40. Fortification of cheese with vitamin D

Vitamin D is essential for bone health and is one of the most studied classes of vitamins to date for its biological role. Currently recognized as a prohormone, this vitamin class promotes musculoskeletal health by maintaining calcium and phosphorus homeostasis. The human body can synthesize vitamin D3 in adequate amounts only from ultraviolet B light exposure through sunlight. However, the efficiency of bodily synthesis from sunlight exposure varies by season, geographic location, time of day and skin color and is not a reliable mechanism to attain sufficient vitamin D3 in regions of low sunlight. In order to provide adequate levels of vitamin D3 throughout the year in such regions dietary supplementation is essential. Bovine whole milk is a poor source of vitamin D3 but is suitable for delivery of fat-soluble vitamins. Among dairy foods, cheese is a suitable medium for long-term vitamin D3 supplementation and has been shown to maintain stable levels of the vitamin during aging. However, several considerations need to be addressed for fortification of cheese with vitamin D, including the choice of cheese type, manufacture process, stage of addition and post addition bioavailability. For example, cheeses that undergo long term aging and flavor development through microbial metabolism or enzyme actions are highly susceptible to undesirable flavor changes even with minor alterations in its chemical composition. Also, during long term cheese ripening, the vitamin may be degraded by cheese bacteria and enzymes. These issues are not critical in short term-stored fresh milk cheeses, except in pasta filata type cheeses that are cooked at a higher temperature and lose fat during the process, which may reduce vitamin D added at an earlier stage of manufacture. This chapter will summarize current issues on fortification of cheese with vitamin D3 and flavor acceptability of fortified cheese.