A vacuum fryer is a machine designed to fry vegetables, fruit, fish, and meat at low temperatures. The equipment has the ability to reduce the oil content of the food, sometimes well below 15 percent. It can also help to inhibit the loss of nutrients that commonly occurs with food cooked or fried at high temperatures. The vacuum fryer also maintains the food item's color, consistency and flavor. Food fried with this frying method can be stored for a longer time than other types of fried food.
These machines are sometimes quite large and were originally manufactured for making potato chips. They are usually made from stainless steel and are basically deep-frying apparatuses used to lessen the harmful results of frying in fat. The technology removes moisture and air from the frying chamber, creating a near vacuum. Several studies suggest that the presence of the carcinogen acrylamide — a chemical compound found in certain foods — is reduced by the vacuum frying method. Regular, atmospheric deep-frying methods apparently do not reduce the presence of this compound.
There are two types of vacuum fryers. Intermittent fryers are used for smaller operations and are suitable for vegetables and fruit. Larger, continuous fryers are better for more sustained commercial use. The intermittent vacuum fryer's oil has to be replaced more often than the continuous fryer. This makes the continuous vacuum fryer more attractive to larger manufacturers as it lowers the cost of production.
The vacuum fryer is relatively simple to operate. Pumps create the vacuum and programmable electronics allow the user to control the system. Food that has been placed in boiling oil is quickly robbed of moisture. A vacuum fryer allows the food to fry at a reduced temperature and retain much of the moisture and taste. This process can also reduce the amount of oil in the fried food item, although the exact amount depends on the particular type of fryer that is being used.
Research has shown that vacuum fried potato chips may have up to 50 percent less oil content than chips that have been deep-fried using regular frying methods. Foods fried in a vacuum fryer also often retain higher levels of nutrients than those fried with other methods. Foods that have been vacuum fried are no match for a fully rounded nutritious diet, but they may go a long way to making snacks a little healthier. The one drawback to using a vacuum fryer is that the process is more expensive than regular atmospheric methods.