Preharvest sprays and their effects on the postharvest quality of fruit

Abstract

Purpose of review: This paper reviews studies on the effects of preharvest spray treatments on the postharvest quality and storage potential of fruits, with the objective of summarising the main effects in each case and identifying major topics requiring further research. Findings: The literature survey shows that most of the studies on preharvest sprays have considered either calcium or growth regulator treatments. Calcium applications are generally reported to delay ripening, decrease postharvest rots and alterations, and extend the keeping period, but their effects are partially dependent on the calcium source and formulation used, and phytotoxicity has also been occasionally observed. Preharvest sprays with growth regulators such as aminoethoxyvinylglycine, gibberellins or polyamines have also been studied and have shown promising potential for delaying ripening and improving storage potential or particular quality traits. Directions for future research: Although some common effects have been identified on fruit physiology for a particular treatment, a certain degree of variability across fruit types or cultivars has been observed in all cases. The suitability and the particular conditions of each treatment should be assessed and adjusted for each fruit type. In addition, because fruit metabolism is complex and strictly regulated, improved keeping potential may be contradicted by detrimental effects on eating quality, meaning that treatment effects should be evaluated as a whole. A third aspect worthy of more intense research efforts involves effects on key quality attributes such as aroma or bioactive compound contents, or on other traits relevant for quality preservation such as fruit cuticles.