Changes in the fatty acid profile and quality parameters produced during storage of organic cottage cheese supplemented with oregano essential oils

C M ASENSIO; M LARRAURI; P R QUIROGA; C G RIVEROS; P MARTÍN; N R GROSSO

New Orleans

Congreso; IFT Annual Meeting and food expo; 2014

Institute of Food and Thecnology

Cheese is a milk concentrate that consists of proteins and fats, mainly. Processed cheese may be considered a stable product. However, its shelf life may be shortened for an extended period of storage. Dairy products as other water?oil emulsions can suffer hydrolytic and oxidative rancidity. The objective of this study was to evaluate the preserving effect of oregano essential oil (EO) on organic cottage cheese acting as a retarding agent of lipid oxidation. Organic cottage cheese was flavored with different Argentinean oregano EO (Compacto, Cordobes, Criollo, and Mendocino) and thymol at 0.05% w/w. Antioxidant activity (FRAP), chemical indicators of lipid oxidation (hydroperoxide value and conjugate diene content) and changes in the fatty acid profile were determined every 10 days during 30 days under thermal storage (60 C). Statistical analysis was performed (ANOVA and Fisher- LSD test). The accumulation of hydroperoxides depended on the duration of storage time (p < 0.001) and the addition of oregano EO (p < 0.013). At storage day 30, the highest hidroperoxide value was observed in Control sample (3.93 μeqO2/kg) and the lowest value in samples added with thymol and Criollo EO (2.66 μeqO2/kg and 2.46 μeqO2/kg, respectively).The samples with Cordobes EO and thymol presented lower conjugated dienes (15.94 and 15.53, respectively), whereas the Control sample exhibited the maximum value (17.54). Relative percentage of unsaturated fatty acids decreased significantly (p < 0.05) because of oxidation reactions during the storage. Meanwhile, saturated fatty acids increased significantly (p < 0.05). Samples flavored with Compacto, Cordobes, and Criollo EOs presented the lowest Saturated/Unsaturated ratio (1.67, 1.62, and 1.68, respectively). At the end of the storage cheese samples with EO showed lower degree of deterioration. Moreover, cottage cheese with the addition of Cordobes and Criollo EO preserved better polyunsaturated fatty acids against oxidation reactions. Oregano EOs act as preserving agents in this organic product.