New pre-processing technologies for fruits and vegetables

Horticultural products constitute one of the most perishable foods and its availability throughout the year requires the application of preservation methods. Traditionally, horticultural products are preserved by freezing, allowing these products to reach longer shelf-life periods. Until nowadays, freezing has been preceded by a blanching step, which has been considered as an efficient and safe food preservation method. However, besides its reliable efficiency in terms of food safety, blanching normally induces various chemical reactions, leading to quality deterioration by producing undesirable changes in sensory and nutritional qualities, affecting the balance between high quality and safety. The increasing consumer quality demanding standards has spurred the search for new and gently processing technologies that prolong shelf-life without the detrimental effects caused by severe heating. Non-thermal methods have emerged as attractive alternatives to conventional methods of thermal processing. There are several new nonthermal technologies of potential interest to the industry, such as ozone, UV-C irradiation, ultrasound, high pressure, and electrical pulses. The application of nonthermal technologies to food processing and preservation may yield processed foods with minor losses of colour, flavour, texture and nutrients, while retaining the desired shelf-life and safety. Ozone, UV-C irradiation, and ultrasound treatments are promising techniques for the fruits and vegetables industry. However, their efficiency depends on the product/microorganism under consideration.