Friday, April 15, 2011

potato storage


Storage facilities need to be carefully designed to keep the potatoes alive and slow the natural process of decomposition, which involves the breakdown of starch. It is crucial that the storage area is dark, well ventilated and for long-term storage maintained at temperatures near 4 °C (39 °F). For short-term storage before cooking, temperatures of about 7 °C (45 °F) to 10 °C (50 °F) are preferred.

On the other hand, temperatures below 4 °C (39 °F) convert potatoes' starch into sugar, which alters their taste and cooking qualities and leads to higher acrylamide levels in the cooked product, especially in deep-fried dishes — the discovery of Acrylamides in starchy foods in 2002 has led to many international health concerns as they are believed to be possible carcinogens and their occurrence in cooked foods are currently under study as possible influences in potential health problems.

Under optimum conditions possible in commercial warehouses, potatoes can be stored for up to ten to twelve months. When stored at homes, the shelf life is usually only for several weeks. If potatoes develop green areas or start to sprout, these areas should be trimmed before using.
Commercial storage of potatoes involves several phases: drying of surface moisture; a wound healing phase at 85% to 95% relative humidity and temperatures below 25 °C (77 °F); a staged cooling phase; a holding phase; and a reconditioning phase, during which the tubers are slowly warmed. Mechanical ventilation is used at various points during the process to prevent condensation and accumulation of carbon dioxide.
When stored in the home, mature potatoes are optimally kept at room temperature, where they last 1 to 2 weeks in paper bag, in a dry, cool, dark, well ventilated location.

If mature potatoes are refrigerated, dark spots can occur and conversion of starch into sugar can give rise to unpleasant sweet flavour when cooked. Only new potatoes can be refrigerated, and should be kept so, where they have a shelflife of 1 week. If kept in too warm temperatures, both mature and new potatoes will sprout and shrivel. Exposure to light causes them to turn green. Also, potatoes absorb odours produced by pears.

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