Potato Processing and Uses
Potatoes are used for a variety of purposes, and not only as a vegetable for cooking at home. In fact, it is likely that less than 50 percent of potatoes grown worldwide are consumed fresh. The rest are processed into potato food products and food ingredients; fed to cattle, pigs, and chickens; processed into starch for industry; and re-used as seed tubers for growing the next season’s potato crop.
Food Uses: Fresh, Frozen, Dehydrated
Fresh potatoes are baked, boiled, or fried and used in a staggering range of recipes: mashed potatoes, potato pancakes, potato dumplings, twice-baked potatoes, potato soup, potato salad and potatoes au gratin, to name a few.
But global consumption of potato as food is shifting from fresh potatoes to added-value, processed food products. One of the main items in that category is frozen potatoes, which includes most of the french fries (“chips” in the UK) served in restaurants and fast-food chains worldwide. The world’s appetite for factory-made french fries has been put at more than 7 million tons a year. Another processed product, the potato crisp (“chips” in the US) is the long-standing king of snack foods in many developed countries.
Dehydrated potato flakes are used in retail mashed potato products, as ingredients in snacks, and even as food aid. Potato flour, another dehydrated product, is used by the food industry to bind meat mixtures and thicken gravies and soups.
A fine, tasteless powder with “excellent mouth-feel,” potato starch provides higher viscosity than wheat and maize starches, and delivers a more tasty product. It is used as a thickener for sauces and stews, and as a binding agent in cake mixes, dough, biscuits, and ice-cream.
In eastern Europe and Scandinavia, crushed potatoes are heated to convert their starch to fermentable sugars that are used in the distillation of alcoholic beverages, such as vodka and akvavit.
Non-Food Uses: Glue, Animal Feed, and Fuel-Grade Ethanol
Potato starch is widely used by the pharmaceutical, textile, wood, and paper industries as an adhesive, binder, texture agent, and filler, and by oil drilling firms to wash boreholes. Potato starch is a 100% biodegradable substitute for polystyrene and other plastics and used, for example, in disposable plates, dishes, and knives.
Potato peel and other “zero value” wastes from potato processing are rich in starch that can be liquefied and fermented to produce fuel-grade ethanol. A study in Canada’s potato-growing province of New Brunswick estimated that 44,000 tons of processing waste could produce 4-5 million liters of ethanol.
In the Russian Federation and other east European countries, as much as half of the potato harvest is used as farm animal feed. Cattle can be fed up to 20 kg of raw potatoes a day, while pigs fatten quickly on a daily diet of 6 kg of boiled potatoes. Chopped up and added to silage, the tubers cook in the heat of fermentation.