REVIEW - INNOVATIONS IN PHYSICAL TREATMEN TS FOR PRESERVED POSTHARVEST QUALITY OF FRUITS AND VEGETABLES .1. HEAT PRETREATMENTS

The reduction of postharvest horticultural crops losses is both econom ically and scientifically important. There is renewed interest in exte nding the use of physical treatments as alternatives to postharvest ag ro-chemicals, to control quality attributes losses, physiological diso rders, diseases and insects in fruits and vegetables, this is because many of these chemicals cause ecological problems or are potencially h armfull to humans and may be withdrawn from use. Shelf-life of horticu ltural crops can be improved by modulating environmental parameters (t emperature, N-2, O-2, CO2 and C2H4 levels) during the postharvest peri od. Heat and gaseous pretreatments and gradual changes of the storage temperature and atmosphere have been demonstrated to eliminate or alle viate postharvest losses of quality of horticultural crops; delay of s torage and conditioning or heat treatments (at moderate or high levels ) before cold storage enhance resistence to pathogen infection, inacti vate pathogens, alleviate chilling injury, reversibly inhibit fruit ri pening or largely delay senescence. These pretreatments are described and the biochemical and physiological basis and their effects on posth arvest fruit quality are discussed in this review, paying special atte ntion to the Spanish contributions to this topic.