Recent Developments to Maintain Overall Sweet Cherry Quality during Postharvest Storage

Sweet cherry (Prunus avium L.) is a deciduous tree originated around the Black and Caspian Seas. Most of sweet cherry production is used for fresh consumption although industrialised produce such as jam, jelly, stewed fruit, marmalade, syrup and several types of soft drinks are increasingly available. Spain is the third European producer with 25,000 ha dedicated to sweet cherry with a yield of 67,600 metric tons of fruit per year. In Spain, early-season production areas begin harvest at the end of April and continue through June, midseason production areas harvest from May through June and late-season production areas harvest from May to July. The concept of "quality" depends on the product itself and the consumer's preferences, and for sweet cherry it is widely accepted that the main characteristics related to fruit quality are fruit weight, colour, firmness, sweetness, sourness, flavour and aroma. For this reason producers use a number of parameters to establish the optimum time for harvesting, the most reliable being skin colour. Red colour development in sweet cherry is used as indicator of quality and ripening, and is due to accumulation and profile of anthocyanins. Sweet cherry horticultural production chain consists of several parts: production, picking, cooling, selection, grading, packaging, transport, distribution and consumption. From the consumer point of view, storage quality is probably the most important factor affecting eating quality, especially for overseas marketing. Sweet cherry fruit is a very perishable commodity, since both the edible part and the stem loose water rapidly as well as decay incidence, which constitutes the main problem for successful transport and marketing. The changes in these quality parameters during postharvest storage lead to reduced shelf life. This keynote aims to give an updated knowledge about some recent developments with the objective of a better control of postharvest deterioration of sweet cherries. The strategies include pre- and postharvest applications and some innovative treatments including oxalic acid, salicylic acid, acetylsalicylic acid, methyl jasmonate and methyl salicylate. Since sweet cherry fruit are also appreciated by their content in bioactive compounds with additional health benefits, special interest will be given to the effect of these treatments on anthocyanins and polyphenols, due to their antioxidant properties.