CROSS REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of the United States Provisional Patent Application, Serial No. 61/316,245 filed March 22, 2010, entitled STABILIZED FRYING OIL, which is hereby incorporated by reference in its entirety.

FIELD OF THE INVENTION

[0002] The present disclosure relates generally to stabilizing a frying oil.

BACKGROUND OF THE INVENTION

[0003] Fried foods are enjoyed by people around the world. Frying is a cooking method in which food is placed in or submerged in hot oil. Often, the frying oil is used to cook many food items, heated for long periods of time, and subjected to several cycles of cooling and re-heating. After frying oil has been subjected to a certain amount of use, food cooked using the frying oil may become poor or rancid tasting. The over-use of frying oil can lead to poor tasting fried foods due to polymerization, oxidation, and creation of deleterious compounds in the frying oil, which are then passed onto the fried food. Thus, after a certain amount of use, frying oil can become spent and should be replaced with fresh oil to continue frying good tasting fried food.

SUMMARY OF THE INVENTION

[0004] One aspect of the invention features a stabilized frying oil containing a vegetable oil and one or more monovalent carbonate salts. Another aspect of the invention features a process for producing a stabilized frying oil. The process includes providing a vegetable oil and adding one or more monovalent carbonate salts to the vegetable oil to yield a stabilized frying oil. Yet another aspect of the invention features a process for utilizing a stabilized frying oil to fry a food product. The process includes providing a stabilized frying oil, heating the stabilized frying oil to a temperature of at least 160°C and utilizing the heated stabilized frying oil to fry a food product. In some embodiments, the stabilized frying oil can be heated to a temperature of at least 180°C. The stabilized frying oil contains a vegetable oil and one or more monovalent carbonate salts.

[0005] In some embodiments, the vegetable oil is a refined vegetable oil. In other embodiments, the vegetable oil can be soybean oil, palm oil, canola oil, corn oil, olive oil, peanut oil, sunflower oil, sesame oil, safflower oil, or mixtures thereof. In yet other embodiments, the one or more monovalent carbonate salts can make up from 50 ppm to 2000 ppm of the stabilized frying oil. In other embodiments, the one or more monovalent carbonate salts include potassium carbonate, potassium bicarbonate, sodium carbonate, sodium bicarbonate, or mixtures thereof. In some particular embodiments, the one or more monovalent carbonate salts is potassium carbonate.

DETAILED DESCRIPTION OF THE INVENTION

Terms

[0006] The term "vegetable oil", as used herein, means an oil suitable for human consumption which is derived from plants. Oils are compositions made up of triacylglycerides. Vegetable oils for use in the present invention are those oils which can be used in frying applications. In some embodiments, these vegetable oils can have a smoke point of at least 160°C. In other embodiments, these vegetable oils can have a smoke point of at least 175°C. In yet other embodiments, these vegetable oils can have a smoke point of at least 190°C. A smoke point is a temperature at which an oil begins to break down to glycerol and free fatty acids, and begins to lose flavor and nutritional value. Examples of vegetable oils which can be used in the present invention include, but are not limited to, canola oil, corn oil, mustard oil, olive oil, palm oil, palm kernel oil, peanut oil, safflower oil, sesame oil, soybean oil, almond oil, cottonseed oil, grape seed oil, sunflower oil, and mixtures thereof.

[0007] Vegetable oils useful in the present invention can also be hydrogenated oils, chemically or enzymatically interesterified oils, fractionated oils, and blended oils. The process of hydrogenation of oils refers to the partial or complete saturation of the free fatty acid components of triacylglycerides. Interesterifi cation refers to a process where fatty acids have been moved from one triacylglyceride molecule to another. Fractionation refers to a process where one fraction of an oil is separated from another fraction. Typically, using temperature modification, an oil can be separated into lower melting point fractions and higher melting point fractions. Blending refers to a process where one or more different oils or oil fractions are mixed together.

[0008] These processes can be carried out to provide a vegetable oil with the desired characteristics to be used in a particular frying application. More than one of these processes can be carried out to provide such a vegetable oil. For example, oils can be blended, then interesterified to yield a useful vegetable oil. The present invention contemplates that any combination of any of the above described oils can be used.

[0009] The term "refined vegetable oil" refers to a vegetable oil which has undergone a refining process. Refining is a process in which unwanted constituents are removed from an oil. Vegetable oils can be refined to varying degrees. It is the desired quality of the refined vegetable oil which determines the degree of refining. Additionally, depending upon the properties of the oil desired, different processing steps can be included. The process of refining oils is well known in the art, and an exemplary description of the refining process is provided in Perkins, E.G., Erickson, M.D., Deep Frying: Chemistry, Nutrition, and Practical Applications, pgs. 12-24, AOCS Press, 1996. In the present invention, the vegetable oil is refined such that it can particularly useful in frying applications, especially in deep frying applications.

[0010] The term "monovalent carbonate salt", as used herein, means an ionic salt compound in which the cation component includes a metal ion having one valence electron and the anion component consists of the carbonate group (C0 ₃ ^2~ ). Metals having one valence electron can be selected from the group of metals labeled "alkali metals". The monovalent carbonate salts which can be used in the present invention include, but are not limited to, potassium carbonate ( ₂ C0 ₃ ), potassium bicarbonate (KHC0 ₃ ), sodium carbonate (Na ₂ C0 ₃ ), sodium bicarbonate (NaHC0 ₃ ), and mixtures thereof.

Stabilized Frying Oil

[0011] One embodiment of the present invention sets forth a stabilized frying oil which includes a vegetable oil and one or more monovalent carbonate salts. In some embodiments, the vegetable oil is a refined vegetable oil.

[0012] In other embodiments, the vegetable oil can be a refined vegetable oil with a smoke point of 200°C and a free fatty acid content of less than 500 ppm. In yet other embodiments, the vegetable oil can be a refined vegetable oil with a smoke point of 210°C and a free fatty acid content of less than 500 ppm. In yet other embodiments, the vegetable oil can be a refined vegetable oil with a smoke point of at least 215°C and a free fatty acid content of less than 500 ppm. A refined vegetable oil having these characteristics is especially useful for deep frying food products.

[0013] The one or more monovalent carbonate salts can be added to the vegetable oil in any concentration useful for producing a stabilized frying oil. In some embodiments, the one or more monovalent carbonate salts can comprise from 50 ppm to 10,000 ppm of the stabilized frying oil. In other embodiments, the one or more monovalent carbonate salts can comprise from 100 ppm to 5,000 ppm of the stabilized frying oil. In yet other embodiments, the one or more monovalent carbonate salts can comprise from 250 ppm to 4,000 ppm of the stabilized frying oil. In yet other embodiments, the one or more monovalent carbonate salts can comprise from 500 ppm to 3,000 ppm of the stabilized frying oil. In yet other embodiments, the one or more monovalent carbonate salts can comprise from 750 ppm to 2,000 ppm of the stabilized frying oil. In yet other embodiments, the one or more monovalent carbonate salts can comprise from 1 ,000 ppm to 2,000 ppm of the stabilized frying oil.

[0014] Any combinations of one or more monovalent carbonate salts can be included with a vegetable oil to yield a stabilized frying oil. In some embodiments, the one or more monovalent carbonate salts utilized in the present invention can comprise potassium carbonate, potassium bicarbonate, sodium carbonate, or sodium bicarbonate included individually with the vegetable oil. In other embodiments, the one or more monovalent carbonate salts included with the vegetable oil can comprise a mixture of potassium carbonate and potassium bicarbonate. In yet other embodiments, the one or more monovalent carbonate salts included with the vegetable oil can comprise a mixture of potassium carbonate and sodium carbonate. In yet other embodiments, the one or more monovalent carbonate salts included with the vegetable oil can comprise a mixture of potassium carbonate and sodium bicarbonate. In yet other embodiments, the one or more monovalent carbonate salts included with the vegetable oil can comprise a mixture of potassium bicarbonate and sodium carbonate. In yet other embodiments, the one or more monovalent carbonate salts included with the vegetable oil can comprise a mixture of potassium bicarbonate and sodium bicarbonate. In yet other embodiments, the one or more monovalent carbonate salts included with the vegetable oil can comprise a mixture of sodium carbonate and sodium bicarbonate. [0015] In some embodiments, the one or more monovalent carbonate salts can be potassium carbonate and can comprise from 50 ppm to 10,000 ppm of the stabilized frying oil. In other embodiments, the one or more monovalent carbonate salts can be potassium carbonate and can comprise from 250 ppm to 4,000 ppm of the stabilized frying oil. In yet other embodiments, the one or more monovalent carbonate salts can be potassium carbonate and can comprise from 1 ,000 ppm to 2,000 ppm of the stabilized frying oil. In yet other embodiments, the one or more monovalent carbonate salts can be sodium bicarbonate and can comprise from 100 ppm to 5,000 ppm of the stabilized frying oil. In yet other embodiments, the one or more monovalent carbonate salts can be sodium bicarbonate and can comprise from 500 ppm to 3,000 ppm of the stabilized frying oil. In yet other embodiments, the one or more monovalent carbonate salts can be sodium bicarbonate and can comprise from 750 ppm to 2,000 ppm of the stabilized frying oil. In yet other embodiments, the one or more monovalent carbonate salts can be a mixture of potassium carbonate and sodium bicarbonate and can comprise from 100 ppm to 5,000 ppm of the stabilized frying oil. In yet other embodiments, the one or more monovalent carbonate salts can be a mixture of potassium carbonate and sodium bicarbonate and can comprise from 750 ppm to 2,000 ppm of the stabilized frying oil. The present invention further contemplates that the stabilized frying oil can be comprised of any combination of the above listed one or more monovalent carbonate salts in any of the above listed concentrations.

Stabilization of Frying Oil

[0016] Another aspect of the present invention sets forth a process for producing a stabilized frying oil. The process includes providing a vegetable oil and adding one or more monovalent carbonate salts to the vegetable oil to yield a stabilized frying oil. In some embodiments, the vegetable oil is a refined vegetable oil.

[0017] The concentrations and types of one or more monovalent carbonate salts which can be added to a vegetable oil to yield a stabilized frying oil are those described above for the stabilized frying oil.

[0018] The addition of one or more monovalent carbonate salts to a vegetable oil provides an oil which surprisingly shows enhanced stabilization in frying applications. This effect can be best examined when the stabilized frying oil of the present invention is compared to the same vegetable oil without the addition of one or more monovalent carbonate salts after both are heated for extended periods of time. In the subsequent Example section, this benefit is exemplified in Examples 1 -4 which compare the total polymers content and p-anisidine value of refined, bleached, deodorized soybean oil (RBD SBO) to samples of RBD SBO to which one or more monovalent carbonate salts have been added.

[0019] A p-anisidine value is a measurement of aldehyde content in an oil, principally 2-alkenals and 2,4 dienals. Aldehydes are secondary oxidation products produced during the oxidation of oils. Aldehydes are also partially responsible for the off flavor and odor of foods containing oils which have been oxidized to too great a degree. A p-anisidine value is, therefore, a measure of the oxidative state of an oil. A lower p-anisidine value in an oil indicates a lower level of oxidation in that oil.

[0020] Polymeric triacylglycerides are the predominant group of non-volatile alteration compounds found in oils which have been used in frying applications. These polymers alter the nutritional properties of frying oils and therefore of the fried foods into which they are absorbed. Large amounts of these polymers in the frying oil may be deleterious when consumed.

[0021] Providing an oil which is slower to oxidize or accumulate polymers in a frying environment would be beneficial because such an oil would not need to be replaced as frequently. The present invention presents such a frying oil. The addition of one or more monovalent carbonate salts surprisingly results in an oil which, in a frying environment, exhibits slower oxidation and slower accumulation of polymers. This slower accumulation of polymers and slower rate of oxidation results in an oil which is beneficially stabilized against deterioration and therefore needs to be replaced less frequently.

[0022] The present invention can additionally allow the use of certain oils in frying applications which would not have been feasible prior to the present invention. Certain oils may not have been utilized in frying applications in the past because they became spent too quickly to feasibly act as commercially useful frying oils. The addition of one or more monovalent carbonate salts to these oils can result in their slower accumulation of polymers and slower oxidation. This improved stabilization can allow these oils to prove commercially useful in frying applications. Use of Stabilized Frying Oil

[0023] Another aspect of the present invention features a process for utilizing a stabilized frying oil to fry a food product. The process includes providing a stabilized frying oil, heating the stabilized frying oil, and utilizing the heated stabilized frying oil to fry a food product.

[0024] The stabilized frying oil includes a vegetable oil and one or more monovalent carbonate salts. The concentrations and types of one or more monovalent carbonate salts which can be included with a vegetable oil to yield a stabilized frying oil are those described above for the stabilized frying oil of the present invention.

[0025] The stabilized frying oil can be heated to any temperature useful to fry food products in the stabilized frying oil. In some embodiments, the stabilized frying oil is heated to a temperature of at least 160°C. In other embodiments, the stabilized frying oil is heated to a temperature of at least 170°C. In yet other embodiments, the stabilized frying oil is heated to a temperature of at least 180°C. In yet other embodiments, the stabilized frying oil is heated to a temperature of at least 190°C. In yet other embodiments, the stabilized frying oil is heated to a temperature of at least 200°C. In yet other embodiments, the stabilized frying oil is heated to a temperature of at least 210°C.

[0026] Any type of frying technique can be used to fry the food product in a stabilized frying oil. Frying can include, but is not limited to, cooking techniques such as sauteing, stir- frying, pan frying, and deep frying. Sauteing refers to a cooking method in which a small quantity of oil is placed into a pan and the food is cooked on this oil. In sauteing, the oil does not come up the side of the food being cooked. Rather, the food is cooked on a thin layer of oil. Stir-frying refers to a cooking technique where oil is placed in a pan and the food product is cooked relatively quickly over high heat. The temperatures used in stir-frying are typically greater than that of sauteing. Additionally, in stir-frying, the food is consistently stirred and cooked more rapidly than in sauteing. Pan frying refers to a cooking method in which food is partially immersed in hot oil and cooked. In pan frying, the food product can be 1/3 to 1/2 submerged in the hot oil and cooked. Deep frying refers to a cooking technique where food is cooked by fully immersing the food in hot oil. In some embodiments, the frying technique used in the present invention is pan frying or deep frying. In other embodiments, the frying technique used in the present invention is deep frying. EXAMPLES

[0027] The present invention is further illustrated by the examples provided below. It is understood that these examples are not intended to limit the scope of the present invention in any way.

[0028] The following measurement methods are used in the examples 1-4 below: Method of obtaining total polymers measurement

[0029] The total amount of polymerized triacylglycerols (polymers) present in the oil was determined in the following manner: A High Performance Size Exclusion Chromatography (HPSEC) using a Waters 2795 liquid chromatograph was coupled to a Sedex 75 Evaporative Light Scattering Detector (ELSD). HPSEC was used for separation and the ELSD was used for quantitation of polymers in the starting RBD SBO and the samples taken after each 8 hour day in which the RBD SBO was heated in a fryer. Liquid chromatography separations were made using one 500 A PLgel (300 mm x 7.5 mm, 5 μπι particle size) and two 50A PLgel (300 mm x 7.5 mm, 5 μηι particle size) HPSEC columns at 20°C. An isocratic mobile phase of tetrahydrofuran (THF) at 1 mL/min was used for the separation. Injection volume was 5 μL·. Samples (20 mg) were diluted in 10 mL THF. The ELSD settings were 40°C, Gain = 1, and Nitrogen = 1.5 L/min. Quantitation was based upon area percent.

Method of obtaining p-anisidine value

[0030] The /?-anisidine method determines the aldehydes present in the oil, primarily 2- alkenals and 2,4-dienals, and is an indicator of the oxidative state of the oil. The p-anisidine value ("p-AV") is defined by convention as 100 times the optical density measured at 350 nm in a 1-cm cuvette of a solution containing 1.0 g of oil in 100 mL of a mixture of solvent and reagent. This method utilized a diode array spectrophotometer in a fixed wavelength mode. A vegetable oil reference material with historical data was also analyzed for quality control. The p-AV was obtained as described below. The method described below is a modification of AOCS Official Method Cd 18-90. For example, the AOCS method was modified to reflect the use of a single beam spectrophotometer (vs. a dual beam spectrophotometer). [0031] -Anisidine reagent was prepared by measuring 0.125 g -anisidine into a 50 mL volumetric flask and diluting to volume with glacial acetic acid. The reagent was kept away from sunlight and made fresh daily.

[0032] Sample solutions were prepared by adding 0.025 - 4.0 g of a sample into a tared 25 mL volumetric flask and recording the mass to the nearest 0.0001 g (this value is 'm' in the calculation shown below). The amount of sample added to a tared 25 mL volumetric flask was 2 g for starting RBD SBO samples and 0.025 to 0.05 g for the daily fryer treated samples. Approximately 15 mL iso-octane was added to each flask to dissolve the sample, and each sample was then diluted to volume, stoppered, and mixed well.

[0033] A 1 cm quartz cuvette was used for all absorbance determinations. The cuvette was rinsed thoroughly with iso-octane, dried, and visually inspected for residue or smudges before each solution was added for measurement. If oil residue or smudges were observed, the cleaning process was repeated. Acetone was also used to rinse the outside of the cuvette between measurements. Absorbance measurements were made at 350 nm on a single path Agilent 8453 spectrophotometer. The background was measured against iso-octane.

[0034] The absorbance of each sample solution was measured three times in succession and the average calculated (Ai in the calculation). Using Class A pipets, 5 mL of sample solution was transferred to a 13 x 100 mm test tube, followed by 1 mL of />-anisidine reagent. The tubes were capped with PTFE lined screw top caps, mixed using a laboratory vortex mixer, and allowed to react for exactly 10 minutes. The absorbance of the reacted solutions were then each measured three times in succession and the average calculated (A ₂ in the calculation). A reagent blank of 5 mL iso-octane was also reacted with /?-anisidine reagent, and its absorbance measured three times in succession with the average calculated (AB in the calculation).

[0035] The p-AV of each sample was then determined according to the following calculation:

25 * [1.2(A ₂ - A _B ) - A ₁ ]

p-AV =

m

[0036] Ai = absorbance of the sample solution before /?-anisidine addition [0037] A ₂ = absorbance of the sample solution after reaction with the >-anisidine reagent

[0038] AB - absorbance of the blank solution after reaction with the -anisidine reagent

[0039] m = mass of the test portion (in grams)

[0040] 1.2, 25 = correction factors

Example 1 : Evaluation of Soybean Oil with and without Potassium Carbonate (at concentrations 250 ppm, 500 ppm, and 1 ,000 ppm)

[0041 ] Four individual 35 lb containers of refined, bleached, deodorized soybean oil (RBD SBO) from a single lot were obtained from Cargill, Inc.'s Charlotte, North Carolina facility. Three containers were immediately stored in a food grade refrigerator upon delivery. The fourth container was left at room temperature for two days prior to use. Potassium Carbonate (K ₂ C0 ₃ ), anhydrous, was obtained from EMD Chemicals (product number PX1390-1). Three experimental samples were prepared: RBD SBO spiked with 1,000 ppm K ₂ C0 ₃ , RBD SBO spiked with 500 ppm K ₂ C0 ₃ , and RBD SBO spiked with 250 ppm K C0 ₃ . RBD SBO without any K ₂ C0 ₃ was used as the control sample.

[0042] Four separate Presto® FryDaddy® electric deep fryers, uniquely labeled as fryers #1 , #2, #3, and #4 were set up on individual 20 amp electrical circuits within an isolated fume hood. These particular fryers have a vendor recommended cooking oil capacity of four 8-ounce cups (960 mL or 883 g) so marked within each fryer by an inscribed line. This amount of sample was added to each fryer. Specifically, the control sample, RBD SBO without any K ₂ C0 ₃ , was added to fryer #1. RBD SBO spiked with 250 ppm K ₂ C0 ₃ was added to fryer #2, RBD SBO spiked with 500 ppm K ₂ C0 ₃ was added to fryer #3, and RBD SBO spiked with 1 ,000 ppm ₂ C0 ₃ was added to fryer #4.

[0043] Each fryer was run for eight hours per day for five consecutive days. Presto® FryDaddy® electric deep fryers do not have temperature control options, but are expected to reach at least the frying oil temperature of 190°C as per vendor specifications. The temperature of the oil in each fryer was measured using a Fluke® Model 51 Series II Digital Thermometer coupled to a SureGrip™ Immersion Temperature Probe. These temperatures were taken 3 times daily: one hour, four hours, and eight hours after the Presto® FryDaddy® electric deep fryers were powered on. After eight hours, the power to each fryer was terminated and a 20 mL sample was retrieved from each fryer. Each sample was stored in a uniquely labeled amber glass bottle with a Teflon® lined screw top lid. Nitrogen was used to purge and sparge both the sample and headspace before sealing the bottle for storage. All samples were then immediately placed in a freezer until analytical testing commenced. The four fryers were allowed to cool down overnight, without a lid or inserted ladle. The following morning, power was restored to each fryer, with a repeat of the above protocol.

[0044] The temperature of oil in each fryer remained relatively steady upon heating. In addition, the temperature of the oil in fryer 2, 3, and 4 (the experimental samples) was similar to that of the control in fryer 1. Daily temperature measurements taken from fryer 1 ranged from 202°C-205°C. Daily temperature measurements taken from fryer 2 ranged from 200°C- 203°C. Daily temperature measurements taken from fryer 3 ranged from 201°C-203°C. Daily temperature measurements taken from fryer 4 ranged from 205°C-208°C.

[0045] Samples were taken from each fryer at the end of each day for analytical testing. These samples were tested for total polymer concentration (%), and for p-anisidine value. Prior to testing, the samples were allowed to warm to room temperature, and were mixed thoroughly to ensure that they were homogenous.

[0046] Tables 5 through 8 show the polymer concentration for each sample prior to placing the oils in the fryers and for samples taken from each fryer at the end of each day's eight hour heating period.

Table 5: Polymer concentrations for starting RBD SBO and daily samples taken from fryer 1

Table 6: Polymer concentrations for starting RBD SBO with 250 ppm ₂ C0 ₃ and daily samples taken from fryer 2

[0047] As seen in Tables 5-8, the addition of ₂ C0 ₃ to RBD SBO resulted in a reduction in polymer content of the oil after being heated in fryers. The RBD SBO with 250 ppm K ₂ C0 ₃ only increased to 20% total polymers after day five, a 21.9% reduction in polymer content compared to the control (RBD SBO without any K ₂ C0 ₃ ). Similarly, RBD SBO with 500 ppm K ₂ C0 ₃ showed a 44.9% reduction in polymer content compared to the control after day five and the RBD SBO with 1 ,000 ppm K ₂ C0 ₃ showed a 51.6% reduction in polymer content compared to the control after day 5. The addition of ₂ C0 ₃ to the starting oil resulted in reduced polymer formation and therefore responded as a capable oil stabilizer in a frying environment.

[0048] Tables 9 through 12 show the p-anisidine for each sample prior to placing the oils in the fryers and for samples taken from each fryer at the end of each day's eight hour heating period.

Table 9: p-anisidine value for starting RBD SBO and daily samples taken from fryer 1

Table 12: p-anisidine value for starting RBD SBO with 1,000 ppm K ₂ C0 ₃ and daily samples taken from fryer 4

[0049] As seen in Tables 9-12, the addition of K ₂ C0 ₃ to RBD SBO resulted in a reduction in p-anisidine value of the oil after being heated in fryers. The RBD SBO with 250 ppm K ₂ C0 ₃ had a p-anisidine value of 200.7 after day 5, a 44.1% decrease compared to the control (RBD SBO without added ₂ C0 ₃ ). Similarly, RBD SBO with 500 ppm K ₂ C0 ₃ showed a 45.7% decrease in p-anisidine value compared to the control and the RBD SBO with 1 ,000 ppm ₂ C0 ₃ showed a 72.4% decrease in p-anisidine value compared to the control. Thus, the addition of K ₂ C0 ₃ to RBD SBO at the above concentrations resulted in a reduced p-anisidine formation in a frying environment. This data indicates that K ₂ C0 ₃ not only functioned as a good anti-polymerization compound, but also a capable antioxidant in a frying environment.

Example 2: Evaluation of Soybean Oil with and without Potassium Carbonate (at concentrations 1 ,000 ppm, 5,000 ppm, and 10,000 ppm)

[0050] Refined, bleached, deodorized soybean oil (RBD SBO) from a single lot was obtained from Cargill, Inc.'s Charlotte, North Carolina facility. The RBD SBO used in this Example was from the same lot as that used in Example 1. Potassium Carbonate (K ₂ C0 ₃ ), anhydrous, was obtained from EMD Chemicals (product number PX1390-1). Three experimental samples were prepared: RBD SBO spiked with 1 ,000 ppm ₂ C0 ₃ , RBD SBO spiked with 5,000 ppm K ₂ C0 ₃ , and RBD SBO spiked with 10,000 ppm K ₂ C0 ₃ . RBD SBO without any K ₂ C0 ₃ was used as the control sample.

[0051] Four separate Presto® FryDaddy® electric deep fryers, uniquely labeled as fryers #1 , #2, #3, and #4 were set up on individual 20 amp electrical circuits within an isolated fume hood. These particular fryers have a vendor recommended cooking oil capacity of four 8-ounce cups (960 mL or 883 g) so marked within each fryer by an inscribed line. This amount of sample was added to each fryer. Specifically, the control sample, RBD SBO without any K ₂ C0 ₃ , was added to fryer #1. RBD SBO spiked with 1 ,000 ppm K ₂ C0 ₃ was added to fryer #2, RBD SBO spiked with 5,000 ppm ₂ C0 ₃ was added to fryer #3, and RBD SBO spiked with 10,000 ppm K ₂ C0 ₃ was added to fryer #4.

[0052] Each fryer was run for eight hours per day for five consecutive days. Presto® FryDaddy® electric deep fryers do not have temperature control options, but are expected to reach at least the frying oil temperature of 190°C as per vendor specifications. The fryers were powered on and temperatures were taken and recorded as described in Example 1. After eight hours, the power to each fryer was terminated and a 20 mL sample was retrieved from each fryer. Samples were taken, labeled, and stored as described in Example 1. The four fryers were allowed to cool down overnight, without a lid or inserted ladle. The following morning, power was restored to each fryer, with a repeat of the above protocol.

[0053] The temperature of oil in each fryer remained relatively steady upon heating. The temperature of the oil in fryer's 2, 3, and 4 (the experimental samples) was slightly below the temperature of the control sample in fryer 1. Daily temperature measurements taken from fryer 1 ranged from 201°C-204°C. Daily temperature measurements taken from fryer 2 ranged from 196°C-201 °C. Daily temperature measurements taken from fryer 3 ranged from 190°C-197°C. Daily temperature measurements taken from fryer 4 ranged from 190°C- 199°C.

[0054] Samples were taken from each fryer at the end of each day for analytical testing. These samples were tested for total polymer concentration (%), and for p-anisidine value. Prior to testing, the samples were allowed to warm to room temperature, and were mixed thoroughly to ensure that they were homogenous.

[0055] Tables 17 through 20 show the polymer concentration for each sample prior to placing the oils in the fryers and for samples taken from each fryer at the end of each day's eight hour heating period.

Table 17: Polymer concentrations for starting RBD SBO and daily samples taken from fryer 1

Table 18: Polymer concentrations for starting RBD SBO with 1 ,000 ppm K ₂ C0 ₃ and daily samples taken from fryer 2

[0056] As seen in Tables 17-20, the addition of K ₂ C0 ₃ to RBD SBO resulted in a reduction in polymer content of the oil after being heated in fryers. The RBD SBO with 1 ,000 ppm K ₂ C0 ₃ only increased to 8.4% total polymers after day five, a 69.5% reduction in polymer content compared to the control (RBD SBO without any K ₂ C0 ₃ ). RBD SBO with 5,000 ppm K ₂ C0 ₃ showed a 77.1 % reduction in polymer content compared to the control after day five and the RBD SBO with 10,000 ppm K ₂ C0 ₃ showed a 75.3% reduction in polymer content compared to the control after day five. Like Example 1 , the addition of K ₂ CO3 to the starting oil resulted in reduced polymer formation, and therefore acts as a capable anti-polymerization compound in frying environment at the added concentrations.

[0057] Tables 21 through 24 show the p-anisidine for each sample prior to placing the oils in the fryers and for samples taken from each fryer at the end of each day's eight hour heating period.

Table 21 : p-anisidine value for starting RBD SBO and daily samples taken from fryer 1

Table 24: p-anisidine value for starting RBD SBO with 10,000 ppm K ₂ C0 ₃ and daily samples taken from fryer 4

[0058] As seen in Tables 21-24, the addition of K ₂ C0 ₃ to RBD SBO resulted in a reduction in p-anisidine value of the oil after being heated in fryers. The RBD SBO with 1 ,000 ppm K ₂ C0 ₃ had a p-anisidine value of 86.2 after day 5, a 77.1 % decrease compared to the control (RBD SBO without added K ₂ C0 ₃ ). Similarly, RBD SBO with 5,000 ppm K ₂ C0 ₃ showed an 87.2% decrease in p-anisidine value compared to the control and the RBD SBO with 10,000 ppm ₂ C0 ₃ showed a 97.8% decrease in p-anisidine value compared to the control. The addition of ₂ C0 ₃ to RBD SBO at the above concentrations resulted in a significant reduction in p-anisidine formation in a frying environment. This example shows that K ₂ C0 ₃ , when added to an oil, acts as a powerful antioxidant in a frying environment.

Example 3: Evaluation of Soybean Oil spiked with different compounds

[0059] Refined, bleached, deodorized soybean oil (RBD SBO) was spiked with three different compounds at various concentrations and heated continuously for 48 hours at approximately 200°C using a Reacti-Therm™ III heating module. At the end of 48 hours of heating, the samples were analyzed for polymer content.

[0060] RBD SBO was obtained from Cargill, Inc.'s Charlotte, North Carolina facility. Compounds utilized in this example were sodium bicarbonate (NaHC0 ₃ ) (obtained from Sigma, product number S6297), a-tocopherol (obtained from Sigma-Aldrich, product number T3634), and γ-tocopherol (obtained from Sigma-Aldrich, product number T1782).

[0061] The RBD SBO and additives were weighed on a five-place analytical balance. Prior to oil introduction, the additives were weighed directly into the appropriate 30 mL glass vial to be placed into the Reacti-Therm™ III heating module. RBD SBO was added to the approximate volume (weight) of 15 g, or to the height of the vial to be placed into the heating module. The samples were manually mixed with a Teflon™ coated spatula prior to vial introduction, without tops, to the heating module.

[0062] Two Reacti-Therm™ III heating modules were obtained from Pierce (product number 18935). Each module contained three aluminum heating Reacti-blocks (obtained from Pierce, product number 18814), with each block having eight individual positions. Each position was subjected to temperatures of approximately 200°C.

[0063] Samples were placed in 30 mL clear glass sample vials (obtained from VWR, product number 66009-555), and the sample vials were placed in the heating modules without lids. The samples were heated continuously in the modules for 48 hours. Temperature measurements were taken six times periodically throughout the 48 hour heating period. All temperature measurements were between 200°C and 209°C.

[0064] After heating for 48 hours, the samples were measured for total polymer content. Results for each sample are shown in Table 25 below. The total polymer content for RBD SBO without any additive after heating continuously for 48 hours was 26.13%.

Table 25: Total polymer content (%) of RBD SBO with various additives

[0065] As seen in Table 25, NaHC0 ₃ , a monovalent carbonate salt, is the only additive tested in this example that displayed useful polymer inhibition effects compared to the control (RBD SBO without additive, 26.13% total polymer content). Surprisingly, a-tocopherol and γ-tocopherol, known anti-oxidants, did not display polymer inhibition in an environment comparable to what would been seen when frying food. Example 4: Evaluation of Soybean Oil spiked with different Carbonate and Bicarbonate combinations

[0066] Procedures as described in Example 3 were used in this example, except that different additives were utilized. Specifically, several carbonate and bicarbonate salts, and combinations of these salts, were tested for anti-polymerization effects. In this example, each additive was added to RBD SBO at a concentration of 1 ,000 ppm. Thus, when a combination of two additives was added to RBD SBO, each was added at 1 ,000 ppm for a total of 2,000 ppm of additive added to the RBD SBO. Temperature measurements were taken six times periodically throughout the 48 hour heating period. All temperature measurements were between 197°C and 204°C.

[0067] After heating for 48 hours, the samples were measured for total polymer content. Results for each experimental sample and the control sample are shown in Table 26 below.

Table 26: Total polymer content (%) of RBD SBO with carbonate and bicarbonate salts, and combinations thereof

KHC0 ₃ + Na ₂ C0 ₃ 19.48%

KHC0 ₃ + NaHC0 ₃ 5.34% HC0 ₃ + CaC0 ₃ 23.27%

KHC0 ₃ + MgC0 ₃ 23.58%

Na ₂ C0 ₃ + NaHC0 ₃ 1 1.63%

Na ₂ C0 ₃ + CaC0 ₃ 28.96%

Na ₂ CO _s + MgC0 ₃ 28.28%

NaHC0 ₃ + CaC0 ₃ 24.72%

NaHC0 ₃ + MgC0 ₃ 22.10%

CaC0 ₃ + MgC0 ₃ 31.90%

[0068] As seen in Table 26, K ₂ C0 ₃ alone and NaHC0 ₃ alone both displayed very good polymer inhibition. In addition, when NaHC0 ₃ or Na ₂ C0 ₃ was added to the ₂ C0 ₃ , the mixture showed increased polymer inhibition compared to ₂ C0 ₃ alone. When NaHC0 ₃ and KHC0 ₃ were combined, the mixture showed increased polymer inhibition compared to NaHC0 ₃ alone. Thus, the data indicate that these monovalent carbonate salts and combinations of monovalent carbonate salts show a capability for polymer inhibition in an environment comparable to what would been seen when frying food.

[0069] Surprisingly, MgC0 ₃ and CaC0 ₃ , the divalent carbonate salts, did not show significant polymer inhibition. Additionally, the data indicate that addition of these divalent carbonate salts to a sample with monovalent carbonate salt did not improve the polymer inhibition. In fact, these divalent carbonate salts seemed to hinder the polymer inhibition activity of the monovalent carbonate salts when added to the same RBD SBO sample. For example, NaHC0 ₃ alone showed a 62.1 % reduction in total polymer content compared to the control. However, when CaC0 ₃ was added to the NaHC0 ₃ , this combination only showed a 22.9% reduction in total polymers compared to the control.