MODELING OF RESPIRATION RATE OF SAPOTA FRUIT UNDER AEROBIC CONDITIONS

Abstract

ABSTRACT Accurate measurement of respiration rate is an important aspect to the success of design and operational features of techniques like controlled and modified atmosphere storage. Two different models based on regression analysis and enzyme kinetics were developed with the help of respiration data generated at temperatures of 0, 5, 10, 15, 20, 25 and 30C for sapota fruit using a closed system method. Temperature was found to influence the model parameters. In the model based on enzyme kinetics, the dependence of respiration rate on O2 and CO2 was found to follow the uncompetitive inhibition. The developed models were tested for its validity at 12C. The models showed good agreement with the experimentally estimated respiration rate, although the model based on enzymatic kinetic with Arrhenius‐type temperature dependence was found to have a closer agreement than the other model studied. The levels of agreement between the respiration rates of sapota at 12C predicted by regression analysis and that obtained through experiments were 18.44 and 22.18% for O2 consumption and CO2 evolution, respectively, while those for the model based on enzyme kinetics were found to be 16.79 and 12.12%.PRACTICAL APPLICATIONSManipulation of respiration rate is the underlying principle behind storage techniques like controlled atmosphere (CA) storage and modified atmosphere packaging (MAP). However, besides being specific to horticultural parameters, respiration rate is also dependent on factors like storage temperature and composition of storage atmosphere. Hence, a mathematical approach to predict the respiration rate under given conditions would be an immense help in both design and process control of such storage systems. For example, predictive models for respiration rate would aid in the selection of packaging material of appropriate permeability for MAP. Also, it would help in protocols for the control of gas compositions in CA systems. In this study, mathematical models have been developed and tested to predict the respiration rate of sapota (cv. Calcutta).