Different methods to extend fruit fresh cut shelf life

Giovanna Giacalone [Dipartimento di Scienze Agrarie, Forestali ed Alimentari – Università di Torino]

Minimal processing has been defined as a combination of procedures, such as washing, sorting, trimming, peeling and slicing or chopping, that does not affect the fresh-like quality of the food. The ready-to-eat fruit and vegetable market has rapidly grown in recent years due to the health benefits associated with these foods and to the increased health-consciousness of consumers with busy lifestyles and increased purchase power. Nevertheless, because the tissular integrity of fruits is more easily altered during processing, ready-to-use commodities are more perishable than the original materials. The main factors affecting the loss of consumer acceptability are discoloration, enzymatic browning, dryness and texture loss. These parameters determine the visual appearance of the fruits. For this reason, the fruit processing industry requires the development of techniques capable of keeping safe shelf life, preserving the original visual and organoleptic fresh-like characteristics of fresh-cut products.
Another problem associated with the ready to eat products, is the microbiological growth. The metabolism of molds and yeasts is responsible for the qualitative decay of minimally processed fruits, so the products sanitation became essential. Fresh cut industry usually uses chlorine, but the possible formation of carcinogenic chlorinated compounds in water requires finding alternative methods. Natural antimicrobials, ozone, chlorine dioxine, UV and cold gas plasma are some of the different treatments proposed.
In parallel or in combination with these treatments, actions are carried out to limit or inhibit the oxidative browning and the firmness loss.
Ascorbic acid is the compound most extensively used to avoid the oxidative browning of the fruits, however nowadays there are many alternatives, chemical or physical, due to its limited effect over time. Regarding firmness loss, instead, the most common way to contrast the softening is the use of calcium salts. Even in this case, the products, the concentration and the methods of use are many and different and have different effect on fruits.
The edible coatings could be effective systems to preserve fresh cut fruits quality, their actions are due to the barrier forming against external agents; in addiction, they could carry functional ingredients (antioxidant, antimicrobial, calcium salts) to ready to eat fruits.
In conclusion, the treatments aimed to preserve minimally processed fruits quality could be chemical or physical, innovative or more established, cheap or expensive or they could require complex equipment. However, sometimes, effective treatments are not suitable because they are too expensive or complex or not accepted by the consumer.
This review describes the most significant contributions regarding preservation of fresh-cut fruits in order to evaluate their effectiveness in preserving quality traits

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