Storage at warmer temperatures: effect on potato physiology and skin finish

Industry Challenge

Storage of potatoes for the fresh market is carried out at low temperatures, typically in the range 2 to 3.5°C. A storage temperature in this range is selected in order to maintain the appearance of crops, with conditions restricting the development of skin blemishing diseases, maintaining bloom and limiting weight loss. The maintenance of a low storage temperature however adds to the costs of storage and induces sweetening. As well as affecting flavour and texture, sugar formation in combination with amino acids, results in relatively high acrylamide levels when certain preparation methods are employed.

This project included an evaluation of the effect of a range of storage regimes and temperature combinations on components of skin finish including skin blemish diseases, on physiology including tuber respiration rates, sprouting and weight loss, and on aspects of processing quality including fry colour, acrylamide content and taste/texture.  The results informed a cost-benefit analysis for warmer potato storage.

Over the three years of the study there were no significant differences during six month storage of four potato varieties at temperatures of 2.5, 4 and 5.5 °C on the decline of skin bloom or on the development of three skin blemish diseases caused by  Helminthosporium solani (silver scurf), Colletotrichum coccodes (black dot) and Polyscytalum pustulans (skin spot), respectively. 

The effects on physiology were mixed as there was an increase in sprouting at warmer temperatures but no effect on weight loss or on respiration rate.  Fry colour and acrylamide content increased at colder storage temperatures.  Taste and texture of steamed tubers was little affected by storage temperature.