HEAT TREATMENTS TO IMPROVE CACTUS PEAR STORABILITY: AN OVERVIEW

Cactus pear fruit are very perishable, due to the high susceptibility to decay and chilling injury (CI) when exposed for long times to low temperatures (Potgieter and D'Aquino, 2017). The primary cause of microbiological spoilage is due to wounds that occur when fruit are harvested and separated from the mother cladode and to punctures caused by spines and glochids when they are placed in baskets or boxes and transported to the packinghouse. Spines and glochids continue to damage the fruit when they are removed; it doesn't matter whether despination is carried out with brooms or in processing lines, in both cases the countless micro-wounds inflicted by the tiny thorns will increase the "load of mechanical injuries" (abrasion, scratches, impacts) that represent entry sites for bacteria or decay-causing fungi. Cold storage can delay microorganisms' growth, and the lower the storage temperature the lower the decay will be at the end of storage, but prolonged exposure to low temperatures also induces metabolic imbalances that reduce natural tissue resistance. Eventually, physiological disorders develop in the form of lenticel spotting, stain dots, peel scald and discolorations, but by the time these damages will appear the tissues would have lost their natural resistance and become more susceptible to decay. Thus, low temperature storage, if on the one hand delays microorganisms' growth, and on the other hand, if metabolic imbalances would occur (CI), may alter fruit appearance, and stimulate microbiological spoilage, especially when fruit from cold storage are transferred to warm temperatures. This article aims to give an up-dated look to the heat treatments to improve cactus pear storability.