## 1 Introduction  
In recent years, donkey milk has gained appeal as a healthy alternative for a newborn's diet [1; 2] due to its resemblance to human milk and lack of risk of allergic reactions. The beneficial effects associated with its intake have been known since ancient times, and it is considered an effective supplement to counteract the effects of various pathologies [3; 4; 5; 6; 7]. A number of researchers [8; 9; 10; 11] have proven that the composition of human and donkey milk is similar under several aspects, and that it can provide to infants a number of benefits from microbiological [12] and anti-inflammatory points of view [13; 14]. In fact, it has been demonstrated that it is a suitable medium for _L. Hammosus_ probiotic strains, with all the derived benefits, and it prompts the production of anti-inflammatory cytokines [15]. In addition, positive aspects on neural functioning have been highlighted [16]. In the literature, only few nutritional drawbacks have been pointed out in donkey milk, such as low caloric, lipid, and iron intake; consequently, it is important to include it in a balanced diet, or to fortify it [1]. In general, this food is recommended for neonate nutrition; therefore, analytical methods to ensure its genuineness have been proposed [17]. Numerous chemical and biochemical studies have been conducted on the components of donkey milk, especially with regards to proteins, such as caseins, whey protein, fats, and vitamins [18; 19; 20; 21]. This milk also contains a rich bouquet of minerals; nevertheless, little attention has been given to the elemental composition of this food. [PERSON] et al. quantified Ca, P, S, Mg, K, and Na in whole, skimmed, ultracentrifuged, and ultrafiltered donkey milk, in order to understand how the different elements distribute in the diverse fractions (fats, caseins, whey proteins, and aqueous phase), and they have even tried to correlate elemental concentrations in milk with those in the animal feed [22; 23; 24]. A similar study has been conducted by [PERSON] et al. [25], who characterized different components of whole donkey milk during lactation (second-ninth month). Among the others, they exploited Atomic Absorption Spectrometry to quantify mineral elements such as: Ca, Mg, Na, K, Zn, Fe, and Cu, and a colorimetric method for P, concluding that the mineral content varies significantly with the lactation period. A further interesting study on this regard is the one from [PERSON] and collaborators, who compared the elemental composition of mills from different mammals (among the others, donkey) with plant-based milks and concluded that the levels of toxic elements in all specimens do not endanger consumers [26]. In the literature, sensory analysis trials of donkey milks, aiming at inspecting consumer acceptance, have been discussed [27; 28]. For example, [PERSON] et al. [29] investigated the sensory characteristics of 30 samples of donkey milk from Greece and Cyprus. Panelists estimated the perceived intensities of different attributes: appearance, taste, scent, flavor, aftertaste, and texture in a standardized sensory test form (with a 5-point hedonic scale). The outcome revealed donkey milk is an excellent culinary option since it presents an appreciated sweet taste because of its considerable lactose content. Despite the scientific attention that donkey milk has aroused in recent years, low focus has been given on how conservative processes can change its properties. It is known that freeze-thaw cycles can alter milk's composition. [PERSON] et al. investigated frozen and thawed (FT) donkey milk, in order to determine whether, despite the process, it was still possible to detect adulterations with cow milk. [PERSON] et al. [14] evaluated the effect of freezing and thawing cycles on goat milk and they observed a considerable reduction in fats and perceived viscosity, higher proteins' oxidation, and alterations on their secondary structure, and, so far, to the best of our knowledge, the same has not been studied on donkey milk.