Vitamin C Stability during Preparation and Storage of Potato Flakes and Reconstituted Mashed Potatoes

High performance liquid chromatography with electrochemical detection was used to follow losses of L-ascorbic acid (AsA) in the processing and serving of fortified mashed potatoes. Cumulative losses of AsA were: 56% for adding AsA to freshly mashed potatoes at 251 ppm (wet basis); 82% drum-drying the potatoes; 82% storing the flakes 4.3 months at 25°C., and 96% reconstituting mashed potatoes and holding them 30 min on a steam table. The mashed potatoes at the point of ingestion would contain 10 ppm AsA (wet basis), and one serving size (100g) would provide 2% of the adult RDA. Fortification with equivalent levels of magnesium L-ascorbate 2-mono-phosphate (AsMP) or sodium L-ascorbate 2-polyphosphate (AsPP) gave overall cumulative losses of 20 or 32%, respectively. Such reconstituted mashed potatoes contained 201 ppm and 171 ppm AsA respectively, and one serving would provide about 33% of the RDA of vitamin C.