HUP9902819A2 - Straw potatoes covered in oil, partially baked - Google Patents

Abstract

Oil-enrobed par-fried potato strips for oven finishing, comprise: (a) 34-58 % bulk moisture; and (b) 8-30 % total fat. The potato strips have a uniform surface coating of fat in amount 2-15 wt. % relative to the strips.

Description

66*.

S.B.G. & K.

International

PUBLICATION

Patent Office H-1062 Budapest, Andrássy út 113. Telephone: 34-24-950, Fax: 34-24-323

COPY

Oil-coated, partially baked straw potatoes

The invention relates to oil-coated, and in particular frozen, oil-coated, partially baked potato cubes which, when finished in the oven, have a crispy surface layer and a moist inner core. The finished straw potatoes have essentially the same taste, quality and characteristics as straw potatoes deep-fried in fat.

French fries are one of the most popular foods. Most fast food restaurants serve fried French fries, commonly called "straw fries," in bulk, from commercial suppliers in the form of partially fried (partly fried French fries) and frozen French fries, which are stored under frozen conditions until shortly before serving. The partially fried French fries are then prepared for consumption by frying in fat or oil. Frozen, partially fried French fries can also be purchased by the consumer for pan-frying, deep-frying, or baking.

Fast food restaurants are widely adopting frozen, partially baked chips instead of fresh chips due to the convenience and labor cost savings they provide. The use of frozen, partially baked chips is also convenient for the consumer who purchases them for home use. Some people insist on the method of making chips from fresh potatoes.

Most restaurants, including large restaurant chains, prefer to produce their potato chips from frozen or frozen partially baked product, typically deep-fried and then formed into a finished product. Although oven-formable, partially baked potato chips are currently available, they have the disadvantage that when baked, they result in soft, stringy potato chips that do not resemble deep-fried potatoes in texture or flavor.

The two most important characteristics of deep-fried straw potatoes are the moisture of the interior and the crispiness of the crust. Well-textured straw potatoes have moderately crispy outer surfaces and are not overly oily. The interior is also well-cooked, soft, floury, and free of stringiness.

Suppliers of frozen, partially baked potato chips have proposed several solutions to improve the crispiness of oven-finished straw potatoes. “Most methods for producing finished fried straw potatoes require coating the partially baked potato chips with stiffening agents, such as modified starches, gums, alginates, calcium salts, and the like. See, for example, U.S. Patent Nos. 5,000,970 and 5,302,410. Another method requires coating the surface of the partially baked straw potatoes with oil or fat, such as U.S. Patent No. 3,865,964. The results obtained with such surface treatment methods have been only of limited success.

The main problem with oven-finished straw potatoes is that they do not have the texture of a good quality oil-baked straw potato. In particular, a texture with the same internal moisture surrounded by a crispy yet soft outer surface or "crust" has not been achieved on a large scale. Although in the past oil or fat coatings have been applied to the surface of partially baked straw potatoes, the oven-finished straw potatoes produced from these are usually soft and sticky or dry and hard. This can be the result of a number of reasons; for example, the specific moisture and fat content of the partially baked straw potatoes may not have been optimized for a desired texture during oven-finished forming, the required moist interior may be lost during processing, or the crust area may become sticky due to the inability of water to escape during baking.

We were surprised to find that partially baked straw potatoes coated with oil/fat, with controlled specific moisture content, internal moisture content and fat content, resulted in straw potatoes with essentially optimized taste, color and texture properties.

The production of oil-coated potato chips is known in the art, as disclosed. However, the present invention provides a significant improvement in the texture of oven-formed potato chips.

The invention enables the production of deep-fried potato chips in the oven with the taste and texture of deep-fried potato chips. In another aspect, the invention is based in part on the surprising discovery that pre-coated, partially fried potato chips should have a certain specific moisture level. In another aspect, the invention is based on the fact that the partially fried potato chips are coated on the surface with a characteristic amount of fat or oil.

Accordingly, the invention provides partially baked potato cubes coated with a surface fat or oil coating that, when finished in the oven, closely resembles the texture and flavor of deep-fried fast food fries.

Another object of the invention is to provide an oven-prepared product that produces a very tasty, crispy potato straw product with a soft, moist interior.

Still another object of the invention is frozen, partially baked potato chips which can be formed in a fast food restaurant oven or in the consumer's home and are virtually indistinguishable from fried potato chips.

The invention relates to oil-coated potato cubes suitable for oven-baking, which:

(a) partially fried potato chips having a specific moisture content of about 34-58%; and (b) containing about 8-30% total fat;

the partially fried potato chips have a substantially uniform coating of oil or fat, wherein the surface coating is about 2-15% by weight of the partially fried potato chips.

When finished in the oven, the potato chips are truly indistinguishable from industrially produced straw potatoes fried in fat, such as McDonald's straw potatoes.

The invention relates to oil-coated, partially baked potato chips. 829/ΒΞ cubes, and in particular to frozen oil-coated, partially baked potato chips suitable for final shaping in an oven prior to consumption. Although the invention is applicable to a variety of ready-to-heat processes, it is particularly applicable to toasters, toaster ovens, forced air ovens, convection ovens, high-velocity ovens, hot air reflection ovens, infrared ovens, combined convection/infrared ovens, combined microwave/convection ovens and conventional domestic ovens. The potato chips of the invention, when final shaping in an oven, have the taste and texture of deep-fried straw potatoes.

As used herein, the term "partially fried straw potatoes" or "partially fried potato chips" refers to potato chips that have been subjected to at least one frying process (e.g. frying) but are not fully fried.

‘Oven-topping’ refers to baking the product in a toaster, toaster oven, forced air oven, convection oven, high-speed oven, hot air convection oven, infrared oven, combination convection/infrared oven, combination microwave/convection oven or a conventional domestic oven.

As used herein, the term "finished product" refers to a product that has been subjected to a baking process to convert it into a ready-to-eat state. The advantages of the invention will obviously not be realized until the oil-coated partially baked straw potatoes are baked in an oven.. \ by finishing, for example in a forced air convection oven, a combined infrared/forced air convection oven or a conventional domestic oven. This does not mean that the final baking step necessarily forms part of the invention, which is primarily directed to the characteristics of partially baked straw potatoes.

As used herein, the terms "fat" or "edible oil" generally include natural or synthetic fats and oils consisting essentially of triglycerides, such as soybean oil, corn oil, cottonseed oil, sunflower oil, palm oil, coconut oil, canola oil, fish oil, lard and tallow, which may be partially or fully hydrogenated or otherwise modified, as well as non-toxic fatty substances having properties similar to triglycerides, referred to herein as fat substitutes, which may be partially or fully indigestible. The terms "fat" and "oil" are used interchangeably. The term also includes reduced calorie fats and edible, non-digestible fats, oils or fat substitutes.

As used herein, the term "coated" means a substantially uniform coating on the surface of the partially baked potato chips. The coating may also be discontinuous (i.e., globules or droplets).

The term "conditioned oil" refers to oil that has been previously used for frying for so long that it has developed a fried flavor.

In the entry, multiply all percentages, ratios, or fractions by

66.829/ΒΞ » - ♦·?« . * * ·· ·* * are expressed in meg, unless otherwise stated.

Pre-coated potato chips

The pre-coated partially baked potato chips can be prepared according to the conventional treatment in most partially baked potato chip production processes. The pre-coated partially baked potato chips can be prepared from either raw potatoes or pre-baked or pre-baked and frozen potato chips. A known raw potato variety suitable for making chips (e.g., Russet Burbank) is washed, peeled, and cut to size according to conventional practice and cut to the size and shape commonly used for chips, such as shoestring chips, wavy-cut chips, and straight-cut thick chips. After crushing, the chips can be washed to remove surface starch.

In the practice of the invention, potato cubes known in the art as "shoe laces" are preferably used. Shoe lace potato cubes, as used herein, correspond to potato cubes having a cross-sectional area of about 1.21 to 2.02 cm ² and a length of about 6.35 to 12.7 cm.

Other potato cubes useful in the present invention are known in the art as "wave cut cubes." Such cubes typically have an average cross-sectional area of about 2.02 to 3.23 cm ² and a length of about 5.08 to 10.16 cm.

Thick, straight-cut potato wedges (also called regular-cut) with a cross-section of about 2.02 to 3.23 cm ² and a length of about 6.35 to 12.7 cm may also be used. Larger potato wedges of the type suitable for "meat-cut" potatoes may also be used. These potato wedges are typically about 1.27 x 2.22 cm rectangular in cross-section.

The potato chips are precooked according to conventional methods known in the art. This is done to inactivate enzymes and remove excess free sugars from the chopped chip surfaces. The chips are typically cooked by immersing them in hot water at about 140-200°F (60-93.3°C) for 3-20 minutes, depending on the chip size. Alternatively, the chips can be precooked in steam at atmospheric pressure for about 2-10 minutes.

Following pre-cooking, the potato chips may be treated according to conventional methods known in the art. For example, the potato chips may be subjected to further immersion in water to further wash away excess sugar or sodium acid pyrophosphate (SAPP), a chelating agent, may be applied to the surface of the chips to prevent discoloration of the chips. Dextrose (corn sugar) may also be applied to the surface of the chips to achieve a desired level of brown color development during subsequent treatment. Other treatments known in the art may also be used.

After pre-cooking and any optional treatments described above, the potato chips are drained and optionally dehydrated to reduce their moisture content. During dehydration of the chips, the moisture content is typically reduced to a point where the chips lose about 10-30%, preferably about 15-20%, of their initial weight. Any of the conventional drying methods used in the production of partially baked potato chips can be used, for example, the potato chips are dried in hot air at temperatures between about 65.6°C and 176.7°C.

66.829/ΒΞ for approximately 5-20 minutes. Microwave or radiofrequency drying can also be used.

The precooked potato chips can then be immersed in a cooking oil for a period of time to produce partially fried potato chips having a specific moisture content of about 38-58%. Shoelace cut potato chips typically have a specific moisture content of about 40-56%. The potato chips preferably have a moisture content of about 42-54%, more preferably about 44-50%. These partially fried potato chips contain about 6-25%, preferably about 8-22%, more preferably about 10-20%, and most preferably about 12-18% total fat. This can be achieved by immersing the potato chips in oil at a temperature of about 132-196°C, for example. Of course, the immersion time depends on the typical oil temperature, the dimensions of the potato cubes, the batch size, the volume of the fryer and the initial moisture content of the potato cubes. This can be determined by a specialist. Other techniques, such as heated oil spraying, which surrounds the potato cubes with hot oil or frying using oil foam, can also be used.

Thicker cut potato wedges (such as straight, regular cut or wavy cut and "meat-cut" straw potatoes) can be baked to slightly higher moisture contents. Regular and wavy cut partially baked straw potatoes (2.02-3.23 ^cm2 cross-section) can be baked to approximately 40-60% specific moisture content; and meat-cut potato wedges (1.27 x -.2z cross-section) can be baked to approximately 42-62% moisture content.

In a preferred embodiment of the invention, the potato chips to be coated are pre-partially fried and frozen. The pre-coated partially fried chips are commercially produced and can be subjected to multiple treatment steps (i.e., partial frying and freezing, multiple partial frying and freezing). The only limitations are that the pre-coated partially fried potato chips meet the desired specific moisture content and fat content.

After partial frying, the potato chips can be coated with oil immediately or cooled or frozen prior to coating. Cooling or freezing of partially fried potato chips can be accomplished by methods known in the art. For example, the partially fried potato chips can be subjected to a stream of cold air at a temperature of less than about -29°C or the chips can be immersed in a liquid coolant, such as liquid nitrogen. Conventional cooling methods can be used. It is preferred that the partially fried potato chips be cooled rapidly, i.e. within 20 minutes, preferably within 5 minutes, after completion of partial frying.

Surface coating/cladding

In order to ensure that the outer crust is similar to that of deep-fried straw potatoes, it is necessary to coat the surface of the partially baked potato cubes with a cooking oil. The surface coating can be applied directly to the partially baked potato cubes after removal from the oven or to the partially baked potato cubes that are frozen, refrigerated, or at room temperature.

The fat compositions used to coat or coat partially baked potato chips 66 . ser' ΞΞ can be applied to the surface of the potato chips by dipping, dipping, spraying, blowing, pouring, pan coating (e.g., in a rotating pan), shake coating, rotating a fat composition in a container, falling film processes, encapsulation, and curtain coating. The edible, liquefied fat is preferably applied as a substantially uniform coating by spraying the liquid fat onto the surface of the partially baked potato chips or by dipping the partially baked potato chips into the liquid fat. The coating may be continuous or intermittent as long as the distribution is uniform.

The following oil spraying technique can be used to achieve an oil content on the surface of the potato chips in the range of about 2-15% by weight of the partially baked potato chips. The oil is maintained at a temperature of about 21-93°C, preferably about 37.8-82.2°C, and more preferably about 48.9-71.1°C. The spray nozzles are arranged to apply the oil uniformly to the partially baked potato chips in a single layer, whether the oil is atomized or simply sprayed in fine droplets during spraying. The rate of application of the oil, determined by the volume of oil sprayed and the amount of partially baked potato chips to be sprayed, is preferably such that the weight of the partially baked potato chips increases by about 2-15% after spraying.

It is important to keep the fat in a substantially liquid state to allow for the application of a sufficient and uniform coating. The application of fat or oil prior to final shaping in the oven is critical to ensuring a product with the traditional deep-fried potato straw texture.

Edible oils

A variety of edible fats and oils can be used to coat and fry the surface of the partially fried potato chips. Suitable edible fats and oils for use include, but are not limited to, beef tallow, lard, cottonseed oil, canola, soybean oil, corn oil, palm oil, fish oil, safflower oil, sunflower oil, coconut oil, peanut oil, medium chain triglycerides, structured triglycerides containing a combination of short or medium chain fatty acids and long chain fatty acids (e.g., caprenin-like), and the like, or combinations thereof. The oils can be conditioned or flavored as desired, see "Flavored Vegetable Oils as a Substitute for Beef Tallow in Deep Frying Applications, Food Technology, pp. 90-94 (1989) and U.S.P. 5,104,678.

The edible fat or oil used to fry and coat the surface of the partially fried potato chips has a free fatty acid content of about 0.8% or less.

Edible oils used for frying or coating partially fried potato chips can be natural or synthetic fats and oils. The oils can be partially or fully hydrogenated or otherwise modified. In addition, non-toxic fatty materials having properties similar to triglycerides, such as sucrose polyesters and OLEAN™ from Procter & Gamble, and reduced-calorie fats, polyol fatty acid polyesters and cross-esterified polyol polyesters or combinations of regular fats and fat substitutes can also be used in the invention. Reduced-calorie fats, polyol fatty acid polyesters and cross-esterified polyol polyesters or combinations of regular fats and fat substitutes can also be used in the invention.

A useful reduced calorie fat contains a relatively high amount (e.g., at least about 85%) of combined MML and MLM triglycerides, where M is typically a mixture of saturated fatty acids having 8-10 carbon atoms and L is predominantly behenic acid, but can also be 20-24 carbon atoms. See U.S.P. 4,888,196 and U.S.P. 5,288,512 for a synthesis and more detailed description of these reduced calorie fats.

MML, LLM triglycerides can further be characterized by a fatty acid composition comprising about 35-60% combined C8-10 fatty acids — the ratio of C8-10 fatty acids being between about 1:5 and 25:1 — and about 35-60% behenic acid.

As used herein, "reduced calorie" refers to fats that provide a calorie reduction of at least about 10%, and preferably at least about 30%, compared to corn oil. The calorie reduction provided by these reduced calorie fats can be determined by studies such as those described by Peters, J.C. et al. in Journal of the American College of Toxicology, 10 3, pp. 35736 (1991).

"Polyol" means a polyhydric alcohol containing at least 4, preferably 4-11, hydroxyl groups. Polyols include sugars (i.e. monosaccharides, disaccharides and trisaccharides), sugar alcohols, other sugar derivatives (i.e. alkyl glucosides), polyglycerols such as diglycerol and triglyceride, pentaerythritol and polyvinyl alcohols. Typical examples of suitable sugars, sugar alcohols and sugar derivatives are xylose, arabinose, ribose, xylitol, erythritol, glucose, methyl glucoside, mannose, galactose, fructose, sorbitol, maltose, lactose, sucrose, raffinose and maltotriose.

"Polyol fatty acid polyester" means a polyol containing at least 4 fatty acid ester groups. Polyol fatty acid polyesters containing 3 or fewer fatty acid ester groups are generally digested in the small intestine in the manner of ordinary triglyceride fats or oils and the products of digestion are absorbed, whereas polyol fatty acid polyesters containing 4 or more fatty acid ester groups are substantially indigestible and consequently are not absorbed by the human body. It is not necessary that all of the hydroxyl groups of the polyol be esterified, but for the purpose of indigestibility it is preferred that the disaccharide molecules contain no more than 3 unesterified hydroxyl groups. Typically, substantially all of the hydroxyl groups, i.e. at least about 85% of the hydroxy groups of the polyol, are esterified. In the case of sucrose polyesters, typically about 7-8 of the hydroxy groups of the polyol are esterified.

Polyol fatty acid esters typically contain fatty acid groups of at least 4 carbon atoms and up to 26 carbon atoms. These fatty acid groups may be naturally occurring or synthetic fatty acids66,329. ΞΞ blind. These fatty acid groups may be saturated or unsaturated, including positional or geometric isomers, such as cis or trans isomers, and may be the same for all ester groups or mixtures of different fatty acids.

Liquid, non-digestible oils with a total melting point below about 37°C include liquid polyol fatty acid polyesters (see U.S.P. 4,005,195); liquid esters of liquid tricarballylic acids (see U.S.P. 4,508,746); liquid diesters of dicarboxylic acids, such as malonic acid and succinic acid derivatives (see U.S.P. 4,582,927); liquid triglycerides of α-branched carboxylic acids (see U.S.P. 3,579,548); liquid ethers and ether esters containing a neopentyl group (see U.S.P. 2,962,419); polyglycerol liquid fatty acid polyethers (see U.S.P. 3,932,532); liquid alkyl glucoside fatty acid polyesters (see U.S.P. 4,840,815); liquid polyesters of diether-linked hydroxy polycarboxylic acids (e.g., citric acid or isocitric acid) (see U.S.P. 4,888,195); liquid esters of epoxide-extended polyols (see U.S.P. 4,861,613); all of which patents are incorporated herein by reference; and liquid polydimethylsiloxanes (e.g., liquid silicones available from Dow Corning).

Liquid polyol fatty acid polyesters contain minimal or no solids at 37°C, i.e., body temperature. These liquid polyol polyesters typically contain fatty acid ester groups having a high proportion of fatty acid groups having 12 carbon atoms or less or having a high proportion of other unsaturated fatty acid groups having 18 carbon atoms or more. For liquid polyol polyesters having a high proportion of unsaturated fatty acid groups having 18 carbon atoms or more, at least half of the fatty acids in the polyester molecule are typically unsaturated.

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 itself. See, for example, U.S.P. 2,831,854,

Nos. 600,186, 3,963,699, 4,517,360 and 4,518,722, all of which are incorporated herein by reference, which disclose suitable processes for preparing polyol fatty acid polyesters. Representative, but non-limiting, examples of the preparation of liquid polyol polyesters suitable for use in the practice of the invention are disclosed in WO91-15964, published October 31, 1991, which is incorporated herein by reference. The liquid polyol polyesters may contain behenic acid.

At temperatures of about 37°C and above, solid polyol fatty acid polyesters are capable of sequestering large amounts of liquid non-digestible edible oils, such as the liquid polyol polyesters disclosed above, when incorporated in appropriate amounts. This capacity to sequester liquid non-digestible oils allows these solid polyol polyesters to control or prevent the problem of passive oil loss associated with the digestion of such liquid oils.

Differently esterified polyol polyesters

A preferred group of solid polyol polyesters suitable for use in liquid/solid mixtures are those materials in which the ester groups comprise a combination of (a) unsaturated fatty acid groups of 12 carbon atoms or greater, fatty acid groups of 4 to 12 carbon atoms, or mixtures thereof, and (b) at least about 15%, preferably at least about 30%, more preferably at least about 50%, most preferably at least about 80%, saturated fatty acid groups of 20 carbon atoms or greater, long chain saturated fatty acid groups.

Suitable unsaturated fatty acid groups have at least 12, preferably 12-26, more preferably 18-22, most preferably 18 carbon atoms. Suitable short-chain saturated fatty acid groups have 4-12, preferably 6-12 and most preferably 8-12 carbon atoms. Suitable long-chain saturated fatty acid groups have at least 20, preferably 20-26, most preferably 22 carbon atoms. The long-chain unsaturated fatty acid groups can be used alone or in mixtures with each other in all proportions, the same is true for short-chain and long-chain saturated fatty acid groups. In addition, straight-chain (i.e. normal) fatty acid groups are characteristic of short-chain and long-chain saturated fatty acid groups6 6 . S 2 ? Ξ Ξ as well as long-chain unsaturated fatty acid groups. Suitable long chain unsaturated fatty acid groups for use in these solid polyol polyesters include monounsaturated groups such as lauroleate, myristoleate, palmitoleate, oleate, elaidate and erucate, and polyunsaturated groups such as linoleate, arachidonate, linoleate, eicosapentaenoate and docosahexaenoate. Monounsaturated and diunsaturated fatty acid groups are preferred in terms of oxidative stability. Suitable short chain saturated fatty acid groups include acetate, butyrate, hexanoate (caproate), octanoate (caprylate), decanoate (caprate) and dodecanoate (laurate). Suitable long chain saturated fatty acid groups include eicosanoate (arachidate), docosanoate (behenate), tetracosanoate (lignocerate) and hexacosanoate (cerotate).

In the preparation of solid polyol polyesters for use in the non-digestible fat component liquid/solid mixture type, the source of fatty acid groups may be mixed fatty acid groups derived from oils containing substantial amounts of the desired long-chain unsaturated fatty acids, short-chain saturated fatty acids, or long-chain saturated fatty acids. The mixed fatty acids derived from such oils 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. For example, palm kernel oil fatty acids may be used in place of a mixture of the desired pure saturated fatty acids having 8 to 12 carbon atoms. Similarly, rapeseed oil fatty acids 66.829/ΒΞ vakat or soybean oil fatty acids may be used in place of a mixture of the respective pure, monounsaturated and polyunsaturated fatty acids of 12-26 carbon atoms, and hardened (i.e., hydrogenated) high erucic rapeseed oil fatty acids may be used in place of a mixture of the respective pure, long-chain saturated fatty acids of 20-26 carbon atoms. The saturated fatty acids of 20 carbon atoms or greater (or derivatives thereof, such as methyl esters) are preferably concentrated, for example by distillation. Oil sources for these solid polyol polyesters include, for example, high oleyl sunflower oil and substantially fully hydrogenated high erucic rapeseed oil. When sucrose is substantially completely esterified with a 1:3 weight ratio of methyl esters of these two oils, the resulting polyester has a molar ratio of unsaturated C18 acid groups to saturated C20 or higher acid groups of about 1:1, with saturated C20 and C22 acid groups accounting for about 28.6% of the total fatty acid groups. The higher the proportion of long chain unsaturated/short chain saturated and long chain saturated fatty acids required in the oil source used to prepare the solid polyol polyesters, the more effective the polyesters will be in their ability to bind liquid undigested oils.

The molar ratio of (a) long chain unsaturated fatty acid groups or short chain fatty acid groups or mixtures thereof to (b) long chain saturated fatty acid groups is from about 1:15 to 1:1. This molar ratio of (a) to (b) is preferably from about 1:7 to 4:4, most preferably from about 1:7 to 3:5.

66.62= ΞΞ

Solid fatty acid polyesters containing groups (a) and (b) are, for example, sucrose tetrabehenate tetracaprylate, sucrose pentabehenate trilaurate, sucrose hexabehenate dicaprylate, sucrose hexabehenate dilaurate, sorbitol hexaester of palmitic and arachis fatty acid groups in a 1:2 molar ratio, raffinose octaester of linoleic and behenic fatty acid groups in a 1:3 molar ratio, maltose heptaester of sunflower oil and lignoceric fatty acid groups in a 3:4 molar ratio, sucrose octaester of oleic and behenic fatty acid groups in a 2:6 molar ratio, sucrose octaester of lauric, linoleic and behenic fatty acid groups in a 1:3:4 molar ratio and mono- and/or di-unsaturated fatty acids with 18 carbon atoms. groups and behenic fatty acid groups in a molar ratio of about 1:7 to 3:5 sucrose hepta- and -octaesters.

Coating parameters

The cooking oil is applied to the surface of the partially fried potato chips in an amount sufficient to prevent rapid evaporation of moisture from the interior during the cooking process in the oven. A typical amount applied to coat the surface of the partially fried potato chips is typically about 2-15%, preferably about 3-12%, and more preferably about 4-10% oil by weight of the partially fried potato chips.

The oil-coated, partially baked potato chips (shoelace cut) have a specific moisture content of about 34-54% prior to frying. The shoelace cut, oil-coated partially baked potato chips preferably have a specific moisture content of about 35-52%, more preferably about 38-5Cz and even more preferably about 40-48%. Furthermore, the oil-coated partially baked potato chips contain about 8-30% total fat prior to frying, with the surface fat being about 2-15% by weight of the partially baked potato chips. The oil-coated partially baked straw potatoes contain about 10-28%, more preferably about 12-26% and even more preferably about 16-24% total fat prior to frying.

Thicker cut, oiled, partially baked potato wedges may have slightly higher moisture content. For example, regular and wavy cut, oiled, partially baked straw potatoes (0.79 x 1.27 cm cross-section) have a specific moisture content of approximately 3656%; and straw potatoes for meatloaf (1.27 x 2.22 cm cross-section) may have a moisture content of approximately 38-58%.

After coating the partially baked potato chips, the oil-coated, partially baked potato chips can be frozen, packaged, and stored or shipped for later use. Typical freezing temperatures are between about -28.9 and -12.2°C. Freezing the oil-coated, partially baked potato chips can be accomplished by methods known in the art. The chips can be contacted with a liquid refrigerant having a temperature below -17.8°C, preferably below -28.9°C. Any fluorocarbon that exists in a liquid state can be used. Liquid nitrogen is particularly preferred.

The contact of the coolant with the oil-coated, partially fried potato chips can be accomplished by immersing the chips in a coolant bath or by spraying the coolant onto them. In either case, the contact time is limited so that only the surface layers of the chips are preferably frozen. The time required to achieve the required degree of freezing will vary depending on factors such as the temperature of the coolant, the size of the potato chips, etc. Freezing can be superficial or complete. It is not essential that the surface freezing be accomplished using a liquid coolant; a gaseous coolant can also be used. The oil-coated, partially fried potato chips can be exposed to a cold air stream at a temperature below -17.8°C, for example. A convenient method is to use a conventional air-flow freezer or high-velocity air flow freezer, where the potato chips are subjected to a cold air stream at a temperature of about -28.9°C or below. Alternatively, the potato chips may be placed in a suitably sized freezer compartment, such as a commercial or industrial unit, at, for example, -23.3°C.

However, freezing can be ruled out and the coated, partially baked potato cubes can be immediately finished in the oven without freezing.

Oven-baking

The cooking time and temperature of pre-formed potato chips in the oven will vary depending on the quantity of chips, their initial temperature, the specific type of oven and the cooking conditions used (e.g. temperature, air speed) and the thermal properties of the oil-coated, partially cooked potato chips. Of particular importance are the thermal conductivity of the low-moisture crust area, the thermal conductivity of the high-moisture inner starch matrix core and the partially cooked potato chips.

66.829/ΞΞ heat transfer coefficient. In general, higher thermal conductivities and higher surface heat transfer coefficients result in faster heat transfer from the oven to the potato chips, resulting in reduced cooking time. Since one of the objects of the invention is a rapid food production process for quickly forming frozen potato chips into a ready-to-cook oven, these properties are particularly important. The required thermal conductivities at the oven temperature of the low moisture crust region in the oil-coated, partially baked potato chips are between about 0.1 and 0.3 watts/m°C. The required thermal conductivities at the oven temperature of the high moisture core region in the oil-coated, partially baked potato chips are between about 0.40.7 watts/m°C. The thermal conductivities of the crust region can be adjusted to the required range by controlling the moisture and fat content of the crust.

The surface heat transfer coefficient of oil-coated, partially baked potato chips is a function of the artificial air velocity, air temperature, and the nature of the oil film on the surface of the potato chips. Higher surface heat transfer coefficients are desirable because they generally result in faster cooking times and a more distinct and crispier low-moisture crust area in the finished potato chips. At the oven temperature of oil-coated, partially baked potato chips, the required surface heat transfer coefficient is approximately cC--00 watts/m²C. The surface heat transfer coefficient is _οθ.. fried straw potatoes with cooking oil. following The temperature of the air increases, which increases the heat transfer from the surrounding air to the surface of the potato chips. The surface of the potato chips can also be modified to improve the absorption of heat radiated from the oven. A typical method for achieving this is to change the color, porosity, and/or reflectivity of the surface. Increasing the air velocity in the oven at the surface of the potato chips also increases the surface heat transfer coefficient. The air velocity in the oven should be high enough to achieve a satisfactory heat transfer coefficient, but not so high as to strip the coating oil from the surface.

Oven-baked fries are golden brown and crispy on the outside and moist on the inside. The baked fries are very similar in color, texture, mouthfeel and flavor to commercial fries prepared by frying in fat, such as McDonald's™.

Additional components

Flavoring agents, such as salt, pepper, butter, onion, or garlic, may be added to the oil to enhance the flavor or modify the flavor to any desired taste. One skilled in the art will readily recognize that the foregoing list of flavoring agents is far from exhaustive, but is merely exemplary of the wide range of additives suitable for use in the practice of the invention.

Other ingredients known in the art, including antioxidants such as TBHQ, chelating agents such as citric acid, and antifoaming agents such as dimethyl polysiloxane, may also be included in the edible fats and oils used to fry the partially fried potato chips.

The primary advantage of the invention is that it is ready-made in the oven

66.829. BE provides partially baked potato chips with excellent texture and flavor.

Another advantage of the invention is that the straw potato maker is able to produce straw potatoes with excellent texture when ready to bake. In commercial operations, partially baked potato cubes are often fried in oil to obtain a desired texture. As a result of the invention, final frying is completely unnecessary because the crispy crust and moist interior of the straw potatoes ready to bake are practically indistinguishable from straw potatoes prepared by frying in oil. In addition to the structural advantage, the invention also provides the manufacturer with an economic advantage. It should be emphasized that one of the major expenses incurred by the straw potato maker is the amount spent on frying oil.

Although specific preferred treatments are disclosed to facilitate understanding of the invention, functional equivalents may be substituted or additional components may be added without departing from the spirit or essential characteristics of the invention.

The methods for determining the specific moisture content and total fat content of partially fried potato chips and partially fried potato chips coated with oil are given as follows:

The methods for determining the moisture content and total fat content of partially fried potato chips and oil-coated, partially fried potato chips are as follows:

Determination of specific moisture content Moisture content is determined using an artificial air flow drying oven method as follows:

1. In a blender or conventional food processor, grind a representative sample of potato chips or straw potatoes evenly.

2. Weigh approximately 5 g of the ground sample accurately (“Weight A”) into a previously tared metal container or plate.

3. Place the metal plate containing the sample in a 105°C convection oven with forced air circulation for 2 hours.

4. After two hours, the metal plate containing the dried sample is removed and allowed to cool to room temperature in a desiccator over a drying agent, such as anhydrous calcium sulfate.

5. Weigh the plate containing the dried sample again and calculate the mass of the dried sample (“mass B”) by subtracting the tare mass of the plate.

6. The percentage moisture content of the sample is calculated as follows:

Moisture content % = [ (A - B)/(A)] x 100

Determination of total fat content

The total fat content is determined by a solvent extraction method as follows:

Equipment

1. Soxtec HT6 extraction system; the unit includes a heating block and a cooler.

2. We circulated a water bath to the cooler.

3. An oil bath was circulated to the heating block.

4. Extraction beakers.

5. Extraction cuvettes, 26 mm (Fischer TC1522-0018)

66.829/BE

6. Nitrogen purge gas.

7. Vacuum drying oven.

8. Analytical balance (4 decimal places).

9. Divided pipette (50 ml).

Materials

1. Methylene chloride (Baker 9315-33)

2. Boiling stone (Chemware PTFE Fischer 09-191-20)

3. Silicone oil (Fischer TC1000-2779)

4. Glass wool (Fischer 11-390)

Proceedings

1. In a blender or conventional food processor, grind a representative sample of potato chips or straw potatoes evenly.

2. Weigh a piece of glass wool (of the size necessary to place the sample pieces in the cuvette) and an extraction cuvette accurately (to four decimal places); record the mass of the cuvette + glass wool (“Mass A”).

3. Place the ground sample in the cuvette and cover the filled cuvette with a piece of pre-wetted glass wool.

4. Weigh accurately (to four decimal places) and record the mass of the ground sample, cuvette + glass wool (“Mass B”).

5. Place two or more boiling stones in an extraction beaker and weigh them (to four decimal places); record the mass of the extraction beaker + boiling stones (‘mass C’).

6. Place the filled cuvettes in the extraction unit and raise the cuvettes to the rinsing position.

Pipette 0.0 ml of methylene chloride into each pre-weighed extraction beaker containing a boiling stone.

8. Set the oil bath to 110°C and the water cooling bath to 28.3°C and allow the temperatures to equilibrate.

9. Lower the filled cuvettes into the extraction beaker containing the solvent and boil the solvent for 60 minutes with the condenser drain tap open.

10. Lift the cuvettes to the rinse position and rinse for 60 minutes.

11. Close the condenser drain valve and allow the solvent to evaporate for 60 minutes. Turn on the nitrogen purge gas to aid in evaporation.

12. Place the beaker in a vacuum oven preheated to 120°C for 30 minutes under full vacuum.

13. Allow the beaker to cool to room temperature and weigh (to four decimal places); record the mass of the beaker + boiling stones + extracted fat (‘mass D’).

14. The percentage total fat content is calculated as follows:

Fat% = [ (D - C) / (B - A)] x 100

Example 1

Frozen, commercial, shoelace-cut, partially baked potato chips are an acceptable starting product (e.g., Simplot Par Fries; J. R. Simplot Co., Caldwell, ID). A typical processing method is to peel, core, cut, and axially slice selected and graded Russet Burbank potatoes into shoelace chips (0.64 x 0.64 cm). The chips are precooked in hot water at 66.529/3E or steamed at 155-180°F (65.5-81.1°C) for 15-20 minutes and oven-dried at about 155-160°F (65.5-70°C) for 6-7 minutes. The partially dried chips are then partially fried in vegetable oil for about 50 seconds at about 190.5-196.1°C for about 30-60 seconds. The partially fried potato chips are then cooled and frozen at -34.4°C and packaged. The partially fried potato chips have a moisture content of about 64%.

About 0.45 kg of partially fried potato chips are further treated by frying them in a 20.41 kg oil capacity commercial fryer containing Primex 108 vegetable oil (a blend of partially hydrogenated soybean oil and corn oil; available from Procter & Gamble Co.) for about 3 minutes at a temperature of about 143.3°C. The resulting partially fried potato chips are then immediately frozen by immersion in liquid nitrogen for about 20 seconds. The resulting partially fried potato chips have a moisture content of about 48% and a fat content of about 14%. The partially fried potato chips are coated with oil by immersion in liquid vegetable oil (conditioned Primex 108) at a temperature of about 168.3°C for about 1-3 seconds immediately after freezing. The resulting oil-coated, partially fried, straw potatoes are refrozen by immersion in liquid nitrogen. The frozen potato cubes are packaged in tightly sealed, i.e., airtight packages and stored at normal freezer temperatures of about -17.8 to -28.9°C. The oil-coated, partially fried straw potatoes contain about 10% surface fat by weight of the cubes. The total fat content is about 22% and the specific moisture content is about 43%.

Example 66.ΞΞ

Frozen, fast food restaurant-grade, shoelace-cut, partially baked potato chips are purchased for further processing (e.g., Payette Farms Shoelace Frozen Potatoes, J. R. Simplot Co., Caldwell, ID). It is well known that such conventional frozen potato chips are derived from whole potatoes that are peeled, chopped, precooked in water or steam, and optionally partially dried with hot air. The potato chips are then partially fried in vegetable oil for about 30-60 seconds at about 190.5°C and frozen. The resulting partially baked straw potatoes have a specific moisture content of about 70%.

The previously mentioned partially fried potato chips are further processed. First, the frozen potato chips are fried a second time by dipping them in Primex 108 vegetable oil (a blend of partially hydrogenated soybean oil and corn oil available from Procter & Gamble Co.) for 3 minutes at 168.3°C. The partially fried potato chips are immediately frozen by dipping them in liquid nitrogen for about 20 seconds and then stored at -28.9°C. The frozen, partially fried potato chips are coated with oil by dipping them in a liquid vegetable oil (Primex 108) at about 168.3°C for 1-3 seconds. The oil-coated partially fried straw potatoes are then frozen by dipping them in liquid nitrogen for about 20 seconds. This coating process applies about 10% fat to the surface of frozen, partially baked potato chips. The oil-coated, partially baked potato chips have a specific moisture content of about 40% and a total fat content of about 23%. The oil-coated, partially baked potato chips are baked in a forced air convection oven (Wells Manufacturing Co., Verdi, NV, model #M42003S) at about 400°F (204.4°C) for about 2.25 minutes. The resulting potato chips are virtually identical to deep-fried potato chips.

Example 3

A reduced calorie fat formulation is used to produce pre-coated, partially baked straw potatoes. The fat formulation comprises a non-digestible fat component and a "conventional triglyceride" component. The non-digestible fat component comprises a mixture of liquid and solid sucrose polyester (SPE). The non-digestible fat component is added to refined, bleached and deodorized soybean oil and the resulting mixture is heated until all solids are dissolved, providing a fat formulation comprising 75% SPE and 25% soybean oil.

Russet Burbank potatoes containing approximately 20% potato dry matter are peeled, washed and cut into 6.35 mm wide and 88.9 mm long potato strips to produce shoelace-type straw potatoes. The potato strips are pre-cooked in warm water (60°C) for approximately 5 minutes. The pre-cooked potato strips are partially dried in an oven for a few minutes and then allowed to equilibrate at ambient temperature for 5 minutes.

The partially dried potato chips are then fried with the above-described fat composition for 90 seconds at about 190.5°C and then flash frozen to produce frozen partially fried 66,329 ΞΞ potato chips. The frozen partially fried potato chips contain about 55% moisture and about 11% fat. The frozen partially fried potato chips are then coated with the reduced calorie fat composition by immersing the frozen potato chips in the fat composition at about 168°C for 1-3 seconds. The oil-coated partially fried potato chips are refrozen. The frozen partially fried potato chips have about 12% oil coating on their surface. The oil-coated partially fried potato chips have about 48% specific moisture and about 22% total fat. The oil-coated, partially baked straw potatoes are packed in tightly sealed, i.e. airtight, packages and stored at freezing temperatures of approximately -17.8°C.

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Claims (10)

PATENT CLAIMS 1. Partially baked potato cubes, coated with oil, suitable for oven-ready shaping, which: a) have a specific humidity of 34-58%; b) 8-30% total fat content; the partially fried potato chips have a substantially uniform surface fat coating, the surface coating comprising 2-15% by weight of the partially fried potato chips. 2. The partially fried potato chips of claim 1, wherein the partially fried potato chips coated with oil are frozen. 3. Oil-coated, partially fried potato chips according to claim 1 or 2, wherein said oil is a flavoured oil or a conditioned oil. 4. The oil-coated, partially fried potato chips of claim 1, 2 or 3, wherein said oil is selected from the group consisting of soybean oil, corn oil, cottonseed oil, sunflower oil, palm oil, coconut oil, tallow, a non-digestible or reduced calorie fat, and mixtures thereof. 5. Oil-coated, partially fried potato chips according to claim 4, wherein said non-digestible oil is selected from a group consisting of sucrose polyesters, polyol fatty acid polyesters or differently esterified polyol polyesters and mixtures thereof. 66.029 ΞΞ 6. A method for producing oil-coated, partially baked potato cubes suitable for oven-forming, the method comprising: a) partially frying potato chips to produce partially fried potato chips with a specific moisture content of 38-58% and a fat content of 6-25%; and b) applying a substantially uniform oil coating to the surface of said fat-containing partially fried potato chips, said surface coating comprising 2-15% by weight of said oil-coated partially fried potato chips; The oil-coated, partially fried potato chips have a specific moisture content of 34-54% and a total fat content of 8-30%. 7. The method of claim 6, wherein (b) coating with oil is preceded by reducing the temperature of the partially fried potato chips, preferably the temperature reduction comprising immediately and substantially freezing the partially fried potato chips to -17.8°C. 8. A method for producing oil-coated, partially baked potato cubes suitable for oven-forming, the method comprising: a) partial frying of potato chips in oil; o) reducing the temperature of partially cooked potato chips; o' frying the reduced temperature, partially fried potato chips in a second portion to produce 66,329 ΞΞ partially fried potato chips with a specific moisture content of 38-58% and a fat content of 6-25%; and d) applying a substantially uniform oil coating to the surface of said partially fried potato chips to form oil-coated partially fried potato chips, wherein said surface coating comprises 2-15% of said oil-coated partially fried potato chips; The oil-coated, partially fried potato chips have a specific moisture content of 3454% and a total fat content of 8-30%. 9. The method of claim 8, wherein the oil coating step (d) is preceded by reducing the temperature of the partially fried potato chips. 10. The oil-coated, partially fried potato chips of claim 1, 2, 3 or 4, wherein said oil-coated, pre-fried, partially fried potato chips have the following thermal properties at the final forming temperatures in the oven: _v a) the thermal conductivity of the crust area is 0.1-0.3 watts/m2°C; ,b) the thermal conductivity of the inner starch matrix core is 0.4-0.7 watts/m2°C; and .c' surface heat transfer coefficient is 50-400 watts/m2°C. --· The oil-coated, partially fried potato chips according to claim 10, wherein the fat in the oil-coated, pre-fried, partially fried potato chips has a free fatty acid content of less than 0.8%. -2. The method according to claim 6 or 7, wherein said coated, partially baked straw potatoes are characterized by the following thermal properties at the oven forming temperature: (a) the thermal conductivity of the crustal area is 0.1-0.3 watts/m ² °C; (b) the thermal conductivity of the inner starch matrix core is 0.4-0.7 watts/m ² °C; and (c) the surface heat transfer coefficient is 50-400 watts/m ² °C. The authorized person: 66.829/BE