Classifications

• • A—HUMAN NECESSITIES
  • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
  • A23L—FOODS, FOODSTUFFS OR NON-ALCOHOLIC BEVERAGES, NOT OTHERWISE PROVIDED FOR; PREPARATION OR TREATMENT THEREOF
  • A23L19/00—Products from fruits or vegetables; Preparation or treatment thereof
  • A23L19/10—Products from fruits or vegetables; Preparation or treatment thereof of tuberous or like starch containing root crops
  • A23L19/12—Products from fruits or vegetables; Preparation or treatment thereof of tuberous or like starch containing root crops of potatoes
  • A23L19/18—Roasted or fried products, e.g. snacks or chips
• • A—HUMAN NECESSITIES
  • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
  • A23L—FOODS, FOODSTUFFS OR NON-ALCOHOLIC BEVERAGES, NOT OTHERWISE PROVIDED FOR; PREPARATION OR TREATMENT THEREOF
  • A23L5/00—Preparation or treatment of foods or foodstuffs, in general; Food or foodstuffs obtained thereby; Materials therefor
  • A23L5/10—General methods of cooking foods, e.g. by roasting or frying
  • A23L5/11—General methods of cooking foods, e.g. by roasting or frying using oil

Definitions

• 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 example, 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 preparing the food for serving.
• parfried foods are prepared in edible oil that is used repeatedly.
• the oil is generally maintained at temperatures of from about 290°F (143°C) to about 400°F (204°C) for prolonged periods.
• Continuous frying at high temperatures 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.
• FFA free fatty acids
• parfried food absorb the oil in which it is fried, the resulting parfried food is high in free fatty acid and polymer.
• 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.
• the oil present in the parfried food contaminates the finish frying oil and reduces the length of time the oil can be used for frying.
• Parfried foods produced from fresh oil will generally have a fat component having a free fatty acid content lower than about 0.02% 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 the fresh oil used to fry the food product.
• 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 commercial 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.
• 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.
• an object of the present invention to provide parfried food products that can be produced on a commercial scale from used oil that are lower in free fatty acids and lower in polymer that those typically produced from used oil. Another object is to provide parfried food products that introduce minimal amounts of contaminants into the fryer during finishing thereby extending the fry ⁇ life of the edible finish frying oil.
• parfried food products comprising a fat component that low in free fatty acid and polymer.
• 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 prepared 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 minimizing the contaminants introduced into the finish frying oil during the frying process.
• the parfried food contains a fat component comprising less than 0.03% tocopherols comprising from about 0.02% to about 0.8% free fatty acid and from about 0.2% to 10% polymer.
• the present invention is concerned primarily with the characteristics of the parfried food product.
• free fatty acid is intended to cover free fatty acids and their common salts.
• used oil refers to any oil wherein any portion of the oil has been used for frying, is recycled (e.g. filtered, chemically treated, turned over) or wherein the oil is used more than one time.
• parfry or “parfried product” refers to food products that have been subjected to at least one frying but which have not been completely cooked.
• the frying process can involve baking or otherwise heating the food with an oil coating or by foam frying.
• the term “finished” or “finishing” refers to cooking by frying or an oven baking to convert the food product to a ready-to-eat form.
• the product may be finished 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.
• frying includes any type of process used to cook food products in a medium such as fats or edible oils.
• 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 apparatus and the removed oil is replaced with fresh oil, used oil or mixtures of fresh and used oil.
• 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 apparatus.
• batch frying refers to a method of frying wherein the materials to be fried are placed into the frying apparatus at the same time, left there to be fried for the appropriate amount of time, and are then all removed at the same time, i.e., in a "batch".
• continuous frying refers to a method of frying wherein the materials to be fried are continuously transported by some means through the frying vessel for a period of time sufficient to satisfactory parfry them and are then removed. As parfried pieces are removed, raw pieces continuously enter the frying apparatus.
• fat or "edible oil” refers to edible fatty substances in a general sense, including natural or synthetic fats and oils consisting essentially of triglycerides, such as, for example soybean oil, corn oil, cottonseed oil, sunflower oil, palmxnl, coconut oil, canola oil, fish oil, lard and tallow, which may have been partially or completely hydrogenated or modified otherwise, as well as non-toxic fatty materials having properties similar to triglycerides, herein referred to as fat substitutes, which materials may be partially or fully indigestible.
• fat substitutes non-toxic fatty materials having properties similar to triglycerides
• the terms “fat” and “oil” are used interchangeably. Reduced calorie fats and edible non-digestible fats, oils or fat substitutes are also included in the term.
• fat component refers to the fat that is extracted from the breading, batter and/or parfried food product.
• polymers refer to all materials in the frying oil having a higher molecular weight than the triglycerides in the o ; ⁇
• tocopherol refe ⁇ alpha-tocopherol, alpha- tocotrienol, beta-tocopherol, plastochromanol-8, g ⁇ .nma-tocopherol, garnma- tocotrienol, delta-tocopherol and delta-tocotrienol. dl- alpha tocopheryl acetate is not included in the use of this term.
• the present invention relates to parfried food products, and in particular, parfried potato products suitable for deep frying or oven finishing prior to consumption and to a method of extending the fry-life of an edible finish frying oil.
• parfried foods 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 the present invention are foods wherein the level of contaminants are reduced. This results in products that when finish fried, helps to extend the fry-life of the edible oil or when oven finished, 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, zucchini, and breaded or battered chicken patties, chicken nuggets, fish filets, and the like.
• 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 containing 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 preparation process.
• the parfried foods comprise from about 0.09% to about 26% fat, preferably from about 3% to about 20% fat, more preferably from about 4% to 10% fat.
• One embodiment is a parfried food that is prepared using a continuous or semi-continuous oil process to replace the parfrying fat comprising a fat component that has two distinct characteristics: 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.
• 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, medium chain triglycerides, structured triglycerides containing 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.
• 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 preferred.
• 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.
• non ⁇ toxic, fatty materials having properties similar to triglycerides such as sucrose polyesters and Olean , 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 substitutes 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-Cin saturated fatty acids and L is predominantly 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 35% to about 60% combined Cg- C ⁇ 0 saturated fatty acids, a ratio of Cg-CjQ saturated fatty acids of from about 1 :5 to about 25:1, and from about 35% to about 60% behenic fatty acid.
• 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 College of Toxicology, Vol. 10, No. 3, 1991, pp. 357-367.
• polyol is meant a polyhydric alcohol containing at least 4, preferably from 4 to 11 hydroxyl groups.
• Polyols include sugars (i.e., monosaccharides, disaccharides, and trisaccharides), sugar alcohols, other sugar derivatives (i.e., alkyl glucosides), sugar ethers (sorbitan), poiyglycerols such as digiycerol and triglycerol, pentaerythritol and polyvinyl alcohols.
• 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.
• 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 ordinary triglyceride fats or oils, whereas those polyol fatty acid esters containing 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 esterified, but it is preferable that disaccharide molecules contain no more than 3 unesterified hydroxyl groups for the purpose of being non-digestible.
• substantially all, e.g., at least about 85%, of the hydroxyl groups of the polyol are esterified.
• 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 acid radicals can be saturated or unsaturated, 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 different fatty acids.
• Liquid non-digestible oils have a complete melting point below about 37°C include liquid polyol fatty acid polyesters (see Jandacek; 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-branched chain carboxylic acids (see Whyte; 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 August 29, 1989
• liquid polydimethyl siloxanes e.g., Fluid Silicones available from Dow Corning
• the polyol fatty acid polyesters that are liquid have minimal or no solids at a temperature of 98.6°F (37°C), i.e., body temperatures.
• These liquid polyol polyesters typically contain fatty acid ester groups having a high proportion of C j 2 or lower fatty acid groups or else a high proportion of C 18 or higher unsaturated fatty acid groups.
• fatty acid ester groups having a high proportion of C j 2 or lower fatty acid groups or else a high proportion of C 18 or higher unsaturated fatty acid groups.
• at least about half of the fatty acids inco ⁇ orated into the polyester molecule are typically unsaturated.
• the liquid polyol fatty acid polyesters can be prepared by a variety of methods known to those skilled in the art. These methods include: transesterification 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 preparation 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 WO91 -15964); published October 31, 1991.
• Polyol fatty acid polyesters that are solid at temperatures of about 37°C and higher 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 associated with the ingestion of such liquid oils.
• esters groups comprise a combination of (a) Cj2 or higher unsaturated 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 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.
• straight chain i.e.
• 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.
• suitable long chain unsaturated fatty acid radicals for use in these solid polyol polyesters are monounsaturated radicals such as lauroleate, myristoleate, palmitoleate, oleate, elaidate, and erucate, and polyunsaturated radicals such as linoleate, arachidonate, linoleate, eicosapentaenoate, and docosahexaenoate.
• the monounsaturated and diunsaturated fatty acid radicals are preferred.
• Suitable short chain saturated fatty acid radicals are acetate, butyrate, hexanoate (caproate), octanoate (caprylate), decanoate (caprate), and dodecanoate (laurate).
• suitable long chain saturated fatty acid radicals are eicosanoate (arachidate), docosanoate (behenate), tetracosanoate (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 preparing the solid polyol polyesters useful in the liquid/solid blend type of non- digestible fat component.
• the mixed fatty acids from such oils should preferably contain 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 or long chain saturated fatty acids.
• palm kernel oil fatty acids can be used instead of a mixture of the respective pure saturated fatty acids having from 8 to 12 carbon atoms.
• rapeseed oil fatty acids or soybean oil fatty acids can be used instead of a mixture of the respective pure monounsaturated 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.
• the C20 °r higher saturated fatty acids or their derivatives, e.g. methyl esters
• An example of source oils for these solid polyol polyesters are high oleic sunflower oil and substantially completely hydrogenated high erucic rapeseed oil.
• the resulting polyester has a molar ratio of unsaturated C ] g acid radicals to 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 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.
• this molar ratio of (a) to (b) radicals is from about 1 :7 to about 4:4, most preferably from about 1 :7 to about 3:5.
• solid polyol fatty acid polyesters containing mixtures of (a) and (b) radicals include sucrose tetrabehenate tetracaprylate, sucrose pentabehenate trilaurate, sucrose hexabehenate dicaprylate, sucrose hexabehenate dilaurate, the sorbitol hexaester 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 lignoceric fatty 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, lino
• 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 lypolysis, 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 composition of the oil, the type of food being parfried and the parfrying temperature.
• Free fatty acid is present in the fat component of the present invention in an amount of from about 0.02% to about 0.8% Preferably, the free fatty acid content is 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 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 thermal 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%.
• 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 during finish 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 less than about 0.02%, more preferably less than about 0.01% and even more preferably less 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.
• antioxidants are added to the food product (raw state) to increase shelf stability and may appear in small amounts after parfrying.
• antioxidants may be added to the parfried food products of the present invention after parfrying since they are typically stored until they are fully cooked (i.e. converted into ready-to eat products).
• antioxidants can be present or added to the parfrying oil.
• the antioxidants are added during storage of the fresh oils to improve shelf stability.
• 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 parfrying temperatures 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% to about 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 palmitate 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 contamination, 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.
• these ingredients are phospholipids (e.g. lecithin), divalent and trivalent metals (e.g., nickel, iron, copper chromium) 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
• the levels should be below 0.0005%, preferably should be less than 0.0001%.
• 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 requisite ranges of the present invention.
• 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 requisite ranges of the present invention.
• 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 finishing oil by introducing low levels of contaminants into the oil.
• DMPS dimethylpolysiloxane
• a preferred 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 blanched, treated and dehydrated and parfned 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 preparing parfned potato products are well known in the art and discussed in detail in the Potato Processing, 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% to 10%, preferably from about 0.7% to about 8% and more preferably from about 1% to about 6% polymer.
• Hash brown potatoes are prepared from small whole potatoes or from the by-product material produced from French fry lines. The material is blanched, shredded or diced and combined with corn flour, wheat flour, salt and pepper. The hash browns are then parfned in oil having tocopherol, 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 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 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.
• 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 apparatus 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 maintains 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%.
• the edible oil maintains 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%.
• raw food or food which has undergone the normal pretreatment preparation (e.g., peeling, blanching, 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 temperatures of from about 350°F (176°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.
• used oil is removed from the frying apparatus and subjected to deodorization in a deodorization apparatus.
• the withdrawn oil is replaced with an equal portion of freshly deodorized oil.
• fresh or used oil is added at a rate such that the oil in the fryer maintains a substantially constant volume.
• food is added and removed. The amount of time needed to partially cook the food product 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 determined by one skilled in the art.
• 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 about 22% 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 preferred 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 the product 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.
• the parfried, food products of the present invention may be frozen, packaged and stored or shipped for subsequent use. Typical frozen storage temperatures 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 temperature below 0 °F, preferably below -20 °F.
• a liquid refrigerant which is at a temperature below 0 °F, preferably below -20 °F.
• One may also use any of the fluorocarbons which exist in the liquid state. Particularly prefe ⁇ ed 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.
• 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.
• the freezing may either be a surface freeze or a total freeze. It is not essential that the surface freeze be accomplished by the use of a liquid refrigerant; one may use a refrigerant in a gaseous state.
• the parfried products may be subjected to a cu ⁇ ent of cold air at a temperature below 0 °F.
• a convenient method is to use a conventional blast freezer or a high velocity cu ⁇ ent of air where the products are subjected to a blast of cold air at a temperature of less than or equal to about -20 °F.
• the products may be placed in a freezer compartment, for example, at -10 °F, of a suitable size such as a commercial or industrial unit.
• the rate at which total free fatty acid and polymers form in the finish frying oil is substantially 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 method can be used in a continuous, semi-continuous or a batch frying process. The frying may be performed in any apparatus normally used for frying, for example, pans, kettles, and deep-fat frying vessels or vats.
• the parfried food used in the finish frying apparatus 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 restaurants 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 extending 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.
• par-fried food having the requisite free fatty acid and polymer content enters the finish frying apparatus.
• the finish frying apparatus contains edible oil at temperatures ranging from about 325° F (163°C) to about 400° F(204°C).
• the parfried food product remains in the frying apparatus for a time sufficient to cook it to a ready-to-eat state. Thereafter, all the food is removed together at the same time.
• the fry-life of the edible finish frying oil lasts 50% longer, preferably about 2 to about 4 times longer than the finish frying oils wherein commercially prepared par-fried products are used.
• Still another method of extending the fry-life of an edible finish frying oil is by using a continuous frying 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 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.
• Net weight x 100 % Fat Sample Wt.
• 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, gamma, delta, tocopherol, plastochromanol-8 (PC-8) and alpha, gamma, delta tocotrienols in unhydrogenated and partially hydrogenated vegetable oils (Iodine Value > 30). This method can be applied to used and thermally abused oils.
• HPLC High Performance Liquid Chromatography
• Spectrophotometer UV range must include 296 nm
• double or single beam e.g. Bausch & Lomb Spectronic
• Guard Column Direct connect guard column 2.1 mm I.D.
• Volumetric flask Class A 50 mL, 100 mL Volumetric pipets Class A, 1 mL, 4 mL, 5 mL, 7 mL, 10 mL Graduated Cylinder 2000 mL, 50 mL Repipet dispenser 10 mL capacity, Fisher Scientific, Cat. No.
• PMHC 2,2,5,7,8-pentamethyl-6- hydroxychroman
• the calibration standards are prepared from the following dilutions of the stock solution in hexane: lmLto50mL 0.02mg/10mL
• Emmision wavelength 330 nm
• alpha-Tocopherol Concentration (g/100 mL) ABS 296 / 86.5 Concentration calculations are based on the following internal standard calculation:
• Slope and Y-intercept 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 "Preparation 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
• the free fatty acid content is a measure of free fatty acid present in the extracted fat component (described above).
• HPSEC 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 properties, 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- ⁇ m 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 ⁇ l; RI detector set 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.
• Whole raw potatoes are washed, peeled, cut into shoestring potato strips, and blanched in water and steam at temperatures of about 170°F (77°C) for about 7 minutes. Thereafter, about 390 lbs. of potatoes are parfried per hour in 1460 lbs. of edible oil having an average free fatty acid level of 0.17% and an average polymer level of 5.6%.
• about 230 lbs. per hour of edible oil is withdrawn from the frying apparatus and subjected to deodorization in a deodorization apparatus. The withdrawn oil is replaced with a substantially equal portion of freshly deodorized oil. Simultaneously about 30 lbs. per hour of fresh edible oil is added as make-up oil for die amount of oil absorbed by the fried food product.
• 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.
• 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 maintained at 0.0050% tocopherol, 0.25% free fatty acid and 3% polymer, at a temperature of about 370° F (188°C).
• the frying process is carried out in about 95,000 lbs. of edible oil.
• Potato strips are continuously fed into the fryer at rates of about 400 lbs. per hour and fried for about 60 seconds. Fresh make-up oil is added at a rate of about 27 lbs. per hour.
• the resulting par-fries have a fat component 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 finished by deep frying in fat at a temperature 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 oil wherein conventional parfried food products are finished.
• a 50 lbs. 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 foaming.
• the oil is heated to a temperature of about 360°F (182°C).
• Commercially produced hash brown potatoes having a fat component comprising 1% free fatty acid and 7% polymer prepared by parfrying in soybean oil with about 0.0006 dimethylpolysiloxane (15 lb. per day in batches of about 1/2 lb.
• 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 temperature of about 335°F (168°C) and then 104 lbs of commercially 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 lb. lots 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.
• the fry-life of the finishing oil is extended to a period of 17 days or more.

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• Chemical & Material Sciences (AREA)
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• Nutrition Science (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Food Science & Technology (AREA)
• Polymers & Plastics (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Edible Oils And Fats (AREA)
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• 1997
  • 1997-05-02 EP EP97922600A patent/EP0906032A1/de not_active Withdrawn
  • 1997-05-02 AU AU28228/97A patent/AU2822897A/en not_active Abandoned
  • 1997-05-02 CA CA002256314A patent/CA2256314A1/en not_active Abandoned
  • 1997-05-02 JP JP9539230A patent/JPH11508149A/ja active Pending
  • 1997-05-02 WO PCT/US1997/007370 patent/WO1997040703A1/en not_active Ceased
  • 1997-05-02 BR BR9709757A patent/BR9709757A/pt not_active Application Discontinuation
  • 1997-05-02 CN CN97195172A patent/CN1220581A/zh active Pending

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