## 4 Discussion  
An appropriate viscosity of the coating solutions is very important to ensure good adhesiveness to the fruit surface. Therefore, in the present study, the rheological behavior of the solutions at two different concentrations (5% and 10%) were analyzed to understand their applicability as an edible coating. In both samples, apparent viscosity decreased as the shear rate increased, underling the presence of a pseudoplastic behavior (shear thinning) [40]. Both samples had \(n\) values \(<\) 1, that is typical for shear thinning behavior, as previously demonstrated by [PERSON] et al. [41]. The K parameter, which is an index of the consistency of the product [42] was higher for the coating at 10% compared to the one at 5%. This result, according to the literature [43, 44], could be explained considering the linear relationship existing between viscosity and soluble solid concentration. In fact, in the present work, higher soluble solid content of alginate solution led to higher viscosity of the coating solution. However, as known by the literature, [22] the obtained viscosity values of both solutions can be considered appropriate for their use as edible coating, promoting an appropriate adhesiveness to the fruit surface. The application of an edible coating on the fruit and vegetable surface can modify the atmosphere surrounding the fruit, by acting as a semipermeable barrier that allows controlling the gas exchange (between fruits and environment) and water loss. As a consequence, it maintains tissue firmness guaranteeing, in addition, the inhibition of microbial spoilage [16, 45]. Polysaccharide-based coatings, realized with sodium alginate, modulate the internal tissue atmosphere, once they represent an obstacle to moisture, O\({}_{2}\), CO\({}_{2}\) and volatiles exchange, slowing down the metabolism and delaying fruit senescence [14]. In the present study, sodium alginate-based coatings applied to fruit, in particular by the dipping method, contributed to give a barrier effect limiting water loss and controlling fruit dehydration, as already observed by [PERSON] et al. [46]. Melon, particularly _Cucumis melo_ var. reticulatus, is highly appreciated due to its nutritional value, and indeed is a source of carotenoids characterized by high antioxidant activity [47]. The decrease in carotenoids during shelf-life may be attributed to their degradation because of the oxygen exposure, and cellular disruption due to wounding that exposes the carotenoids to lipoxygenase action [1]. As also demonstrated by moisture results (Figure 2), up to seventh d of storage, coatings applied on fresh-cut melon by dipping at the highest concentration had a barrier effect reducing the water loss and the oxygen exposure, thus contributing to a reduction of carotenoids degradation. Moreover, the coating applied at a concentration of 10% preserved better carotenoid's content than the one at 5%, probably because of its higher ascorbic acid content, which exerted antioxidant activity. The observed increase in TPC in all melon samples during storage could probably be related to the wounding mechanism response of fruits [6, 7, 8, 9, 10]. It is known that the coating contributes to reducing the interaction between polyphenols and oxidative enzymes, by oxygen restriction, maintaining high polyphenols levels [11]. [PERSON], [PERSON], & [PERSON] [48], in a study conducted on minimally processed lettuce, highlighted the presence of synergism between ascorbic acid (AA) and phenols, causing an increase of the latter in a higher presence of AA. Concerning the application method, in general, a higher TPC was observed in melon samples treated by dipping, in agreement with the study of [PERSON] et al. [49] that observed an immersion of fresh fruits in the edible coating by dipping was correlated with an increase in the polyphenols content. Moreover, the homogenous distribution of coating solution by dipping contributes to the TPC maintenance, avoiding their oxidative degradation as also reported by [PERSON] et al., [PERSON] et al.