Production of functional karish cheese fortified with vitamin D3 in Nanoemulsion

Karish Cheese is one of the most Egyptian low fat dairy products consumed. The deficiency of vitamin D is a major global public health problem especially in Middle East. The aim of this research is to develop fortification methods to improve the vitamin retention and Karish cheese properties.  VD₃ nanoemulsion was formulated using maltodextrin (MD) and modified starch (MS) to achieve a fortification level 600 IU/100g of VD₃ in cheese. The vitamin was added to cheese with two different addition methods either direct in skim milk after heat treatment or by spraying into the scooped curd before the whey draining. Four treatments were made to investigate the effect of the fortification methods on vitamin retention and the properties of cheese. T1 and T2 were the treatments of cheese fortified with nanoemulsion with two addition methods direct and spraying respectively. T3 and T4 represent the treatments of cheese fortified with VD₃ emulsion under the same two methods. However, the most of VD₃ was lost for T1, T3 and T4 in the drained whey. Treatment T2 has a significant (P < 0.05) difference exposed in vitamin retention by 87 % in comparison with T1, T3 and T4 which retain only 33.3, 6.66 and 40.25 % respectively. Slight changes were observed in pH and titratable acidity and no changes were reported in fat and salt contents. Moisture content of T1 was about 1.3 - 2.3% higher than other treatments and control in zero time and was achieved 1.9-2.9% after 28 days. T1 was significantly (P < 0.05) lower in protein and ash contents than control and other treatments. There were no differences between the sensory properties of T2, T4 and control. The lowest score of sensory properties was observed for T1 and T3. Karish cheese fortified by spraying with VD₃ nanoemulsion could be a suitable strategy for production of functional free fat Karish cheese for those  suffering from vitamin D deficiency.