Strategies to preserve quality and extend shelf life of dried fruits and vegetables: a review

In recent times, consumers' interest in quick, “ready-to-use” fruit and vegetables has increased. This growing interest is attributed to consumers' fast-paced lifestyles and increased health awareness. Research has shown that the supply of fruit and vegetables can be maintained throughout the year using preservation methods such as drying. Unfortunately, many health-promoting bioactive compounds found in horticultural products are susceptible to thermal degradation. During the process of drying, enzymatic browning may also cause undesirable changes such as off-flavour and an unpleasant odour in fruit. Some products require prolonged drying periods to attain optimum moisture content. The use of various approaches in combination with drying could alleviate the undesirable effects of drying and shorten the drying duration. Pre-treatment technologies were reported to inactivate enzymes and expel intercellular and intracellular gases resulting in better retention of certain pigments and inhibition of oxidation, respectively. While storage atmosphere and temperature strategies, as well as packaging materials, were found to protect food from oxidation by controlling gas entry into dried products. A major factor influencing shelf life of dried products was the increase in moisture content over time. There is limited scientific research available on mechanical pre-treatment methods.