ABSTRACT
CONTENTS 5.1 Introduction .......................................................................................................................... 93 5.2 Respiration ............................................................................................................................ 94
5.2.1 Factors Affecting Respiration.................................................................................. 94 5.2.2 Model Approaches to Respiration.......................................................................... 95 5.2.3 Michaelis-Menten Approach .................................................................................. 95 5.2.4 Outlook: Metabolic Flux Models ............................................................................ 97
5.3 Gas Transport ....................................................................................................................... 98 5.3.1 Lumped Gas Transport............................................................................................ 98
5.3.1.1 Effusion or Efflux Method ......................................................................... 98 5.3.1.2 Limitations.................................................................................................. 100
5.3.2 Reaction-Diffusion.................................................................................................. 100 5.3.2.1 Model .......................................................................................................... 101 5.3.2.2 Parameter Estimation................................................................................ 102 5.3.2.3 Numerical Solution ................................................................................... 103 5.3.2.4 Case Study.................................................................................................. 104
5.3.3 Outlook: Multiscale Analysis of Gas Exchange ................................................. 105 5.4 Relating Metabolic Rate to Rate of Quality Change..................................................... 106 5.5 Conclusions......................................................................................................................... 107 5.6 Future Research Needs ..................................................................................................... 107 Acknowledgments ..................................................................................................................... 108 References.................................................................................................................................... 108
In a controlled atmosphere storage, the O2 partial pressure is typically reduced while that of CO2 is often increased. The purpose of this procedure is to lower the respiration rate and, consequently, slow down those associated metabolic pathways that negatively affect the quality of the stored product. The respiration rate is therefore a good indicator of the physiological stage of the fruit and its storage potential, and has been measured in the past for many fruit and vegetables at various storage temperatures and gas compositions. As the respiration rate depends on the species and even the cultivar, season, development stage, climate, and many more factors, it needs to be determined for every new cultivar before it is introduced in the market.
