Chlorophyll fluorescence image analysis for non-destructive monitoring of physiological changes in fresh and fresh-cut prouce

Proceedings of the International Conference “Environmentally friendly and safe technologies for quality of fruit and vegetables”, held in Universidade do Algarve, Faro, Portugal, on January 14-16, 2009. This Conference was a join activity with COST Action 924.Chlorophyll a fluorescence analysis(CFA) is a sensitive indicator of the stability and efficiency of photosynthesis. This fundamental physiological process closely reflects the effects of internal (maturation, aging, senescence etc.) and external (salinity, drought, heat, cold stress etc.) factors on the physiological capacity or vitality of plants. In contrast to many other techniques, CFA can be actually applied remotely and non-invasively. Hence, this method has found widespread applications in plants science. During recent years, CFA has been accepted as a valuable tool to study the metabolic activity of vegetables and salad greens, and some fruits in postharvest. A number of different fluorescence parameters can be used to comprehensively characterize various aspects of photosynthetic performance. For this purpose, commercial chlorophyll fluorescence imaging (CFI) systems may be advantageous because they provided information on both spatial and temporal dynamics of photosynthesis. This yields information on various physiological aspects that are affected by postharvest handling and processing. CFI can, thus, help to objectively, rapidly and non-destructively evaluate and characterize the internal quality of green produce and its changes at many steps of the entire postharvest chain. For a proper application of CFA, a comprehensive knowledge of the physiological background of chlorophyll fluorescence and fluorescence analysis is helpful. Hence, a brief introduction of the physiological basics will be given here. Furthermore, information about alternative approaches to analyse fluorescence data as well as the current technical standard of an available CFI device will be provided. Finally, recent applications of this technique should illustrate the use of this method in fresh food quality research