**2.5 Calcium Ca2+ treatments**

Calcium (Ca2+) delays ripening and senescence-related processes by regulating signalling responses and inhibiting ethylene biosynthesis and respiration in fruits and vegetables [6, 36]. Ca2 + is also believed to be the most important mineral element determining fruit quality [52]. Postharvest Ca2+ treatments prevent loss of flavour and nutritional value, enhance antioxidant capacity, reduce physiological disorders and decay incidence, and increase cell wall strength, thus prolonging the shelf life of FFVs [6, 52, 53]. Fruits and vegetables may be dipped, washed, vacuumed or pressure infiltrated, mixed with wax coatings, or electrostatic powder coatings [6, 52].

Optimum Ca2+ application rates either alone or in combination with other techniques may be different for specific fruits and vegetables [6]. Other properties of Ca2+, such as the form and source of the application are also based on the interaction with the type of fruit or vegetable [6]. For example, pressure infiltration with calcium chloride solution is more effective in increasing the calcium concentration of apple fruits than vacuum infiltration and dipping. However, excessive Ca2+uptake may cause injury [52]. **Table 6** provides information on some of the latest applications of calcium treatments on fresh fruits and vegetables.

#### **2.6 Heat treatments**

Heat or thermal treatment of fresh fruits and vegetables is an efficient, easy, safe, and cost-effective method for controlling postharvest decay and maintaining quality [7]. Postharvest heat treatment has been used to maintain firmness, preserve colour, prevent overripening, alleviate chilling injury, control insect infestation, and improve the shelf life of fruits and vegetables [7, 59]. Heat treatments include hot water treatment or dips, short hot water rinsing and brushing, hot air or steam treatments [6, 7, 11]. These methods retain the quality of fresh produce during prolonged cold storage, reduce rot development, and provide security [6, 7, 11, 60, 61]. Heat treatments can


*Alternative Green and Novel Postharvest Treatments for Minimally Processed Fruits… DOI: http://dx.doi.org/10.5772/intechopen.111978*


**Table 5.**

*Oxalic acid (OA) treatment on some fresh fruits and vegetables (FFVs).*

