UBC Theses and Dissertations
Evaluation of methods for fortifying skim milk powder with vitamin A Paquette, Gaëtan Marc Andre
The fortification of skim milk powder with vitamin A has been found to be ineffective with available methods. The purpose of this study was to assess new methods and materials for their effectiveness in providing stability to vitamin A in fortified skim milk powder. The first phase of the project involved trials in Pilot Plants which evaluated 14 different treatments for vitamin A stability during storage periods of twelve months at 22°C and six months at 37°C. The second and third phases of the experiment consisted of primary and instant powder trials in commercial plants using the most stable methods from the Pilot Plant trials. In the latter phases of the project, eight treatments were tested for primary powder and ten for instant type of powder. Results show that levels of antioxidants were important to control the oxidative degradation of vitamin A in the milk powder. The vitamin A concentrate containing BHA (5 mg), BHT (55 mg) and ⍺-tocopherol (12.5 mg) antioxidants produced the best results for primary powder. Ascorbyl palmitate-⍺-tocopherol combination of antioxidants was found to be more effective than the BHA-BHT-⍺-tocopherol blend for instant powder. The level of hydrogenated coconut oil (HCO) used as the vitamin carrier was also found to be important for stability, 0.2% being slightly better than 0.1% in primary powder. A 12% emulsion injected at such a rate as to add 0.027% oil in milk solids was the best treatment of the instant powder trials. Hay-like flavour in reconstituted skim milk powder was correlated with vitamin A destruction.