Effect of Milk Fat on the Stability of Vitamin A in Ultra-High Temperature Milk

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Abstract
The stability of vitamin A in ultra-high temperature milks with .15, 2.92, 6.16, and 9.7% fat during storage at 26.degree. C was studied over 3 wk. Milks were fortified with synthetic retinyl palmitate to a final concentration of approximately 120 .mu.g retinol equivalent/100 ml milk. The four milk samples were ultra-high temperature processed and packaged in 100 ml sterile milk dilution bottles and stored in the dark at 26.degree. C for 3 wk. Vitamin A concentrations decreased rapidly during the first 2 wk of storage then stabilized. Degradation rates during the first 2 wk were linear and varied inversely with the fat content in the milk (the more fat, the slower the rate of degradation). Final vitamin A concentrations at the end of 3 wk of storage were higher in milk with high fat and closely corresponded to the native vitamin A concentrations present in milk prior to fortification. The results indicate a possible protective effect due to fat or a difference in stability between native and synthetic vitamin A.