Food or edible material: processes – compositions – and products – Processes – Preparing or treating triglyceridic fat or oil – or processes...
Reexamination Certificate
2001-04-13
2002-04-09
Yeung, George C. (Department: 1761)
Food or edible material: processes, compositions, and products
Processes
Preparing or treating triglyceridic fat or oil, or processes...
C210SDIG008, C426S330600, C426S423000
Reexamination Certificate
active
06368648
ABSTRACT:
This invention relates to a process for treating used cooking oil or fat from frying operations such as industrial frying operations in order to remove impurities such as free fatty acids from the cooking oil or fat. More particularly, this invention relates to a system, preferably an automated system, for treating used cooking oil or fat that may be run continuously, thus providing for a more efficient process of treating used cooking oil.
Cooking oils and fats are employed in general for the cooking or frying of foods such as chicken, fish, potatoes, potato chips, vegetables, and pies. Such frying may take place in a restaurant wherein food is prepared for immediate consumption, or in an industrial frying operation where food is prepared in mass quantities for packaging, shipping, and future consumption.
In a typical restaurant frying operation, large quantities of edible cooking oils or fats are heated in vats to temperatures of from about 315° F. to about 400° F. or more, and the food is immersed in the oil or fat for cooking. During repeated use of the cooking oil or fat, the high cooking temperatures, in combination with water from the food being fried, cause the formation of free fatty acids (or FFA). An increase in the FFA decreases the oil's smoke point and results in increasing smoke as the oil ages.
Industrial frying operations involve the frying of large amounts of food for delayed consumption. Often, this is a continuous operation with the food being carried through the hot oil via a conveyor.
Industrial fryers of meat and poultry must follow the guidelines of the FDA Food Safety and Inspection Service (FSIS) Meat and Poultry Inspection Manual. The following are excerpts from that manual:
Section 18.40 Frying (a) Meat
Length of time fats and oils may be used for deep fat frying varies with temperature, quality of new fat added daily, and fat treatment during use. Suitability of these fats for further use can be determined from degree of foaming during use or from color, odor, and flavor.
Fat or oil should be discarded when it foams over the vessel's side during cooking, or when its color becomes almost black as viewed through a colorless glass container.
Section 18.40 Frying (b) Poultry (5) Fat Acceptability
Used fat may be made satisfactory by filtering, adding fresh fat, and cleaning the equipment regularly.
Large amounts of sediment and free fatty acid content in excess of 2 percent are usual indications that frying fats are unwholesome and require reconditioning or replacement.
Industrial fryers of meat and poultry, in general, use the 2% free fatty acid (FFA) limit, or less if mandated by their customers, as their main specification for oil quality.
In addition to hydrolysis, which forms free fatty acids, there occurs oxidative degeneration of fats which results from contact of air with hot oil, thereby producing oxidized fatty acids (or OFA). Heating transforms the oxidized fatty acids into secondary and tertiary by-products which may cause off-flavors and off-odors in the oil and fried food.
Caramelization also occurs during the use of oil over a period of time, resulting in a very dark color of the oil which, combined with other by-products, produces dark and unappealing fried foods.
Because of the cost resulting from the replacing of the cooking oils and fats after the use thereof, the food industries have searched for effective and economical ways to slow degradation of fats and oils in order to extend their usable life.
U.S. Pat. No. 4,112,129, issued to Duensing, et al., discloses a composition comprised of diatomite, synthetic calcium silicate hydrate, and synthetic magnesium silicate hydrate may be employed for reclaiming used fats and oil.
U.S. Pat. No. 4,681,768, issued to Mulflur, et al., discloses a process for treating used cooking oil or fat by contacting used cooking oil or fat with a high surface area amorphous synthetic magnesium silicate having a surface area of at least 300 square meters per gram.
U.S. Pat. No. 5,597,600, issued to Munson, et al., discloses the treatment of cooking oil or fat with magnesium silicate and at least one alkali material to reduce the content of free fatty acids in the oil or fat.
In present systems for treating used cooking oil or fat, however, the frying system is shut down periodically in order to remove the oil or fat from the fryer to a batch treatment tank where a purifying material is mixed for a specified time and then removed by filtration. The oil or fat then is ready to return to the fryer.
It is an object of the present invention to provide a filter system, which may be an automated system, for treating used cooking oil or fat wherein used cooking oil or fat may be treated continuously without shutting down the frying system.
In accordance with an aspect of the present invention, there is provided a process for treating used cooking oil or fat. The process comprises: (a)passing the used cooking oil or fat from a cooking oil or fat source to a holding vessel; (b)contacting the used cooking oil or fat with a predetermined amount of purifying material upon accumulation of a first predetermined amount of the oil or fat in the holding vessel; (c)passing the used cooking oil or fat and the purifying material from the holding vessel to a filter apparatus upon accumulation of a second predetermined amount of the oil or fat in the holding vessel, wherein the second predetermined amount of oil or fat is greater than the first predetermined amount of oil or fat, and whereby upon passing of the used cooking oil or fat and the purifying material from the holding vessel to the filter apparatus, the purifying material becomes entrained in the filter apparatus; and (d)passing the used cooking oil or fat from the filter apparatus to the source.
In one embodiment, step (a) comprises passing the used cooking oil or fat through a first transport line from said source to a first diverting valve. The used cooking oil or fat then is passed through a second transport line from said first diverting valve to a second diverting valve. The used cooking oil or fat then is passed through a third transport line from the second diverting valve to the filter apparatus, and the cooking oil or fat is passed through the filter apparatus and then through a fourth transport line from the filter apparatus to the holding vessel.
In another embodiment, in step (b), the used cooking oil or fat is contacted with the purifying material in the second transport line upon accumulation of the first predetermined amount of the cooking oil in the holding vessel. Upon contact of the used cooking oil or fat with the purifying material in the second transport line, the second diverting valve is diverted such that the used cooking oil or fat is passed from the source through the first transport line, the first diverting valve, the second transport line, the second diverting valve and through a fifth transport line from the second diverting valve to the holding vessel until the used cooking oil or fat is accumulated in the holding vessel at the second predetermined level.
In yet another embodiment, step (c) comprises diverting the first diverting valve such that the used cooking oil or fat and the purifying material are passed from the holding vessel to a sixth transport line from the holding vessel to the first diverting valve, and then are passed through the second transport line from the first diverting valve to the second diverting valve. The used cooking oil or fat and the purifying material then are passed through the third transport line to the filter apparatus. The used cooking oil or fat and the purifying material then are passed through the filter apparatus, whereby the purifying material becomes entrained in the filter apparatus. The used cooking oil or fat then is passed through the fourth transport line from the filter apparatus to the holding vessel.
In another embodiment, step (d) comprises diverting the first diverting valve such that the used cooking oil or fat is passed through the first transport line, the first diverting va
Abrams Chris
Bertram Bryan
Kauffman Jeffrey
Lillie Raymond J.
Olstein Elliot M.
The Dallas Group of America, Inc.
Yeung George C.
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