Low-pressure retort processing of root vegetable products

Abstract

A method of processing a root vegetable product. The method includes retort processing the root vegetable product while the root vegetable product is in a hermetically sealed container. The container is subject to a pressure during the retort processing that is up to a retort processing pressure, the retort processing pressure being between a vapor pressure within the container and 50 psi. The root vegetable product is removeable from the container for deep frying following the retort processing and suitable to make a deep fried root vegetable product.

Description

LOW-PRESSURE RETORT PROCESSING OF ROOT VEGETABLE PRODUCTSFIELD

[0001] This disclosure relates generally to the manufacture of root vegetable products such as potato products, and in particular to low-pressure retort processing of root vegetable products.INTRODUCTION

[0002] United States Patent App. No. 2004 / 0191382 to Cooper et al. (“Cooper”) purports to disclose that vegetables, specifically potatoes, are sterilized using ultra-high- pressure processing. Cooper further purports to disclose that the freshly cooked flavor of the vegetables is retained by preprocessing the vegetables by partially cooking quickly and thereafter subjecting to ultra-high-pressure sterilization.

[0003] United States Patent App. No. 2022 / 0000129 to Rizvi et al. (“Rizvi”) purports to disclose a shelf stable potato / sweet potato French fry product packaged in a hermetically sealed flexible bag / pouch without the need for a surrounding acidic solution. Rizvi purports to disclose that such product has a lower pH, preferably below 4.6, with enhanced taste and texture profile features, such as: (a) 0% -2% fat content, (b) a hardness of the exterior layer between 350 gram to 2500 gram after frying, that allows for little to no need for battering of such products, and (c) a moisture content above 55%. Rizvi further purports to disclose that these benefits are typically obtained by processing the pre-cut potato via a single-step processing technique which may or may not require pre-processing steps.

[0004] United States Patent App. No. 2004 / 0033296 to Yuan et al. (“Yuan”) purports to disclose a treatment process for preserving a food or food product against microbiological contamination, which improves the quality of such food and enhances the safety of food and food products for consumption by mammals, especially humans. Yuan purports to disclose that the process utilizes a treatment of food or food products, or packaged food or food products, with a high pressure gas treatment process (HPP) to provide a reduction of the level of microorganisms or spores on and in such foods or food products. Yuan purports to disclose that the method includes exposing the food or food product to a gas and / or injecting a gas into a container containing the food or food product; optionally, closing or sealing the container; and subjecting the food or food product and / or the container containing the foodor food product to a temperature of less than about 50° C. and, concurrently, to more than one pressure treatment cycle at a pressure of at least about 10,000 psig. Yuan purports to disclose that, alternatively, the HPP treatment method may instead substitute, or be combined with, one or more pressure treatment cycles at a pressure of less than about 250 psig.SUMMARY

[0005] The following introduction is provided to introduce the reader to the more detailed discussion to follow. The introduction is not intended to limit or define any claimed or as yet unclaimed invention. One or more inventions may reside in any combination or subcombination of the elements or process steps disclosed in any part of this document including its claims and figures.

[0006] In accordance with one broad aspect of this disclosure, there is provided a method of processing a root vegetable product, the method comprising: retort processing the root vegetable product while the root vegetable product is in a hermetically sealed container, wherein the container is subject to a pressure during the retort processing that is up to a retort processing pressure, the retort processing pressure being between a vapor pressure within the container and 50 psi, and wherein the root vegetable product is removeable from the container for deep frying following the retort processing and suitable to make a deep fried root vegetable product.

[0007] Another embodiment relates to a method of processing a root vegetable product, the method comprising: retort processing the root vegetable product, optionally while the root vegetable product is in a container, optionally a hermetically sealed container, optionally applying a retort processing pressure to the container during the retort, optionally the retort processing pressure being between a vapor pressure within the container and 50 psi, and optionally next frying the root vegetable product as described herein, such as deep frying to make a deep fried root vegetable product, optionally suitable for consumption by a user or suitable for packaging for future freezing, reheating (e.g. frying) and / or consumption.

[0008] In some embodiments, the method further comprises, prior to retort processing the root vegetable product, blanching the root vegetable product and subjecting the root vegetable product to a sodium acid pyrophosphate treatment.

[0009] In some embodiments, the sodium acid pyrophosphate treatment includes exposure of the root vegetable product to a solution that is 1% by mass of sodium acid pyrophosphate in water.

[0010] In some embodiments, the method further comprises peeling and cutting a root vegetable to produce the root vegetable product.

[0011] In some embodiments, the method further comprises, following the retort processing: storing the root vegetable product in the hermetically sealed container, and removing the root vegetable product from the hermetically sealed container and deep frying the root vegetable product.

[0012] In some embodiments, retort processing includes raising a temperature of the root vegetable product to at least 120°C.

[0013] In some embodiments, retort processing is performed using a Steriflow® retort system or a MATS™ system.

[0014] In some embodiments, retort processing is performed using the MATS™ system.

[0015] In some embodiments, retort processing is performed using a reel and spiral retort system, a hydrostatic retort system, or a raining water retort system.

[0016] In some embodiments, the retort processing pressure is between 14.7 psi and 40 psi.

[0017] In some embodiments, the retort processing pressure is between 15 psi and 30 psi.

[0018] In some embodiments, the retort processing pressure is between 18 psi and 40 psi.

[0019] In some embodiments, the retort processing pressure is between 18 psi and 30 psi.

[0020] In some embodiments, the retort processing pressure is between 20 psi and 40 psi.

[0021] In some embodiments, the retort processing pressure is between 20 psi and 30 psi.

[0022] In some embodiments, the container is a pouch.

[0023] In some embodiments, the container is a large-capacity container holding more than 10 kilograms of the root vegetable product.

[0024] In some embodiments, the retort processing includes retort processing until the root vegetable product in the container is shelf-stable.

[0025] In some embodiments, the root vegetable product is a French fry.

[0026] In some embodiments, the method further comprises providing, following the retort processing, the root vegetable product in the hermetically sealed container to a user to remove the root vegetable product from the container and fry the root vegetable product.

[0027] In accordance with one broad aspect of this disclosure, there is provided a method of processing a root vegetable product, the method comprising: retort processing the root vegetable product while the root vegetable product is in a hermetically sealed container, wherein the container is subject to a pressure during the retort processing that is up to a retort processing pressure, the retort processing pressure being between a vapor pressure within the container and 50 psi, and wherein the root vegetable product is removeable from the container for finish cooking following the retort processing and suitable to make a finish cooked root vegetable product.

[0028] It will be appreciated by a person skilled in the art that an apparatus or method disclosed herein may embody any one or more of the features contained herein and that the features may be used in any particular combination or sub-combination.

[0029] These and other aspects and features of various embodiments will be described in greater detail below.DRAWINGS

[0030] For a better understanding of the described embodiments and to show more clearly how they may be carried into effect, reference will now be made, by way of example, to the accompanying drawings in which:

[0031] FIG. 1 is a simplified flow diagram of retort processing of root vegetable products;

[0032] FIG. 2 is a simplified flow diagram of the method of sterilizing root vegetable articles in the retort process of FIG. 1 ;

[0033] FIG. 3A is a depiction of audio wavelengths of Treatment 1 from Example 2 as described below;

[0034] FIG. 3B is a depiction of audio wavelengths of Treatment 1 of Example 2 as described below; and

[0035] FIG. 4 is a graph depicting an analysis of the audio wavelengths of FIGS. 3A- 3B.

[0036] The drawings included herewith are for illustrating various examples of articles, methods, and apparatuses of the teaching of the present specification and are not intended to limit the scope of what is taught in any way.DETAILED DESCRIPTION

[0037] Various apparatuses, methods and compositions are described below to provide an example of an embodiment of each claimed invention. No embodiment described below limits any claimed invention and any claimed invention may cover apparatuses and methods that differ from those described below. The claimed inventions are not limited to apparatuses, methods and compositions having all of the features of any one apparatus, method or composition described below or to features common to multiple or all of the apparatuses, methods or compositions described below. It is possible that an apparatus, method or composition described below is not an embodiment of any claimed invention. Any invention disclosed in an apparatus, method or composition described below that is not claimed in this document may be the subject matter of another protective instrument, for example, a continuing patent application, and the applicant(s), inventor(s) and / or owner(s) do not intend to abandon, disclaim, or dedicate to the public any such invention by its disclosure in this document.

[0038] Furthermore, it will be appreciated that for simplicity and clarity of illustration, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements. In addition, numerous specific details are set forth in order to provide a thorough understanding of the example embodiments described herein. However, it will be understood by those of ordinary skill in the art that the example embodiments described herein may be practiced without these specific details. In other instances, well-known methods, procedures, and components have not been described indetail so as not to obscure the example embodiments described herein. Also, the description is not to be considered as limiting the scope of the example embodiments described herein.

[0039] Referring to Figure 1 , illustrated is a method 100 of preparing a root vegetable, product, such as a potato product. I n some embodiments, the root vegetable product includes one or more products selected from the group comprising a whole root vegetable, a root vegetable half, a root vegetable quarter, a root vegetable wedge, a strip or stick of a root vegetable, a cube of root vegetable, a slice of root vegetable, a novelty cut of root vegetable such as but not limited to a crinkle cut, waffle cut or spiral shape, an extruded root vegetable product, mashed and formed root vegetable product (e.g., potato balls or potato smiles), grated root vegetable, and grated and formed root vegetable (e.g., potato hashbrowns).

[0040] In some examples, the root vegetable is a starchy root vegetable. In some examples, the root vegetable has total carbohydrate levels in the range of 8-35% of the total and 60-90% by weight. In some examples, the root vegetable is or includes a taro, sweet potato, yam, swede, rutabaga, or parsnip. In some examples, the root vegetable product is a potato product. In some examples, the root vegetable product is or includes potato wedges and / or potato strips or sticks. In some examples, the potato product is or includes potato strips or sticks. In some examples, the potato strips or sticks are shoestring French fires or square cut French fries. The potato product may include product made from conventional potatoes. The potato product may be made from one or more potatoes selected from the group comprising red potatoes, white potatoes, yellow potatoes, blue potatoes, purple potatoes, fingerling potatoes, and petite potatoes. The root vegetable product may be peeled or unpeeled, cut or uncut, and / or coated or uncoated. In some examples, the root vegetable product includes a coating (e.g., a batter coating) and / or seasoning (e.g., a dusting of a spice blend).

[0041] The method 100 includes retort processing at step 112. Step 112 includes heating the root vegetable product while the root vegetable product is vacuum sealed in a container. The root vegetable product is heated to kill or damage microorganisms to improve the shelf-stability of the root vegetable product. In some examples, the root vegetable product is heated to at least 90°C, at least 100°C, at least 110°C, or between 100°C and 140°C, or between 100°C and 160°C. In some embodiments, the root vegetable product may be heatedsuch that each part has a temperature of at least 90°C, at least 100°C, at least 110°C, or between 100°C and 140°C, even though parts of a package may reach higher temperatures due to hotspotting.

[0042] Heating the root vegetable product involves supplying energy to the root vegetable product while the root vegetable product is sealed in the container. In some examples, heating includes applying hot water (e.g., cascading or via steam) to an exterior of the container in which the root vegetable product is sealed. For example, step 112 may include retorting using a retort system, such as a Steriflow™ retort system. In some examples, heating includes irradiating the root vegetable product with microwave energy. For example, heating may include Microwave Assisted Thermal Sterilization™ (MATS™) from 915 Labs™ . MATS™ uses a combination of microwave energy in long-wavelengths and pressurized hot water to sterilize food products.

[0043] Step 112 also typically includes holding a pressure against the container in which the root vegetable product is sealed to, e.g., counter pressure generated within the container during the heating. For example, pressurized gas and / or liquid may be circulated around the container while the root vegetable product is heated. In some examples, the pressurized gas and / or liquid also delivers heat to the container and / or root vegetable product. For example, heating may include circulating pressurized hot water against the container. In some embodiments, the pressure held outside the container is above atmospheric pressure (i.e. , the container is within a pressure vessel). It will be appreciated that in some embodiments the pressure held outside the container is at atmospheric pressure, and in some embodiments may be below atmospheric pressure (i.e., the container is within a pressure vessel).

[0044] In some examples, the root vegetable product after heating has an acceptable microbial count and / or that does not require refrigeration and is shelf-stable for long periods of time. For example, the root vegetable product may have a microbial count that remains acceptable after storing at 35 degrees Celsius for 12 months. In some examples, an acceptable microbial count includes having the root vegetable product meet a third party standard. For example, the root vegetable product may meet the micro requirements of a Certificate of Analysis (CoA), such as one requiring an absence of mesophilic anaerobicunits, mesophilic aerobic units, thermophilic anaerobic units, and thermophilic aerobic units, where an absence is defined as less than 10 colony forming units per gram. In another example, the root vegetable product is acceptable if it has a lethality (Fo) number of > 6.0 and / or an absence of mesophilic anaerobic units, mesophilic aerobic units, thermophilic anaerobic units, and thermophilic aerobic units, where an absence is defined as less than 10 colony forming units per gram (in some embodiments the quantity is a limit of detection related to sampling methodology).

[0045] As exemplified in Figure 1 , in some embodiments the method 100 of preparing the root vegetable product includes at least one pre-processing step 101. The pre-processing step 101 reduces the whole root vegetable to the root vegetable product (e.g., fry or extruded root vegetable product). As exemplified, pre-processing may include peeling a root vegetable at step 102. In some embodiments the method 100 includes reducing (e.g., cutting) the root vegetable at step 104. It will be appreciated that steps 102 and 104 may take place in any order, and may be sequential or concurrent. It will be appreciated that pre-processing step 101 may include additional and / or alternative pre-processing procedures.

[0046] In some examples, at step 102 the root vegetable is peeled to remove a skin of the root vegetable. Step 102 may include, e.g., one or more of steam peeling, peeling using a carborundum peeler, and hand peeling. In some embodiments, a carborundum peeler and / or steam peeling is used for a set amount of time and then the remaining skin are removed by hand.

[0047] In some examples, at step 104 the root vegetable is reduced, such as cut or sliced to a desired size. The root vegetable may be cut to any length and width as desired, such as fry strips. The root vegetable may be cut to any shape as desired, such as wedges, crinkle, curly, waffle, shoestring, chip, shreds, or any other shape. Example cut sizes are 9 / 32 to 19 / 64 inch shoestring cut French fries or 3 / 16 to 1.5 inch square cut French fries. Optionally, the root vegetables are sliced or 7 / 16 inch cut French fries, 9 / 16 inch cut French fries, 11 / 32 inch cut French fries, 15 / 32 inch cut French fries or 8 cut wedges. It will be appreciated that in some embodiments, the root vegetable may be cut or mashed and formed, such as shredded and formed into hashbrowns or mashed and formed (e.g., into potato balls or smiles).

[0048] Referring still to Figure 1 , method 100 includes, at step 106, blanching the articles of root vegetable. Blanching may include exposing the root vegetable to heated water. For example, step 106 may include immersing the root vegetable articles in a heated water bath for a period of time and / or running heated water over the root vegetable. The blanching step allows for the increase in the cell permeability. The root vegetable articles may be subjected to heated water over a time period of at least 30 seconds, 1 , 2, 3, 4, or 5 minutes and / or less than 30, 25, 20, 15, 10, or 5 minutes. In such embodiments, this water heat treatment can occur at around atmospheric pressures and at a temperature of at least 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, or 80°C. Additionally or alternatively, in various embodiments, the water heat treatment can occur at a temperature of less than 150°C, 125°C, 100°C, 95°C, 90°C, 85°C, or 80°C. It will be appreciated that in some embodiments, a method of processing a root vegetable product may not include a blanching step.

[0049] It will be appreciated by a person skilled in the art that certain blanched root vegetable articles can undergo a discoloration that is commonly referred to as after-cooking darkening (ACD) due to a reaction comprising the oxidation of an iron-containing complex. In some circumstances, a consumer may find such a discolored root vegetable to be cosmetically unappealing. Accordingly, at step 108, method 100 includes an antidiscoloration treatment. In some embodiments, step 108 includes exposing the blanched product to a solution containing an acidulant, such as citric acid, lactic acid, acetic acid, malic acid, tartaric acid, 15 cream of tartar, EDTA (Ethylenediaminetetraacetic acid), ascorbic acid, sodium ascorbate, sodium acid sulfate (SAS), sodium acid pyrophosphate (SAPP) or other phosphate salts (such as Sodium tripolyphosphate (STPP) and Sodium hexametaphosphate (SHMP)).

[0050] At step 110, the root vegetable product is vacuum sealed within a container. In some embodiments, step 110 includes drying or partially drying the blanched root vegetable product prior to sealing the root vegetable product within the container. For example, step 110 may include draining or otherwise dewatering the root vegetable product prior to sealing the root vegetable product within the container. In some embodiments, step 110 includes parfrying the blanched root vegetable product prior to sealing the root vegetable product within the container. In some embodiments, step 110 includes both drying or partially drying the blanched root vegetable product prior to sealing the root vegetable product withinthe container and parfrying the blanched root vegetable product prior to sealing the root vegetable product within the container.

[0051] In some embodiments, the root vegetable product is drained of moisture and placed within a container, and the container is sealed closed (i.e. , hermetically sealed). The container may be a rigid-walled container and / or a flexible-walled container, e.g., a tray or a pouch. It will be appreciated that any container may be used. The container may be made of a packaging material suitable for storage and able to withstand temperatures up to and greater than 130° C. The pouches may be designed to physically protect the root vegetables while ensuring low oxygen and water transmission rates.

[0052] In some embodiments, the container is a pouch. The pouch may be formed by flexible packaging material shaped in a tubular form and then sealed on both ends. In some embodiments, the container is a pouch sealed on all sides (e.g., all four sides) and able to stand on one end. In some embodiments, the container is a tray sealed with a flat lid or sheet.

[0053] The root vegetables may be packaged in commercial quantities. Each container may contain more than about 0.1 kilogram, more than about 0.5 kilograms, more than about 1 kilogram, more than about 10 kilograms, or more than about 20 kilograms of the root vegetable product.

[0054] It will be appreciated that step 110 may, in some embodiments, include the packaging of the root vegetable articles in containers other than hermetically sealed pouches or trays. For example, the root vegetables may be packaged in cans or jars (e.g., hermetically sealed cans or jars).

[0055] At step 112, the root vegetables articles are sterilized using retort processing.

[0056] At step 114, after completion of the retort processing, the containers may be cooled and the root vegetable product may remain sealed in the packaging and stored until use by the end consumer.

[0057] At step 116 the root vegetable product in the container is supplied to a user for the user to remove the root vegetable product from the container and finish cook the root vegetable product. In some examples, finish cooking includes frying. In some examples, finish cooking includes deep frying. The user may be, e.g., a commercial user such as arestaurant operator. Supplying the root vegetable product may include providing instructions for finish cooking (e.g., deep fry, air fry, oven bake, or microwave) the root vegetable product. In some examples, supplying the root vegetable produce includes providing instructions for deep frying the root vegetable product.

[0058] In some examples, at step 116, the end consumer may fry the root vegetable articles using conventional frying methods prior to eating the root vegetable product, after removing the root vegetable product from the container. For example, the end consumer may fry the root vegetables in any desired oil, such as sunflower oil, rapeseed oil, soybean oil, cottonseed oil, olive oil, canola oil, coconut oil, avocado oil, or any combination thereof. A user may remove the root vegetable product from the container and consume the root vegetable product directly, without first frying. It will be appreciated that in some cases the user may choose to consume the root vegetable product without frying it, such as consuming it directly out of the container or proceeding with an alternative finish cooking (e.g., oven baking).

[0059] Referring now to Figure 2, illustrated is an exemplary retort method 200. The retort method 200 may be used at, e.g., step 112 of method 100.

[0060] Method 200 is a low-pressure retort method. In many retort methods, a container holding a product is subject to high pressures during a heating step, a holding step, and / or a cooling step. The present inventors have discovered that root vegetable products (e.g., fries) subjected to a high-pressure retort method and then later fried tended to explode and / or sputter during frying. Root vegetable product explosions during frying can eject oil from the frying vessel, which may create fires and / or burn a user. Root vegetable sputtering during frying may include explosive emissions of steam and / or oil from the fryer. Explosions or sputtering may be due to, e.g., nucleation of steam bubbles within superheated water that then rapidly propagates to convert water into explosive steam.

[0061] The present inventors have discovered that applying a low-pressure retort method results in a reduction in the likelihood of explosion and / or sputtering of the root vegetable product during later frying. The present inventors have discovered that applying a low-pressure retort method as the most recent retort method prior to frying results in a reduction in the likelihood of explosion and / or sputtering during later frying. For example,subjecting the root vegetable product to a high-pressure retort method and then to a lower pressure retort method results in a reduced likelihood of explosion and / or supporting during later frying.

[0062] The method of retort processing 200 described below may be conducting using various retort systems, such as a Steriflow™ retort system, a reel and spiral retort system, a hydrostatic retort system, a raining water retort system, or a Microwave Assisted Thermal Sterilization™ (MATS™) system. For a retort system to be suitable, it must have the capacity to bring the internal temperature of the root vegetable articles to at least 100°C, at least 115°C, at least 120°C, or at least 121 °C. Suitable manufacturers of equipment known in the art include, e.g., Hydrolock™, JBT Corporation™, or DTS™.

[0063] As shown in Figure 2, the retort method 200 includes, at step 201 , heating the root vegetable product. Step 201 may include a preheating step 202 and a main heating step 204.

[0064] Optionally, the root vegetable products are subject to a preheating step 202 prior to the main heating step. The pre-heating step 202 may increase the temperature of the root vegetable product above that of a storage temperature. The root vegetable product may have a substantially uniform temperature after the preheating step 202. In some examples, preheating step 202 raises the temperature of the root vegetable product to a preheating temperature between 30°C and 100°C. The preheating step 202 may include holding the root vegetable product at the preheating temperature for a preheating time of between 1 minute and 60 minutes.

[0065] Step 201 includes heating the root vegetable product at step 204. Any retort system may be used at step 204. For example, the retort system may irradiate the root vegetable product with microwave energy and / or expose the root vegetable product and / or container to heated fluid (e.g., steam, a water bath, a sprinkling of water, etc.). The heated fluid of step 204 may be at a temperature of anywhere between 30°C and 150°C. For example, lower temperature below a desired temperature of the root vegetable product may be used with an additional heat transfer technique, such as the use of microwave energy.

[0066] In some embodiments, the heating step 201 includes partially or entirely submerging the root vegetable product and / or container in a liquid. In some embodiments,heating step 201 includes subjecting the root vegetable product and / or the container to a raining water process. In some embodiments, heating step 201 includes placing the root vegetable product and / or container within a full water bath. In some embodiments, heating step 201 includes exposing the root vegetable product and / or container to direct steam heating. Step 201 (e.g., step 204) includes raising the temperature of the root vegetable product to a heating step temperature of at least 115°C, at least 120°C, at least 121 °C, or at least 130°C.

[0067] Optionally, method 200 includes, at step 206, holding the root vegetable product at the heating step temperature for a predetermined length of time. It will be appreciated that the length of time may be any suitable length of time, such as at least 1 second, at least 5 seconds, or at least 20 seconds. The predetermined length of time of holding step 206 may be any time less than 20 minutes and greater than 30 seconds.

[0068] The root vegetable product is then cooled at step 208. At cooling step 208 the temperature of the root vegetable product is lowered so the root vegetable product can be removed from the retort process 200 and stored. At cooling step 208, the root vegetable product is cooled to a temperature of anywhere between 25-40°C, and may be cooled to a temperature of around 30°C. The cooling step 208 may include immersing the root vegetable product and / or container in a water bath with water at a temperature of or below 30°C, 25°C, or 20°C. The root vegetable articles may be subject to the water bath to reduce the temperature prior to storage. In some embodiments, the root vegetable product is stored in an unrefrigerated state, at a temperature of more than -18°C, more than -10°C, more than 0°C, more than 10°C, or more than 20°C (e.g., at about room temperature).

[0069] In some embodiments, step 201 (e.g., step 204) includes irradiating the root vegetable product with microwave energy to heat the root vegetable product (e.g., using a MATS system). The microwave energy used may have a frequency of anywhere between 300 MHz and 30 GHz. In some embodiments, the heating step 204 uses microwave energy having a frequency of between 850 MHz and 1000 MHz, between 900 MHz and 950 MHz, between 900 MHz and 930 MHz, about 915 MHz, or about 922 MHz. In some embodiments, the heating step 204 uses microwave energy having a frequency of 2.45 GHz.

[0070] As discussed above, low-pressure retort processing results in improved performance of the root vegetable product during subsequent frying. In some examples, the entire retort method 200 is performed at a pressure that is less than or equal to a retort processing pressure (i.e., a maximum pressure reached during the retort method 200). In some embodiments, the retort processing pressure is between the vapor pressure within the container and 55 psi, the vapor pressure within the container and 40 psi, the vapor pressure within the container and 30 psi. In some embodiments the retort processing pressure is between 18 psi and 40 psi, 18 psi and 30 psi, 20 psi and 40 psi, or 20 psi and 30 psi. In some embodiments, the retort processing pressure is below 55 psi, 50 psi, 40 psi, 30 psi, or 20 psi. In some embodiments the retort processing pressure is at least above the vapor pressure within the container to enable the desired temperature of the root vegetable product (e.g., above 120 degrees Celsius) to be reached. The vapor pressure within the container may depend upon the materials added during processing. For example, the vapor pressure may be about 14.7 psi (i.e., about atmospheric pressure), e.g., for water. The vapor pressure may be lower in the presence of acid. In some examples, no acid is used. In some embodiments, lowering the operating pressure allows for reductions in equipment costs. In some embodiments, a method takes into account possible pressure fluctuations, such as due to regular operation of a pump, and so a range of pressures may be used or a higher than necessary pressure may be targeted to ensure that fluctuations do not result in sub-optimal pressures.

[0071] In some embodiments, step 112 of method 100 includes a plurality of retort cycles. For example, step 112 may include a first cycle of method 200 wherein the root vegetable product and / or container is subject to a first maximum pressure and a second cycle of method 200 wherein the root vegetable product and / or container is subject to a second maximum pressure. The second maximum pressure is different from the first maximum pressure.

[0072] In some embodiments, the second maximum pressure is less than the first maximum pressure. In some embodiments at least one of the second maximum pressure and the first maximum pressure is the retort processing pressure discussed above. In some embodiments, the second maximum pressure is the retort processing pressure discussed above.

[0073] In some embodiments, step 112 includes a single cycle of method 200 and method 200 includes step 201 (e.g., step 204) repeated twice, first at the first maximum pressure described above and then at the second maximum pressure described above.

[0074] In some embodiments, the root vegetable product and / or containers is loaded into one or more carriers configured to secure the product and / or container during at least one of the pre-heating, microwave heating, holding, and cooling steps as described. The carriers configured to secure the articles may be used when, for example, all or a portion of these steps are performed when the articles are at least partially, or entirely, submerged in a liquid.

[0075] In some embodiments, applying a retort process allows the root vegetable product to be stored and / or shipped without prior parfrying (also referred to as pre-frying herein). Method 100 may include only two heating steps - blanching at step 106 and retort processing at step 112. Method 100 may include no frying or par frying prior to storing and / or shipping at step 114. It will be appreciated that pre-frying may also be carried out, however it may not be required and in some embodiments is eliminated. Parfrying in manufacturing facilities brings hazards such as fryer fires. By removing the need to parfry the root vegetable articles prior to sterilization, manufacturers may be able to remove fryers from processing facilities, thereby reducing the likelihood of the workplace hazards the fryers bring. The elimination of a process step reduces the space required for equipment, reduces the capital investment and reduces the energy usage.

[0076] The following non-limiting examples are illustrative of the present application:ExamplesExample 1

[0077] Potatoes were peeled and cut using processes known in the art. Potato strips were then blanched and subjected to a sodium acid pyrophosphate dip. Potato strips were then divided into 120g samples and packaged in hermetically vacuum sealed pouches.

[0078] Samples were heated using Microwave Assisted Thermal Sterilization™ (MATS™) alone, or MATS™ preceding or following one of the following treatments: boiled in water, microwaved, pressure cooked (i.e., lower pressure but still above atmosphericpressure) and modified high amylose corn starch such as Crisp Film™ from Ingredion™. The pressure-cooking treatment was used to imitate the low-pressure retort processing by subjecting the potato strips to a constant, measurable low pressure.

[0079] Following pre-treatment, the samples were test fried with observations noted as to the amount of splattering and explosions that occurred during frying. Observations are recorded below:Heating Conditions Results Summary When Subsequently FriedMATS™ only MATS (123°C, 50 psi) Very explosive with vigorous splatteringBoiling in water preceded MATS then pouch boiled in Vigorous splattering by MATS™ water for 10 minDomestic microwave MATS then pouch immersed Vigorous splattering heating preceded by in 120g water and heated for MATS™ 60 sec in a domestic microwave (1100W)Pressure Cooking MATS then pressure cook Little splatter preceded by MATS™ pouch for 10 mins at 80 Kpa above atmospheric pressurePressure Cooking MATS then pressure cook Little splatter preceded by MATS™ pouch for 10 mins at 60 Kpa above atmospheric pressurePressure Cooking MATS then pressure cook Moderate splatter preceded by MATS™ pouch for 10 mins at 40 Kpa above atmospheric pressurePressure Cooking MATS then pressure cook Moderate splatter preceded by MATS™ pouch for 10 mins at 20 Kpa above atmospheric pressurePressure Cooking MATS then pressure cook Moderate splatter preceded by MATS™ pouch for 10 mins at 10 Kpa above atmospheric pressureSteam Cooking preceded MATS then pouch steamed Little splatter by MATS™ for 10 minsCrisp Film on potato 1 % dry coated Moderate splatter strips after MATS™Crisp Film on potato 2% dry coated Little splatter strips after MATS™

[0080] Results shown above indicated that the potato strips pre-treated in the pressure cooker resulted in reduced amounts of oil splatter when fried.Example 2

[0081] Potatoes were peeled using a carborundum peeler for 1 minute and 20 seconds to remove the skins. Any remaining skin left was removed by hand peeling. Whole peeled potatoes were then cut to 9.5 mm by 9.5 mm size using a potato chipper. The potato strips were then blanched in a blanching container. The strips were agitated during blanching to ensure even heating. The potato strips were then removed from the blanching container and left to drip for a few seconds. The partially dried potato strips were then submerged in a solution of 1.0% sodium acid pyrophosphate (SAPP) at a temperature of 65°C for 60-90 seconds, with the strips being agitated to ensure even coverage. The strips were then drained, and excess solution was removed.

[0082] The following retort treatments were conducted using a Steriflow™ retort system. The retort process was conducted using a raining water process.

[0083] Treatment 1 : The potato strips were measured out into 6 groups of 120g each. Each group was packed in clear retort pouches and vacuum sealed for 2 seconds at a pressure between 50-70mbar. The pouches were then preheated at 65°C in a controlled steam heated water bath before being transferred to a preheated raining water retort at 70°C. The pouch was then heated for 10 minutes at 123°C at 52 PSI. The pouches were cooled to 40°C, and then stored in a chiller after processing.

[0084] Treatment 2: The potato strips were measured out into 6 groups of 120g each. Each group was packed in clear retort pouches and vacuum sealed for 2 seconds at a pressure between 50-70mbar. The pouches were then preheated at 65°C in a controlled steam heated water bath before being transferred to a preheated raining water retort at 70°C. The pouch was then heated for 10 minutes at 123°C at 21 PSI. The pouches were cooled to 40°C, and then stored in a chiller after processing.

[0085] Treatment 3: The potato strips were measured out into 6 groups of 120g each. Each group was dried in a dryer. The strips were then parfried in sunflower oil for 60 sec at 185°C, and then blast frozen.

[0086] Following each treatment, the subject potato strips were fried. Prior to frying, the potato strips were tempered up to room temperature (i.e. , 25 degrees Celsius). Each treatment consisted of 6 groups. Each group was fried for 3 minutes in an oil of a temperature of 175°C.

[0087] Results were determined based on video and audio recording of the deep frying to assess the difference between samples. The audio recording was analyzed as a way to determine the intensity of the explosions that occurred during deep frying.

[0088] Shown in Figure 3A are the 6 audio recording waveforms 300A for the Treatment 1 potato strip groups. In comparison, Figure 3B shows the 6 audio recording waveforms 300B of the Treatment 2 potato strips. As shown clearly in Figures 3A-3B, the audio recording of Treatment 1 potato strips, treated at 52 PSI, are of a higher intensity than the recorded audio of Treatment 2 potato strips, which were treated at 21 PSI.

[0089] The results are further depicted in Figure 4, which shows a graph analysis 400 of the audio recordings of treatments in the experiment. Illustrated is the number of distinct times that the volume passed a certain threshold during the frying process. The X axis is the threshold and the Y axis is the count (logarithmic scale). It will be appreciated that the higher the threshold the bigger the sound events (e.g., explosions). Larger events are illustrated to the right of the chart, and smaller events are illustrated to the left. Trials included in the graph include Treatment 1 402, Treatment 2 404, Treatment 3 frozen 406 and Treatment 3 thawed 408. As illustrated, a difference between the 21 psi and 52psi treatments is low at the small event end, the expectation of boiling whilst frying (e.g., many crackling noises), whereas the difference at the large event end is very different, this is where the more violent events would be expected to be measured.

[0090] Analysis of both the audio recordings shown in Figures 3A-3B and the graphical analysis in Figure 4 shows that the lower pressure used in Treatment 2 results in less splatting and explosions than the higher pressure as used in Treatment 1.Example 3

[0091] Root vegetable products were cut into strips with a strip size of 10 mm by 10 mm. Strips were cut from parsnip, swede, sweet potato, or taro root vegetables. Strips were treated with either MATS™ processing or pressure cooker processing. MATS™ processing was performed at 123 degrees Celsius for 10 minutes at 50 psi. Pressure cooker processing was performed at 80 kPa for 10 minutes. The results are summarized in the following table:

[0092] As used herein, the wording “and / or” is intended to represent an inclusive - or. That is, “X and / or Y” is intended to mean X or Y or both, for example. As a further example, “X, Y, and / or Z” is intended to mean X or Y or Z or any combination thereof.

[0093] The terms “an embodiment”, “embodiment”, “embodiments”, “the embodiment”, “the embodiments”, “one or more embodiments”, “some embodiments”, and “one embodiment” mean “one or more (but not all) embodiments of the present invention(s)”, unless expressly specified otherwise.

[0094] The terms “including”, “comprising”, and variations thereof mean “including but not limited to” unless expressly specified otherwise. A listing of items does not imply that any or all of the items are mutually exclusive, unless expressly specified otherwise. The terms “a”, “an”, and “the” mean “one or more”, unless expressly specified otherwise.

[0095] It should be noted that terms of degree such as "substantially", "about" and "approximately" as used herein mean a reasonable amount of deviation of the modified term such that the end result is not significantly changed. These terms of degree may also be construed as including a deviation of the modified term, such as by 1 %, 2%, 5%, or 10%, for example, if this deviation does not negate the meaning of the term it modifies.

[0096] While the above description describes features of example embodiments, it will be appreciated that some features and / or functions of the described embodiments are susceptible to modification without departing from the spirit and principles of operation of the described embodiments. For example, the various characteristics which are described by means of the represented embodiments or examples may be selectively combined with each other. Accordingly, what has been described above is intended to be illustrative of the claimed concept and non-limiting. It will be understood by persons skilled in the art that other variants and modifications may be made without departing from the scope of the invention as defined in the claims appended hereto. The scope of the claims should not be limited by the preferred embodiments and examples, but should be given the broadest interpretation consistent with the description as a whole.

Claims

CLAIMS:

1. A method of processing a root vegetable product, the method comprising: retort processing the root vegetable product while the root vegetable product is in a hermetically sealed container, wherein the container is subject to a pressure during the retort processing that is up to a retort processing pressure, the retort processing pressure being between a vapor pressure within the container and 50 psi, and wherein the root vegetable product is removeable from the container for deep frying following the retort processing and suitable to make a deep fried root vegetable product.

2. The method of claim 1 , further comprising, prior to retort processing the root vegetable product, blanching the root vegetable product and subjecting the root vegetable product to a sodium acid pyrophosphate treatment.

3. The method of claim 2, wherein the sodium acid pyrophosphate treatment includes exposure of the root vegetable product to a solution that is 1% by mass of sodium acid pyrophosphate in water.

4. The method of any one of claims 1 to 3, further comprising peeling and cutting a root vegetable to produce the root vegetable product.

5. The method of any one of claims 1 to 4, further comprising, following the retort processing: optionally storing the root vegetable product in the hermetically sealed container, and removing the root vegetable product from the hermetically sealed container and deep frying the root vegetable product.

6. The method of any one of claims 1 to 5, wherein retort processing includes raising a temperature of the root vegetable product to at least 120°C.

7. The method of any one of claims 1 to 6, wherein retort processing is performed using a Steriflow® retort system or a MATS™ system.

8. The method of claim 7, wherein retort processing is performed using the MATS™ system.

9. The method of any one of claims 1 to 6, wherein retort processing is performed using a reel and spiral retort system, a hydrostatic retort system, or a raining water retort system.

10. The method of any one of claims 1 to 9, wherein the retort processing pressure is between 14.7 psi and 40 psi.

11. The method of any one of claims 1 to 9, wherein the retort processing pressure is between 15 psi and 30 psi.

12. The method of any one of claims 1 to 9, wherein the retort processing pressure is between 18 psi and 40 psi.

13. The method of any one of claims 1 to 9, wherein the retort processing pressure is between 18 psi and 30 psi.

14. The method of any one of claims 1 to 9, wherein the retort processing pressure is between 20 psi and 40 psi.

15. The method of any one of claims 1 to 14, wherein the container is a pouch.

16. The method of any one of claims 1 to 15, wherein the container is a large-capacity container holding more than 10 kilograms of the root vegetable product.

17. The method of any one of claims 1 to 16, wherein the retort processing includes retort processing until the root vegetable product in the container is shelf-stable.

18. The method of any one of claims 1 to 17, wherein the root vegetable product is a French fry.

19. The method of any one of claims 1 to 18, further comprising providing, following the retort processing, the root vegetable product in the hermetically sealed container to a user to remove the root vegetable product from the container and finish cook the root vegetable product.

20. A method of processing a root vegetable product, the method comprising: retort processing the root vegetable product while the root vegetable product is in a hermetically sealed container, wherein the container is subject to a pressure during the retort processing that is up to a retort processing pressure, the retort processing pressure being between a vapor pressure within the container and 50 psi, and wherein the root vegetable product is removeable from the container for finish cooking following the retort processing and suitable to make a finish cooked root vegetable product.

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