Microwaveable Packaged Food Product

Abstract

A package containing nuts and suitable for microwave heating is described herein. The package is configured to heat the nuts and provide an aroma reminiscent of traditional, freshly-roasted nuts. The freshly-roasted nut attributes include an aroma, temperature, texture and taste, which are reproduced with the microwave package. The package preferably, though not necessarily, incorporates one or more susceptors in order to provide additional heating, such as conductive heating, to the nuts. The package also preferably includes a sufficient headspace to allow for the aromas to develop.

Claims

1. A packaged food product comprising: a flexible film forming a pouch having an interior cavity formed by seals, the flexible film pouch being substantially hermetically sealed; about 0.75-oz. to about 2-oz. shelled nuts disposed within the interior cavity of the flexible film pouch; and a patterned susceptor disposed in the interior cavity of the flexible film pouch, wherein over 60% of the patterned susceptor is not in contact with the food product when the food product is heated; wherein the packaged food product is configured to be microwaved while sealed in a closed configuration to roast the shelled nuts to a temperature of about 120 F. to about 260 F.

2. The packaged food product of claim 1 wherein a weight of the shelled nuts is about 1.0 oz. to about 1.5 oz., the flexible film pouch is expandable and capable of remaining sealed in the closed configuration during a microwave operation lasting about 20 seconds to about 130 seconds roasting the shelled nuts contained therein, so as to enable a concentrated roasted aroma release upon subsequent package opening, and the flexible film is a multilayered structure having at least one of the following layers therein: a barrier material; a printable film layer; an oriented film layer; a sealable layer; a varnish, protective layer; a coefficient of friction modified layer; and a partial or patterned layer of any of the above.

3. The packaged food product of claim 1 wherein the pouch further includes a paper layer enabling stiffness and insulation thereof, the pouch includes three side seals and a film fold, the flexible film pouch is gas flushed prior to sealing the shelled nuts therein to reduce oxygen presence and provide a modified atmosphere in the flexible film pouch.

4. The packaged food product of claim 1 wherein the flexible film pouch further includes a gusset providing stand-up pouch stability, and a tear notch disposed in a portion of one of the seals, the tear notch facilitating opening of the flexible film pouch from the closed configuration to an open configuration.

5. The packaged food product of claim 1 wherein a volume of shelled nuts is less than 75% of a total internal package volume.

6. The packaged food product of claim 1 wherein the volume of shelled nuts is about 20% to about 40% of the total internal package volume, and wherein the shelled nuts are arranged on a single layer within the package, and wherein the flexible film includes a metalized layer that forms the susceptor, and wherein the metalized layer has been treated with an acid solution to remove portions of the metalized layer forming a discontinuous metalized layer as a patterned susceptor, and wherein the susceptor includes at least one to three discrete susceptors.

7. The packaged food product of claim 6 comprising a first susceptor on a first panel wall of the pouch and a second susceptor on a second panel wall of the pouch, wherein the first and second susceptors are configured to heat and brown the shelled nuts and provide an aroma release.

8. The packaged food product of claim 1 wherein the susceptor is disposed in a pattern on the flexible film, spaced from package seals.

9. The packaged food product of claim 1 further comprising nut flavorings comprising at least one of: salt, black pepper, cinnamon, honey, sugar, peanut oil, caramel, and coconut, and at least one of a coating and dry seasonings.

10. The packaged food product of claim 9 wherein the coating is effective to absorb and/or reflect microwave energy during exposure of the packaged food product thereto, while also being permeable to a portion of the microwave energy.

11. The packaged food product of claim 1 wherein the shelled nuts comprise one or more of peanuts, cashews, almonds, and other tree nuts, whole, halves, or pieces with dimensions of about -1 in length and - in width and have been pre-roasted and steam pasteurized prior to packaging within the flexible film pouch.

12. The packaged food product of claim 11 wherein the shelled nuts have a moisture level that decreases by 15%-25% during pre-roasting as compared to unroasted, shelled nuts, while increasing the composition of volatile compounds associated with roasting.

13. The packaged food product of claim 12 wherein the pre-roasted shelled nuts have undergone at least one of a dry roast or an oil roast.

14. The packaged food product of claim 1 wherein the shelled nuts comprise peanuts having a moisture level between about 1.1% to about 1.4%.

15. The packaged food product of claim 1 further comprising at least one of: an aromatic compound disposed on an inside surface of the flexible film pouch prior to packaging the shelled nuts; or a sprayable aromatic compound that is sprayed into the flexible film pouch after depositing the shelled nuts therein; wherein a headspace of the flexible film pouch is reduced via vacuum packaging after the shelled nuts are disposed therein, and the shelled nuts include at least one of almonds, cashews, or peanuts.

16. The packaged food product of claim 1 wherein the patterned susceptor has a grid-like configuration.

17. A packaged food product comprising: a flexible film forming a pouch having an interior cavity formed by seals and having one or more vents therein; about 0.75-oz. to about 2-oz. shelled nuts disposed within the interior cavity of the flexible film pouch; a patterned susceptor disposed in the interior cavity of the flexible film pouch, the susceptor configured to roast the shelled nuts during microwaving, the shelled nuts are roasted to a temperature of about 120 F. to about 260 F.; and a sealed overwrap around the flexible film forming the pouch that is removed prior to microwaving; wherein over 60% of the patterned susceptor is not in contact with the food product when the food product is heated; wherein the flexible film pouch filled with the shelled nuts is configured to be microwaved in a closed configuration where the seals have not ruptured; wherein the vents limit internal pressure within the pouch during microwave heating, and enable internal pressure to decrease after completion of microwave heating.

18. The packaged food product of claim 17 wherein the flexible film pouch includes a longitudinal seal extending between end seals, and the one or more vents includes a pin hole at a juncture between the longitudinal seal and one of the end seals, and wherein the pouch and overwrap have been gas flushed to provide a modified atmosphere therein.

19. The packaged food product of claim 17 wherein the patterned susceptor has a grid-like configuration.

20. A method of making a packaged food product comprising: wrapping a web of multi-layer flexible film into a film tube; providing at least one patterned susceptor inside the film tube; forming a first end seal to partially form a flexible film pouch; depositing about 0.75 oz. to about 2 oz. shelled nuts in the partially formed flexible film pouch; gas flushing the partially formed flexible film pouch to reduce oxygen therein; forming a second end seal in the flexible film pouch; wrapping the flexible film pouch in an overwrap film thereby forming an overwrap pouch; gas flushing the overwrap pouch to reduce oxygen in the overwrap pouch; and sealing the overwrap pouch around the flexible film pouch, and further comprising at least one of: depositing flavoring on an inside surface of the multi-layer flexible film that forms the film tub; spraying flavoring into the film tube prior to forming the second seal of the flexible film pouch; and spraying flavoring onto the shelled nuts prior to depositing the shelled nuts in the flexible film pouch.

21. A method of using a packaged food product comprising about 1 oz. to about 1.5 oz. of shelled nuts and a heat-activated aroma-release composition, each of the shelled nuts individually having a mass of 28 grams+/5 grams to 42 grams+/5 grams, the shelled nuts being arranged in a single layer on a portion of a patterned susceptor within a sealed flexible package having a vent opening with a frangible closure, the shelled nuts comprising about 1.0% to about 2.0% moisture and having a predetermined aggregate surface area, the method comprising: first maintaining the packaged food product at ambient temperature and pressure; thereafter exposing the packaged food product to microwave energy in a 900 to 1200 W microwave oven for a period of about 45 seconds to about 100 seconds to heat the shelled nuts and reduce their moisture content to between about 0.9% and about 1.3%, and simultaneously vaporizing moisture within the package to inflate the package and increase its interior pressure; wherein exposing the packaged food product includes over 60% of the patterned susceptor not contacting with the food product; wherein heating the nuts results in a darkening of portions of the aggregate nut surface area; wherein the darkened portions are in contact with the susceptor during heating, and comprise about 10% to about 25% of the aggregate nut surface area; thereafter removing a portion of the package to release a roasted-nut aroma, and to provide an open-topped container to provide hand-held access to the heated shelled nuts, wherein the packaged food product includes a headspace and a flavor treatment disposed within the sealed flexible package, and wherein heating the packaged food product results in an increase of aroma components in the headspace.

22. The method of claim 21 wherein the shelled nuts include cashews, and wherein the increase of aroma components in the headspace comprises an increase in furfural aroma by a factor of 100 to 250; an increase in ethylpyrazine aroma by a factor of 50 to 200; and an increase in diacetyl aroma by a factor of 200 to 400.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] FIG. 1 is a rear perspective view of a first embodiment of a microwave susceptor package containing shelled nuts, showing a pair of end seals and a fin seal configured to form a top panel and a bottom panel;

[0023] FIG. 2 is a plan view of a segment of a susceptor material disposed on one of the panels of the package of FIG. 1;

[0024] FIG. 3 is a front perspective view of a second embodiment of a bottom-gusseted, standup microwave susceptor package containing shelled nuts, showing a pair of side seals, a top portion having been removed, and showing a food product comprising shelled nuts following microwave heating;

[0025] FIG. 4 is a schematic diagram of a process for providing a heated food product, including placing a packaged food product in a microwave oven, heating the packaged food product, then removing a portion of the package to serve the food product;

[0026] FIG. 5 is a front elevation view of a packaged food product in accordance with FIG. 3, empty and prior to removal of the top of the package, showing a peripheral seal area along the top and sides of the package;

[0027] FIG. 6 is a plan view of a web of film showing sealing areas and cut lines for use in forming the package of FIG. 5;

[0028] FIG. 7 is a plan view of a first alternative web of film showing sealing areas and cut lines for use in forming the package of FIG. 5, similar to that of FIG. 6 but showing a susceptor added to the interior of what will be one of the panels of the package;

[0029] FIG. 8 is a plan view of a second alternative web of film showing sealing areas and cut lines for use in forming the package of FIG. 5, similar to that of FIG. 6 but showing susceptors added to the interior of what will be both panels of the package;

[0030] FIG. 9 is a plan view of a third alternative web of film showing sealing areas and cut lines for use in forming the package of FIG. 5, similar to that of FIG. 6 but showing one or more susceptors added to the interior of what will be one of the panels of the package;

[0031] FIG. 10 is a graph showing comparative magnitudes of selected aroma components associated with shelled mixed nuts at room temperature, and after warming with and without a susceptor;

[0032] FIG. 11 is a table showing comparative magnitudes of selected aroma components associated with individual varieties of shelled nuts at room temperature and after warming with a susceptor; and

[0033] FIGS. 12-15 illustrate examples of raw data generated using gas chromatography-mass spectroscopy to measure aroma components.

[0034] FIG. 16 provides numerical data that is illustrated graphically in FIG. 10.

[0035] FIG. 17 is a table showing comparative magnitudes of selected aroma components associated with individual varieties of shelled nuts at room temperature and after warming with a susceptor.

[0036] FIG. 18 is a side elevational sectional view of the packaged food product of FIG. 1.

[0037] FIG. 19 is an end sectional view of the packaged food product of FIG. 1.

[0038] FIG. 20 is a side view of a packaged food product in accordance with FIG. 3.

[0039] FIG. 21 is a front view of the packaged food product in accordance with FIG. 3.

[0040] FIG. 22 is a front view of a second embodiment of a microwave susceptor package containing shelled nuts.

[0041] FIG. 23 is a rear view of a second embodiment of a microwave susceptor package of FIG. 22, showing a pair of end seals and a fin seal configured to form a top panel and a bottom panel.

[0042] FIG. 24 is a top plan view of an opened microwave susceptor package where at least some portion of a majority of the food product is in direct contact with the lower surface of the food package when disposed on one of its panels.

[0043] FIG. 25 is a cross sectional view of the packaged food product of FIG. 22 at line 25-25 in a heating position wherein the package inflates and the first side of the package lifts away from the food product during heating.

[0044] FIG. 26 is a graph showing comparative magnitudes of selected aroma components associated with raw almonds at room temperature, and after warming with and without a susceptor,

[0045] FIG. 27 is a graph showing comparative magnitudes of selected aroma components associated with raw cashews at room temperature, and after warming with and without a susceptor

DETAILED DESCRIPTION

[0046] Packaged food products suitable for microwave heating are described herein, including with reference to FIGS. 1-27.

[0047] In one embodiment, a packaged food product, shown in FIGS. 1, 18, and 19, has a low profile and is configured to be microwaved on its side, i.e., in a generally horizontal position such that its length and width are greater than its height. In this embodiment, the packaged food product includes a pouch or package 10 that includes an uninterrupted, continuous bottom wall 22, pair of end seals 12, 14 and a top wall 16 having a fin seal 18 extending longitudinally thereof. In some embodiments, the package 10 may include a pin hole vent 19 at a juncture between the fin seal 18 and one of the end seals 12, 14. If the package 10 over-pressurizes during heating, some pressure may be relieved through the pin hole vent 19, or any other vents strategically included in the package 10. Other types of vents may include slits, flaps, scored regions, or weakened regions.

[0048] In some embodiments, the package 10 may be made in a high-speed, high volume automated form-fill-seal operation in which a web of film is formed into a tube, with edges brought together to form the longitudinal fin seal 18, and with the transverse end seals 12, 14 formed at predetermined spacing before and after loading of product and gas flushing, and with the packages 10 being separated from one another by cuts through the end seals 12, 14. The interior of the package optionally includes one or more susceptors 20. For example, a patterned susceptor, or more specifically a grid-like susceptor 20 material, shown in FIG. 2, can be provided on one or both sides, i.e., on one or both of the top and bottom surfaces of the package so as to be positioned above, below, or both above and below the food product during heating. In some embodiments, the susceptor 20 may only cover a portion of the top or bottom of the package 10. In some embodiments, the package 10 contains a large number of discrete food items 32, e.g., a mixture of shelled nuts, such as almonds, cashews and peanuts. In some embodiments, the food items 32 may be arranged where at least some portion of a majority of the food items is in direct contact with the lower surface of the package 10 when disposed on either the top wall 16 or the bottom wall 22. In these embodiments, most or all of the food items 32 may also be in contact with, or at least in close proximity to, the top of the package 10 as well, at least initially during microwave heating. As microwave heating progresses, expansion of the package 10 may lift the top surface and an associated susceptor 20 from the food items 32, which may have a self-regulating effect on the heating operation to reduce or avoid overheating and/or or scorching due to variations in microwave energy, heating time or other parameters. Expansion of the package 10 may also result in the edges of the top wall being raised from the floor of the microwave oven, and may change the arrangement of some or all of the food items from a single-layer configuration to a multiple-layer configuration in which some of the food items to overlie others, which may also have a self-regulating effect on the heating operation to help reduce or avoid overheating and/or scorching. In some embodiments that employ a patterned susceptor, such as a grid-like pattern, the food items 32 that are on the edges of the susceptor may roast more quickly, possibly due to remaining in a configuration on the edge of the package where at least a portion of the food items are in direct contact with susceptor as opposed to a configuration which may occur in the middle of the package where some food items may not be in direct contact with the susceptor.

[0049] In a second embodiment, shown in FIGS. 3, 5, 20 and 21, a packaged food product includes a package or pouch 24 that is configured to stand up during and/or following microwave heating. The pouch 24 can include a pair of side seals 26, a top seal 28 and a bottom 30, shown schematically in FIG. 5. A top portion 34 of the pouch 24, which encompasses the top seal 28, is configured for removal. The pouch 24 is shown after removal of the top portion 34 in FIG. 3.

[0050] As shown in the schematic diagram of FIG. 4, in some embodiments, a packaged food product such as any of the above-described packaged food products can be inserted into a microwave oven, heated using microwave energy, then removed from the microwave oven, after which a portion of the package 24 may be removed, separated or otherwise opened to provide access to the food items 32. In some embodiments, the package 110 may be separated and unfolded, such as in FIG. 24, where the food items 32 remain on the susceptor 120 to receive any residual heat from the susceptor 120. In this manner, the food products 32 may continue to be warmed by the susceptor 20 while being consumed from the package 110.

[0051] In some embodiments including but not limited to those described above, the pouch 24 can be formed from a web of film 36, various examples of which are shown in FIGS. 6-9. The web of film can be folded so that regions 38 and 40 form the front and rear of the package, with seals 42 and 44 being formed on the sides and top. In some embodiments, the bottom can comprise a single fold along line 46. Alternatively, a gusseted bottom may be provided. A web of film 36 can be configured without a susceptor, as shown in FIG. 6, or with one or more susceptors 48 added prior to singulating the package 24 from the web of film 36, as shown in FIGS. 7-9. For example, a single susceptor 48 can be attached to the web of film 36 in an area that will be an interior surface of one of the front or rear walls of the package 24, as shown in FIG. 7. Alternatively, a pair of susceptor 48 surfaces can be provided on the web of film 36 in areas that will be interior surfaces of the front 38 and rear 40 walls of the package, as shown in FIG. 8. In another alternative, multiple types of susceptors 48 may be incorporated on a single panel, as shown in FIG. 9, or on other panels, to provide increased localized conductive heat transfer in a particular region of a susceptor 48. Optionally, the susceptor 48 surfaces can be positioned closer to the bottom 30 of the package than the top 34 such that they will be adjacent the food product near the bottom 30 of the package 24 during microwave heating.

[0052] In a third embodiment, shown FIGS. 22-25, a packaged food product includes a package or pouch 110 with an uninterrupted, continuous first side 122, pair of end seals 112, 114 and a second side 116 having a fin seal 118 extending longitudinally thereof. The interior of the package 110 includes a patterned susceptor 120, such as, for example, a grid-like susceptor having overlapping lines. In one illustrative configuration, the susceptor 120 only covers a portion of the interior of the package 110, as seen in FIGS. 23 and 24, such that the susceptor 120 does not extend to the end seals 112, 114 or the fin seal 118. In other embodiments, the susceptor 120 may extend to the end seals 112, 114, to the fin seal 118, and/or to both side seals 112, 114 and fin seal 118. In some embodiments, the susceptor 120 patterns may include, for example, fuse or star, lined, circular, herringbone, chevron, Greek key, gingham, houndstooth, quatrefoil, scale pattern, or another geometric pattern optimal for heating for a food product.

[0053] As indicated by instructions 132, the package 110 is heated with the first side 122 of package 110 facing upward in a microwave such that the food product 32 is disposed on the second side 116 the package. In some embodiments, the food items 32 may be arranged where at least some portion of a majority of the food items is in direct contact with the second side 116 of the package, as seen in FIG. 25. In such an arrangement, all or most of the discrete food items may be contact with or at least in close proximity to the second side 116 of package 110 during heating. Initially, most or all of the food items may also be in contact with, or at least in close proximity to, the first side 122 of package 110. However, as microwave heating progresses, expansion of the package 110 may lift the first side 122 and a portion of the susceptor 120 associated with the first side 122 lifts away from the food items, such that the susceptor 120 associated with the first side 122 is not in direct contact or touching the food items. The portion of the susceptor 120 associated with the first side 122 may shield the food items, such that the portion of the susceptor 120 associated with the first side 122 may absorb microwave energy but, due to a lack of direct contact with the food items, may reduce the amount or rate of microwave energy transferred to the food items. This shielding effect may allow the food items to cook more slowly and evenly. In some embodiments, the number of susceptors 120 shielding the food items may be, for example, over 20%, over 30%, over 40%, over 50%, over 55%, or over 60% of the susceptors 120 in the package 110. In other words, if over 20% of the susceptor 120 is shielding the food item(s), at least 20% of the susceptor 120 surface area inside the package 110 does not contact the food item(s) during heating of the food product.

[0054] Expansion of the package 110 may also result in the edges of the second side 116 being raised from the floor of the microwave oven, and may change the arrangement of some or all of the food items 32 from a single-layer configuration to reconfigure a bit such that more of the food items 32 overlap one another, which may also have a self-regulating effect on the heating operation to help reduce or avoid overheating and/or scorching. As used herein, a single layer can include some overlapping of the food products, but are disposed such that at least some portion of a majority of the food products are in direct contact with the lower surface of the food package during the heating operation. In some embodiments that employ a pattern, such as, for example, a grid-like susceptor, food items 32 on the edges of the grid-like susceptor may roast more quickly, possibly due to remaining in a single-layer configuration as opposed to the multiple-layer configuration which may occur in the middle of the package.

[0055] Aroma is created during microwave heating due to a combination of the product and the packaging, and is released upon opening of the package following microwave heating, and/or through a vent during heating. The aroma from the product can be generated not only by the nuts but also by additional ingredients. Liquid coatings, dry seasonings and/or other ingredients may include heat stable components that are added to nuts prior to packaging and provide aroma upon opening of the package following microwave heating. In addition to a dry seasoning or coating, a liquid seasoning can optionally be added to the nuts either before or after the application of a dry seasoning to increase the amount of volatile components released during microwave heating. One option is to also, or instead, add aroma-contributing compounds to the packaging material, such as by spraying the compounds on one or more interior surfaces of the package, such as in the headspace, after depositing the nuts and prior to sealing.

[0056] The blend of sizes of particulates in the coating as well as the physical characteristics, such as high melting temperatures, can help to moderate heating of nuts by absorbing or reflecting microwave energy and/or by shielding shelled nuts from microwave energy. This can advantageously reduce the amount of microwave energy that is absorbed by the interior and surface of the nut, thereby leading to increased homogeneity of the heating among the nuts and allowing the product to achieve an overall higher temperature without overheating individual areas of the nuts. Certain coatings may tend to increase susceptor temperature by reflecting microwave energy that would otherwise be absorbed by shelled nuts or other edible substrates to which the coatings are applied. This can help to provide desirable organoleptic properties such as crunchiness of the coatings and underlying shelled nuts, while avoiding undesirable organoleptic properties such as undesirable softness of the shelled nuts. Other coatings may tend to decrease susceptor temperature by absorbing microwave energy.

[0057] In some embodiments, low-moisture sugar-based coatings or other low-moisture coatings may be preferable to higher moisture coatings including those based on corn syrup from the standpoint that coatings based on corn syrup may tend to flow more easily when heated to temperatures of, e.g., 215 or 230 F., with portions of the coatings undesirably liquefying and running off the underlying food items when heated rather than remaining adhered thereto. Specific flavor notes that may be provided by the food products and/or coatings include but are not limited to sweet, savory, and salty flavor notes, and combinations thereof. Specific flavors for food products and/or coatings may include but are not limited to, e.g., salted caramel, cinnamon almond, and sweet roasted cashew flavors. Examples of specific product formulas that may be used in some embodiments are provided below.

TABLE-US-00001 Seasoned Cashew Ingredient Range (%) Cashew 92-98 Peanut oil 0.5-2.5 Powdered seasoning 2-6

TABLE-US-00002 Sea Salt Nut Blend Ingredient Range (%) Almond 30-50 Cashew 24-44 Peanut 16-36

TABLE-US-00003 Crunchy Salty Coating for Nut Blend Ingredient Range (%) Nut Blend 78-93 Sugar 4-20 Corn Syrup 2-3 Salt 1.5-3

TABLE-US-00004 Sea Salt Almond Ingredient Range (%) Almond 94-99 Peanut oil 0.5-3 Salt 0.5-3

TABLE-US-00005 Coconut Cashew Ingredient Range (%) Cashews 60-85 Sugar 20-40 Coconut 2-5 Corn syrup 2.5-5 Butter 1-2 Salt 0.5-2 Flavor 0.05-.2

TABLE-US-00006 Salted Caramel Peanut Ingredient Range (%) Peanuts 60-85 Sugar 20-40 Salt 0.5-2 Caramel seasoning 0.25-0.75

TABLE-US-00007 Cinnamon Almond Ingredient Range (%) Almonds 55-85 Sugar 20-40 Salt 0.5-2 Cinnamon 0.5-3

[0058] In some embodiments, thicker coatings can contribute to increased cooking homogeneity. In some embodiments, coatings may have a thickness of about 1 to 3 mm., and in some cases, may have an average thickness of about 1 mm.

[0059] The packaging can contribute to the aroma by providing suitable barrier layers and a headspace for the aroma to accumulate. For example, the pouch can be a multilayered structure that contains a barrier material, such as EVOH (ethylene vinyl alcohol), AlO.sub.x (aluminum oxide) or SiO.sub.x (silicon oxide), that limits the migration of aroma components through the package during both shelf life and microwave heating. The barrier material can be provided either as part of the pouch or in outer packaging that is removed prior to microwave heating. If more than one barrier layer is employed, such layers may not envelop the paper layer. A configuration where the barrier layers surround the paper layer may undesirably trap any moisture in the paper between the barrier layers when the package is heated. The package is preferably sealed during microwave heating so that volatile compounds that provide the aroma do not leave the package until opened. It can be desirable to optimize the headspace in the package in order to enable a more concentrated aroma while also ensuring space for the aroma to develop.

[0060] The thickness of the paper in the packaging may also contribute to the homogenous heating of the food product. The packaging may employ about 20 lb. paper to about 40 lb. paper, about 20 lb. paper to about 35 lb. paper, about 23 lb. paper to about 35 lb. paper, about 25 lb. paper to about 35 lb. paper, about 23 lb. paper, or about 35 lb. paper. The designation of lb. for thickness of paper indicates the weight of 500 sheets of that specific paper. Hence, the thicker the paper, the larger the weight. In some embodiments, thicker paper, such as 35 lb. paper, may be used. The thicker paper may absorb more heat to help the food product from burning, scorching, or overcooking. For example, as heat is transferred from the barrier layer or the susceptor lining, the thicker paper may absorb more heat than thinner paper. However, the thicker paper may also be more difficult to fold into a desirable configuration for packaging.

[0061] In some embodiments, thinner paper, such as 23 lb. paper, may be employed. By one approach, use of the thinner paper may allow for easier folding of the package into more desired configurations, such as a package with a top wall, a bottom wall, and a fin seal. The thinner paper may be sufficient to adhere to the susceptor and barrier material layer prior to heating. For some susceptor patterns or strengths, the thinner paper may not allow for particularly good adherence to the susceptor and barrier material layer during heating, possibly due to less than adequate surface tension. In one illustrative embodiment, the 23 lb. paper is sufficiently thick for adhering to a grid-patterned susceptor during heating and also provides for easy folding. In some configurations, optimized, homogenous heating of the food product is achieved through a combination of the type of susceptor, the thickness of the paper, and the amount of food product in contact with the susceptors.

[0062] The temperatures achieved during microwave heating contribute to the aroma as well as to heating of the nuts. One way to use temperatures during microwave heating to contribute to aroma is to design the coating and dry seasoning ingredients to maximize their dielectric properties when applied to a nut to enable more quick and homogenous heating. Another way to use temperatures during microwave heating to contribute to aroma is to add one or more susceptors within the package to enable localized, conductive heating with the package, as suggested above. The susceptor can be disposed and/or more concentrated in an area of the package most likely to contain the nuts, e.g., the bottom portion in a stand-up package. Further, as described herein, certain package configurations, including those with a majority of the susceptor centrally located, but not in direct contact with the food product are particularly suitable for warming the food product and producing a pleasant aromatic experience, without overheating and/or scorching the food product.

[0063] In one example, the package contains about 1 to 1.5 ounces of either cashews, almonds or shelled peanuts, or combinations thereof. The package can include a susceptor to optimize heating of the nuts during microwave heating. The package can optionally be gas-flushed. The package can be heated in a microwave for between 30 and 60 seconds, for example.

[0064] In some embodiments, strategically-configured susceptors are provided in a configuration that enables localized heating of certain portions of the mixed nuts to a higher temperature that enhances the aroma characteristics of the product without unacceptably overheating the shelled nuts, optionally in combination with one or more coatings that may provide quantitative and qualitative aroma enhancements. Coatings may also enable positive or negative variation of the shelled nuts' thermal response to microwave heating.

[0065] The aroma data in FIGS. 10 and 11 were compiled by exposing roasted, shelled nuts to microwave energy with and without susceptors, and using gas chromatography-mass spectroscopy to quantify increases in particular aroma components as a result of use of a particular susceptor configuration.

[0066] FIGS. 11 and 17 show data from roasted, shelled nuts, some including flavor treatments, measured at room temperature and after microwave heating with a susceptor in a package as described above. FIG. 11 shows, for example, that microwave warming of almonds resulted in about a two-fold increase in an ethyl-pyrazine aroma component, which is associated with a roasted or nutty aroma, an eighteen-fold increase in a diacetyl aroma component, which is associated with a buttery aroma, and a relatively small increase in furfural (caramel) aroma. FIG. 17 provides additional data for the same microwave warming, showing that it resulted in a two-fold increase of methyl pyrazine (roasted) aroma.

[0067] Each aroma component (furfural; 2,5 dimethyl pyrazine (associated with a nutty aroma); ethyl pyrazine; diacetyl; and benzaldehyde (oil of bitter almond)) may have a threshold concentration range (i.e., minimum concentration typically required for olfactory perception.) The aroma threshold for furfural is between about 280 parts per billion (ppb) and about 8 parts per million (ppm). The aroma threshold for 2,5 dimethyl pyrazine is between about 80 ppb and about 1.8 ppm. The aroma threshold for diacetyl is between about 0.3 ppb and about 15 ppb. The aroma threshold for benzaldehyde is between about 100 ppb and 4.6 ppm.

[0068] Further, food products may have a maximum availability of aroma components. For example, almonds may have up to 460 ppm of furfural, 66.5 ppm of 2,5 dimethyl pyrazine, 3 ppm of ethyl pyrazine, and 2,934 ppm of benzaldehyde. Cashews may have up to 7 ppm of furfural, 0.4 ppm of 2,5 dimethyl pyrazine, 1.6 ppm of diacetyl, and 0.24 ppm of benzaldehyde. In another example, pistachios may have up to 53 ppm of furfural and 93 ppm of 2,5 dimethyl pyrazine.

[0069] In some embodiments, microwave heating of a 1 oz. package of cinnamon almonds, i.e. almonds with a cinnamon coating as described above, according to instructions provided on packaging as described above, may desirably result in a significant increase of aroma components in the headspace, e.g., an increase in furfural aroma by a factor of 100 to 200, or more specifically a factor of 120 to 170, or a factor of about 144; an increase in ethyl pyrazine aroma by a factor of 10 to 50, or more specifically, a factor of about 31; an increase in methyl pyrazine by a factor of 15 to 100, or by a factor of about 50 to 60, or by a factor of about 56; and an increase in diacetyl aroma by a factor of 5 to 200, a factor of 40 to 60, or a factor of about 50. (See FIGS. 11 and 17.)

[0070] In some embodiments, microwave heating of a 1 oz. package of cashews according to instructions provided on the packaging as described above may desirably result in a significant increase of aroma components in the headspace, e.g., an increase in furfural aroma by a factor of 100 to 250, or more specifically a factor of 150 to 200, or a factor of about 167; an increase in ethyl pyrazine aroma by a factor of 50 to 200, or more specifically, a factor of 100 to 150, or a factor of about 125; an increase in methyl pyrazine by a factor of 25 to 80, or by a factor of about 50 to 60, or by a factor of about 56; and an increase in diacetyl aroma by a factor of 200 to 400, a factor of 250 to 350, or a factor of about 289. (See FIGS. 11 and 17.)

[0071] FIGS. 10, 16, 26, and 27 illustrate differences in aroma values that result from using a particular susceptor package or a non-susceptor package in microwave heating of mixed nuts. To obtain the data used in FIGS. 26 and 27, a grid-like patterned susceptor was employed, where a majority of the susceptor did not contact the nuts during microwave heating. Specifically, FIGS. 26 and 27 demonstrate that even without roasting or coating the nuts, the use of a patterned susceptor may still increase the desirable aroma properties over microwave heating without employing a susceptor. However, pre-roasting and coating the nuts and using a susceptor to heat the nuts additionally increases various key aroma components.

[0072] The data in FIGS. 10, 11, 16 and 17 correspond to desirable aroma properties of packaged food products described herein, and such packaged food products in some embodiments may enable consumers to achieve increases in various key aroma components similar to those described herein, e.g., within 10%, 20%, 30%, 40% or 50% of the values in FIGS. 10, 11, 16 and 17, while also providing other desirable organoleptic properties, without scorching or generating undesirable aromas.

[0073] Examples of raw data generated using gas chromatography-mass spectroscopy to measure selected individual aroma components are provided in FIGS. 12-15. The areas under the plots shown in FIGS. 12-15 is the Peak Area represented by the y-axis in FIG. 10.

[0074] Data shown in FIGS. 12-15 was gathered by collecting gases from within pouches containing a mixture of shelled nuts, specifically almonds, cashews and peanuts, on thermal desorption tubes before and after microwaving with and without susceptors. Sampling was performed using adhesive septas (Illinois Instrument PPL-193456). Headspace samples were collected for 2 min using a vacuum pump pulling 50 mL/min (FIG. 1). Gas displaced was replaced using food grade nitrogen.

The following additional equipment was used in sampling and analysis:

Agilent Technologies 5975 Mass Spectrometer

Agilent Technologies 6890N Network GC System

Gerstel TDS3 Thermal Desorption System

Gerstel TDSA Thermodesorption Autosampler

Envirochem Multiple Tube Conditioner

[0075] Thermal Desorption tubes; 3.8 mm Tenax-TA, 2.0 mm Carboxen 1003

[0076] Additional information on equipment and parameters used is set forth below: GC-MS Parameters:

Oven

[0077] Equilibration time: 1.00 min
Maximum temp: 250 C
Initial temp: 35 C (On)
Initial time: 4.00 min

Ramps:

[0078]

TABLE-US-00008 # Rate Final Temperature Final Time 1 3.00 82 0.00 2 6.00 210 10.00 3 0 (off)
Post temp: 240 C
Post time: 5.00 min
Run time: 51.00 min

Column: Agilent VF-WAX P/N CP9295

Back Inlet (Cis4)

Mode: Solvent Vent

[0079] Initial temp: 0 C (Off)

Pressure: 8.8 psi (On)

[0080] Vent time: 0.00 min
Vent flow: 50.0 mL/min

Vent Pressure: 8.8 psi

[0081] Purge flow: 50.0 mL/min
Purge time: 2.00 min
Total flow: 54.0 mL/min
Gas saver: Off
Gas type: Helium

Thermal Aux 2

[0082] Initial temp: 240 C (On)

Gerstel Maestro

System Settings

Maestro Runtime: 55.99 min

GC Cool Down Time: 8.00 min

Cryo Timeout: 25.00 min