0524 Effect of selenium fortification on mozzarella cheese quality

Abstract

Selenium (Se) is an important trace element that has significant impacts on human and animal health. The objective of this study is to investigate the effect of Se fortification on mozzarella cheese quality. The mozzarella cheese was made following the manufacturing procedures until hand-stretched and cooled in cold water. The made-up cheese was divided into five pieces of 1 kg each, and put into 2% salt water without (control) or with Se yeast (1.25, 2.5, 5, and 10 mg Se/L, respectively) overnight. The cheese was then cut, vacuum packaged and stored at 4°C for 3, 30, and 60 d until analysis. On d 3 after adding Se yeast at 1.25, 2.5, 5, and 10 mg Se/L, the Se content of the outside or center of cheese was at 27.6, 35.7, 42.3, and 45.1 µg/kg or 20.4, 22.7, 23.4, and 23.9 µg/kg, respectively, significantly higher than that in control (15.4 for outside and 15.7 for center). After storage for 60 d, the Se concentration of the outside reduced to 24.1, 31.6, 34.1 and 36.4 µg/kg, while that of cheese center increased to 22.3, 27.8, 30.1, and 31.9 µg/kg, respectively. No significant differences were found in the cheese composition and texture between the control and Se fortified cheeses. However, compared with the control, the functional properties (meltability, flowability and stretchability) were improved, while the pH and water activity were lower in the Se-fortified cheese (5 and 10 mg/L) after 60 d storage. For the total bacteria count, the 5 and 10 mg/L Se fortified cheese were significantly lower (P < 0.05), but the 1.25 and 2.5 mg/L Se fortified cheese were higher than the control. The results of this study indicated that the Se content in mozzarella cheese can be increased by dipped into Se fortified solution without affecting the cheese quality, and that Se could migrate from the outside into center of the cheese during the storage.