CA2256314A1 - Parfried food products containing low levels of free fatty acids and polymers - Google Patents

Abstract

Parfried food products low in free fatty acid and polymers and a method for extending the fry-life of an edible oil during the finishing process. The parfried foods are suitable for oven finishing or deep-fry finishing. When the parfried food is finished by deep fat frying the fry-life of the finishing oil is extended. The parfried food products are produced by frying raw food products in used oil in which the free fatty acid, polymers and tocopherol content of the oil is controlled.

Description

CA 022~6314 1998-11-02 W O 97/40703 PCT~US97/07370 PARFRIED FOOD PRODUCTS CONTAINING LOW LEVELS
OF FREE FATTY ACIDS AND POLYMERS

BACKGROUND OF THE INVENTION
Many restaurants, and in particular "fast food" restaurants, serve foods such as chicken, fish, onion rings, and especially French fries, which are deep-fried in edible cooking fats or oils. The wide plefe.cl1ce for such fried foods have brought about a substantial increase in the nurnber of drive-thru and fast food restaurants that prepare and serve such foods. Most restaurants prefer to prepare these foodproducts from the frozen or chilled partially fried product (hereinafter parfried) rather than go through the procedure of prep~;ng the foods from raw materials.
The parfried products are converted by restaurants into ready-to-eat products.
The use of parfried foods has been widely adopted in restaurants because of the advantages they offer. A few of the recognized advantages associated with the use of chilled and frozen parfried products are, for exarnple, less oil is used during the frying process, the use of the frozen parfried products simplifies storage and inventory control, the parfried food assures uniform quality and reduces the labor and time spent in plepa mg the food for serving.
Most commercially produced parfried foods are plc~aled in edible oil that is used repeatedly. The oil is generally m~int~in~d at te~ ,c.d~Llres of from about 290~F (143~C) to about 400~F (204~C) for prolonged periods. Continuous frying at high tell,pe.~l Ires causes the formation of free fatty acids (FFA) and polymers in the frying oil. This continuous process tends to push the frying oil to a limit where polymers, free fatty acids and other oxidation products build up. Since parfriedfood absorb the oil in which it is fried, the resulting parfried food is high in free fatty acid and polymer. For example, a food product can be fried in oil that is only 75% pure and contains 25% polymers. The food product during the parfrying picks up about 10% by weight, oil. The resulting parfried food then contains 2.5%
polymers. Subsequently when the parfried foods are finished by frying, the oil present in the parfried food cont~min~tes the finish frying oil and reduces the length of time the oil can be used for frying.
One method of controlling the level of free fatty acid and polymer in the food product is to always use fresh oil. Parfried foods produced from fresh oil will generally have a fat component having a free fatty acid content lower than about0.02% and a polymer content lower than about 1%. Tocopherols would be present in the fat component of the parfried food in an amount slightly lower than that in CA 022~6314 1998-11-02 the fresh oil used to fry the food product. Of course the tocopherol, free fatty acid and polymer content will vary depending on the starting free fatty acid content of the fresh oil, how long the oil is used or frying and the type of food product being parfried. This constant fresh oil method is rarely if ever used when producing parfried foods on a comrnercial scale. The process is uneconomical and results in large quantities of oil being wasted because the oil is not reused. The oil utilized in this process can only be used for a short time. The length of time it can be used will depend on factors such as how much food is fried, the water content of the food product and the time that the oil remains at elevated temperatures.
Although the oil, once used for frying could be treated by well known methods (e.g., oil filtration, antioxidant addition etc.) and then returned to the fryer, this alone would not allow one to control the level of free fatty acids and polymer or delay the build up of "both" free fatty acid and polymer to any appreciable degree.
Heretofore, it can be seen that known methods have concentrated on treating the "oil" used for finish frying and has not placed any importance on or recognized the advantages of producing parfried food products low in free fatty acid and polymer for extending the frylife of an edible oil. These methods focus on removing con~---;n~ once they are produced in the finish frying oil whereas the present invention provides a parfried food product that reduces the formation ofcont~rnin~nt~ during frying. Further, known methods have the disadvantages of being either too costly or unable to control the free fatty acids and polymer in the parfried food product on a commercial scale and/or unable to produce parfried food capable of extçn~lin~ the frylife of the frying oil by any appreciable amount. To the extent that parfried food products are used in commercial practice (e.g. fast food re~t~r~nt~, foodservice operations) for p.el)~lng food products, a great need exists for parfried foods which do not detract from the fry-life of the finiching oil but rather extends the frylife of the fini~hing oil. Additionally, a need exists for a parfried food product low in free fatty acid and polymer. Further a need exists for a method of producing parfried food products low in free fatty acid and low in polymer on a com~llc.cial scale without subsequent oil loss, that is economical and that controls both the level of free fatty acids and polymer.
It is, accGrdingly, an object of the present invention to provide parfried food products that can be produced on a cornmercial scale from used oil that are lower in free fatty acids and lower in polymer that those typically produced from used oil.

CA 022~6314 1998-11-02 W O 97/40703 PCT~US97/07370 Another object is to provide parfried food products that introduce minim~
amounts of contarninants into the fryer during fini~hing thereby extending the fry-life of the edible finish frying oil.
These and other objects of the present invention will be made clear by the disclosure herein.
SUMMARY OF THE INVENTION
In accordance with the present invention, parfried food products comprising a fat component that low in free fatty acid and polymer is provided. Parfried food products low in free fatty acids and low in polymer prepared using a continuous or semi-continuous oil process to replace the parfrying fat is also provided. The parfried food is unique in that it is ~ ,~ed by frying the raw food product in used oil. Additionally, the parfried food can be used to extend the frylife of the finish frying oil by minimi7ing the cont~min~ntc introduced into the finish frying oil during the frying process. The parfried food contains a fat co.lll,onellt comprising less than 0.03% tocopherols comprising from about 0.02% to about 0.8% free fattyacid and from about 0.2% to 10% polymer.
Although the advantages of the invention cannot be realized until the parfried food is converted to a ready-to-eat product, the present invention is concerned primarily with the characteristics of the parfried food product.

DETAILED DESCRIPTION
Definitions As used herein the term "free fatty acid" is intet~ to cover free fatty acids and their common salts.
As used herein the term "used oil" refers to any oil wherein any portion of the oil has been used for frying, is recycled (e.g. filtered, ch~-mic~lly treated, turned over) or wherein the oil is used more than one time.
As used herein the term "parfry" or "parfried product" refers to food products that have been subjected to at least one frying but which have not beencompletely cooked. The frying process can involve baking or otherwise heating the food with an oil coating or by foam frying.
As used herein the term "fini~h~d" or "fini~hing" refers to cooking by ~ frying or an oven baking to convert the food product to a ready-to-eat form. The product may be fini.ch~cl by frying or cooking in a toaster, toaster oven, forced air oven, convection oven, high air velocity oven, hot air impingement oven, infrared oven, combined convection/infrared oven, combined microwave/convection oven or a conventional home oven.

CA 022~6314 1998-11-02 W O 97/40703 PCT~US97/07370 As used herein the term "frying" includes any type of process used to cook food products in a medium such as fats or edible oils.
As used herein the term "semi-continuous oil process" refers to a method wherein one or more times at least a portion of the oil is removed from the frying apl)a~dlus and the removed oil is replaced with fresh oil, used oil or mixtures of fresh and used oil.
As used herein the term "continuous oil process" refers to a method wherein used oil, fresh oil or a mixture of used and fresh oil is continuously circulated to the frying appdldl~ls.
As used herein the term "batch frying" refers to a method of frying wherein the materials to be fried are placed into the frying a~l.aldl~ls at the same time, left there to be fried for the ap~,n)~l;ate amount of time, and are then all removed at the same time, i.e., in a "batch".
As used herein the term "continuous frying" refers to a method of frying wherein the m~t~ lc to be fried are continuously ~ pol~ed by some means through the frying vessel for a period of time sufficient to s~ticf~ctory parfry them and are then removed. As parfried pieces are removed, raw pieces continuously enter the frying appdldllls.
As used herein the term "fat" or "edible oil" refers to edible fatty substances in a general sense, including natural or synthetic fats and oils concicting essçnti~lly of triglycerides, such as, for example soybean oil, corn oil, cottonseed oil, sunflower oil, palmpil, coconut oil, canola oil, fish oil, lard and tallow, which may have been partially or completely hydrogenated or modified otherwise, as well asnon-toxic fatty materials having pl~ ies similar to triglycerides, herein referred to as fat substitutes, which materials may be partially or fully indigestible. The terms "fat" and "oil" are used interchangeably. Rçduçed calorie fats and edible non-digestible fats, oils or fat substitutes are also included in the term.
As used herein "fat component" refers to the fat that is extracted from the breading, batter and/or parfried food product.
As used herein, "polymers" refer to all materials in the frying oil having a higher molecular weight than the triglycerides in the oil.
As used herein the term "tocopherol" refers to alpha-tocopherol, alpha-tocotrienol, beta-tocopherol, plastochromanol-8, garnma-tocopherol, garnma-tocotrienol, delta-tocopherol and delta-tocotrienol. dl- alpha tocopheryl acetate is not included in the use of this term.
- All ~.elcenldges and ratios are by weight unless otherwise indicated.

CA 022~6314 1998-11-02 Food Products The present invention relates to parfried food products, and in particular, parfried potato products suitable for deep frying or oven fini~hing prior to consumption and to a method of exten-ling the fry-life of an edible finish frying oil.
There are many methods taught for making parfried foods. However, it is believed that the art does not teach the production of parfried foods low in free fatty acid and low in polymers produced from used oil. The parfried foods of thepresent invention are foods wherein the level of cont~min~nt~ are reduced. This results in products that when finish fried, helps to extend the fry-life of the edible oil or when oven fini~he~ results in products that are better for human consumption.
The parfried food of the present invention includes any food product that is subjected to frying in edible fats or oils, at any time during its production. Such products, include but are not limited to, potato products (e.g. French fries, hash brown, potato cakes, potato rounds, rissole potatoes, and potato skins), breaded or battered vegetables such as mushrooms, onion rings, cauliflower, 7~lcçhini, and breaded or battered chicken patties, chicken nuggets, fish filets, and the like.Particularly p~r~ d are potato products (i.e. French fries and hash browns).
The food product of the present invention has been partially cooked (i.e., parfried) by a deep frying process or by other means known in the art, such as film frying, or oven frying and generally contain moderate levels of fat or are coated with batters or breading co~ ining fat (e.g. at least about 0.05% by weight). "Fat"
for the purpose of the present invention refers to fat present in the food products which includes naturally present fat" fat added as or to ingredients, or fat absorbed into or on the food from a previous cooking or plep~dlion process. Typically theparfried foods colllpllse from about 0.09% to about 26% fat, preferably from about 3% to about 20% fat, more pltÇ.,I~bly from about 4% to 10% fat.

The Fat Component One embodiment is a parfried food that is p~ ared using a continuous or semi-continuous oil process to replace the parfrying fat comprising a fat component that has two distinct ch~.;l. l;stics: a free fatty acid content less than 0.8% and a polymer content of less than 10%.
The free fatty acid and polymer content of the fat component is obtained by well known analytical methods, the methods of which are set forth below in the Analytical Method portion of the specification.

CA 022~6314 1998-11-02 W 0 97/40703 PCTrUS97/07370 The fat component of the present invention comprises an edible oil. A
variety of used edible fats and oils may be present in the fat component of the food products of the present invention. Used edible fats and oils present in the fat component include but are not limited to beef tallow, lard, butter, margarine, hydrogenated vegetable shortening and oil such as cottonseed oil, canola oil, soybean oil, corn oil, palm oil, fish oil, safflower oil, sunflower oil, coconut oil, peanut oil, olive oil, mediurn chain triglycerides, structured triglycerides cont~ining a combination of short and/or medium chain fatty acids and long chain fatty acids (e.g. Caprenin-like) and the like or combinations thereof. Preferably the edible oils have a low linoleic acid content. Short chain fatty acids can lower the flash point or smoke point of the oil so they are not l~r~ cd.
The used edible oils present in the fat component of the food products of the present invention include natural or synthetic fats and oils. The oils may be partially or completely hydrogenated or otherwise modified. Additionally non-toxic, fatty materials having pl.~pcllies similar to triglycerides such as sucrose polyesters and OleanTM, from the Procter and Gamble Company, and reduced calorie fats, polyol fatty acid polyesters, and diversely esterified polyol polyesters or combinations of regular fats and fat ~l~b~ e~ may also be used herein.
One reduced calorie fat that has been found to be useful comprises a fairly high level (e.g., at least about 85%) of combined MML and MLM triglycerides, where M is typically a mixture of Cg-C 10 saturated fatty acids and L is predomin~ntly behenic acid, but can be C20-C24 . See U.S. Patent 4,888,196 to Ehrman et al., issued December 9, 1989 and U.S. Patent 5,288,512 issued to Seiden, February 22, 1994 for the synthesis and more detailed description of these reduced calorie fats.
The MML, LLM, triglycerides are further characterized by having a fatty acid composition which comprises from about 3S% to about 60% combined Cg-C l o sa~ ed fatty acids, a ratio of C8-C I o saturated fatty acids of from about I :5 to about 25: 1, and from about 35% to about 60% behenic fatty acid.
By "reduced calorie " as used herein is meant fats that provide an at least 10%, and preferably an at least about 30%, reduction in calories relative to corn oil.
The reduction in calories provided by these reduced calorie fats can be determined by studies similar to that described by Peters, J.C. et al., Journal of the American Colle~e of Toxicolo~Y, Vol. 10, No. 3, 1991, pp. 357-367.
By "polyol" is meant a polyhydric alcohol cont~inin~ at least 4, preferably from 4 to 11 hydroxyl groups. Polyols include sugars (i.e., monosaccharides, disaccharides, and tri~cch~rides), sugar alcohols, other sugar derivatives (i.e., CA 022~6314 1998-11-02 W O 97/40703 PCTrUS97/07370 alkyl glucosides), sugar ethers (sorbitan), polyglycerols such as diglycerol andtriglycerol, pentaerythritol and polyvinyl alcohols. Specific examples of suitable sugars, sugar alcohols and sugar derivatives include xylose, arabinose, ribose, xylitol, erythritol, glucose, methyl glucoside, mannose, galactose, fructose, sorbitol, maltose, lactose, sucrose, raffinose, and maltotriose.
By "polyol fatty acid polyester" is meant a polyol having at least 4 fatty acid ester groups. Polyol fatty acid esters that contain 3 or less fatty acid ester groups are generally digested in, and the products of digestion are absorbed from, the intestinAl tract much in the manner of oldil1~y triglyceride fats or oils, whereas those polyol fatty acid esters cont~ining 4 or more fatty acid ester groups are substAntiAlly non-digestible and consequently non-absorbable by the human body.
It is not necessary that all of the hydroxyl groups of the polyol be estPnfied, but it is preferable that disaccharide molecules contain no more than 3 unesterified hydroxyl groups for the purpose of being non-digestible. Typically, subst~ntiAlly all, e.g., at least about 85%, of the hydroxyl groups of the polyol are esterified. In the case of sucrose polyesters, typically from about 7 to 8 of the hydroxyl groups of the polyol are esterified.
The polyol fatty acid esters typically contain fatty acid radicals typically having at least 4 carbon atoms and up to 26 carbon atoms. These fatty acid radicals can be derived from naturally occurring or synthetic fatty acids. The fatty acidradicals can be saturated or ~ulsaluldled, including positional or geometric isomers, e.g., cis- or trans- isomers, and can be the same for all ester groups, or can be mixtures of dir~.el~l fatty acids.
Liquid non-digestible oils have a complete melting point below about 37~C
include liquid polyol fatty acid polyesters (see J~n-lAcek; U.S. Patent 4,005,195;
Issued January 25, 1977); liquid esters of tricarballylic acids (see Hamm; U.S.
Patent 4,508,746; Issued April 2, 1985); liquid diesters of dicarboxylic acids such as derivatives of malonic and succinic acid (see Fulcher; U.S. Patent 4,582,927;Issued April 15, 1986); liquid triglycerides of alpha-l,~dnchcd chain carboxylicacids (see Whyte; U.S. Patent 3,579,548; Issued May 18, 1971); liquid ethers andether esters contAinin~ the neopentyl moiety (see Minich; U.S. Patent 2,962,419;Issued Nov. 29, 1960); liquid fatty polyethers of polyglycerol (See Hunter et al;
U.S. Patent 3,932,532; Issued Jan. 13, 1976); liquid alkyl glycoside fatty acid polyesters (see Meyer et al; U.S. Patent 4,840,815; Issued June 20, 1989); liquid polyesters of two ether linked hydroxypolycarboxylic acids (e.g., citric or isocitric - acid) (see Huhn et al; U.S. Patent 4,888,195; Issued December 19, 1988); liquid esters of epoxide-extended polyols (see White et al; U.S. Patent 4,861,613; Issued CA 022~6314 1998-11-02 W O 97140703 PCTr~S97/07370 August 29, 1989); as well as liquid polydimethyl siloxanes (e.g., Fluid Silicones available from Dow Corning).
The polyol fatty acid polyesters that are liquid have minim~l or no solids at a temperature of 98.6~F (37~C), i.e., body te.n~ldL~lres. These liquid polyol polyesters typically contain fatty acid ester groups having a high proportion of C12 or lower fatty acid groups or else a high proportion of C1g or higher unsaturated fatty acid groups. In the case of those liquid polyol polyesters having high proportions of unsaturated C 18 or higher fatty acid groups, at least about half of the fatty acids incorporated into the polyester molecule are typically unsaturated.
The liquid polyol fatty acid polyesters can be pllp~cid by a variety of methods known to those skilled in the art. These methods include:
tr~ncesterification of the polyol (i.e. sugar or sugar alcohol) with methyl, ethyl or glycerol fatty acid esters using a variety of catalysts; acylation of the polyol with a fatty acid chloride; acylation of the polyol with a fatty acid anhydride; and acylation of the polyol with a fatty acid, per se. See, for example, U.S. Patent Nos.

2,831,854, 3,600,186, 3,963,699, 4,517,360 and 4,518,772, which disclose suitable methods for preparing polyol fatty acid polyesters. Specific, but non -limiting,examples of the plep~alion of liquid polyol polyesters suitable for use in the practice of the present invention are disclosed in Young et al; World Patent Application US91-02394 (publication number W091-15964); published October 31, 1991.
Polyol fatty acid polyesters that are solid at ttlllp~.dl~lres of about 37~C andhigher have the ability to bind high levels of edible liquid non-digestible oils, such as liquid polyol polyesters previously described, when included in appropriate amounts. This capacity to bind liquid non-digestible oils enables these solid polyol polyesters to control or prevent the passive oil loss problem ~soci~te~ with theingestion of such liquid oils.
One preferred class of suitable solid polyol polyesters for use in the liquid/solid blend are those wherein the esters groups comprise a combination of(a) C12 or higher ullsdlu,dled fatty acid radicals, C2-C12 fatty acid radicals or mixtures thereof, and (b) at least about 15% C20 or higher saturated fatty acid radicals, preferably at least about 30%, more preferably at least about 50%, most preferably at least about 80%, long chain saturated fatty acid radicals.
Suitable unsaturated fatty acid radicals contain at least 12, preferably from 12 to 26, more preferably from 18 to 22, most preferably 18, carbon atoms.
Suitable short chain saturated fatty acid radicals contain from 4 to 12, preferably from 6 to 12, and most preferably from 8 to 12, carbon atoms. Suitable long chain CA 022~6314 1998-11-02 W O 97/40703 PCT~US97/07370 saturated fatty acid radicals contain at least 20, preferably from 20 to 26, most preferably 22, carbon atoms. The long chain unsaturated fatty acid radicals can be used singly or in mixtures with each other, in all proportions, as is also the case with the short chain and long chain saturated fatty acid radicals. In addition, straight chain (i.e. normal) fatty acid radicals are typical for the short chain and long chain saturated fatty acid radicals, as well as the long chain unsaturated fatty acid radicals. Exarnples of suitable long chain unsaturated fatty acid radicals for use in these solid polyol polyesters are monounsaturated radicals such as lauroleate, myristoleate, palmitoleate, oleate, el~ te, and erucate, and polyunsaturated radicals such as linoleate, arachidonate, linoleate, eicosape~t~n~ ate, and docosahexaenoate. In terms of oxidative stability, the monounsaturated and diunsaturated fatty acid radicals are prefe.l~d. Examples ofsuitable short chain saturated fatty acid radicals are acetate, butyrate, hexanoate (caproate), octanoate (caprylate), dec~no~te (caprate), and dodec~no~te (laurate).
Exarnples of suitable long chain saturated fatty acid radicals are eicos~no~te (araçhi~t~), docosanoate (behenate), tetraco.s~no~te (lignocerate), and hexacosanoate (cerotate).
Mixed fatty acid radicals from oils which contain substantial amounts of the desired long chain unsaturated fatty acids, short chain saturated fatty acids, or long chain saturated fatty acids can be used as sources of fatty acid radicals in plc~ g the solid polyol polyesters useful in the li~uid/solid blend type of non-digestible fat component. The mixed fatty acids from such oils should preferablycontain at least about 30% (more preferably at least about 50%, most preferably at least about 80%) of the desired long chain unsaturated, short chain saturated orlong chain saturated fatty acids. For example, palm kernel oil fatty acids can be used instead of a mixture of the l~pc~ e pure saturated fatty acids having from 8 to 12 carbon atoms. Similarly, rapeseed oil fatty acids or soybean oil fatty acids can be used instead of a mixture of the respective pure monouns~ ed and polyunsaturated fatty acids having 12 to 26 carbon atoms, and hardened (i.e., hydrogenated) high erucic rapeseed oil fatty acids can be used in place of a mixture of the respective pure long chain saturated fatty acids having from 20 to 26 carbon atoms. Preferably, the C20 or higher saturated fatty acids (or their derivatives, e.g.
methyl esters) are concentrated, for example, by ~ tili~tion An example of source oils for these solid polyol polyesters are high oleic sunflower oil and subst~nti~l~y completely hydrogenated high erucic rapeseed oil. When sucrose is substantially completely esterified with a 1:3 by weight blend of the methyl esters of these two oils, the resulting polyester has a molar ratio of unsaturated Clg acid radicals to CA 022~6314 1998-11-02 W O 97/40703 PCT~US97/07370 saturated C20 or higher acid radicals of about 1:1, the saturated C20 and C22 acid radicals being about 28.6% of the total fatty acid radicals. The higher the proportion of the desired long chain unsaturated/short chain saturated and long chain saturated fatty acids in the source oils used in making the solid polyol polyesters, the more efficient the polyesters will be in their ability to bind the liquid non-digestible oils.
The molar ratio of (a) long chain unsaturated fatty acid radicals or short chain fatty acid radicals or mixtures thereof, to (b) long chain saturated fatty acid radicals, is from about 1:15 to about 1:1. Preferably, this molar ratio of (a) to (b) radicals is from about 1:7 to about 4:4, most preferably from about 1:7 to about3:5.
Examples of solid polyol fatty acid polyesters cont~ining mixtures of (a) and (b) radicals include sucrose tetrabellt n~te t~IIdca~ late, sucrose pentabehenate trilaurate, sucrose hexabehenate dicaprylate, sucrose hexabehenate dilaurate, the sorbitol h~Y~est~r of palmitoleic and arachidic fatty acid radicals in a 1:2 molar ratio, the raffinose octaester of linoleic and behenic fatty acid radicals in a 1:3 molar ratio, the maltose heptaester of a mixture of sunflower oil and lignocericfatty acid radicals in a 3:4 molar ratio, the sucrose octaester of oleic and behenic fatty acid radicals in a 2:6 molar ratio, the sucrose octaester of lauric, linoleic and behenic fatty acid radicals in a 1:3:4 molar ratio, and the sucrose hepta- and octaesters of C 1 8 mono- and/or di-uns~ aled fatty acid radicals and behenic fatty acid radicals in a molar ratio of uns~l~dled:behenic acid radicals of about 1:7 to 3:5.
The fat component of the parfried food comprise a low level of free fatty acid. Free fatty acids are those fatty acids that result from Iypolysis, hydrolysis and oxidation of the edible oil. The type of free fatty acid present in the fat component of the parfried food product will depend on a number of factors such as, the colllposilion of the oil, the type of food being parfried and the parfrying tempe~Iw~,.
Free fatty acid is present in the fat colllp~nent of the present invention in anamount of from about 0.02% to about 0.8% Preferably, the free fatty acid contentis from about 0.04% to about 0.6% and more preferably from about 0.2% to about 0.4%. The amount of free fatty acid includes free fatty acid present in breading, coating, flavoring, oil or any additional ingredients.
The fat component of the parfried food also contains low levels of - polymers. High levels of polymers in the parfried food product are undesirable from a health, taste and textural standpoint. The polymers present in the fat CA 022~6314 1998-11-02 W 0 97/40703 PCTrUS97/07370 Il component include non-polymeric compounds involving the alkoxy radical (e.g.
hydroxy and epoxy acid), dimeric and polymeric acids and dimeric and polymeric glycosides resulting from therrnal and oxidative free radical combinations.
The polymer content of the fat component in the parfried food products of the present invention is from about 0.2% to about 10%. Preferably, the polymer content is from about 0.7% to about 8% and more preferably from about 1% to about 6%.
Another embodiment of the present invention is a parfried food comprising fat component that has three distinct characteristics: a tocopherol content less than 0.03%, a free fatty acid content less than 0.8% and a polymer content of less than 10.0%.
The fat component of the parfried food of the present invention in addition to being low in free fatty acid and polymer can also be low in tocopherol.
Tocopherol is naturally present in vegetable oils and to a small degree, animal fat.
High levels of tocopherol are undesirable in the fat component of the present invention because they can act as prooxidants and because upon oxidation they result in colored products. These colored products can leach into the oil duringfinish frying thereby reducing the frylife of the oil. The parfried food parfried in used oil or parfried in a mixture of used oil and fresh oil, in particularly when there is a high level of used oil, will typically have a low tocopherol content. The amount of tocopherol present is generally less than about 0.03%, preferably lessthan about 0.02%, more p~cf~.~bly less than about 0.01% and even more preferablyless than about 0.005%.
The parfried foods of the present invention or the oil used for parfrying can contain natural antioxidants or commercially available antioxidants. Antioxidants may be naturally present in the food products, may be absorbed from the par-frying oil or used as an ingredient during formulation. Typically antioxidants are added to the food product (raw state) to increase shelf stability and may appear in small amounts after parfrying. However, antioxidants may be added to the parfried foodproducts of the present invention after parfrying since they are typically stored until they are fully cooked (i.e. converted into ready-to eat products).
Low levels of antioxidants can be present or added to the parfrying oil.
Generally, the antioxidants are added during storage of the fresh oils to improve shelf stability. Although antioxidants may serve to delay the onset of oil deterioration (induction period), they have no effect on the rate of free fatty acid - and polymer production once past the induction period and may serve as prooxidants. Once oxidation has reached a certain point and as the oil reaches CA 022~6314 1998-11-02 parfrying telllp~.dLures the antioxidant becomes ineffective and the oil returns to its unprotected state. The products produced by the breakdown of the antioxidants may then form products (e.g. color bodies, free fatty acids, etc.) which accelerate the deterioration of the oil. The period of protection depends on the rate at which the antioxidant is destroyed, the temperature of the oil, the length of time the oil remains at frying temperatures, and other factors.
Antioxidants that may be present or added to the parfried products or used oils include the tocopherols, rosemary, oryzanol (from rice bran oil), sesamol, rice bran oil, nordihydroguaiaretic acid (NDGA), propyl gallate, gallic acid, gum quaiac, butylatedhydroxyanisol (BHA), butylatedhydroxytoluene (BHT), hydroquinone, citric acid, ascorbic acid, mono-tertiarybutylhydroquinone (TBHQ),and mixtures thereof. The antioxidants can be present in the parfried food product at amounts of about 0.01% to about 2% depending on the type of antioxidant used.THBQ and citric acid can be used in combination at levels of from about 0.01% toabout 0.03%, and preferably at 0.02%. BHA and BHT can be combined at levels of from about 0.02% to about 0.05%. Other combinations of antioxidants include THBQ and ascorbyl p~lmit~te and mixed tocopherols( i.e. within the requisite level) with rosemary extract.
The parfried food products of the present invention or the used edible oil may contain low levels of ingredients that are naturally present or are added (as processing aids, through cont~min~tion, etc.). These ingredients, in particular metals, can be deleterious to the stability of the product and to the used edible oil and therefore are not desirable. Examples of these ingredients are phospholipids(e.g. Iecithin), divalent and trivalent metals (e.g., nickel, iron, copper chromiurn) prooxidants (e.g. chlorophyll, phytins), esters, aldehydes, ketones, and hydrocarbons or mixtures thereof. The levels of these materials are preferably below 1% and most preferably are at a level of from 0 to 0.1%. The level of chlorophyll and other phytins should be less than 0.005% and most preferably less than 0.00 01%. For metals the levels should be below 0.0005%, preferably should be less than 0.0001%.

Other In~redients If desired, flavoring agents, such as salt, pepper, butter, onion, or garlic may be added to the parfried food product or the oil used to parfry the parfried food product to enhance the flavor or modify the flavor to any desired taste as long as the tocopherol level, free fatty acid level and polymer level remain within the CA 022~6314 1998-11-02 W 0 97/40703 PCTrUS97/07370 requisite ranges of the present invention. One skilled in the art will readily appreciate that the aforementioned listing of flavoring agents is in no way exhaustive, but is merely suggestive of the wide range of additives which are suitable for use in the practice of the present invention.
Other ingredients known in the art may also be added to the used edible oil.
These ingredients include anti-foaming agents such as dimethylpolysiloxane (DMPS). Although these ingredients may be added, the addition of such ingredients will decrease the frylife of the fini ching oil by introducing low levels of cont~min~ntc into the oil.
A plefel.cd embodiment of the present invention are parfried potato strips known in the art as shoestrings, crinkle cut, regular-cut or steak fries.
The potato strips are bl~n~h~d treated and dehydrated and parfried according to conventional procedures known in the art used to produce conventional par-fries. However, it is critical that the potato strips be fried in used oil having tocopherol, free fatty acid and polymer contents within the range of the present invention. Each of the steps for plepal;llg parfried potato products are well known in the art and ~liccllcsed in detail in the Potato Procecsing, published in 1975 by the A.V.I. Publishing Co., Inc., Westport, Conn., and edited by W.F. Talbert and O. Smith. The potato strips of the present invention have from about 38% to about 70%, preferably from about 40% to about 60%, and more preferably from about 50% to about 55% moisture and from about 4% to about 20%, preferably from about 6% to about 15% and more preferably from about 8% to 10% of a fat component wherein the fat component comprises less than 0.03% tocopherol, from about 0.02% to about 0.8%, preferably from about 0.04% to about 0.6% and more preferably from about 0.2% to about 0.4% free fatty acid, and from about 0.2% to10%, pl~Ç~.dbly from about 0.7% to about 8% and more preferably from about 1%
to about 6% polymer.
Another pl~rellc;d embodiment is hash brown potatoes. Hash brown potatoes are prepared from small whole potatoes or from the by-product material produced from French fry lines. The material is bl~nçhe~l shredded or diced and combined with corn flour, wheat flour, salt and pepper. The hash browns are thenparfried in oil having tocophelol, free fatty acid and polymer contents within the range of the present invention. The hash browns of the present invention have from about 60% to about 70%, preferably from about 62% to about 68% moisture and from about 4% to about 20%, preferably from about 6% to about 15% and - more preferably from about 8% to 10% of a fat component wherein the fat component comprises less than 0.03% tocopherol, from about 0.02% to about CA 022~6314 1998-11-02 O.B%, preferably from about 0.04% to about 0.6% and more preferably from about 0.2% to about 0.4% free fatty acid content and from about 0.2% to 10%, preferably from about 0.7% to about 8% and more preferably from about 1% to about 6%
polymer.

Preparation of the Parfried Food Products The parfried food products of the present invention are unique in that they are capable of being produced on a commercial scale and can be produced from used oil. The food products are parfried in used oil in a continuous, semi-continuous or batch frying method yet they are low in free fatty acid and polymer.
The par-frying may be performed in any appaldl~ls normally used for frying, for example, pans, kettles, and deep-fat frying vessels or vats.
The preferred process used to prepare the parfried products of the present invention combines bleed streaming and simultaneous deodorization of the recycled edible oil so that the edible parfrying oil m~int~in~ a tocopherol content less than 0.03%, a free fatty acid content within the range of from about 0.02% to about 0.8% and a polymer content less than 10%. ~lere.ably the edible oil m~int~in~ a free fatty acid content within the range of from about 0.04% to about 0.2% and a polymer content less than about 6%. Although the process of bleed streaming the oil alone without the use of deodorization may be used it requires the repl~c.~mçnt of subst~nti~lly all of the used oil in order to keep the free fatty acid and polymer content low. This process is wasteful and costly and would not be practical for commercially producing parfried products. Therefore, the method ofbleed streaming alone is undesirable.
In a preferred process raw food or food which has undergone the normal ~l~tl~ nt ~lepal~lion (e.g., peeling, bl~n~hing, dehydration) or battered/breaded products are fried in used oil having less than about 0.03% tocopherol, less than about 0.8% free fatty acid and less than 10% polymer at tel~p~ res of from about 350~F (1 76~C) to about 400~F (204~C). It shall be noted that a portion of the oil has been used. Edible oils suitable for parfrying are described above as the fat component.
During the parfrying of the food product, used oil is removed from the frying a~dlLIs and subjected to deodorization in a deodorization a~cu~ s. The withdrawn oil is replaced with an e~ual portion of freshly deodorized oil.
Simultaneously, fresh or used oil is added at a rate such that the oil in the fryer m~int~in~ a substantially constant volume. Throughout the frying process food isadded and removed. The amount of time needed to partially cook the food product CA 022~6314 1998-11-02 W O 97/40703 PCTrUS97/07370 depends on the specific oil temperature, dimensions of the food product, the batch size, the volume of the frying kettle and the initial moisture content of the food.
This can easily be determine~l by one skilled in the art.
Several methods in combination with the preferred parfrying process may be used to limit the level of free fatty acid and polymer resulting in the fat component of the parfried food product. One method includes limiting the amount of free fatty acid and polymer in the oil used to make batters or breading. It has been found that the batters and breading typically contain from about 0.05% to about 22% fat wherein the free fatty acid level ranges from about 0.15% to about22% and polymer contents range as high as 25%. During finish frying these free fatty acids and polymers tend to leach into the frying medium and act as catalysts thus accelerating the degradation of the edible oil.
Another method when used in combination with the ~ ,fell~d process that helps limit the level of free fatty acid and polymer in the parfried food product include limiting the amount of flavoring and additional ingredients added to theproduct that contain free fatty acid precursors (aldehydes, ketones, esters). It has been found that the flavor components raise the free fatty acid level of the food product. The flavor ingredients can act to catalyze the degradation process of the oil.

Stor~e The parfried, food products of the present invention may be frozen, packaged and stored or shipped for subsequent use. Typical frozen storage temp~"dlllres ranges from about -20 ~F to about 10 ~F. Freezing the parfried food products may be accomplished by methods known in the art. The products may be contacted with a liquid refrigerant which is at a tc;ll~pe~ below 0 ~F, preferably below -20 ~F. One may also use any of the fluorocarbons which exist in the liquid state. Particularly plcfel~,d is the use of liquid nitrogen.
The step of contacting the refrigerant with the parfried food products may be accomplished by dipping the products in a pool of the refrigerant, or by spraying the refrigerant on them. In any case, the time of contact is limited so that preferably only the surface layers of the products become frozen. The time required to achieve the desired degree of freezing will vary depending on such factors as the temperature of the refrigerant, the size of the products etc. Thefreezing may either be a surface freeze or a total freeze. It is not essenti~l that the - surface freeze be accomplished by the use of a liquid refrigerant; one may use a refrigerant in a gaseous state. For example, the parfried products may be subjected W O 97/40703 PCT~US97/07370 to a current of cold air at a temperature below 0 ~F. A convenient method is to use a conventional blast freezer or a high velocity current of air where the products are subjected to a blast of cold air-at a t~ e.dL lre of less than or equal to about -20 ~F. Alternatively, the products may be placed in a freezer co~llp~lment, for example, at -10 ~F, of a suitable size such as a cornmercial or industrial unit.
Method of Extenl~inP the Frv-life of Edible Finish Fryin~ Oil When the parfried food products of the present invention are used during the finish frying process the rate at which total free fatty acid and polymers form in the finish frying oil is subst~nti~lly decreased. It has been found that the parfried food products must have certain characteristics in order to extend the fry-life of an edible finish frying oil. It has further been found that the present method is unlike other methods in that the rate of free fatty acid build-up in the finish frying oil can be reduced and/or delayed as opposed to having to be removed after the frying process. Further, the use of the parfried foods herein do not accelerate the deterioration of oil as is in the case with some chemical treatments. The methodcan be used in a continuous, semi-continuous or a batch frying process. The frying may be ~ olllled in any al,l)~dLus normally used for frying, for exarnple, pans,kettles, and deep-fat frying vessels or vats.
Conventional methods used for frying foods may be used as the finish frying steps of the present invention. What is critical is that the parfried food used in the finish frying ~ dldlllS comprises a fat component having from about 0.02%to about 0.8% free fatty acid and from about 0.2% to about 10% polymer.
The method of the present invention significantly improves the fry-life of the oils used in foodservice lc~duldnts by significantly retarding the rate of degradation of the oil in the frying kettles used to finish fry parfried foods. The method may be used in combination with anti-oxidants or other methods for extçn~ling the fry-life of the oil however the use of such additional methods are not necessary to practice the present invention.
Another method of extending the fry-life of a edible finish frying oil is by using a batch method. In the batch method, par-fried food having the requisite free fatty acid and polymer content enters the finish frying a~p~dl.ls. The finish frying ~l~a,dlus contains edible oil at tel~ dl lres ranging from about 325~ F (163~C) to about 400~ ~(204~C.). The parfried food product remains in the frying ap~dldlllsfor a time sufficient to cook it to a ready-to-eat state. Thereafter, all the food is - removed together at the same time. When using this method the fry-life of the edible finish frying oil lasts 50% longer, preferably about 2 to about 4 times longer CA 022~6314 1998-11-02 W O 97140703 PCT~US97/07370 than the finish frying oils wherein commercially prepared par-fried products areused.
Still another method of extending the fry-life of an edible finish frying oil isby using a continuous frying method. In this method parfried food products having the requisite free fatty acid and polymer content are, and continuously transported using a transporting means through the finish frying oil for a period of time sufficient to satisfactorily fry them to an ready-to-eat state and then they areremoved. As finished fried pieces are removed, parfried pieces having a fat component comprising free fatty acid and polymer within the requisite range continuously enter the edible finish frying oil.

CA 022~6314 1998-11-02 W 0 97/40703 PCTrUS97/07370 Analvtical Methods Extraction of the ~at ComPonent 1. Weigh the parfried food sample and/or batter and/or breading into a 1 liter beaker. Record weight.
2. Add enough petroleum ether/ethyl ether (1:1) to cover sample.
3. Heat sample to a boil on a steam bath for 30 minutes.

4. Remove and vacuum filter sample through Whatman glass microfibre filter paper (11.0 cm).

5. Evaporate filtrate on steam bath under a nitrogen blanket.

6. Transfer to a tarred beaker or flask when the volume is approximately 200 ml.

7. Evaporate to dryness. Let sarnple come to room temperature. Weigh and record weight.
Calculation:
Net wei~ht x 100 = % Fat Sample Wt.

Analysis of Tocols (Tocopherol) in V~etable Oil By Hi~h Performance Liquid Chromato~raphv and Fluorescence Detection The tocopherol content is a measure of tocopherol present in the extracted fat component (described above). This method is suitable for quantification of alpha, beta, g~mm~, delta, tocopherol, plastochromanol-8 (PC-8) and alpha, g~mm~, delta tocotrienols in unhydrogenated and partially hydrogenated vegetableoils (Iodine Value > 30). This method can be applied to used and th~?rrn~lly abused oils.

II. Principle A normal phase High Performance Liquid Chromatography (HPLC) technique using an Arnino bonded column with gradient elution is used to separate prominent tocols in oils. Fluorenscen~ e detection (excitation 295 nm, emmision 330 nm) provides desired selectivity from interferences and permits analysis with no sample cleanup steps. Quantification is based on an internal standard calculation applying relative response factors based on alpha-tocopherol to all tocols. Concentrations are reported as mg tocol / g of oil.

CA 022~6314 1998-11-02 III. Apparatus Spectrophotometer UV (range must include 296 nrn), double or single beam (e.g. Bausch & Lomb Spectronic 2000) UV Cells Quartz, I cm. path, Fisher Scientific, Cat. No.

HPLC System Miniml-m Configuration: Binary Gradient System Detector variable wavelength fluorescence detector, Integrator ~iniml-m Configuration: HP 3396 or equivalent Sample Loop 10 uL
Analytical Colurnn Supelcosil LC-NH2, 5 um, 4.6 mm I.D., 25 cm length, Supelco Cat. No. 5-8338 Guard Colurnn Direct connect guard column, 2.1 mrn I.D., 3.0 cm length, Alltech Assoc. Inc., Cat. No.

Inline Filter Column prefilter, Alltech Assoc. Inc., Cat.
No. 2~689, repl~cement filter element (0.5 um) Alltech Assoc. Inc., Cat. No. 28646 Volumetric flask Class A, 50 mL, 100 rnL
Volurnetric pipets Class A, I rnL, 4 mL, S mL, 7 mL, 10 mL
Gr~d~l~tecl Cylinder 2000 mL, 50 mL
Repipetdispenser 10 mL capacity, Fisher Scientific, Cat. No.

Weighing funnel 1.5 x 4 cm, Fisher Scientific, Cat. No. 14-IV. Re~ent~
d-alpha-Tocopherol F~tm~n Kodak Co., Cat. No. 118 4175, 100 mg, sample sealed under vacuum, must be stored in freezer until use, disposal date one year after received.
Glacial Acetic Acid Baker Analyzed, HPLC grade, J.T. Baker Co., Cat. No. 9515-3 Hexane (W) Burdick & Jackson, W grade, American Scientific, Cat. No. 216-4L

W O 97/40703 PCTrUS97/07370 Isopropanol Burdick & Jackson, American Scientific, Cat.
No. 323-4L
Guard column p~cking Pelliguard LC-NH2, 40 um Supelco, Cat. No.

V. P~e~)~d~ion of Mobile Phase A. Add a stirring bar to a clean 4 liter solvent bottle. ~ill with 100%
hexane. This is mobile phase A.
B. Pipet S mL of glacial acetic acid into a 100 mL volumetric flask.
Dilute to volume with hexane.
C. Add 200 mL of isopropanol into the 2000 mL (I mL per liter) of the acetic acid solution made in B. Transfer the solution to a 4 liter solYent bottle. Add stirring bar and mix well. This is a mobile phase B.
D. Label both bottles carefully degass by helium sparging. Mobile phase is stable for at least two weeks if kept tightly capped.

Vl. Plcpalalion of the lnternal Standard Solution A. SynthPsi7lo the internal standard 2,2,5,7,8-pentamethyl-6-hydroxychroman (PMHC). The prepared PMHC should be stored in a desiccator in the freezer.
B. Weigh 0.02 g + 0.0001 g of PMHC into a weighing funnel and 4u~~ alively transfer to a 100 mL volumetric flask with hexane.
Dilute to volume with hexane.
C. 1.0 mL of this solution is used for each sample.

VII. ~ ion of Calibration Standards A. Weigh 0.0100 g + 0.0002 g of alpha-tocopherol into a weighing funnel and quantitatively rinse into a 100 mL volumetric flask with hexane. Dilute to volume with hexane.
B. The calibration standards are ~ al~d from the following dilutions of the stock solution in hexane:
1 mL to 50 mL 0.02 mg / 10 mL
4mLto50mL 0.08mg/lOmL
7mLto 50mL 0.14mg/ lOmL
- lOmLto50mL 0.20mg/ 10mL

CA 022~6314 1998-11-02 W O 97/40703 PCT~US97/07370 C. Accurately pipet 5 mL of the internal standard solution into each flask. Dilute to volume with hexane.
D. Zero the UV at 296 nrn with hexane. Fill the sample cell with the stock solution plep~d in A and record the absorbance.

VIII. P~)~a~ion of Oil Samples A. Gently melt the sample and shake well to make homogeneous.
B. Accurately weigh 0.25 to 0.35 grams (+ 0.0001 g) of the oil sample into a 4 drarn vial.
C. Accurately pipet 2 mL of internal standard into each of the vials.
Add approximately 8.5 mL of hexane to each of the vials via the Repipet dispenser.
D. Gentle warrning of the solution may be necessary to dissolve the fat sample. If heated, allow the solution to come to room temperature before injection onto the HPLC.
IX. Instrument Pararneters 1. Detector Excitation wavelength: 295 nm Emmision wavelength: 330 nm Attenuation:
Gain: x100 Filter: 1.5 sec.
Detector Output: lV/AUFS

2. Gradient Prograrn Time %A %B
0.00 90 10 10.0 55 45 12.0 90 10 20.0 90 10 Flow Rate: 2.0 mL / min.
3. Injection: 10 uL

X. Inte~ration Typical integration pararneters for a HP 3396 are:
- Attenuation (ATT 2) = 6 (approx. 2mV full scale) Peak Width= 0.04 minlltes CA 022~6314 1998-11-02 W O 97/40703 PCT~US97/07370 Threshold= 3 Area ReJect = 100 counts These parameters can be used as a starting point. Actual pararneters will be a function of the specific equipment used.

XI. Calculations Concentration of the alpha-tocopherol calibration stock solution:
alpha-Tocopherol Concentration (g/100 rnL) = ABS 296 / 86.5 Concentration calculations are based on the following internal standard calculation:
Tocol Concentration (mg / g) =
Tocol Area- Y-intercept x I x 1 x RRF
PMHC Area Slope SampleWeight Slope and Y-i~llc~ are obtained through a least squares linear regression equation of the ration of responses (Tocol:PMHC) vs alpha-tocopherol concentration (mg / 10 mL) for the standards prepared under "P~ lion of Standards". Relative response factors (RRF) are multipliers that relate the response of the individual tocol species to the response of alpha-tocopherol (given below).
Tocol Species RRF

alpha-tocopherol 1.00 alpha-tocotrienol1.00 beta-tocopherol 0.63 plastochromanol-80.66 gamma-tocopherol 0.66 gamma-tocotrienol0.66 delta-tocopherol0.5 1 delta-tocotrienol0.5 1 CA 022~6314 1998-11-02 Free Fatty Acid Titration The free fatty acid content is a measure of free fatty acid present in the e~tracted fat component (described above).

A. Reagents 1. Ethyl alcohol - 3A. Titrated to the phenolphthalein endpoint with 0.1N sodiurn hydroxide solution.
2. Sodium hydroxide - 0. lN or 0.25N.
3. Phenolphthalein - 0.5% in alcohol.
B. Apparatus 1. Balance - torsion.
2. Magnetic stirrer. Labline Magnestir, or equivalent.
3. Stirring bars. Magnetic, 0.25 in. O.D. x 1.5 in. Iength, Teflon-covered.
4. Buret. Digital - 25 ml., Fisher Cat. #03-840. Adapter set to fit solution bottle - Fisher Cat. #13-688-106.
5. pH meter. ~eç~m~n Expandomatic IV pH Meter.
6. Electrode. Combination - Orion Cat. #910400/Fisher Cat. #14-641-681.
C. Reference Standard A reference standard, lauric acid (4.5 g.) dissolved in white mineral oil (1335 g.), is run with each group of samples. The results are con.l)~ed with the known value for the reference standard to determine the accuracy of the sample results.
D. Titration 1. Weigh approximately 50 g. of sample into a 250 ml. Erlenmeyer flask to the nearest 0.01 g. Weigh a 15 g. sample of the lauric acid Iefelcllce standard.
2. Add 50 ml. of hot neutralized 3A alcohol to the melted sample in the flask. Note: Sample should be heated only long enough to liquefy before the titration. Overhe~ting increases the possibility of hydrolysis occurring and a consequent elevation of the free fatty acid content.
3. Add about 0.5 ml of phenolphthalein indicator to the sample.
Titrate the sample with the 0.1N NaOH solution. For light-colored - samples, titrate while stirring until a very pale pink color is evident in the stirring emulsion. For dark samples, titrate until the alcohol CA 022~6314 1998-11-02 layer, when allowed to separate, is pale pink (color should persist for at least 30 seconds). Occasionally the free fatty acid content of an a~l,ale,ltly fresh sample is quite high. If 50 g. of sample titrates over 10 ml. with 0.1N NaOH, titrate it with 0.25N NaOH. For very high free fatty acid-glyceride mixtures, it may be neces~ry to weight 10 g. of sample and titrate with 0.25N NaOH.
5. Record the titration volume (T).

E. Calculation:

T x N 28.2 Sample Weight (g) Where: T = sample titration in ml. of NaOH
N = normality of NaOH
28.2 = millequivalent weight of oleic acid x 100 Method for Measurin~ Polymers The polymer content is measured in the extracted fat colllpollent (described above). High performance size exclusion chromatography (HPSEC) is the method used for measuring these materials. HPSEC is a high performance liquid chromatography (HPLC) technique which separates molecules according to their size instead of their bonding ~lo~ ies~ as conventional HPLC does.
A 3% solution of the sample of frying oil in tetrahydrofuran (THF) is prepared and filtered through a 0.45 micron filter. Twenty microliters of this sample solution is injected into an HPLC system equipped with one 60 cm x 7.5 mm 500A Porosity, 5-~1m column from Polymer Laboratories. The HPLC detector consists of a refractive index detector (RI) which can detect any compound that has an RI value different from that of the mobile phase. THF is the mobile phase.
HPSEC conditions: THF flow rate--1.0 ml/min.; injection loop--20 ~1; RI detectorset at 8X. The sample solution is injected, a chromatogram is obtained, and the peak areas for the high molecular weight materials, the triglycerides, and the low molecular weight materials are obtained.
Calculations:
~ p I AreaofPolymerPeak(s) 100 Total Area of All Peaks CA 022~6314 1998-11-02 W O 97/40703 PCTrUS97/07370 The following examples illustrate various aspects of the present invention.
They are not intended to limit the claims.

Whole raw potatoes are washed, peeled, cut into shoestring potato strips, and blanched in water and steam at l~ p~lalules of about 1 70~F (77~C) for about 7 minlltes Thereafter, about 390 Ibs. of potatoes are parfried per hour in 1460 Ibs. of edible oil having an average free fatty acid level of 0.17% and an average polymer level of 5.6%. During the frying of the product, about 230 Ibs. per hour of edible oil is withdrawn from the frying al)paldllls and subjected to deodorization in adeodorization a~ s. The withdrawn oil is replaced with a su~stantially equal portion of freshly deodorized oil. Simultaneously about 30 Ibs. per hour of fresh edible oil is added as make-up oil for the amount of oil absorbed by the fried food product. Throughout the frying process potato strips are added and removed. The par-fries are removed after about 70 seconds of frying in the used oil. The resulting parfries comprise a fat component having 0.17% free fatty acid about 5.6% polymer and 0.002% tocopherol.
A comparison was made (Table I) between par-fries of the present invention (p~p~ed according to Example I) against par-fries typically sold to fast food restaurant owners (processed according to conventional methods). It is evident that the commercial products differ significantly from the product of the present invention. The fat colllpollent was extracted and analyzed according themethods described herein.
TABLE I
FROZEN PRODUCTS (AS SOLD) PRODUCT INVENTION I Collll.,c.cially 2Cornmercially Produced Par- Produced Par-fries fries % FFA 0.17 15 1.1 % POLYMER 5.6 9.4 10.3 I Commercially available par-fries from Simplot.
2Commercially available par-fries from Lamb-Wesson.

CA 022~6314 1998-11-02 W 0 97/40703 PCT~US97/07370 ~XAMPLE 2 Raw potatoes are peeled cut into strips, blanched at about 170~F (77~C) in a combination of hot water and steam, and dried at about 225~ F (107~C). The raw potatoes are then placed in a perforated tray and fried in hot oil m~int~in~l at0.0050% tocopherol, 0.25% free fatty acid and 3% polymer, at a temperah re of about 370~ F (188~C). The frying process is carried out in about 95,000 Ibs. of edible oil. Potato strips are continuously fed into the fryer at rates of about 400 Ibs.
per hour and fried for about 60 seconds. Fresh make-up oil is added at a rate ofabout 27 Ibs. per hour.
The recl~lting par-fries have a fat conll)olicl,t having a free fatty acid content of about 0.25%, a polymer content of about 3% and a tocopherol content of about 0.005%.
The resulting parfries when fini.ched by deep frying in fat at a t~ pclal~Ire of about 370~ F (188~C) have been found to give up to 50% or more added frying life to the finish frying oil when compared to the fry-life of finish frying oilwherein conventional parfried food products are fint~h~fl A 50 Ibs. frying kettle is used for frying mixed menu items, i.e. French fried potato strips and hash brown potatoes. The kettle is filled with fresh vegetable oil which is a mixture of soybean oil (80%), corn oil (20%), about 0.015% TBHQ as an antioxidant and about 0.0006% dimethylpolysiloxane to control fo~ming. The oil is heated to a tell~ "alulc of about 360~F (182~C). ConL-nercially produced hash brown potatoes having a fat component comprising I % free fatty acid and 7%polymer p,epalcid by parfrying in soybean oil with about 0.0006 dimethylpolysiloxane (15 Ib. per day in batches of about 1/2 Ib. each) are fried to a ready-to-eat state (to a moisture content of about 50%) and removed from the kettle. The oil used for frying the hash brown potatoes is then cooled to a tt;l~ , of about 335~F (168~C) and then 104 Ibs of col,~ cially produced parfried French fried potato strips having a fat component comprising 1.2% free fatty acid and 9.4% polymer are fried in 1.6 Ib. Iots to a ready-to-eat state ( to a moisture content of about 38%). The oil is then held at 168~C for about 4 hours. It is then cooled, filtered, topped off with fresh oil, and allowed to sit overnight. The next day the kettle is heated, and the frying cycle is continued.
The free faty acid and polymer content of the finish frying oil was monitored for an entire frying cycle. The free fatty acid content and polymer - content reached an unacceptable level in about 11 days.

W O 97/40703 PCTrUS97/07370 When the process is repeated, using only parfried food products having a free fatty acid content less than 0.2% and a polymer content less than about 10%the fry-life of the fini~hing oilis extended to a period of 17 days or more.

Claims (30)

What is claimed:

1. A parfried food product comprising a fat component wherein said fat component comprises, from about 0.02% to about 0.8% free fatty acid, from about 0.2% to 10.0% polymer and less than about 0.03% tocopherol, the parfried food product being prepared by frying raw food in used oil.

2. The parfried product of Claim 1 further comprising a fat component having less than 0.02% tocopherol.

3. The parfried food product of Claim 1 wherein the free fatty acid content in the fat component is from about 0.04% to about 0.6%.

4. The parfried food product of Claim 3 wherein the free fatty acid content in the fat component is from about 0.04% to about 0.6%.

5. The parfried food product of to Claim 4 wherein the polymer content in the fat is from about 0.7% to about 8%.

6. The parfried products of Claim 5 wherein the parfried product is a potato product or a battered food or a breaded food.

7. The parfried food product of Claim 6 wherein the parfried product a shoestring potato or a hash brown potato.

8. The parfried food product of Claim 5 wherein the batter or breaded food is battered or breaded chicken of fish.

9. A parfried food product prepared by frying raw food in oil comprising from about 0.02% to about 0.8% free fatty acid, from about 0.2% to about 10% polymer and less than 0.03% tocopherol.

10. The parfried food product of Claim 9 wherein the parfried product a shoestring potato or a hash brown potato.

11. The parfried food product of Claim 9 wherein the batter or breaded food is battered or breaded chicken of fish.

12. A parfried food product having a fat component comprising from about 0.02% to about 0.8% free fatty acid and from about 0.2% to about 10% polymer, the parfry food product having been prepared by frying a raw food product in a frying apparatus comprising an edible oil and wherein at least a portion of the edible oil in the frying apparatus is removed and is replaced with fresh or used oil.

13. A parfried food product having a fat component comprising from about 0.02% to about 0.8% free fatty acid and from about 0.2% to about 10% polymer, the parfry food product having been prepared by frying a raw food product in a frying apparatus comprising an edible oil selected from the group consisting of used oil, fresh oil or a mixture thereof and wherein the fresh oil, used oil or mixture is continuously circulated to the frying apparatus.

14. A parfried shoestring potato prepared by frying in raw potatoes in used oil,said shoestring potato comprises:
a) from about 38% to about 70% moisture; and b) from about 4% to about 8% of a fat component;
said fat component comprises less than about 0.03% tocopherol, from about 0.02%
to about 0.8% free fatty acid and from about 0.2% to 10.0% polymer.

15. The parfried potato of Claim 7 wherein the free fatty acid content in the fat component is from about 0.2% to about 0.4%.

16. A parfried hash brown potato prepared by frying raw hash brown potatoes in used oil, said hash brown potatoes comprise:
a) from about 38% to about 70% moisture; and b) from about 4% to about 8% fat component;
said fat component comprises less than 0.03% tocopherol, from about 0.02% to about 0.8% free fatty acid and from about 0.2% to 10.0% polymer.

17. The parfried product of Claim 2 further comprising a fat component having less than about 1% prooxidants selected from the group consisting of metal ions,chlorophyll, phytins and mixtures thereof.

18. The parfried product of Claim 1 further comprising a fat component having less than about 1% contaminants selected from the group consisting of phospholipids, sodium and potassium soaps and mixtures thereof.

19. The parfried food product of Claim 2 having a moisture of less than about 70%.

20. The parfried products of Claim l further comprising a fat component having an antioxidant wherein said antioxidant is selected from the group consisting of THBQ, citric acid, BHA, BHT, tocopherols, rosemary extract and mixtures thereof.

21. A method for extending the life of an edible oil during finish frying comprising continuously contacting the edible oil with parfried food products having a fat component comprising from about 0.02% to about 0.8% free fatty acidand from about 0.2% to about 10% polymer.

22. The method of Claim 21 wherein the fat component further comprises less than about 0.03% tocopherol.

23. The method of Claim 21 wherein said parfried food products are selected from the group consisting of potato products, breaded or batter vegetable or breaded or battered meats.

24. The method of Claim 23 wherein said parfried food products are French fries, hash browns, breaded or battered onion rings, or breaded or battered chicken.

25. The method of Claim 1 wherein said edible oil further comprises anti-oxidants, chelating agents, anti-foaming agents or mixtures thereof.

26. The method of Claim 22 wherein said edible oil is selected from the group consisting of soybean oil, corn oil, cottonseed oil, sunflower oil, palm oil, coconut oil, canola oil, fish oil, lard, tallow, partially hydrogenated soybean oil, partially hydrogenated corn oil, partially hydrogenated cottonseed oil, partially hydrogenated sunflower oil, partially hydrogenated palm oil, partially hydrogenated coconut oil, partially hydrogenated canola oil, partially hydrogenated fish oil and mixtures thereof.

27. The method of Claim 1 wherein said edible oil is selected from the group consisting of nondigestible oils and reduced calorie oils.

28. The method of Claim 27 wherein said oil is selected from the group consisting of polyol fatty acid polyesters and triglycerides of medium chain fatty acids and long chain fatty acids.

29. The method of Claim 21 further comprising an antioxidant wherein said antioxidant is selected from the group consisting of tocopherols, sesamol, nordihydroguaiaretic acid (NDGA), propyl gallate, gallic acid, gum quaiac, butylatedhydroxyanisol (BHA), butylatedhydroxytoluene (BHT), hydroquinone, citric acid, ascorbic acid, mono-tertiarybutylhydroquinone (TBHQ), rosemary extract, ascorbyl palmitate, oryzanol, and mixtures thereof.

30. The method of Claim 21 wherein the polymer content in the fat is from about 0.7% to about 6%.