Preharvest factors and fresh-cut quality of leafy vegetables

This review describes some of the studies carried out in my research group related to the impact of preharvest factors on quality of leafy vegetables, mainly freshcut lettuce and baby leaves. The preharvest factors that affect quality and shelf-life are: genotype, environmental conditions, agricultural practices, maturity at harvest, and harvest time. For fresh-cut lettuce, cultivar selection should be based on low browning potential and off-odor development. Environmental conditions including temperature, relative humidity, irradiation, and rainfall affect the quality of the raw material and therefore the fresh-cut product. These conditions impact cultivation in different production areas and growing cycles by influencing the incidence of diseases and disorders as well as changes in the raw material, which may necessitate changes in specifications. Agricultural practices, including type and rate of fertilization, irrigation and salinity, affect fresh-cut quality. Low irrigation doses are recommended for quality and economic reasons. Drought can be beneficial in some herbs, such as basil, as a way to increase the content of polyphenols and essential oils without affecting the postharvest quality. Maturity at harvest impacts the quality of fresh-cut lettuce, with the immature stage more susceptible to fermentation and the over-mature stage more prone to browning. Harvest time may also impact the quality and shelf-life of baby leaves. The quality of fresh-prepared spinach was maintained regardless of harvest time in winter, but was superior if harvested early in the morning in spring.