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.