## 3 Results and Discussion  
### \({}^{1}\)H-NMR Measurements  
\({}^{1}\)H-NMR revealed characteristic peaks in the cheese samples, as can be seen in Figure 1. As anticipated, the NMR spectrum indicates the prevalent presence of the lactate resonance signal at 1.33 ppm (a) across all samples. Lactate emerges as the predominant component, given its status as the primary product resulting from the fermentation of lactose during the cheese-making process [24]. It is also predominant in the peak at 5.21-5.26 ppm due to the presence of a CH anomeric of \(\alpha\)-glucose and a CH anomeric of \(\alpha\)-galactose. These signals likely originate from the metabolism of lactose, affirming the widely accepted notion that glucose was the favored microbial substrate among the two end products resulting from lactose hydrolysis [25]. That is why the signal of \(\alpha\)-galactose at 5.26 ppm (b) is lower than that of \(\beta\)-galactose at 4.58-4.60 ppm (c) due to the CH axial proton. The results of a study by [PERSON] [26] suggested that lactic acid bacteria survived throughout the ripening of Kefalotyri cheese; thus, they catalyze the hydrolysis of lactose to \(\alpha\)-glucose and \(\alpha\)-galactose. Contrastingly, in Cheddar cheese, lactic acid bacteria die early, with no presence of CH anomerics of \(\alpha\)-glucose and CH anomerics of \(\alpha\)-galactose.  
Figure 1: A representative spectrum of Cheddar cheese, with main peaks as they appear in the text at (a) 1.33 ppm, (b) 5.26 ppm, (c) 4.58–4.60 ppm, (d) 2.00 ppm, (e) 2.23 ppm, (f) 2.80 ppm, (g) 8.40 ppm, (h) 1.42 ppm, (i) 1.93 ppm, and (j) 0.95–1.03 ppm.  
In addition, it was observed (and confirmed by chemometrics) that proline (d), methionine (e), citric acid (f), and formic acid (g) at 2.00, 2.23, 2.80, and 8.40 ppm, respectively, are different in cow and goat and sheep cheese. Moreover, in heavily salty cheese, there are relatively high levels of lactic acid at 1.42 ppm (h) and citric acid compared to other less-salty cheese samples. In contrast, the content of acetic acid at 1.93 ppm (i) can change according to the salt content, and this is the reason explaining its absence from some cheese samples of this study, like the spreadable, soft cheees [27]. Leucine, isoleucine, and valine in the range 0.95-1.03 ppm (j) are in higher proportion in the cow-origin cheese samples. The quality of cheese is significantly influenced by the up-regulation and determination of amino acids, which are directly affected by the diet of the animals.  
The potential of NMR as a method for characterizing food products appears promising. Despite its inherent low sensitivity, NMR is limited to gathering data on the most abundant elements in foods, including sugars, amino acids, and carbohydrates. Nevertheless, the extensive and detailed information that NMR can provide significantly compensates for its lower sensitivity. _Special attention should paid be towards the region of weak signals ranging from 2.2 to 3.1 ppm, as these signals originate from trace compounds present in milk_[12]. _It is noteworthy that_ many authors [12; 13] reported these signals with complementary measurements, suggesting that they could be further investigated with other techniques and the aid of chemometrics.