Evaluation of freshness of fruits and vegetables in relation to their Metabolic Activities

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The present study was carried out to investigate the relationship between the evaluation of freshness of fruits and vegetables and their metabolic activities.There was a high correlation between the dagreening and the reduction of vitamin C content in broccoli floret, and the ethylene production increased with degreening and the gas induced the senescence shown as degreening of broccoli. The ratios of NAD^+/NADH and NADP^+/NADPH, indicating redox potential, changed with degreening. Changes in AMP,ADP,ATP and energy charge were very small so that it did not meet the evaluation of freshness of perishable crops. The dietary fiber content of some crops was almost constant during storage.The freshness was considered to be evaluated by using indices such as contents of chlorophyll and carotenoids, enzymes activities related to sucrose synthesis, redox systems, membrane system and cell wall synthesis. The complexing of two or three of these indices may be effective to evaluating the freshness of fruits and vegetables.