 2 and CO 2 concentrations has been described assuming the enzyme kinetics model for combined type of inhibition proposed by Peppelenbos and Van't Leven (1996). The effect of surrounding temperature on the respiratory parameters has been evaluated using the Arrhenius relationship (Fonseca et al 2002;Benkeblia 2004;Charles et al 2005;Kaur et al 2011). The changes in the respiratory parameters on account of minimal processing have also been discussed.…”

“…A two to three fold increase in biological reactions has been reported for every 10°C rise in temperature within the range of temperatures normally encountered in the distribution and marketing chain. Arrhenius law has been widely used to describe temperature dependence of respiration rates (Fonseca et al 2002;Kaur et al 2011;Benkeblia 2004;Charles et al 2005). All the parameters of enzyme kinetics model were evaluated using Arrhenius law [ k ¼ Ae ÀEa RT ] to study the effect of storage temperature.…”

Modified Atmosphere Packaging Technology of Fresh and Fresh-cut Produce and the Microbial Consequences—A Review

“…Most respiration rate models have been oriented towards either one or two out of the three functions of time, temperature and gas composition. The Michaelis-Menten type equations (uncompetitive, noncompetitive, or uncompetitive/competitive) based on CO 2 inhibitory effect (Lee et al 1991;Peppelenbos and Leven 1996;Del Nobile et al 2006;Rocculi et al 2006;Bhande et al 2008), and the Arrhenius-type equations, which describe temperature as a function of respiration (Jacxsens et al 2000;Kaur et al 2010;Uchino et al 2004;Torrieri et al 2010), have been widely reported for respiration rate of fresh produce as a function of both temperature and gas composition. A major limitation of respiration rate modelling is of the lack of adequate respiratory data information.…”