# Development of \"Quadrello di Ovino\", a Novel Fresh Ewe's Cheese
## 4 Discussion
[48] stated that an increase of yellowness in Stracchino cheese, impacts both cheese shelf life and acceptability. An increase of yellowness is commonly observed during storage of high moisture cheeses [52]. In this study, the hardness of QdO cheese, which is the force required to obtain a given deformation of the sample, was 0.22 N/mm\({}^{2}\) on average. This value is extremely lower than those estimated for \"Primosale\" cheese for which hardness was in the range 0.98-1.10 N/mm\({}^{2}\)[8]. For this reason, the texture of Crescenza type cheese is considered soft and somewhat viscous [53]. The basic chemical composition of QdO cheese showed an average content of fats and proteins of 35.24 and 23.32%, respectively, which are much higher than the levels reported for Crescenza cheese generally characterized by 24% of fats and 14% of proteins [31; 36]. These results were quite expected, due to the high content of dry matter, proteins and fats of ewe's milk [54]. Furthermore, the compositional analysis of ovine QdO cheeses showed data comparable to those measured for other ovine fresh cheeses such as pressed Primosale cheese and stretched Vastedda-like cheese [8; 16]. QdO-P1 cheese showed a higher antioxidant activity, in terms of TBARs, than QdO-P2 cheese. The lower values registered for the latter cheese are presumably due to the higher content in polyphenols of the bulk milk [55] or to the high ability of SF2 starter bacteria to inhibit lipid oxidation [56; 57]. Regarding the composition of FAs, both experimental cheeses showed profiles comparable to those detected for other Sicilian ewe's milk cheeses [49; 58]. The two productions were characterized by different levels of SFA, MUFA and PUFA. Bacterial metabolism during cheese processing clearly contributed to the final cheese FAs profiles. The lipolytic activity of the two commercial strain preparations could be characterized by a different enzyme kinetics and act selectively against the FAs present in milk triglycerides, leading to a different concentration of free FAs (FFA) on which beta-oxidation occurs [59]. Furthermore, it could be possible that elongation reactions can lead to the re-elaboration of the FFA present. Barely a few studies evaluated the effect of starter cultures on cheese FAs composition, obtaining conflicting results: [PERSON] et al. [60] reported an effect of different bacteria inoculums on the final FAs composition of white pickle cheese, while [PERSON] et al. [61] registered no effect on Pecorino cheese. VOCs emitted from food products are decisive for the perception of aroma and taste [62]. Recently, the relationship between VOCs and sensory attributes has been successfully evaluated for Gorgzonola cheese [63]. QdO cheese was characterized by alcohols, ethers, aldehydes, ketones, carboxylic acids, esters, amines, and monoterenes. The class of carboxylic acids is mostly present in cheees [64]. In particular, a significant increase in ester and ketones can be induced by ruminants' diet [65]. Acetoin was the most abundant ketone detected in Qdo cheese. This chemical derives from the metabolism of lactose and citrate and is a common compound found in many other cheeses made with sheep and goat milk; it is responsible for the smell of butter perceived by panelists. Phenethyl hexanoate, the only ester that does not derive from linear FAs, was the second most abundant compound of this novel cheese. Carboxylic acids can be formed through lipolysis, proteolysis and fermentation of lactose. The presence of these acids provides dairy products with their characteristic aroma. Among the main acids detected, butanoic acid is characterized by a rancid and unpleasant smell [64]. According to [PERSON] et al. [66], esters are originated by esterification between SCFA and ethanol, derived from the catabolism of amino acids. The presence of ethyl esters (mainly ethyl acetate, ethyl butanoate and ethyl octanoate) is characteristic of ovine cheeses.