LIPID COMPOSITION, CHOLESTEROL AND CHOLESTEROL OXIDATION PRODUCTS CONTENTS IN COMMERCIAL GRATED PARMESAN CHEESE

Abstract: Grated Parmesan cheese is widely consumed due to its distinctive sensory characteristics and convenience. However, grating increases the product surface area and its interaction with oxygen and light, while processing and storage conditions may affect lipid stability and promote cholesterol oxidation. Therefore, this study evaluated the lipid composition and oxidative stability of three commercial grated Parmesan cheese samples (PCA, PCB, and PCC). The fatty acid profile and the contents of cholesterol and cholesterol oxides, such as 25-hydroxycholesterol (25-OH) and 7-ketocholesterol (7-keto), were determined. Results were expressed as mean ± standard deviation (n = 3) and compared by Tukey's test (p < 0.05). Total lipid contents varied from 21.46 ± 0.88 to 24.65 ± 1.05 g/100 g, with PCB and PCC samples showing higher values than PCA (p < 0.05). Saturated fatty acids predominated in all samples (62.11-66.15), followed by monounsaturated (23.48-23.82) and polyunsaturated fatty acids (2.68-3.14), g/100 grams of total fatty acids. Palmitic acid (C16:0) was the major fatty acid (34.49-36.65), followed by oleic acid (C18:1 cis; 22.21-23.43) and stearic acid (C18:0; 11.01-13.02%). Additionally, PCB samples had the highest saturated and polyunsaturated fatty acid contents, whereas PCC had the highest n-3 levels. The highest cholesterol (60.19 ± 4.02 g/100 g), 25-OH (5.25 ± 0.57 µg/g), and 7-keto (7.71 ± 0.44 µg/g) were determined in PCB samples. In contrast, QPC showed the lowest concentrations of 25-OH (1.88 ± 1.58 µg/g) and 7-keto (0.17 ± 0.06 µg/g). Therefore, these findings demonstrate substantial variability in the composition and oxidative status of commercial grated Parmesan cheese across different brands, reinforcing the importance of monitoring both fatty acid and cholesterol oxidation when evaluating product quality.