Available at www.sciencedirect.com journal homepage: www.elsevier.com/locate/issn/15375110 Research Paper: PH—Postharvest Technology Modelling the respiration rate of green mature mango under aerobic conditions Menon Rekha Ravindra 1 , T.K. Goswami à Department of Agricultural and Food Engineering, Indian Institute of Technology, Kharagpur, West Bengal 721 302, India article info Article history: Received 8 January 2007 Accepted 4 October 2007 Available online 11 December 2007 Accurate measurement of respiration rate is an important aspect in designing and operating systems such as controlled and modified atmosphere storage. Models based on regression analysis and enzyme kinetics were developed with the help of respiration data generated at temperatures 5, 10, 15, 20, 25 and 30 1C for green mature mango fruit using the closed system method. A model based on second-order polynomial regression, simulta- neously incorporating the factors influencing respiration, such as temperature, O 2 consumption, CO 2 evolution and storage time, was proposed. All the developed models were tested for their validity at 12 1C. All showed good agreement with the experimentally estimated respiration rate, although models based on enzymatic kinetic with Arrhenius- type temperature dependence and three-parameter second-order polynomial regression were found to have a closer agreement than the other models studied. & 2007 IAgrE. Published by Elsevier Ltd. All rights reserved. 1. Introduction Respiration can be defined as the metabolic process that provides energy for plant biochemical processes. It involves oxidative breakdown of organic reserves to simpler mole- cules, including CO 2 and water, with the release of energy. The significance of respiration in extending the shelf-life of fresh fruits and vegetables stems from the fact that there exists an inverse relationship between respiration rate and the shelf-life of the commodity. Respiration rate, which is commonly expressed as rate of O 2 consumption and/or CO 2 production per unit weight of the commodity, reflects the metabolic activity of the fruit tissue in the form of biochem- ical changes associated with ripening. Another important parameter associated with respiration is the respiration quotient (RQ). It is the ratio of CO 2 produced to O 2 consumed during the respiration cycle. Depending on the organic reserve being oxidised, the RQ values for fresh produce normally range from 0.7 to 1.3 (Fonseca et al., 2002). Very high values of the RQ or a sudden shift in RQ value indicates a shift in the respiration cycle to the anaerobic cycle (Saltveit, 2004). Modelling of respiration rate gives an advanced insight into the respiratory kinetics of the storage system and also helps to predict the respiratory quotient. This helps select appropriate packaging materials when designing modified atmosphere (MA) packaging systems, identifying the vital heat in calculation of refrigeration load, select fan size and location for optimal air flow within controlled atmosphere (CA) facilities and formulate appropriate process control for ventilating storage facilities. Thus, the accurate modelling of respiration kinetics is an important step in the successful design and operation of storage techniques for horticultural produce. Many models have been proposed for the prediction of respiration kinetics of different fruits and vegetables under different storage conditions. Respiration rate is dependent on ARTICLE IN PRESS 1537-5110/$ - see front matter & 2007 IAgrE. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.biosystemseng.2007.10.005 à Corresponding author. Tel.: +91 3222 283122; fax: +91 3222 282244. E-mail address: tkg@agfe.iitkgp.ernet.in (T.K. Goswami). 1 Permanent address: NDRI Southern Campus, Adugodi, Bangalore 560 030, India BIOSYSTEMS ENGINEERING 99 (2008) 239– 248