Estimation and fortification of vitamin D3 in pasteurized process cheese

The objective of this study was to develop methods for the estimation and fortification of vitamin D-3 in pasteurized Process cheese. Vitamin D3 was estimated using alkaline saponification at 70degreesC for 30 min, followed by extraction with petroleum ether:diethyl ether (90:10 vol/vol) and HPLC. The retention time for vitamin D-3 was approximately 9 min. A standard curve with a correlation coefficient of 0.972 was prepared for quantification of vitamin D3 in unknown samples. In the second phase of the study, pasteurized Process cheeses fortified with commercial water- or fat-dispersible forms of vitamin D-3 at a level of 100 IU per serving (28 g) were manufactured. There was no loss of vitamin D-3 during Process cheese manufacture, and the vitamin was uniformly distributed. No losses of the vitamin occurred during storage of the fortified cheeses over a 9-mo period at 21 to 29degreesC and 4 to 6degreesC. There was an approximately 25 to 30% loss of the vitamin when cheeses were heated for 5 min in an oven maintained at 232degreesC. Added vitamin D-3 did not impart any off flavors to the Process cheeses as determined by sensory analysis. There were no differences between the water- and fat-dispersible forms of the vitamin in the parameters measured in fortified cheeses.