Spray-dried whole milk powders have been prepared containing 0·01% of four flavones, propyl and dodecyl gallates, butylhydroxyanisole (BHA) and nordihydroguaiaretic acid (NDGA). The powders were stored at 20 and 37°C and examined at intervals of 25 days for taste of the reconstituted milk, peroxide value of the fat and oxygen absorption of the powder. Three of the four flavones, 7,8-dimethoxy-3,2',5'-trihydroxyflavone, 6-ethyl-3,7,2',5'-tetrahydroxyflavone and 6-dodecyl-3,7,2',5'-tetrahydroxyflavone improved the keeping quality of the powder, the last-named compound being the most effective, but 3,7,8,2'5'-pentahydroxyflavone was without antioxidative properties in this system. These results are briefly discussed with respect to substitution within the flavone molecule.
Dodecyl gallate was a very effective antioxidant for spray-dried whole milk powder and propyl gallate and NDGA, whilst affording good protection, were less so; BHA did little to improve keeping quality.
The best antioxidant of the flavones investigated, 6-dodecyl-3,7,2',5'-tetrahydroxyflavone, appeared to be almost as effective as propyl gallate and NDGA in these milk powders.