WO2001003518A1

WO2001003518A1 - Oven-baked french fries comprising 2,4-decadienal and/or methional

Info

Publication number: WO2001003518A1
Application number: PCT/US1999/015554
Authority: WO
Inventors: Jeffrey John Kester; Michael Robert Sevenants
Original assignee: The Procter & Gamble Company
Priority date: 1999-07-09
Filing date: 1999-07-09
Publication date: 2001-01-18
Also published as: AU4869099A

Abstract

The present invention relates to French fried potatoes produced from an oven that approximate the attributes and characteristics of French fries that have been finished by deep fat frying. The oven-finished French fries of the present invention can be differentiated from commercial and prior-art oven fries in that they possess a combination of attributes, in particular, bulk moisture, total fat, internal moisture, surface water activity and a Texture Value, that renders them virtually indistinguishable from deep fried French fries. Furthermore, the oven-finished French fries of the present invention are characterized by the level of selected positive flavor components (2,4-decadienal and methional). The oven-finished French fries comprises from about 32% to about 50 % bulk moisture, from about 8% to about 25% total fat, from about 55% to about 80% internal moisture content, a surface water activity of less than or equal to about 0.55, and a Texture Value (maximum force [grams] or area under the force deformation curve [gram sec] within the first one-third of a specific compression test) of at least about 200. The oven-finished fries further comprise at least about 0.5 ppm 2,4-decadienal and at least about 0.2 ppm methional.

Description

OVEN-BAKED FRENCH FRIES COMPRISING 2,4-DECADIENAL AND/OR METHIONAL

BACKGROUND OF THE INVENTION

The present invention relates to French fried potatoes baked in an oven. More particularly, it relates to oven-finished French fried potatoes that approximate the attributes and characteristics of French fries that have been finished by deep fat frying.

French fried potatoes are one of the most popular convenience foods whether they are prepared at home or purchased from fast food restaurants. Deep-fried French fries are particularly well liked by virtue of their textural dichotomy. This textural dichotomy manifests itself in a product which has a fairly crisp exterior and a fairly tender and moist interior. The method of deep frying has been found to be a particularly suitable way for imparting this desired textural dichotomy to French fried potatoes.

Recent attention has been directed to the use of ovens for preparing French fries from the partially fried (herein after par-fried) frozen state. The prior art oven-finished products are by no means equivalent to deep fried French fries. This is because during oven finishing, moisture migrates from the internal core outward to the crust region. This tends to make the oven-finished French fries limp, i.e., the fries lack surface crispness.

Attempts to improve the texture by longer heating time, higher oven temperature, rapid heating (e.g., microwave), etc. have generally been unable to provide the desired balance of moist interior encased by a low-moisture, crisp crust Generally, the French fries produced are leathery, dry and tough. Examples of some methods for altering the par-fries and/or methods to produce fully cooked fries, which upon oven-finishing or oven reheating generally result in French fries having poor textural qualities (i.e., dry interiors and tough or soggy exterior crusts), can be found in the prior ait, see for example, U.S. 5,000,970 (Shanbhag et al.), U.S. 5,302,410 (Calder et al.), U.S. 3,865,964 (Kellermeier) and U.S. 5,242,699 (Bednar et al.). The poor textural qualities affect the palatability of the oven-finished product. Thus, a great demand exists today for French fried potatoes that are oven-finished and that, in the ready- to-eat state, have the color, texture, mouthfeel and taste of deep fried French fries

The oven-finished French fries of the present invention provide one or more advantages in relation to the organoleptic properties, specifically the crust crispness and the moistness of the internal core. The oven finished fries have substantially the same textural dichotomy as deep-fried French fries. The external surface (i.e., crust) is moderately crisp and not excessively oily and the interior portion (i.e., core) is well cooked, tender, mealy and moist, yet free from sogginess. The oven-finished French fries of the present invention can be differentiated from commercial and prior art oven-finished French fries in that they possess a combination of attributes, in particular, bulk moisture, total fat, internal moisture content, surface water activity (Aw) and Texture Value, that renders them virtually indistinguishable from deep fried French fries. The oven-finished French fries of the present invention can also be differentiated from commercial oven fries based on the level of selected positive flavor components and based on subjective evaluations (i.e., expert sensory panelists).

It is therefore an objective of the present invention to provide oven-finished French fries that are significantly preferred over commercial and prior art oven finished products on the basis of taste/eating satisfaction and that are parity in taste with deep fried French fries.

It is also an objective of the present invention to provide oven-finished French fries which are virtually indistinguishable from deep-fat fried French fried potatoes which may be purchased in fast food restaurants.

It is also an objective of the present invention to provide oven finished French fries which have a moist interior surrounded by a crisp yet tender outer surface.

It is further an objective of the present invention to provide oven finished French fries containing a certain level of selected positive flavor components.

These and other objectives of the present invention will be made clear by the disclosure herein.

All percentages are by weight unless otherwise indicated.

SUMMARY OF THE INVENTION

The present invention relates to oven-finished French fried potatoes comprising: a) from about 32% to about 50% bulk moisture; b) from about 8% to about 25% total fat; c) from about 55% to about 80% internal moisture content; d) a surface water activity (Aw) of less than or equal to about 0.55; and e) a Texture Value of at least about 200; wherein said Texture Value is the maximum force (grams) or the area (gram sec) under the force deformation curve during the first one-uurd of a compression test.

The oven finished French fries have a texture which is virtually indistinguishable from commercial French fries that have been prepared by deep fat frying such as M^onald's French fries.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is concerned primarily with the attributes of oven finished French fries. The present invention further relates to oven finished French fries which are ready to eat, and are virtually indistinguishable from deep-fried French fries. Definitions

As used herein the term "deep fried French fries" refers to potato strips which have been cooked to a ready-to-eat form by immersion in hot oil.

As used herein the terms "par-fry" or "par-fried" refer to potato strips that have been subjected to at least one frying process (e.g., deep frying), but which have not been completely cooked.

As used herein the term "oven finishing" refers to converting the product to a ready-to-eat form by cooking in a toaster, toaster oven, forced air convection oven, high air velocity oven, hot air impingement oven, infrared oven, combined convection/infrared oven, microwave oven, combined microwave/convection oven or a conventional home oven. Typically, cooking entails reducing the moisture content of the food.

As used herein the term "fat" or "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, canola oil, sunflower oil, palm oil, coconut 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. The terms "fat" and "oil" are used interchangeably.

As used herein the term "finished" refers to a product that has been subjected to a cooking process to convert it to a ready-to-eat form.

As used herein the term "conditioned oil" refers to oil which has been previously used for frying for such a time that it has developed fried flavor.

As used herein the term "oven finished" refers to a product that has been subjected to an oven baking process to convert it to a ready-to-eat form.

As used herein the term "oven baking" refers to baking in an oven such as a forced air convection oven, hot air impingement oven, infrared oven, a combination of infrared radiation and convection oven, a toaster, toaster oven, a microwave oven, a combination microwave and forced air convection oven, or a conventional home oven.

As used herein the term "Texture Value" is the maximum force (grams) or the area (gram sec) under the force deformation curve recorded during the first one-third of a compression test (see section on analytical test methods for more details).

OVEN-FINISHED FRENCH FRIES

The textural features of the present invention are the Texture Value, the bulk moisture, the internal moisture content, the surface Aw, and the amount of fat present in the oven-finished product. Importantly, it is the combination of these attributes and not a single attribute that distinguishes the present invention from commercial and prior art oven-finished fries and renders them virtually indistinguishable from deep fried French fries. The flavor features that distinguish the present invention from commercial and prior art oven- finished fries are the levels of selected positive flavor components in the oven-finished fries. These flavor components include 2,4-decadienal and methional.

The distinguishing features of the present invention reside in part in the recognition of critical physical characteristics of the par-fries and their thermal properties wherein this relationship can be used to insure oven-finished French fries having moist interiors and crisp crusts for a variety of different oven- finishing processes. More particularly, the present invention recognizes that for oven-finished French fries, a certain range of values for surface Aw and Texture Value are required for optimum palatability.

One embodiment of the present invention is the par-fried potato strips which may be prepared by processing steps known in the art. The par-fries may be prepared from a variety of raw potatoes known to be suitable for preparing French fries. Preferably the par-fried potato strips are prepared from potatoes of the Russet Burbank, Shepody or Katahdin varieties. The par-fried strips may be of varying shapes and sizes. However, it is preferred that the relatively thin and elongated potato strips known in the art as "shoestrings" be used. Shoestring potato strips, as used herein refer to potato strips that are from about 3/16 to about 5/16 inch square in cross-section and from about 2.5 to about 5 inches in length. Thicker- cut potato strips may also be used herein; e.g., "crinkle cut" strips, straight cut thick potato strips (also known as "regular-cut") and "steak fry" cuts.

The potato strips are blanched according to conventional procedures known in the art. Following blanching, the potato strips may be subjected to additional treatments known in the art. For instance, the potato strips may be treated with sodium acid pyrophosphate (SAPP), a chelating agent used to prevent discoloration of the strips. Dextrose (corn syrup) may also be applied to the surface of the strips in order to yield a desired level of brown color development during subsequent processing. In addition, the potato strips may be optionally dried partially to reduce their moisture content.

One method of producing par-fries is low temperature frying. In this method the raw, blanched, or dehydrated potato strips are totally immersed in hot oil at a temperature of from about 270°F to about 335°F (132°C to about 168°C) for a time sufficient to reduce the moisture of the potato strips to a final moisture content of from about 32% to about 52%. Preferably, this frying step is conducted at an oil temperature of about 280°F to about 320°F (138°C to about 160°C), most preferably at about 290°F to about 310°F (143°C to about 154°C). Any variety of edible fats and oils may be used to par-fry the potato strips.

Another par-frying process that can be used is the deluge process. In this process a heated oil having a temperature of from about 270°F (132°C) to about 335°F (168°C ) is sprayed onto the potato strips and surrounds the potato strips for a time sufficient to reduce the moisture to the requisite moisture content. Other frying techniques such as mist frying and foam frying may also be used.

Par-frying can also be accomplished using a multiple immersion frying process wherein the potato strips are partially fried more than one time. The par-fried potato strips may be cooled, chilled or frozen between par-frying steps or par-fried in oils adjusted to different temperatures. Preferably, in the multiple immersion frying process the blanched potato strips, which may have been partially dried with hot air are fried a first time in oil having a higher oil temperature than the next frying oil. This process may be repeated multiple times (e.g., high temperature, low temperature, high temperature, low temperature, etc.) until the par-fries reach a moisture content of about 54%. The temperature of the first fryer may range from about 300°F to about 390°F (148.9°C to about 198.9°C), while the combined par- frying times may range from about 10 to about 120 seconds or for a time sufficient to reduce the moisture content of the potato strips to about 54%.

Once the par-fried potato strips reach a moisture content of about 54% the par-fried strips are once again fried in oil having a temperature ranging from about 270°F (132°C) to about 335°F (168.3°C), preferably from about 280°F (138°C) to about 320°F (160°C), and most preferably at about 290°F (143° C) to about 310°F (154°C). This may consist of single or multiple immersions in the frying oil. The par- frying time ranges from about 1 minute to about 6 minutes or a time sufficient to reduce the moisture content such that the resulting potato strips have a moisture content of about 32% to about 52%. The actual time required for any given frying step is determined by several factors; including the specific oil temperature, dimensions and temperature of the potato strips, the batch size, volume of the frying kettle, and initial moisture content of the potato strips.

The par-fries can also be prepared by vacuum frying. This allows frying at high oil temperatures (e.g., 370°F or higher), while resulting in par-fries having a low 2,5-dimethyl pyrazine level. In this method the blanched potato strips or dehydrated potato strips are placed in a vacuum fryer and fried at a temperature of about 250°F to about 400°F under a full or partial vacuum. The pressure in the vacuum fryer is less than about 400mm/Hg, preferably less than about 200mm/Hg, even more preferably less than about lOOmm/Hg. When par-frying the fryer is continuously heated and vacuum-pumped so that the temperature and pressure within the fryer is kept within the desired range. The par-fries are fried for a time sufficient to obtain the requisite moisture content. The time is typically in the range of from about 1 to about 6 minutes.

The moisture, and fat content and thermal properties of the par-fries are important to produce the oven baked fries of this invention. Of particular importance is the distribution of water in the par-fry and the control of water migration from the internal core to the crust region of the par-fries during storage and oven finishing. By controlling moisture transfer from the internal core to the crust region during frozen storage and oven-finishing, ready-to-eat oven-baked French fries can be prepared that possess a highly palatable moist interior surrounded by a low-moisture, crisp crust region. The textural dichotomy that results in the oven-finished fry is very similar to that which exists in French fries that are finished by deep frying.

Moisture migration from the internal core to the crust region during frozen storage can be partially controlled by frying the potato strips to bulk moisture contents that are preferably equal to or greater than about 40%, more preferably equal to or greater than about 42%, and most preferably equal to or greater than about 44%. Moisture migration can also be minimized during frozen storage by hydrating the crust region prior to frozen storage in order to increase the crust Aw and, thereby, reduce or eliminate the Aw differential between the internal core and the crust, which is the driving force for moisture transfer. Hydration of the crust region can be accomplished by application of water, a water mist, an aqueous solution, or an aqueous dispersion to the surface of the par-fry. Preferably a spraying process is used to hydrate the crust region of the par-fries.

Moisture migration from the internal core to the crust region during oven finishing can be minimized by employing oven-finishing conditions that rapidly and/or preferentially dry the surface of the French fry. This can be achieved by selecting oven conditions (temperature, air velocity) that yield a relatively high surface heat transfer coefficient at oven temperature. Higher surface heat transfer coefficients are desirable because this will lead to faster cooking time and the formation of a more distinct and crisp low-moisture crust region. Preferable surface heat transfer coefficients at oven temperature are from about 50 to about 400 watts/m^°C. Preferential drying of the surface of the par-fry can also be achieved by enrobing the par-fries with an edible fat or oil, which increases the conduction of heat from the surrounding air to the fry surface during oven baking. Desired thermal conductivities at oven temperatures of the crust region of the par-fry are from about 0.1 to about 0.3 watts/m°C. Desired thermal conductivities of the high-moisture internal core are from about 0.4 to about 0.7 watts/m°C. Enrobing par-fries with fat or oil also serves the purpose of providing an added barrier to moisture loss from the internal core as the enrobing oil is partially absorbed into the outer crust region during baking. The surface of the par-fry may also be modified to improve the absorption of radiant heat from the oven. A typical method of accomplishing this would be to alter the color, porosity, and/or reflectivity of the par- fry surface.

Thermal conductivities and surface heat transfer coefficients can be calculated as follows.

Surface heat transfer coefficient

The general equation for heat transfer across an interface is well known: Q_t = UA (T₂ - Υι) - ΔH_W + Q_r where:

Q_t = amount of heat transferred across the boundary (watts, or equivalent energy unit). U = surface heat transfer coefficient (watts/m - C or equivalent)

2

A = surface area of the boundary region (m or equivalent) T₂ = Temperature on the hot side of the boundary ( C or equivalent) Tj = Temperature on the cooler side of the boundary ( C or equivalent) ΔH_W = heat lost due to evaporation of water from the surface

4 4

Q_r = radiative heat transfer = AFσ(T₂ - T_\ ) where F is the shape factor and σ is the Stefan-Boltzman constant. A careful measurement of temperature on either side of the boundary versus time as well as the moisture level on either side of the boundary versus time, and the temperature of any infrared heating source to which the surface is directly expose will allow calculation of the surface heat transfer coefficient (U).

Thermal Conductivity

Thermal conductivity for a food material with a crust can be calculated once U, T₂ and T] are known. k = UL(T₂-T₁)/(Tι-T_i) k = thermal conductivity (W/m- C or equivalent) L = crust thickness (m or equivalent) Tj = reference temperature

While not wishing to be bound by theory, it is believed that prior art oven fries lack the desirable textural dichotomy associated with high-quality deep-fried French fries because the par-fry attributes (moisture; fat; surface fat; thermal properties) and oven-finishing conditions are not optimized for producing a finished oven fry with a moist interior and a crisp low-moisture crust. For example, many commercial or prior art par-fries are so high in moisture content that upon the recommended oven baking the oven-finished fry is not sufficiently low in bulk moisture content or the crust region has not been sufficiently dehydrated to yield a crisp surface texture. While using more rigorous oven conditions may remove water from the surface of the fries and may improve the crispness of the crust, excessive internal moisture transfer from the internal core to the surface often occurs simultaneously, resulting in oven- finished French fries having one or more of the following textural deficiencies: a tough surface texture; an interior that is perceived as excessively dry; and/or an excessively crunchy overall texture (i.e., the oven-finished fries do not possess the desired textural dichotomy associated with deep fried French fries).

Other methods may also be used to control water migration and water distribution of the par- fries. However the preferred method, as described above, comprises controlling the bulk moisture and thermal properties (i.e., thermal conductivity of the high-moisture internal core, thermal conductivity of the crust region, and the surface heat transfer coefficient) of the par-fries. The bulk moisture of the par- fries may be controlled by the process conditions used in producing the par-fries; e.g., the conditions used for dehydrating the potato strips before frying; the par-frying conditions; and the level, if any, of surface hydration of the par-fries. The thermal properties of the par-fries may be the modified likewise and additionally may be modified by application of various ingredients onto the surface of the par-fries (e.g., enrobing with oil; coating with hydrocolloids; etc.).

The par-fries useful in the present invention have a moisture content of greater than about 30%. Typically the moisture content is from about 32% to about 52%, preferably from about 34% to about 50%, more preferably from about 36% to about 48% even more preferably from about 38% to about 46, and most preferably from about 40% to about 44% bulk moisture.

The bulk moisture and thermal properties of the par-fries provide a method for controlling moisture loss from par-fried potato strips during oven finishing such that the resulting French Fries have substantially the same textural dichotomy as deep fried French fries. Further, the bulk moisture and thermal properties of the par-fries indicate how the par-fry processing conditions and oven-finishing conditions may be altered to insure optimum textural characteristics in the oven-finished French fry.

Another embodiment of the present invention is the oven-finished French fries. The oven- finished French fries of the present invention may be baked in various types of ovens, including a forced air convection oven, hot air impingement oven, infrared oven, a combination of infrared radiation and convection oven, a toaster, a toaster oven, a microwave oven, a combination microwave and forced air convection oven, or a conventional home oven. The baking time in a conventional home oven is less than or equal to about 15 minutes, preferably less than or equal to about 12 minutes, more preferably less than or equal to about 10 minutes. In a forced air convention, hot air impingement, infrared, or microwave oven the baking times are significantly shorter; i.e., less than or equal to about 4 minutes, preferably less than or equal to about 3 minutes, and most preferably less than or equal to about 2 minutes. Upon removal from the oven, the baked fries may optionally be coated with oil to further enhance flavor and mouthfeel. Preferably the oil used for coating the baked fries is a flavored or conditioned oil. The oil may be applied to the surface of the baked fries by methods known in the art; e.g., by spraying warm oil onto the surface or by rapid immersion of the fries into a reservoir of warm oil. The oven-finished French fries of the present invention can be differentiated from commercial and prior art oven-finished French fries in that they possess a combination of attributes, in particular, a certain Texture Value, bulk moisture, internal moisture, surface Aw, and total fat that renders them virtually indistinguishable from French fries that have been finished by deep-fat frying. Further, the oven-finished French fries of the present invention can be differentiated from commercial and prior art oven-finished French fries based on the level of selected positive flavor components (2,4-decadienal and methional) and based on subjective evaluation (i.e., expert sensory panelists).

Texture Value

A critical attribute of the present invention is the Texture Value of the oven-finished French fries. This value is dependent on a combination of factors such as moisture content, crispness of the crust, degree of dehydration of the crust, and other physical properties of the fries. The Texture Value is determined by the use of a Texture Analyzer equipped with a rectangular, blunt steel plate probe. A compression test is run in which the plate compresses the French fry while the force of resistance is measured (see section on analytical test methods for details). The force (grams) vs. time (sec) data is plotted to produce a force deformation curve. Two textural parameters obtained from the force deformation curves are used to characterize the texture of French fries, average maximum force (grams) and average area (gram sec) within the first 1/3 of the compression test. We have found both of these parameters to coπelate with the crispness of French fries and either one may be designated as the Texture Value. High quality oven-finished French fries of the present invention exhibit distinctive textural dichotomy and are characterized by a Texture Value (i.e., maximum force or area) of at least about 200. Preferably the Texture Value is from about 210 to about 1000, more preferably from about 220 to about 600, and even more preferably from about 240 to about 500. Further, the oven-finished French fries of the present invention have a ratio of the average area to the average maximum force of at least 1.0, preferably 1.04 or greater, more preferably 1.08 or greater, even more preferably 1.12 or greater, and most preferably 1.16 or greater. Commercial oven-finished fries prepared according to the manufacturer's oven instructions lack dichotomous textural characteristics as found in the fries of the present invention. Typically the average maximum force (grams) and the average area (gram sec) for commercial and prior-art oven fries are below 200 and the ratio of the average area to the average maximum force is about 1.0 or less.

Over-cooked commercial oven fries may exhibit an average maximum force or area of at least about 200 or greater. However, the oven-finished fries of the present invention can be distinguished from the overcooked commercial oven fries based on the bulk and/or internal moisture and based on the fact that the ratio of the average area to the average maximum force of the overcooked commercial oven fries generally remains at about 1.0 or less.

Bulk Moisture

Another critical attribute of the present invention is the bulk moisture content of the oven- finished French fries. Bulk moisture is the total amount of water in the fries of the present invention. The oven-finished French fries of the present invention have a bulk moisture of from about 32% to about 50%. Shoestring cut, oven-finished French fries of the present invention have a bulk moisture of from about 32% to about 46%. Preferably the bulk moisture of shoestring-cut, oven-finished French fries should be from about 33% to about 44%, and more preferably the bulk moisture should be from about 34% to about 40%. Thicker-cut oven-finished French fries of the present invention (e.g. regular cut, crinkle-cut and steak fries) typically have a bulk moisture of from about 35% to about 50%. Preferably the thicker-cut oven-finished French fries have a bulk moisture of from about 38% to about 48% and more preferably from about 40% to about 46%. The bulk moisture of the products herein can be measured using well-known techniques and commercially available instruments. An oven-finished French fry with a bulk moisture much greater than about 50% will not have developed a sufficient crust structure to yield the desired textural dichotomy (i.e., the fries will lack crispness). At a bulk moisture much less than about 32% the oven- finished fries can become too dry. Keeping the bulk moisture of the oven-finished fries of the present invention at a level between about 32% and 50% allows production of oven fries that possess both a low-moisture, crisp crust region as well as a high-moisture internal core.

Internal Moisture

The internal moisture content is also an important characteristic of the present invention. The internal moisture content of oven-finished French fries is the moisture content of the interior starch matrix. As mentioned before the interior portion (i.e., core) is well cooked, tender, mealy and moist, yet free from sogginess. The oven-finished French fries of the present invention have an internal moisture of from about 55% to about 80%, preferably from about 60% to about 77%, more preferably from about 63% to about 75%.

Surface Aw of the Crust

A distinguishing characteristic of the oven-finished fries of the present invention is the exterior crust. The exterior crust is comprised of dehydrated gelatinized starch and oil or fat. Preferably, the exterior crust has substantially the same composition as the crust of deep fried French fries made from raw potatoes. However, the crust may contain ingredients typically applied to the surface of potato strips such as starches, hydrocolloids, gums, flavorings and the like.

It is important that the outer crust region is crisp and relatively low in water activity (Aw). The texture of fried and baked food products is known to be related in part to the Aw of the product. Crisp textures are generally associated with Aw values less than or equal to about 0.55. The surface Aw is a measurement of the water activity of the crust region of the oven-finished French fries (see section on analytical test methods for details concerning surface Aw measurement). The surface Aw is equal to the vapor pressure of water in the outer crust region divided by the vapor pressure of pure water at the same temperature.

The oven-finished French fries of the present invention preferably have a surface Aw of less than or equal to about 0.55, preferably from about 0.10 to about 0.52, more preferably from about 0.15 to about 0.5, and even more preferably from about 0.2 to about 0.45.

Total Fat

Edible oil, natural or synthetic, is generally on the surface and within the crust region of the oven-finished French fry of the type disclosed in the present invention. Edible oils contribute to the flavor, lubricity and texture of the oven-finished French fry. The edible oils or fats present on the surface and within the crust region of the oven-finished French fry are well known by one skilled in the art and 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 may be conditioned or flavored, see Flavored Vegetable Oils as a Substitute for Beef Tallow in Deep Frying Applications. Food Technology, pp 90-94 (1989) and U.S. Patent 5,104,678 (Yang et al.)

The oils may be partially or completely hydrogenated or modified otherwise. Additionally non-

TM 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 present on the surface and/or within the crust region of the oven-finished French fries.

Some preferred oils are soybean oil and corn oil. The total amount of oil or fat present in and on the oven-finished French fries of the present invention is from about 8% to about 25%. Shoestring French fries of the present invention typically have from about 12% to about 25% total fat, preferably from about 13% to about 23% fat, and more preferably from about 14% to about 20% total fat. Thicker- cut oven-finished French fries (e.g. regular cut, crinkle-cut and steak fries) typically have a total fat level of from about 8% to about 22%. Preferably the thicker-cut oven-finished French fries have a total fat level of from about 10% to about 20%, and more preferably from about 12% to about 18%.

Preferably the edible fat or oil present on the surface and within the crust region of the oven- finished French fries of the present invention has a free fatty acid level of about 0.8% or less.

Flavor Components

Oven-finished French fries of the present invention are characterized by the level of the positive flavor components 2,4-decadienal and methional. The flavor component 2,4-decadienal, which is derived from the oxidation of the unsaturated fatty acid linoleic acid, contributes a positive fried oil flavor character to the oven-finished fries. The oven-finished French fries of the present invention contain a level of 2,4-decadienal equal to or greater than about 0.5 ppm. Preferably the oven-finished fries contain at least about 0.7 ppm, more preferably at least about 1.0 ppm, even more preferably at least about 1.3 ppm, and most preferably at least about 1.6 ppm 2,4-decadienal. The flavor component methional, which is a Strecker aldehyde derived from the amino acid methionine in the Strecker degradation reaction, contributes a positive fried potato flavor character to the oven-finished fries. The oven finished French fries of the present invention contain a level of methional equal to or greater than about 0.2 ppm. Preferably the oven-finished fries contain at least about 0.3 ppm, more preferably at least about 0.4 ppm, even more preferably at least about 0.5 ppm, and most preferably at least about 0.6 ppm methional.

Additional Ingredients

Flavoring agents, such as salt, pepper, butter, onion, or garlic may be added to the par-fries or the oven-finished fries oil to enhance the flavor or modify the flavor to any desired taste. One skilled in the art will readily appreciate that the aforementioned listing of flavoring agents is in no way exhaustive, but is merely suggestive of the wide range of additives which are suitable for use in the practice of the present invention.

Other ingredients known in the art may also be added to the edible fats and oils used to fry and/or enrobe the par-fried potato strips, including antioxidants such as TBHQ, chelating agents such as citric acid, and antifoaming agents such as dimethylpolysiloxane.

The oven-finished French fries of the present invention can also be distinguished from commercial and prior-art oven fries based on sensory evaluation and Nuclear Magnetic Resonance (NMR) Imaging. Sensory evaluation reveals that the oven-finished French fries of the present invention possess a desirable textural dichotomy (i.e., a crisp surface surrounding a moist interior) typically associated with deep-fried French fries. Commercial and prior-art oven fries do not typically display this desired textural dichotomy. NMR imaging provides a cross-sectional image depicting the moisture and fat distribution within the fries. The high-quality oven-finished French fries of the present invention are characterized by NMR images that appear qualitatively similar to the images of deep-fried French fries, i.e., both products are characterized by images that reveal a high moisture internal core suπounded by a low moisture crust region that contains the fat. In contrast, NMR images of commercial oven fries typically appear qualitatively different; i.e., the dichotomous feature of a low-moisture crust surrounding a high-moisture core is not as readily apparent.

Accordingly, the disclosed embodiments are considered in all respects to be illustrative and not restrictive. The scope of the invention is indicated by the appended claims.

ANALYTICAL TEST METHODS

A number of parameters are used to characterize elements of the par-fried potato strips and the oven-finished French fries of the present invention. They are quantified by particular experimental analytical procedures. Each of these procedures is described in detail as follows:

Bulk Moisture Content Test

Moisture content of par-fried potato strips and finished French fries is determined by a forced air oven method as follows:

1. Uniformly grind up a representative sample of potato strips or French fries in a blender or conventional food processor.

2. Accurately weigh approximately 5 grams of ground sample (weight "A") into a previously tared metal pan or dish.

3. Place the metal dish containing the sample in a forced air convection oven at 105°C for 2 hours.

4. After 2 hours, remove the metal dish containing the dried sample and allow to cool to room temperature in a desiccator over a desiccant such as anhydrous calcium sulfate. 5. Re-weigh the dish containing the dried sample and calculate the weight of the dried sample (weight "B") by subtracting the dish tare weight.

6. Calculate the percent moisture of the sample as follows:

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

French Fry Texture Value Test

The Texture Value of finished French fries, which correlates with crispness of the fries, is measured with a TA-XT2 Texture Analyzer (version 05.16 equipped with 25-1 load cell, Texture Technologies Corp., Scarsdale, NY). The Texture Analyzer is linked to a standard personal computer (e.g. IBM 433DX) that records the data via a software program called XT.RA Dimension (version 3.7H, Texture Technologies Corp., Scarsdale, NY).

The Texture Analyzer is configured with a rectangular, blunt steel plate probe (2.5-3.0 mm thickness, 70 mm width, 90 mm length) that is fastened vertically to the main arm. A "Compression Test" on a single French fry will be run to generate a plot of Force (grams) vs. Time (sec), from which the Texture Value is obtained.

Procedure for Set-up and Calibration of the Texture Analyzer

1. Set-up the Texture Analyzer as follows:

Mode: Measure Force in Compression

Option: Return to Start

Force Units: Grams

Time Units: Seconds

Distance Format: Strain

Pre-Test Speed: 2.0 mm/sec

Probe Test Speed: 1.0 mm/sec

Post-Test Speed: 10 mm/sec

Strain: 85.0%

Trigger Type: Auto 10

2. Set the texture method as follows:

Graph Type: Force vs. Time

Auto-Scaling: Off

Force Scaling Max: 5000 grams

Force Scaling Min: 0 grams

Peak Confirmation: On

Force Threshold: 20 grams File Type: Lotus 1-2-3

Display and Export: Plotted points

Acquisition Rate: 200 pps

Force Units: Grams

Contact Area: 1.00 mm^

Contact Force: 5.0 grams

3. Calibrate the force by placing a 5 kg weight on the calibration platform and press the "calibrate" button on the Texture Analyzer key pad.

4. Calibrate the probe distance from the base plate with a probe starting distance from the plate of 10 mm for shoestring-cut fries (increase probe starting distance to 15 mm for thick-cut or steak fries). Ensure that the bottom surface of the probe is parallel to the surface of the base plate.

Procedure for Sample Measurements

1. Immediately following removal of finish-cooked French fries from a fryer (deep-fried) or oven (oven-baked), place the batch of fries under a heat lamp for 1 minute prior to beginning the texture analysis. The air temperature under the heat lamp is between about 130°F and about 180°F (about 54.3°C to about 82.2°C).

2. After the 1 minute hold time has elapsed, place a single French fry flat on the base plate of the Texture Analyzer (oriented perpendicular to the probe width). Initiate the Compression Test (1.0 mm/sec probe speed) while manually holding the ends of the French fry flush against the base plate.

3. The resulting Force (grams) vs. Time (sec) data is saved for later analysis. Nine additional fry samples from the same batch are tested in an identical manner. The ten fry samples from each batch are selected randomly. Texture analysis of the ten fry samples should be completed within 3-4 minutes. (3-4 minutes after Step 1).

4. Steps #l-#3 are repeated for each new batch of French fries. Generally, 5 to 10 batches of each type of French fry are evaluated in this manner.

Data Analysis

1. The "Force vs. Time" plot for each individual French fry sample is evaluated for the following:

• Maximum Force (grams) within the first 1/3 of the test.

• Area (gram sec) under the curve within the first 1/3 of the test.

(e.g. if the Compression Test requires 6 seconds to complete, the Maximum Force and Area are obtained from the 0-2 second time period) 2. After analysis of the "Force vs. Time" data for all ten French fry samples selected from a given batch, the ten Maximum Force values are averaged and the ten Area values are averaged. A computer program written in Excel automates the task of analyzing the Force vs. Time data for each fry sample and averaging the Maximum Force and Area values for each batch of fries.

3. Remaining batches of a particular French fry type are analyzed in a similar manner (5-10 batches are tested; 10 fries/batch are analyzed). The Maximum Force and Area values for each batch are then averaged to yield an overall average Maximum Force (grams) and Area (gram sec) for that particular fry type.

4. For the purpose of this invention, either the overall average Maximum Force or Area may be designated as the French fry Texture Value. Both texture measurements correlate to crispness of finished French fries.

Determination of the Internal Moisture Content of French Fries

Internal moisture content of finished French fries, i.e. moisture content of the interior starch matrix, is determined as follows:

1. Immediately following removal of finish-cooked French fries from a fryer (deep-fried) or oven (oven-baked), immerse the fries in liquid N2 for 20 seconds to completely freeze the products and stabilize the internal moisture distribution.

2. Store the frozen French fries at about -112°F (-80°C) until analysis.

3. Remove several fries from the freezer and place on a stainless steel tray. Allow the fries to warm slightly for several minutes at room temperature to facilitate removal of the crust.

4. Carefully cut off the crust on one side of each frozen fry with a razor blade. Rotate the fries and repeat this procedure until the crust has been removed from all four sides.

5. Collect the frozen interior starch matrix (white solidified material) and immediately place in a capped glass vial. Take care only to collect the interior starch matrix; do not include any crust remnants.

6. Repeat steps #3-#5 until approximately 5 grams of frozen interior starch matrix is collected. This may require about 15-20 fries.

7. Accurately weigh approximately 5 grams of the interior starch matrix (weight "A") into a previously tared metal pan or dish.

8. Place the metal dish containing the interior starch matrix in a forced air convection oven at 105 °C for 2 hours.

9. After 2 hours, remove the metal dish containing the dried sample and allow to cool to room temperature in a desiccator over a desiccant such as anhydrous calcium sulfate. 10. Re-weigh the dish containing the dried sample and calculate the weight of the dried sample (weight "B") by subtracting the dish tare weight.

11. Calculate the percent moisture of the interior starch matrix as follows: % internal moisture = [(A - B) / (A)] x 100

Determination of the Surface Water Activity (Aw) of French Fries

Surface Aw of finished French fries is determined as follows:

2. Store the frozen French fries at about -112°F (-80°C) until analysis.

3. Transfer a bag of French fries (-0.5-1 lb.) from the -112°F (-80°C) freezer to a cooler containing dry ice; ensure the bag is thoroughly packed in dry ice in order to maintain the fries in a frozen state at low temperature.

4. Remove one French fry at a time from the sample bag and rapidly scrape the surface of the fry with a single-edged razor blade. Collect the surface shavings onto a stainless steel tray and immediately transfer the shavings to a capped glass vial.

Take care only to collect surface shavings from the outer crust region of the French fry; do not scrape so hard such that the crust region is penetrated and the interior starch matrix core is exposed.

5. Repeat step #4 until approximately 0.3-0.7 gram of surface shavings is collected; this will require scraping about 10-20 frozen fries.

6. Determine the water activity (Aw) of the surface shavings using a Rotronic Hygroskop Model DT relative humidity meter (Rotronic Instrument Corp., Huntington, NY), as follows: a. Transfer the surface shavings to a plastic Aw dish (Rotronic Instrument Corp.). b. Immediately place the Aw dish containing the surface shavings into one of the humidity cells of the Hygroskop Model DT relative humidity meter and close the cell cover tightly. c. Allow the meter reading to stabilize (wait 1 hour or longer) before recording the reading and temperature. d. Convert the stabilized meter reading to % Relative Humidity (RH) using a previously prepared calibration graph (meter reading vs. %RH) prepared with the following RH standards:

11% RH Saturated solution of Lithium Chloride (see Greenspan, L., 1977, J.

Res. Natl. Bur. Stand., Section A, 81A:89) 35% RH Standard solution from Rotronic Instrument Corp. 50% RH Standard solution from Rotronic Instrument Corp.

65% RH Standard solution from Rotronic Instrument Corp. e. Convert %RH of the surface shavings to Surface Aw as follows:

Surface Aw = [%RH / 100].

Total Fat Content Test

Total fat content of par-fried potato strips, and finished French fries is determined by a solvent extraction method as follows:

Apparatus

1. Soxtec HT6 extraction system; unit includes heating block and cooling condenser.

2. Recirculating water bath for cooling condenser.

3. Recirculating oil bath for heating block.

4. Extraction beakers.

5. Extraction thimbles, 26 mm (Fisher TC1522-0018).

6. Nitrogen purging gas

7. Vacuum drying oven

8. Analytical balance (4 place)

9. Dispensing pipette (50 ml)

Materials

1. Methylene chloride (Baker 9315-33)

2. Boiling stones (Chemware PTFE Fisher 09-191-20)

3. Silicone oil (Fisher TC 1000-2779)

4. Glass wool (Fisher 11-390)

Procedure

1. Uniformly grind a representative sample of potato strips or French fries in a blender or conventional food processor.

2. Accurately weigh (to four places) a piece of glass wool (sufficient in size to contain sample pieces in the thimble) and the extraction thimble; record weight of thimble + glass wool (weight "A").

3. Load the ground sample into the thimble and cap the loaded thimble with the pre-weighed piece of glass wool.

4. Accurately weigh (to four places) and record the weight of the ground sample, thimble, + glass wool (weight "B"). 5. Place two or more boiling stones into an extraction beaker and weigh (to four places); record weight of extraction beaker + boiling stones (weight "C").

6. Place loaded thimbles on the extraction unit and raise the thimbles to rinse position.

7. Pipette 50 ml of methylene chloride into each pre-weighed extraction beaker with boiling stones.

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

9. Lower the loaded thimbles into the extraction beaker containing the solvent and allow to boil in the solvent for 60 minutes with the condenser's pet cock in the open position.

10. Raise the thimbles to the rinsing position and rinse for 60 minutes.

11. Turn the condenser's pet cock to the closed position and allow the solvent to evaporate for 60 minutes. Turn the nitrogen purging gas on to aid the evaporation.

12. Transfer the beaker to a vacuum oven, pre-warmed to 120°C, for 30 minutes at full vacuum (about 30 mm Hg pressure or less).

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

14. Calculate percent total fat as follows:

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

Simultaneous Distillation. Extraction and GC Analysis for Volatile Compounds in French Fries

References

(l)Schultz, T.H., Fath, R.A., Mon, T.R., Eggling, S.B., and Teranishi, R. "Isolation of Volatile Compounds" J. Agric. Food Chem.. Vol. 25, No. 3, May-June (1977) pp. 446-449.

(2)Likens, S.T., Nickerson, G.B. Proc. Am. Soc. Brew. Che . 5 (1964) Scope

This procedure has been applied to recovering volatiles (e.g., 2,5- dimethyl pyrazine and 2,4- decadienal) from French fries. This procedure is applicable to other food components and finished products as long as the desired analyte is steam distillable. ' '

Principle

As the sample is steam distilled at atmospheric pressure the steam distillate and methylene chloride vapors are co-mingled then co-condensed. After liquid phase separation occurs in the extractor u-tube, the lighter aqueous phase returns to the sample flask and the heavier methylene chloride phase returns to the analyte concentration flask. When distillation/extraction is complete the methylene chloride is gently blown down and a portion of this concentrate is analyzed further by capillary GC/FID. An internal standard is added to the sample at the onset of the method to track analyte recovery.

Accuracy and Precision

The areas of the internal standard peak (TMP) were looked at for eleven samples over a 20 day period. Areas, averages, standard deviation and recovery data follows:

Sample Date Area

VVDV 2227 2/20/97 356988

2228 2/25/97 310625

2229 2/25/97 431832

2230 2/26/97 322811

2231 2/26/97 322811

WKJ 547 3/04/97 421138

548 3/05/97 418766

549 3/06/97 466864

550 3/06/97 432748

WHS 110-101-1 3/11/97 321636

WHS 110-101-2 3/11/97 453519

ave: 385262 std. dev.: 62911 % rec: 16.3 Equipment

Gas Chromatograph Hewlett Packard 5890 equipped with FID and

3396 integrator

Autosampler (optional) Hewlett Packard 7673 A Capillary Column Stabilwax 30m, 0.32 mm ID, 0.25 umdf Autosampler Vials (with inserts) Kimble EKONICAL 60745-1232

(Kimble 60820-1232 with

66009-996 inserts)

Balance Top loading, two place, four place

Support Jacks (2) VWR 60142-546

Hot plate/stiπer (3) Corning 6795-220

Circulating Bath/cooler Lauda RM3

250mL Flat Bottom Round Flask Pyrex 4100-250

2000 mL Flat Bottom Round Flask Kontes 601000-0829

Reducing Adapter 24/40-29/42 Pyrex 8825-2924

Size 24 Stopper Kimble 4189OR-2440

50 mL, 100 mL and Pyrex 24710-102,124

1000 mL Graduated Cylinder Kimax 34795-062

1 mL Reacti Vial Accuform Kimble 60700-1

Scintillation Vials VWR 66022-081

Pasteur Pipets VWR 14672-200

Syringe (2) Hamilton 100 ul

Volumetrics Kimax 28014-100

SDE Glassware Kontes 523010-0000, 52301, 523012

Boiling Stones VWR 26397-409

Stir Bar 76.2 x 12.7 mm VWR 58948-193

Support Base VWR 60110-266

3 Prong Clamp VWR 21570-404

Pie Plate (2)

Equivalent equipment may be substituted for that recommended above Reagents

Solvent Usage and Disposal: Solvents, such as methylene chloride and acetone should be used in a hood while wearing eye and skin protection. Disposal of excess solvent should be in an appropriately marked waste solvent container.

Tetramethylpyrazine (TMP) Aldrich 18,393-8

Methylene Chloride B&J 300-4

Acetone B&J 010-4

Antifreeze

Deionized water Milli-Q

Dry Ice Pellets

N2

Operation

A. Internal Standard(s) Preparation

1. Tetramethylpyrazine (TMP)

Weigh 0.10g ± 0.001 TMP into a 100 mL volumetric flask. Add fresh deionized distilled water to volume. Label flask. Add 50 ul of this standard to the 2000 ml sample flask when performing extraction.

B. Distillation and Extraction Procedure

1. Circulation bath / cooler

See Attachment I: Safe Practice for Circulating bath/coolers -

a. Place coolant (1:1 antifreeze^O) in cooler chamber. Fill to above cooling coil. b. Set cooling dial to 0 C. Distillation and Extraction

a. Place SDE condenser insert into main chamber making sure inlet glass tube is to the right. Shut stopcock at the bottom of apparatus.

b. Place SDE apparatus into three prong clamp. Connect tubing to that cooler. Turn on cooler.

c. Place dry ice and approx. one inch of acetone into top condenser piece. Place top condenser piece onto assembly (may have to add dry ice throughout extraction.)

d. Place 100 mL Methylene Chloride (measured from a 100 mL graduated cylinder) and one boiling stone into the 250 mL flat bottom round flask. Join flask to right side of condenser. Place pie pan on hot plate on support jack. Add approx. 1 liter distilled H2O to pie plate and adjust support jack upwards until flask is secure to apparatus. Turn hot plate to heat setting "4" ( 60° C).

e. Place stir bar and 700 mL of fresh, deionized distilled water into the 2000 mL flask. Add sample to be extracted according to the following table:

Sample type Weight fries 50.0 ± 0.1 g

Add 50 ul of 0.1% TMP internal standard to flask.

f. When enough MeCl2 has boiled to fill loop of condenser, attach the large flask to left side of condenser using the 24/40-29/42 reducer. Raise 2nd hot plate on jack until flask is secure. Turn hot plate heat setting to above "6" ( a setting adequate to generate rapid boiling without foaming) then turn the stir setting to full.

g. Place insulating sleeve on left arm of condenser and paper towel around stopcock (if needed to catch condensation). h. Allow sample flask to come to a boil (approx. 20 minutes from starting to heat.) Time the extraction/distillation for 90 minutes.

i. After 90 minutes turn off the heat on both hot plates. Lower right hot plate with water pan, rest bottom of flask on edge of pan. Allow condensation to stop and MeCl2 flask to cool (approx. 15 minutes).

j. When MeCl2 has cooled, remove the 250 mL flask from right side and add the MeCl2 still in loop of condenser to the flask via the stopcock. Place glass stopper in 250 mL flask and store in explosion-proof freezer until ready to concentrate (Section 3).

k. Using hot mitts (caution, sample flask will still be hot) lower and remove 2000 mL flask.

1. Turn off cooler. Disconnect top (inlet) hose and allow as much coolant to drain back into cooling chamber as possible. Carefully disconnect bottom (outlet) hose. Drain any remaining coolant into cooling chamber.

m. Set condenser pieces aside to wash (section 4).

3. Sample Extract Concentration

Extract may be stored either before step "a" or after step "d" in explosion-proof freezer indefinitely. If storing extract after step "h", MeCl2 may evaporate and volume may need to be adjusted before further analysis -

a. Set up the third hot plate with second pie pan containing distilled H2O in fume hood equipped with N2 line.

b. Heat water in pan on setting "3" ( 60° C).

c. Place 250 mL sample flask (Section 2j) into water and concentrate MeCl2 to 40 mL under gentle stream N2. d. Transfer 20ml of concentrate to a 20ml scintillation vial and place vial in hot water bath on hot plate and concentrate the MeCl2 under N2 until approx. 2ml remain. Hold or clamp vial so it does not float or become contaminated by H2O during concentration.

e. Remove scintillation vial from H2O and replace with a 1 ml Reacti vial. Add 1 ml of concentrate from step (d) to reacti vial using a Pasteur pipette. Transfer MeCl2 carefully, it will drip from pipette tip.

3. Sample Extract Concentration (cont'd)

f As MeCl2 blows down, continue to add sample concentrate until all has been transferred from scintillation vial. Rinse scintillation vial with appox. 1 mL of fresh MeCl2 and transfer this rinse to reacti vial.

g Continue to concentrate MeCl2until 100 ul remains. Take extreme care to not allow the extract to evaporate to dryness. Transfer the 100 ul (via a syringe to a GC vial (with insert). Cap GC Vial.

4. Glassware Clean-up

General Hazards: Use acetone in fume hood. Wear gloves and eye protection. Dispose of used acetone in appropriate waste solvent can. -

a. Soap and rinse distillation apparatus, flasks, condenser, graduated cylinders and reacti vials.

b. Rinse all glassware with distilled H2O.

c. Rinse all glassware with acetone. Also rinse with acetone and vacuum the syringe used to transfer extract to GC vial.

d. Dry all glassware with N2 to remove acetone. C. GC Analysis

See attachment II: Safe Practice for HP 5890 Gas Chromatograph -

1. Set up Instrument conditions as per Table I and integrator and sequence as per Table II.

2. To light FID detector open H2 and compressed air at tanks. Open valves on GC, detector 2.

Press FID button, listen for "pop". Open auxiliary gas valve.

3. Fill two large vials (for syringe rinse on auto sampler) and one GC vial with MeCl2-

4. The first run each day is a MeCl2 wash. Place MeCl2 containing GC vial in position "1" on autosampler. To start run, press:

SHIFT SEQ START

CHT SP

on 3396 integrator. After method has loaded can change rate to 10/min for MeCl2 only.

5. To analyze sample replace MeCl2 vial with the vial prepared in step "g" of sample extract concentration. Advance integrator to clean sheet of paper by holding the SHIFT and ENTER keys down together. Type sample ID and hit BREAK key at end of line to return printer carriage. To start run press:

SHIFT SEQ START

CHT SP

C. GC Analysis (cont'd)

6. If using inserts in vials and no solvent peak appears on run; hit ABORT to stop run, re-center insert ad replace vial seal and perform step "5" again.

7. After last GC analysis allow oven to cool to 40C. Turn off aux gas. H2 and air valves on instrument and turn H2 and air gauges on tanks to closed. D. Calculation Method

To calculate the amount (ppm) of analyte per sample, use the following calculation:

Area of Analyte X weight of Internal Standard (g) X 1 ppm = ppm Analyte

-6 Area of Internal Std. weight of sample (g) 10

Example:

503191 area units analyte X (5 x 10^* ) g X 1 ppm = 0.30 ppm analyte 1667783 area units ISTD 50 g 10^"6

ATTACHMENT I

Safe Practice for Circulation/Cooling Baths

"Avoid personal injury. Never use these circulators for any application involving direct investigation or treatment of human beings. They are not medical devices. They are laboratory instruments intended only for analysis and control of laboratory samples or laboratory specimens.

These circulators are designed for normally supervised laboratory use. If unattended or overnight operation is required, a suitable back-up safety system can be used to eliminate the risk of possible secondary damage due to leakage or uncontrolled heating.

Circulators are fitted with heaters which provide the necessary heating energy for the bath liquid. If the temperature control fails, or if the liquid level is too low, the heater may reach a temperature which, in combination with flammable liquids, can cause a fire in the laboratory.

When using the circulator with external circulation, failure of the tubing can cause discharge of hot liquid and endanger persons and material in the laboratory.

Only non-flammable liquids should be used. The operating range of the bath liquid and tubing may limit the operating temperature range of the circulator.

Secure tubing with clips to prevent it from slipping off. Always use water or some other non-flammable liquid. Never use alcohol or flammable liquids. The water must completely cover the heating coils. The liquid level should be checked periodically and additional liquid added if necessary. Never operate the circulator with the heating coils exposed to the air as severe damage can occur if the coils are exposed and allowed to over heat. Devices to retard the evaporation of liquid, such as a layer of plastic balls on the liquid surface, should not be used."

from "Operating Instructions Lauda RM Circulating Bath."

ATTACHMENT II

Safe Practices: HP 5890 GC

General Hazards:

These instruments are operated with heated temperature zones and with flammable and pressurized gases delivered from gas cylinders. These could cause personal injury or explosions.

Personal Protective Equipment: Wear safety glasses at all times. When working with the heated zones wear insulated gloves to protect against burns.

Specific Safety Steps:

Turn off and allow heated zones to cool before changing columns or working with injector or detector areas.

Gas cylinders must be securely fastened with chains to wall or appropriate storage rack. Transport cylinders only with a four-wheeled gas cart.

Gas lines and fittings must be leak checked on a periodic basis and whenever tubing or fittings are serviced to avoid explosion and asphyxiation hazard.

When rebuilding FID detector, the power must be disconnected because the electronic detector board must be removed.

The autosampler controller must be turned off when changing syringes to avoid accidental startup of the injector. Instrument Set-Up:

1. Column Installation

Refer to Chapter 2 (installing columns) of the Hewlet-Packard 5890 operating manual for the procedures to properly install capillary or packed columns. Leak test the column nut at both the detector and injector.

2. Oven Temperature Setting

Refer to Chapter 3 of the operating manual.

3. System Flow Rates

Refer to Chapter 4 of the operating manual.

4. Detector System Control

Refer to Chapters 5 and 6 in the operating manual.

General Operation Checks:

1. Before running a sample, check that the gas flow rates (carrier, make-up, hydrogen and air) are at the correct values.

2. Visually inspect the septa and the injector liner at regular intervals. Replace if worn or dirty. A drop in column head pressure usually indicates a leaking septa.

3. If using the FID, verify that the signal is below 20 picoamps. If above 20 picoamps the FID may be dirty. A blank solvent run and bake out will usually reduce the background signal, but if the signal is still unacceptable the detector parts should either be cleaned or replaced.

4. Inject a sample of blank solvent to verify that the detector and injector are operating properly.

TABLE I

GC Parameters

Run parameters: Zero = 0 Attn 2 = 2 Cht sp = 1.0 Ar Rej = 0 Thrsh = 1 Pk Wd = 0.04

Oven Temp = 40 Equib time = 1 Oven Max = 260 Initial temp = 40 Initial time = 0

Temp prgm: rate = 4.0 Final temp = 250 Final time = 20.0

Inj temp = 250 Det temp = 325 Signal 2 = B

Range = 0

Zero = 15.1

Atten = 2

Detect B = FID (ON)

Purge B = OFF On time = 0.5 Offtime = 0.0

TABLE 2

Sequence Parameters:

inet sampler control = yes equil time = 0 method = m:above method. injector:

# of pumps 4 viscosity = 7 volume = 1

# of solvent washes = 6 EXAMPLES Example 1

Two oven-finished French fry products and one deep-fried French fry product are prepared as follows:

A. Oven-finished French fries according to the present invention:

Frozen shoestring-cut par-fried potato strips are an acceptable starting product (e.g., Simplot Par-Fries; J. R. Simplot Co., Caldwell, ID). A typical processing history may include: sorted and graded Russet Burbank potatoes are peeled, washed, trimmed and cut axially into shoestring strips (0.25 inch square cross-section). The potato strips are blanched in hot water or steam and partially dried with hot air such that the potato strips are reduced in weight by about 15%. The partially dried strips are then par- fried in partially-hydrogenated soybean oil (Iodine Value of about 67) for about 50 seconds at an oil temperature of about 375°F (190.5°C). The par-fried potato strips are then cooled and frozen in a blast freezer at -30°F (-34.4°C) and packaged. The par-fried potato strips have a moisture content of about 64% and a fat content of about 6%.

About 1 lb. of the frozen par-fried potato strips are further processed by deep frying in a 45 lb. oil capacity foodservice frying kettle containing Primex 108 vegetable oil (blend of partially hydrogenated soybean oil and corn oil available from the Procter & Gamble Co.) for about 3 minutes at a temperature of about 290°F (143.3°C). The resulting par-fries are immediately frozen by immersion in liquid nitrogen for 20 seconds. The moisture content of the resulting par-fry is about 47% and the fat content is about 15%. Immediately after being frozen the par-fries are enrobed with oil by immersing in liquid vegetable oil (conditioned Primex 108) having a temperature of about 335°F (~168°C) for about 1-3 seconds. The resulting oil-enrobed par-fries are again frozen by immersion in liquid nitrogen. The frozen par-fries are packed into sealed foil-laminate bags and stored at noπnal freezer temperatures of approximately 0°F (-18°C) to about -20°F (-29°C). The oil-enrobed par-fries contain about 9% surface fat by weight of the fries. The total fat level is about 22% and the bulk moisture level is about 43%.

About 128 grams of the above frozen oil-enrobed par-fries are placed on an open wire mesh oven tray in a single layer and then baked at a temperature of about 400°F (204°C) in a forced air convection oven (Wells Manufacturing Co.; Model No. M42003S) for about 1 minute. Then the fries are transferred to a solid stainless steel oven tray in a single layer and baked an additional 1.5 minutes. A turbulent hot airflow exists within the oven chamber. The air velocity at the center of the oven chamber (immediately above the product bed) is about 900 feet per minute (274 meters per minute). Upon removal from the oven, the fries are immediately evaluated for various technical attributes or are salted and evaluated for flavor and texture by sensory testing. B. Commercial oven-finished French fries:

Frozen retail Ore-Ida® "Shoestrings" French fried potatoes (Ore-Ida Foods, Inc., Boise, ID) are purchased at a local grocery store. The fries comprise about 63% moisture and about 6% fat. The fries are baked in a conventional home oven (General Electric) as follows: approximately 8 oz. of frozen fries are spread uniformly in a single layer over a 9" x 13" solid cooking sheet and baked for about 10 minutes at a temperature of about 450°F (232°C). Upon removal from the oven, the fries are immediately evaluated for various technical attributes or are salted and evaluated for flavor and texture by sensory testing.

C. Deep-fried French fries (McDonald's™ French fries; "gold standard"):

The frozen shoestring-cut par-fried potato strips used as the starting par-fry for preparation of product "A" of this example (Simplot Par-fries; J. R. Simplot Co.; Caldwell, ID) are further processed by deep-frying. The par-fried potato strips have a moisture content of about 64% and a fat content of about 6%.

About 1.5 lb. of the frozen par-fried potato strips are allowed to thaw for about 1 hour at room temperature (70°F; 21.1°C) and then are deep-fried in a 45 lb. foodservice frying kettle containing conditioned Primex 108 vegetable oil (blend of partially hydrogenated soybean oil and corn oil available from the Procter & Gamble Co.) for about 3 minutes at an oil temperature of about 335°F (168°C). Upon removal from the fryer, the deep-fried French fries are immediately evaluated for various technical attributes or are salted and evaluated for flavor and texture by sensory testing.

The above French fry products (A, B and C) are evaluated for bulk moisture, total fat, internal moisture content, surface Aw and Texture Value. The results are shown in the following table:

The above data show that the oven-finished French fries according to the present invention (A) have technical attributes that are very similar to deep-fried French fries (C) that are considered the "gold standard." The commercial oven-finished French fries (B) fall outside the desired ranges for surface Aw and the textural parameters (maximum force, area, and ratio of area to maximum force).

The above French fry products are also evaluated for flavor and texture by sensory testing. A panel of ~40 trained individuals rate the products for various sensory attributes on a scale of 1 to 9. Two sensory tests are run, evaluating each of the oven fry products directly against the deep-fried French fries. Following are the sensory test results; each numerical value is the average rating for that attribute.

Note: Within each sensory test, attribute ratings with letter superscripts are significantly different at a 95% confidence level.

The sensory test results reveal that the oven-finished French fries according to the present invention (A) have flavor and textural attributes very similar to the deep-fried French fries (C). In particular, the oven-finished French fries according to the present invention possess the desired textural dichotomy, i.e., a moist interior and a crisp crust, that is typically associated with deep-fried French fries. In contrast, the commercial oven fries (B) do not possess the desired textural dichotomy as revealed by a significantly lower surface crispness rating.

Example 2

D. Oven-finished French fries according to the present invention:

The frozen shoestring-cut par-fried potato strips used as the starting par-fry in Example 1A are an acceptable starting product for this example (Simplot Par-Fries; J. R. Simplot Co.; Caldwell, ID). The par-fried potato strips have a moisture content of about 64% and a fat content of about 6%.

About 1 lb. of the frozen par-fried potato strips are further processed by deep frying in a 45 lb. oil capacity foodservice frying kettle containing Primex 108 vegetable oil (blend of partially hydrogenated soybean oil and com oil available from the Procter & Gamble Co.) for about 3 minutes at a temperature of about 290°F (143.3°C). The resulting par-fries are immediately frozen by immersion in liquid nitrogen for 20 seconds. The moisture content of the resulting par-fry is about 48% and the fat content is about 14%. The frozen par-fries are packaged into foil-laminate bags and stored at about 0°F (-18°C).

The frozen par-fries are baked in a double impingement oven (Wolverine Corporation, Merrimac, MA; Model 2.0 x 051 pilot plant Jetzone™ oven) equipped with a continuous conveyor. The par-fries are arranged in a single layer on an open wire mesh tray that is placed on the oven conveyor belt. Hot air impinges on the product from both the top and bottom, delivered from two banks of tubes located above and below the conveyor belt. The air velocity measured at the product bed is about 5,500 feet per minute (1,676 meters per minute). The air temperature within the oven chamber is 450°F (232° C) and the conveyor speed is adjusted such that the residence time in the oven is 1.25 minutes. Immediately after exiting the oven, the fries are lightly sprayed with warm (~150°F) conditioned Primex 108 vegetable oil; about 3% oil by weight of the fries is sprayed onto the surface. The oven-finished fries are then immediately evaluated for various technical attributes or are salted and evaluated for flavor and texture by tasting.

E. Commercial oven-finished French fries:

Frozen samples of the Ore-Ida® Vend Fry® for use in the Ore-Ida French Fry Vendor™ (shoestring-cut; Ore-Ida Foods, Inc., Boise, JO) are obtained from a local distributor and stored at 0°F (- 18°C) or lower. The frozen Ore-Ida® Vend fries are loaded into the freezer compartment of an Ore-Ida Model 890 French Fry Vendor™ vending machine (Crane National Vendors, Division of Unidynamics Corp., Bridgeton, MO). The Vend fries are baked in the French Fry Vendor™ according to the manufacturer's recommendations: about 3.5 oz. of frozen Vend fries are deposited into a rotating basket and then baked for about 40 seconds with forced hot air at 465°F (240°C) blowing through the basket. Upon completion of the baking cycle, the oven-finished fries are automatically dispensed and then immediately evaluated for various technical attributes or are salted, and evaluated for flavor and texture by tasting.

F. Deep-fried French fries (McDonald's™ French fries: "gold standard"):

The frozen shoestring-cut par-fried potato strips used as the starting par-fry for preparation of product "D" of this example (Simplot Par-fries; J. R. Simplot Co.; Caldwell, ID) are further processed by deep-frying. The par-fried potato strips have a moisture content of about 64% and a fat content of about 6%.

About 1.5 lb. of the frozen par-fried potato strips are allowed to thaw for about 1 hour at room temperature (70°F; 21.1°C) and then are deep-fried in a 45 lb. foodservice frying kettle containing conditioned Primex 108 vegetable oil (blend of partially hydrogenated soybean oil and co oil available from the Procter & Gamble Co.) for about 3 minutes at an oil temperature of about 335°F (168°C). Upon removal from the fryer, the deep-fried French fries are immediately evaluated for various technical attributes or are salted and evaluated for flavor and texture by tasting. The above French fry products (D, E and F) are evaluated for bulk moisture, total fat, internal moisture content, surface Aw and Texture Value. The results are shown in the following table:

The above data show that the oven-finished French fries according to the present invention (D) have technical attributes that are very similar to deep-fried French fries (F) that are considered the "gold standard." The commercial oven-finished French fries (E) fall outside the desired ranges for surface Aw and the textural parameters (maximum force, area, and ratio of area to maximum force).

The above French fry products are also evaluated for flavor and texture by tasting. The oven- finished French fries according to the present invention (D) have a flavor and texture similar to the "gold standard" deep-fried French fries (F). In particular, the oven-finished French fries of the present invention possess the desired textural dichotomy, i.e., a moist interior and a crisp crust, that is typically associated with deep-fried French fries. In contrast, the commercial oven fries (E) lack sufficient crispness and do not possess the desired textural dichotomy.

Example 3

A non-digestible fat composition is used to prepare the par-fried potato strips in the following example. The non-digestible fat composition is Olean™, from the Procter & Gamble Company, which comprises a blend of liquid and solid sucrose polyester. Sorted and graded Russet Burbank potatoes are peeled, washed, trimmed and cut axially into shoestring strips (0.25 inch square cross-section). The potato strips are blanched in hot water or steam and partially dried with hot air such that the potato strips are reduced in weight by about 15%. The partially dried strips are then par-fried in Olean™ at an oil temperature of about 375°F (190.5°C) for a time sufficient to reduce the moisture content of the par-fries to about 54%. The par-fried potato strips are then cooled and frozen in a blast freezer at -30°F (-34.4°C) and packaged About 1 lb. of the packaged frozen par-fried potato strips are further processed by frying in a 45 lb. oil capacity foodservice frying kettle containing Olean™ for about 3 minutes at a temperature of about 300°F (149°C). The resulting par-fried potato strips are immediately frozen by immersion in liquid nitrogen for 20 seconds, packaged in foil laminate bags, and stored at normal freezer temperatures of approximately 0°F (-17.8°C). The par-fried potato strips have about 45% moisture and about 20% fat.

About 128 grams of the frozen par-fries are placed on an open wire mesh oven tray in a single layer and then baked at a temperature of about 400°F (204°C) in a forced air convection oven (Wells Manufacturing Co., Model No. M42003S) for about 2.5 minutes. A turbulent air flow exists within the oven chamber, with an air velocity at the center of the oven chamber just above the product bed of about 900 feet per minute (274 meters per minute). The fries are then transferred to an open wire mesh basket in a single layer and the basket placed within the treatment zone of a high velocity impingement oven (manufactured by Industrial Combustion Services, Inc., Tyrone, GA). Hot air at 375°F is directed onto the surface of the fries at a velocity of about 5,000 feet per minute (1,524 meters per minute). The fries are held in the impingement oven for 15 seconds.

The resulting reduced calorie oven finished French fries have a texture and flavor very similar to gold standard deep-fried French fries. The finished fries have a bulk moisture content of about 35%, a total fat content of about 15%, an internal moisture content of about 72%, a surface Aw of about 0.4, and a Texture Value of about 250.

Example 4

About 1 lb. of the frozen par-fried potato strips are further processed by frying in a 45 lb. oil capacity foodservice frying kettle containing Primex 108 vegetable oil (blend of partially hydrogenated soybean oil and com oil available from the Procter & Gamble Co.) for about 3 minutes at a temperature of about 335°F (168.3°C). The resulting par-fries are immediately frozen by immersion in liquid nitrogen for 20 seconds, and then equilibrated to about 0°F (-17.8°C). The par-fries have about 38% moisture and about 17% fat. The frozen par-fries are then surface hydrated by spraying a fine mist of water at ~70°F (21.1°C) onto the surface of the par-fries. During the hydration process, the frozen par-fries are tumbled in order to achieve a uniform application of water onto the surface of the par-fries. Spraying of the water mist is continued until about 7% (by weight of the par-fries) of water is applied to the surface of the par- fries. The frozen hydrated par-fries are then stored at between 0°F (-17.8°C) and 20°F (-6.7°C). The hydrated par-fries comprise about 43% bulk moisture and about 15% total fat. Hydration of the par-fry surface increases the Aw of the crust region, thereby reducing or eliminating the Aw differential between the internal core and the crust region, which is the driving force for moisture migration during frozen storage.

About 128 grams of the frozen, hydrated par-fries are prepared for consumption by baking in a forced air convection oven (Wells Manufacturing Co.; Model No. M42003S). The hydrated par-fries are arranged in a single layer on an open wire mesh oven tray and baked for 1.5 minutes at an air temperature of about 425°F (218.3°C). A turbulent hot air flow exists within the oven chamber. The air velocity at the center of the oven chamber (immediately above the product bed) is about 900 feet per minute (274 meters per minute). The oven-finished French fries have a desirable textural dichotomy, i.e., a crisp surface texture and moist interior. The finished fries have a bulk moisture content of about 39%, a total fat content of about 16%, an internal moisture content of about 72%, a surface Aw of about 0.4, and a Texture Value of about 290 (maximum force = 237 grams; area = 289 gram sec; ratio of area to maximum force = 1.22).

Claims

What is claimed is:

1. Oven-finished French fried potatoes comprising at least about 0.5 ppm 2,4,-decadienal.

2. Oven-finished French fried potatoes comprising at least about 0.2 ppm methional.

3. Oven-finished French fried potatoes according to Claim 1 further comprising: a) from about 32% to about 50% bulk moisture; b) from about 8% to about 25% total fat; c) at least about 0.2 ppm metiiional; and d) a maximum force of at least about 200 grams.

4. Oven-finished French fried potatoes according to Claim 1 further comprising: a) from about 32% to about 50% bulk moisture; b) from about 8% to about 25% total fat; c) at least about 0.2 ppm methional; and c) an area under the force deformation curve during the first one-third of a compression test of at least about 200 gram'second.

5. The oven-finished French fried potatoes of Claim 3 wherein said oven-finished fries comprise at least about 0.7 ppm 2,4-decadienal, at least about 0.3 ppm methional, a bulk moisture of from about 33% to about 44%, a total fat of from about 13% to about 23% and a maximum force of from about 210 to about 1,000 grams.

6. The oven-finished French fried potatoes of Claim 4 wherein said oven-finished fries comprise at least about 0.7 ppm 2,4-decadienal, at least about 0.3 ppm metiiional, a bulk moisture of from about 33% to about 44%, a total fat of from about 13% to about 23% and an area under the force deformation curve during the first one-third of a compression test of from about 210 to about 1,000 gram second

7. The oven-finished French fried potatoes of Claim 3 wherein said oven-finished fries comprise at least about 1.0 ppm 2,4-decadienal, at least about 0.4 ppm methional.

8. The oven-finished French fried potatoes of Claim 4 wherein said oven-finished fries comprise at least about 1.0 ppm 2,4-decadienal, at least about 0.4.

9. The oven-finished French fried potatoes of Claim 3 wherein said oven-finished French fries have a surface water activity of less than or equal to about 0.55 and an internal moisture of from about 55% to about 80%.

10. The oven-finished French fried potatoes of Claim 4 wherein said oven-finished French fries have a surface water activity of less than or equal to about 0.55 and an internal moisture of from about 55% to about 80%.

11. The oven-finished French fried potatoes of Claim 9 wherein said oven-finished French fries have a surface water activity of from about 0.1 to about 0.52 and an internal moisture content of from about 60% to about 77%.

12. The oven-finished French fried potatoes of Claim 10 wherein said oven-finished French fries have a surface water activity of from about 0.1 to about 0.52 and an internal moisture content of from about 60% to about 77%.

13. The oven-finished French fried potatoes of Claim 11 wherein said oven-finished French fries are shoestring-cut fries.

14. The oven-finished French fried potatoes of Claim 12 wherein said oven-finished French fries are shoestring-cut fries.

15. The oven-finished French fried potatoes of Claim 13 wherein the surface water activity is less than or equal to about 0.55.

16. The oven-finished French fried potatoes of Claim 14 wherein the surface water activity is less than or equal to about 0.55.

17. The oven-finished French fried potatoes of Claim 2 comprising at least about 1.3 ppm 2,4- decadienal.