ABSTRACT
Horticultural products such as fresh fruits and vegetables are still metabolically active when harvested. Under certain conditions some anabolic processes such as photosynthesis and synthesis of avor components may still take place. The major metabolic processes are of a catabolic nature and include respiration and fermentation and also other processes such as cell wall degradation. Respiration and fermentation are of particular interest to
18.1 Introduction 739 18.2 Fundamental Considerations 740
18.2.1 Respiration and Fermentation 740 18.2.1.1 Respiration Rate 742 18.2.1.2 Respiration and Fermentation Models 743 18.2.1.3 Gas Transport Properties 747
18.2.2 Measurement Techniques 748 18.2.2.1 Oxygen Consumption and Carbon Dioxide Production Rate 748 18.2.2.2 Measurement of O2 and CO2 Concentration 749 18.2.2.3 Measurement of Heat of Respiration 752 18.2.2.4 Skin Resistance and Gas Diffusion Properties 753
18.2.3 Gas Exchange Data for Selected Fruits and Vegetables 755 18.3 Applications 760 Acknowledgments 765 Symbols 765 References 766
postharvest technologists because they are strongly associated with quality-associated processes taking place in fruits and vegetables. As a consequence, the reduction of the respiratory activity of horticultural products has been a major concern in postharvest technology. Appropriate refrigeration procedures, often in combination with the application of controlled atmosphere storage conditions, have therefore been developed to reduce the respiration rate and are applied nowadays on a large scale.
