CHANGES IN NUTRIENT COMPOSITION OF DEHYDRATED POTATO PRODUCTS DURING COMMERCIAL PROCESSING

Unit operations in several commercial potato dehydration plants were evaluated to determine the direct effects on protein and vitamin content of the product. The investigation included processing lines for potato granules and flakes as well as dehydrated slices and dices. Protein and vitamin retentions, in general, were lowest at any point where potatoes were exposed to high temperature for prolonged periods of time. The addition of sulfites had a deteriorating effect on thiamine resulting in losses of up to 96% for this vitamin. The other vitamins most severely affected were ascorbic acid and folic acid with retention values as low as about 40%. In the granule process, vitamin retention was most severely affected during the mixing and mashing steps. During the flake operation, water blanching and the drum drying operation resulted in the greatest reduction of retention values. Thiamine retention was a relatively high 64% during the production of potato flakes. The manufacture of dehydrated slices and dices showed the lowest retention values of all the dehydrated potato products investigated.