Degassing frying oil

Abstract

The present technology relates to, in part, a method of treating frying oil. Frying oil is pumped through a vat outlet of a vat to a volume of a thin film degasser. The frying oil is exposed to a vacuum in the volume of the thin film degasser. The frying oil is returned to the vat through an inlet conduit.

Description

DEGASSING FRYING OILCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 512.318, filed July 7, 2023. the disclosure of which is incorporated by reference herein in its entirety.TECHNOLOGICAL FIELD

[0002] The present disclosure is generally related to frying oil. More particularly, the present disclosure is related to degassing frying oil.BACKGROUND OF THE INVENTION

[0003] In conventional frying processes, frying oil is heated to an appropriate cooking temperature, and food is immersed in the heated frying oil until cooked to a particular specification. The quality of the frying oil is known to generally degrade over time as gases, moisture, particulates, flavors, and odors from the food is released in the frying oil. Furthermore, the frying oil may be aerated over time with oxygen, moisture, and other gases (including vapors) from the ambient air. The substances transferred to the frying oil may facilitate degradation in the quality of the oil.

[0004] Food and other particles may linger in the frying oil long after the food has been cooked and removed from the oil, which may lead to further contamination of the frying oil as such particles are burned. Additionally, absorbed flavors and odors from some fried food, especially when fry ing a strongly flavored food such as seafood, may impair the quality of other ty pes of food that are fried in the same frying oil. Furthermore, the presence of moisture in the frying oil causes hydrolysis of triglycerides, thus generating free fatty acids (FFA), diglycerides, monoglycerides, and glycerol. Further still, as the fatty7acid content of the frying oil increases, the moisture content of the frying oil also increases, further accelerating the degradation of the frying oil. In some industries, frying oil is discarded when the FFA content is above 2.5%. As another example, the formation of total polar materials (TPM) is associated with the hydrolysis, oxidation, and polymerization of heated oils duringfrying. In some industries, frying oil is discarded when the TPM content is greater than or equal to 25%.

[0005] Deodorization is a process that can be used to remove undesirable components, for example, moisture, FFA, dissolved oxygen, breakdown components of frying oil, and aroma within frying oil to extend the lifetime of the fry ing oil. During deodorization, the frying oil is heated to at least 220 °C and then exposed to a vacuum, and relatively high-pressure steam is passed through the heated oil. Deodorization systems are generally' separate from the fry ing system within which the frying oil is employed. Deodorization generally occurs after the frying oil has been used for a particular period of time to fry' a food product, after which the deodorized oil is reused in the frying system.

[0006] Another practice is the use of an adsorbent to remove FFA and polar compounds from the frying oil. Frying oil can be treated, for example, at the end of a frying operation with an adsorbent such as silica gel to remove FFA and polar compounds. Such a treatment can extend the lifetime of the frying oil. However, this practice does not remove all the FFA or total polar material and over time the oil still must be disposed of within a particular time period that may be less than 24 days.

[0007] Yet another approach is to use a commercially available vacuum fry er where a vacuum is applied to the entire frying oil vat within which the food is fried in oil. Depending on the size of the frying oil vat, it can take a relatively long period of time to reduce the moisture content of the frying oil to a desirable level.SUMMARY OF THE INVENTION

[0008] Various aspects of the present technology relate to the use of a thin film degasser to reduce hydrolysis in frying oil. In some aspects, the degassed frying oil has a moisture content of less than 1000 ppm after use of the thin film degasser. Additionally or alternatively, the degassed frying oil has a moisture content of less than 400 ppm. Additionally or alternatively, the degassed frying oil has a moisture content of less than 200 ppm. Additionally or alternatively, the frying oil has a temperature of at least 150°C when introduced to the thin film degasser. Additionally or alternatively, the frying oil has a temperature of less than 200°C when introduced to the thin film degasser.

[0009] Additionally or alternatively, the method includes fry ing a food product in a frying oil vat, wherein the frying oil is introduced to the thin film degasser from the frying oil vat. Additionally or alternatively, the thin film degasser is configured to remove oxygen and moisture from its volume. Additionally or alternatively, the thin film degasser is configured to remove fatty' acids. Additionally or alternatively, the method includes filtering the frying oil upstream of the thin film degasser.Additionally or alternatively, the vacuum pressure in the volume of the thin film degasser is less than 80 mbar. Additionally or alternatively, the frying oil is returned to a fry ing oil vat after using the thin film degasser on the frying oil.

[0010] Additionally or alternatively, the thin film degasser has a feed rate of 1,000 L / hr-m2to 6.000 L / hr-m2. Additionally or alternatively, the thin film degasser has a feed rate of 7,000 L / hr-m2to 14,000 L / hr-m2. Additionally or alternatively, the thin film degasser has a feed rate of 13,000 L / hr-m2to 20,000 L / hr-m2. Additionally or alternatively, the frying oil has an average composite age of at least 10 days. Additionally or alternatively, the frying oil has an average composite age of at least 17 days. Additionally or alternatively, the degassed frying oil has a moisture content of less than 500 ppm. Additionally or alternatively, the degassed frying oil has a moisture content of less than 400 ppm.

[0011] Additionally or alternatively, the degassed frying oil has an FFA content of less than 2.5 wt%. Additionally or alternatively, the degassed frying oil has an FFA content of less than 1 wt%. Additionally or alternatively, the degassed frying oil has an FFA content of 0.2 - 0.5 wt%. Additionally or alternatively, the degassed frying oil has a TPM content of less than 25 wt%. Additionally or alternatively, the degassed frying oil has an TPM content of less than 20 wt%. Additionally or alternatively, the degassed frying oil has an TPM content of 5 - 10 wt%. Additionally or alternatively, the degassed frying oil has a low molecular weight FFA content of less than 0.01 wt%. Additionally or alternatively, the degassed frying oil has a low molecular weight FFA content of 0.0 wt%. Additionally or alternatively, the thin film degasser removes light volatile aroma compounds from the frying oil.

[0012] Some aspects of the technology disclosed herein relate to a method. Frying oil is pumped through a vat outlet of a vat to a volume of a thin film degasser. The frying oil is exposed to a vacuum in the volume of the thin film degasser. The frying oil is returned to the vat through an inlet conduit.

[0013] In some such aspects, the frying oil contained in the vat has a minimum height, and the inlet conduit is positioned vertically below the minimum height. Additionally or alternatively, the frying oil returned to the vat has a moisture content of less than 1000 ppm. Preferably, the frying oil returned to the vat has a moisture content of less than 400 ppm. More preferably, the fry ing oil returned to the vat has a moisture content of less than 200 ppm. Additionally or alternatively, the frying oil has a temperature of at least 150°C at the vat outlet. Additionally or alternatively, the frying oil has a temperature of less than 200°C at the vat outlet. Additionally or alternatively, the pumping, exposing, and returning is a continuous cycle.

[0014] Additionally or alternatively, the method includes frying a food product in the vat. where the continuous cycle is executed during the frying. Additionally or alternatively, the thin film degasser is configured to remove oxygen and moisture from its volume. Additionally or alternatively, the thin film degasser is configured to remove fatty acids. Additionally or alternatively, the method includes filtering the frying oil upstream of the thin film degasser. Additionally or alternatively, the vacuum pressure in the volume of the thin film degasser is less than 80 mbar. Additionally or alternatively, returning the frying oil to the vat is after exposing the frying oil to the vacuum. Additionally or alternatively, food product is fried in the frying oil in the vat.

[0015] Additionally or alternatively, the thin film degasser has a feed rate of 1.000 L / hr-m2to 6,000 L / hr-m2. Additionally or alternatively, thin film degasser has a feed rate of 7,000 L / hr-m2to 14,000 L / hr-m2. Additionally or alternatively, the thin film degasser has a feed rate of 13,000 L / hr-m2to 20,000 L / hr-m2. Additionally or alternatively, the frying oil in the vat has an average composite age of at least 10 days and a moisture content of less than 1000 ppm. Additionally or alternatively, the frying oil in the vat has an average composite age of at least 17 days. Additionally or alternatively, the fry ing oil in the vat has a moisture content of less than 500 ppm. Additionally or alternatively, the frying oil in the vat has a moisture content of less than 400 ppm.

[0016] Additionally or alternatively, the frying oil in the vat has an average composite age of at least 10 days and an FFA content of less than 2.5 wt%. Additionally or alternatively, the frying oil in the vat has an average composite age of at least 17 days. Additionally or alternatively, the frying oil in the vat has an FFA content of less than 1 wt%. Additionally or alternatively, the frying oil in the vat hasan FFA content of 0.2 - 0.5 wt%. Additionally or alternatively, the fry ing oil in the vat has an average composite age of at least 10 days and an TPM content of less than 25 wt%. Additionally or alternatively, the frying oil in the vat has an average composite age of at least 17 days. Additionally or alternatively, the frying oil in the vat has an TPM content of less than 20 wt%. Additionally or alternatively, the fry ing oil in the vat has an TPM content of 5 - 10 wt%.

[0017] Additionally or alternatively, the frying oil in the vat has an average composite age of at least 10 days and a low molecular weight FFA content of less than 0.01 wt%. Additionally or alternatively, the fry ing oil in the vat has an average composite age of at least 17 days. Additionally or alternatively, the frying oil in the vat has a low molecular weight FFA content of 0.0 wt%. Additionally’ or alternatively, the thin film degasser removes light volatile aroma compounds from the frying oil.

[0018] Some aspects of the technology disclosed herein relate to a system. The system has a fluid flow line having an inlet conduit configured to fluidly communication with an interior volume of a frying oil vat and an interface configured to fluidly couple to an outlet of the frying oil vat. A thin film degasser defines a volume configured for fluid communication with the fluid flow line. A particle filter is configured to be positioned upstream of the thin film degasser along the fluid flow line. A vacuum pump is configured for fluid communication with the volume of the thin film degasser.

[0019] In some such aspects, the system has a high temperature liquid pump configured for fluid communication with the fluid flow line. Additionally or alternatively, the vacuum pump is configured to maintain a pressure of less than 300 mbar in the volume of the thin film degasser. Additionally or alternatively, the liquid pump has a pump capacity of at least 2 liters / minute. Additionally or alternatively, the interface is configured to be positioned vertically below the inlet conduit when coupled to the fry ing oil vat. Additionally or alternatively, the system has a knockout pot is in fluid communication with the thin film degasser and the vacuum pump, where the knockout pot is configured to be positioned between the thin film degasser and the vacuum pump. Additionally or alternatively, the thin film degasser is configured to remove oxygen and moisture from its volume. Additionally or alternatively, the thin film degasser is configured to remove fatty acids. Some aspects relate to a method of reducing hydrolysis in frying oil using systems described above.

[0020] Some other aspects relate to a system having a frying oil vat having an open interior volume, a vat inlet, and a vat outlet. A fluid flow line has an inlet conduit configured to be in fluid communication with the open interior volume and an interface configured to be fluidly coupled to the vat outlet. A thin film degasser defines a volume configured for fluid communication with the fluid flow line. A particle filter is configured to be positioned upstream of the thin film degasser along the fluid flow line. A vacuum pump is in fluid communication with the volume of the thin film degasser.

[0021] In some such aspects, a high temperature liquid pump is configured for fluid communication with the fluid flow line. Additionally or alternatively, the frying oil vat has a base and a sidewall, and the sidewall has a proximal end integrated with the base, a distal end, and a height between the proximal end and the distal end. The open interior volume extending from the base to the distal end of the sidewall. Additionally or alternatively, the inlet conduit is vertically spaced from the base no more than half of the height of the sidewall. Additionally or alternatively, the vat outlet is defined towards the proximal end of the sidewall. Additionally or alternatively, the vacuum pump is configured to maintain a pressure of less than 300 mbar in the volume of the thin film degasser. Additionally or alternatively, the liquid pump has a pump capacity of at least 2 liters / minute. Additionally or alternatively, the interface is configured to be positioned vertically below the inlet conduit when coupled to the frying oil vat. Additionally or alternatively, the system has a knockout pot in fluid communication with the thin film degasser and the vacuum pump, where the knockout pot is configured to be positioned between the thin film degasser and the vacuum pump. Some aspects relate to a method of reducing hydrolysis in frying oil using systems described above.

[0022] The above summary is not intended to describe each aspect or every implementation. Rather, a more complete understanding of illustrative embodiments will become apparent and appreciated by reference to the following Detailed Description and claims in view of the accompanying figures of the drawing.BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present technology may be more completely understood and appreciated in consideration of the following detailed description of various aspects in connection with the accompanying drawings.

[0024] FIG. 1 depicts an example system consistent with the technology disclosed herein.

[0025] FIG. 2 depicts an example method consistent with the technology disclosed herein.

[0026] FIG. 3 depicts predicted frying oil moisture content as a function of vacuum and temperature in accordance with thermodynamic calculations of partial pressure data.

[0027] FIG. 4 reflects moisture content of four samples of frying oil in accordance with experimental procedures described herein.

[0028] FIG. 5 reflects diacylglycerol (DAG) content of three samples of frying oil in accordance with experimental procedures described herein.

[0029] FIG. 6 reflects total polar material (TPM) content of three samples of frying oil in accordance with experimental procedures described herein.

[0030] FIG. 7 reflects free fatty acids (FFA) content of three samples of frying oil in accordance with experimental procedures described herein.

[0031] The figures are rendered primarily for clarity and, as a result, are not necessarily drawn to scale. Moreover, various structure / components, including but not limited to fasteners, electrical components (wiring, cables, etc.), instruments, and the like, may be shown diagrammatically or removed from some or all of the view s to better illustrate aspects of the depicted embodiments, or w here inclusion of such structure / components is not necessary to an understanding of the various exemplary embodiments described herein. The lack of illustration / description of such structure / components in a particular figure is, however, not to be interpreted as limiting the scope of the various aspects in any way.DETAILED DESCRIPTION

[0032] Some aspects of the technology disclosed herein may advantageously lengthen the lifetime of frying oil by removing contaminants that have been introduced into the frying oil during cooking operations. Some aspects of the technology disclosed herein are configured to purify the fry ing oil. Some aspectsconsistent with the present technology may advantageously reduce the moisture, oxygen, relatively light volatile components such as some fatty acids and other content entrained in the frying oil. Some aspects may extend the lifetime of frying oil by reducing hydrolysis, resulting in reduced generation of FFA, monoglycerides and diglycerides. Some aspects consistent with the present technology' may advantageously reduce the amount of FFA and TPM in the fry ing oil or slow the development of FFA and TPM in the frying oil over time. Some aspects may advantageously reduce the frequency for replacing frying oil, which may reduce the amount of frying oil usage for Prying food, reduce oil usage costs, and reduce labor costs associated with replacing the frying oil.

[0033] Aspects described herein may advantageously facilitate the elimination of deodorization processing that is currently used for extending the lifetime of frying oil. In some implementations, methods consistent with the technology' of the disclosure described herein may advantageously supplement deodorization processing. Aspects described herein may advantageously facilitate the elimination or reduction of treatment of frying oil with adsorbent material that is currently used for extending the lifetime of frying oil. In some implementations, methods consistent with the technology' of the present disclosure described herein may advantageously supplement oil processing with adsorbents. Some aspects of the present technology may additionally improve the quality of fried food. These and other potential advantages will be discussed in more detail below.

[0034] As used herein, the term “edible oil” refers to a fat or oil that is suitable for human or animal consumption. Edible oils are ty pically compositions including triacylglycerols (“TAG”). (Scrimgeour et al., “Chemistry of Fatty Acids,” Bailey’s Industrial Oil and Fat Products, Seventh Edition, 2020) Edible oils may be obtained from plant, animal, microbial sources, or mixtures thereof. The edible oils, as described herein, may be a modified edible oil; for example, the edible oil may be a hydrogenated oil, a chemically or enzymatically interesterified oil, a fractionated oil, oil made by fermentation, or mixtures thereof. Edible oils may include, but is not limited to, edible oils selected from sunflower oil, grape seed oil, sesame oil, peanut oil, nut oil (such as almond oil, cashew oil, walnut oil, hazelnut oil, macadamia oil, or mixtures thereof), com oil, wheat kernel oil, rapeseed oil, safflower oil, soybean oil, canola oil, cottonseed oil, rice bran oil, olive oil, or mixtures of two or more thereof. The edible oil may be a high oleic edible oil, such as high oleic sunflower oil, higholeic rapeseed oil, high oleic safflower oil, high oleic soybean oil, high oleic canola oil, high oleic cotonseed oil, or mixtures of two or more thereof. Edible oils may also include, but are not limited to, lard, tallow, coconut oil, palm oil, palm olein, palm kernel oil, hydrogenated vegetable oil (such as hydrogenated fractionated palm kernel oil, hydrogenated cotonseed oil, hydrogenated soybean oil, hydrogenated sunflower oil, hydrogenated canola oil, hydrogenated rapeseed oil. and the like or mixtures thereof), or mixtures of two or more thereof. As used herein, ‘"vegetable oils” refers to oils derived from vegetables and / or oil seeds or produced by fermentation.

[0035] A "triacylglyceride" refers to a molecule having a glycerol moiety that is linked to three fatty acid residues via ester bonds. The terms "triacylglycerol," "triacylglyceride," "triglyceride," and "TAG" are used interchangeably herein.

[0036] The term "fatty acid" as used herein can refer to a molecule including a hydrocarbon chain and a terminal carboxylic acid group. As used herein, the carboxylic acid group of the fatty acid may be modified or esterified, for example as occurs when the fatty’ acid is incorporated into a glyceride or another molecule (e.g, COOR. where R refers to, for example, a carbon atom). Alternatively, the carboxylic acid group may be in the free fatty acid or salt form (i.e., COO" or COOH). The 'tail' or hydrocarbon chain of a faty acid may also be referred to as a fatty’ acid chain, fatty acid sidechain, or fatty chain. The hydrocarbon chain of a fatty acid will typically be a saturated or unsaturated aliphatic group. A faty acid having N number of carbons will typically have a fatty acid side chain having N-l carbons. However, the subject application also relates to modified forms of fatty acids, e.g., epoxidized fatty’ acids, and thus the term fatty acid may be used in a context in which the faty acid has been substituted or otherwise modified as described.

[0037] Non-limiting examples of fatty acids include C6, C8, CIO, C12, C14, C 16 (e.g., C16:0, C16: 1), C18 (e.g., C18:0, C18: 1, C18:2, C18:3, C18:4), C20 and C22 fatty acids. For example, the fatty acids can be caprylic (8:0), capric (10:0), lauric (12:0), myristic (14:0), palmitic (16:0), stearic (18:0), oleic (18: 1), linoleic (18:2) and linolenic (18:3) acids.

[0038] As used herein, "total polar material" or "TPM" refers collectively to compounds formed from the chemical degradation of frying oils that are more polar than the triacylglycerols of the frying oil.

[0039] As used herein, "average composite age" refers to the calculated age of a frying oil within a defined time period (days) of continuous frying, where the fryingoil may be a mixture of used frying oil and fresh frying oil. As used herein, "used frying oil" refers to frying oil that has undergone one or more frying cycles in the preparation of fried food items and typically includes a detectable amount of frying oil degradation products (e.g., FFA, TPM, polymerized gums, and the like). Conversely, "fresh fry ing oil" as used herein refers to a fry ing oil that has not undergone a fryring cycle. The average composite age of the frying oil in the vat is defined by the following equation:where:Dn is the average composite age in days of used frying oil in vat after frying n days and topping-off with fresh frying oil;Wn is the weight of fresh frying oil needed to top-off the used frying oil in the frying vat and reach the vat capacity; vat capacity is the weight of frying oil required in the vat for frying; and D(n-1) is the average age in days after fryring n-1 days.

[0040] In a "continuous fry ring" process, fresh frying oil is used to top-off used frying oil within a frying vat of a frying apparatus, where used fryring oil may be absorbed by the food product that is being fried. The term "continuous" as used in the phrase "continuous fryring" does not require that the fryring itself occurs continuously, but "continuous fry ing" refers to the use of a combination of the used frying oil and top-off with fresh frying oil, and optionally discharging an amount of used frying oil, without requiring entirely changing out the frying oil in the frying vat as frequently as compared to conventional frying (i.e., batch frying) processes.

[0041] The average composite age of the frying oil can be calculated based on frying oil having a daily food load in a range of about 0.5 or greater. As used herein, the "daily food load" refers to the calculated daily food-to-oil (or food-to-vat oil capacity) ratio of the weight amount of food prepared via frying to the vat capacity' (by weight) of a fr er (e.g., if the vat capacity7is 30 lbs, 30 lbs of fryring oil maintains in vat or fry ing) on a given day of a continuous fry ing process. For example, the daily food load may be about 0.5, about 1.0. about 1.5, about 2.0. about 2.5, about 3.0, about 3.5, about 4.0, about 4.5, about 5.0, about 5.5, about 6.0, about 6.5, about 7.0, about 7.5, about 8.0, or any range including and / or in between any two of the preceding values. In any aspect, the daily food load may be in a range of about 0.7 toabout 4.0. In any aspect, the daily food load may be in a range of about 0.5 to about 5.0.

[0042] FIG. 1 depicts example systems consistent with the technology disclosed herein. A frying system 200 generally has a degassing system 100 and a fr ing oil vat 210 that may be a restaurant or industrial fryer. The fry ing system 200 is generally configured to fry food and purify frying oil 202 contained in the frying oil vat 210. The degassing system 100 generally has a fluid flow line 110. a thin film degasser 140, a particle filter 170, and a vacuum pump 160. The degassing system 100 is generally configured to purify the oil in the frying oil vat 210. Purifying the oil can include removing moisture, dissolved oxygen, light volatile components, and other contaminants.

[0043] The frying oil vat 210 is generally configured to contain frying oil 202 that is used to fry food. In some embodiments, the frying oil vat 210 is also configured to heat the frying oil 202, but in some other aspects the frying oil 202 is heated by a heating element outside of the frying oil vat 210 such as an external heat exchanger. The frying oil vat 210 has an open interior volume 220. The open interior volume 220 is generally configured to contain the frying oil 202. The frying oil vat 210 has a base 230 and a sidewall 240 having a proximal end 260 integrated with the base 230. The sidewall 240 has a distal end 250. The sidewall 240 has a height between the proximal end 260 and the distal end 250. The open interior volume 220 extends from the base 230 towards the distal end 250 of the sidewall. In various aspects, the open interior volume 220 is defined from the distal end 250 of the sidewall 240 to the base 230.

[0044] The frying oil 202 is generally any edible oil. The fry ing oil 202 contained in the frying oil vat 210 generally has a minimum height 280 from the base 230 towards the distal end of the sidewall. In some aspects, the frying oil 202 has a minimum height 280 that is at least a quarter of the height of the sidewall 240 or, in some aspects, at least half the height of the sidewall 240.

[0045] In some aspects, the frying system 200 is configured to heat the frying oil vat 210, which heats the frying oil 202. In some aspects, a heating element is coupled to the frying oil vat 210. Additionally or alternatively, a heating element is positioned within the volume of the frying oil vat 210. The temperature of the frying oil 202 is generally sufficient to cook food to a particular specification. Various frying oil temperatures may be suitable for systems consistent wi th the present technology. In some aspects, the frying oil 202 is heated to a temperature greater than or equal to 100°C, 120 °C, 140 °C, or 150 °C. In some embodiments, the temperature of the frying oil 202 is heated to a temperature no greater than 220 °C, 200 °C, or 190 °C. In some aspects, the frying oil 202 is heated to a temperature between 150 °C to 200 °C. In some aspects, the frying oil 202 is heated to a temperature between 170 °C to 190 °C.

[0046] In various aspects, the frying oil vat 210 has a vat inlet 112. In some embodiments, including the one depicted, the vat inlet 112 is defined by the distal end 250 of the sidewall 240. In some other aspects, the vat inlet 112 can be defined by the sidewall 240 or the base 230. The vat inlet 112 generally defines a fluid flow pathway into the frying oil vat 210.

[0047] In various aspects, the fry ing oil vat 210 has a vat outlet 114. The vat outlet 114 defines a fluid flow pathway out of the frying oil vat 210. In some aspects, the vat outlet 114 is defined towards the proximal end 260 of the sidewall 240. In some aspects, the vat outlet 114 is defined by the base 230. Positioning the vat outlet 114 towards the proximal end 260 of the sidewall 240, whether defined by the sidewall 240 or the base 230, may advantageously facilitate the draining of particulate contaminants that may have settled in the frying oil 202 towards the base 230 during frying operations.

[0048] The degassing system 100 and, therefore, the fry ing system 200 includes a fluid flow line 110 that defines a fluid flow pathway for the frying oil 202 to and from the frying oil vat 210. The fluid flow line 110 is configured to be fluidly coupled to the frying oil vat 210 and the thin film degasser 140, the latter of which will be discussed in more detail below. The fluid flow line 110 is generally configured to be fluidly coupled to the vat inlet 112 and the vat outlet 114 of a frying oil vat 210. The systems 100 and 200 are configured such that the frying oil 202 flows along the fluid flow line 110 from the frying oil vat 210, to the thin film degasser 140, and back to the frying oil vat 210.

[0049] The fluid flow’ line 110 has an inlet conduit 116. The inlet conduit 116 is configured to define a passage for frying oil to flow into the frying oil vat 210 through the vat inlet 112. In aspects consistent with the present figure, the inlet conduit 116 extends through the vat inlet 112. In various aspects, the inlet conduit 116 is configured to be positioned vertically below7the minimum height 280 of the fry ing oil 202. In some aspects, the inlet conduit 116 is vertically spaced from the base 230 no more than half of the height of the sidewall 240. Such configurations may’ advantageously prevent the fry ing oil 202 that is being introduced into the fry ing oilvat 210 from making contact with ambient air, which may advantageously limit the entrainment of gas and / or vapor from the ambient air in the frying oil 202.

[0050] In some aspects where the vat inlet 112 is defined in the sidewall 240 or the base 230, the inlet conduit 116 and the vat inlet 112 are generally configured to form a fluid-tight connection. Various structures may be used to establish a fluid-tight connection, such as an elastomeric seal, metallic seal, ceramic seal, or polymer seal disposed between the inlet conduit 116 and the vat inlet 112. In some aspects, the fluid-tight connection is configured to accommodate the relatively high temperature of the frying oil 202, as discussed above. In some aspects, the fluid-tight connection may be a bayonet connection, a threaded connection, or the like.

[0051] The fluid flow line 110 has an interface 118. The interface 118 is configured to be fluidly coupled to the vat outlet 114 of the frying oil vat 210. The interface 118 and the vat outlet 114 are generally configured to form a fluid-tight connection. The connection between the interface 118 and the vat outlet 114 can be consistent with those described above with respect to the connection between the inlet conduit 116 and the vat inlet 112 when the vat inlet 112 is defined by the sidewall 240 or the base 230.

[0052] The position of the vat inlet 112 relative to the fry ing oil vat 210 is generally consistent with the position of the inlet conduit 116 relative to the frying oil vat 210. The position of the vat outlet 114 is generally consistent with the position of the interface 118 relative to the frying oil vat 210. In some aspects, the vat outlet 114 is positioned vertically below the inlet conduit 116. In such aspects, the interface 118 is positioned vertically below the inlet conduit 116 when coupled to the frying oil vat 210. Such configurations may advantageously facilitate the draining of oil and debris from the frying oil vat 210.

[0053] The fluid flow line 110 is configured to accommodate flow of the frying oil 202 through the vat outlet 114 of the fry ing oil vat 210 to the volume 142 of the thin film degasser 140 for degassing. The fluid flow line 110 is configured to accommodate flow of the degassed frying oil 202 from the thin film degasser 140 to the frying oil vat 210 through the vat inlet 112.

[0054] The fluid flow line 110 is generally configured for fluid communication with the thin film degasser 140. The thin film degasser 140 is generally configured to degas the frying oil 202. The term “thin film degasser7’ is used herein to include, for example, thin film deodorizers, thin film dryers, thin film evaporators, thin filmdistillation, falling film evaporator, and thin film vacuum centrifugal flow, as examples. The thin film degasser 140 is configured to be coupled to the fluid flow line 110. The thin film degasser 140 defines a degassing volume 142 that is configured for fluid communication with the fluid flow line 110. The thin film degasser 140 has a degasser inlet 146 that is configured to receive the frying oil 202 from the fluid flow line 110 and a degasser outlet 148 that is configured to release the frying oil 202 to the fluid flow line 110. The degasser inlet 146 and the degasser outlet 148 are in fluid communication with the degassing volume 142.

[0055] The thin film degasser 140 is configured to maintain a vacuum in the degassing volume 142. The thin film degasser 140 has a disk 144 disposed in the degassing volume 142 that is configured to rotate during operation of the thin film degasser 140 while there is a vacuum in the degassing volume 142. In some other embodiments the thin film degasser 140 has a disk 144 that is stationary and blade that rotates to create the thin film. Other configurations of thin film degassers are also possible. Generally, the thin film degasser 140 is configured to receive the frying oil 202 and creates a thin film of the frying oil 202 on the surface of the disk 144. Creating a thin film of the frying oil 202 provides a relative increase the frying oil 202 surface area, which facilitates gas and vapor removal from the fry ing oil 202. Furthermore, the vacuum within the degassing volume 142 also facilitates relatively efficient gas and vapor removal from the frying oil 202. The degassed frying oil 202 is returned to the frying oil vat 210 via the degasser outlet 148 and the fluid flow line 110 after degassing by the thin film degasser 140.

[0056] The degassing system 100 generally has a vacuum pump 160 configured for fluid communication with the degassing volume 142 of the thin film degasser 140. The vacuum pump 160 is generally configured to create and maintain the vacuum within the volume 142 of the thin film degasser 140. The vacuum pump 160 is configured to be coupled to a gas transmission line 180. The degassing volume 142 of the thin film degasser 140 is configured to be coupled to the gas transmission line 180. The vacuum pump 160 can pump gas and vapor from the degassing volume 142 of the thin film degasser 140 to an exhaust 162. In some aspects, the gas transmission line 180 is configured to extend from the thin film degasser 140 to the vacuum pump 160 through a knockout pot 150. The knockout pot 150 is configured to be positioned between the thin film degasser 140 and the vacuum pump 160. The knockout pot 150 is configured for fluid communication with the gas transmission line 180. Theknockout pot 150 is generally configured to prevent liquid (such as mist or light volatile material) passage to the vacuum pump 160 from the thin film degasser 140. For example, the vacuum generated by the vacuum pump 160 might draw some moisture and / or light volatile components from the frying oil 202 into the gas transmission line 180. The knockout pot 150 is configured to trap such components and prevent them from passing to the vacuum pump 160. In some aspects, the knockout pot 150 is a “cold trap’?that is filled with dry ice or another coolant material. In some embodiments, the knockout pot 150 is a condenser.

[0057] During thin film degassing, the vacuum pressure impacts the degassing of the heated frying oil 202. In some aspects, the vacuum pump 160 is configured to maintain a pressure of less than 300 mbar in the degassing volume 142 of the thin film degasser 140. In some aspects, the vacuum pump 160 is configured to maintain a pressure of less than 150 mbar in the degassing volume 142 of the thin film degasser 140. In some aspects, the vacuum pump 160 is configured to maintain a pressure of less than 80 mbar in the degassing volume 142 of the thin film degasser 140. In some aspects, the vacuum pump 160 is configured to maintain a pressure of less than 50 mbar in the degassing volume 142 of the thin film degasser 140. In some aspects, the vacuum pump 160 is configured to maintain a pressure of greater than 0. 1 mbar, 1 mbar, 10 mbar. or 50 mbar in the volume 142 of the thin film degasser 140. In various aspects, the vacuum pump 160 is configured to maintain a pressure from 50 to 100 mbar in the volume 142 of the thin film degasser 140.

[0058] The temperature of the frying oil 202 in the thin film degasser 140 also impacts the degassing of the frying oil 202. As discussed above, the frying oil 202 generally has a relatively high temperature associated with frying food in the frying oil vat 210. As such, the thin film degasser 140 is configured to treat the frying oil 202 having such a relatively high temperature. The frying oil 202 would generally be heated in the fry ing oil vat 210 during system operation. As such, in some aspects, the thin film degasser 140 does not heat the frying oil 202 due to the relatively high temperature of the frying oil 202 resulting from the frying operation. As such, in some aspects, the thin film degasser 140 lacks a heating function. In some aspects, the thin film degasser 140 has a heating function to heat the frying oil 202, however. Such an aspect may be desirable where, for example, the frying oil 202 cools during transport to the thin film degasser 140 and where a higher frying oil temperature is desirable for suitable degassing than the cooking temperature of the fry ing oil 202.

[0059] The thin film degasser 140 is configured to degas the frying oil 202 by reducing the moisture content of the frying oil 202. At atmospheric pressure, frying oil may have a moisture content ranging from 1000 ppm to 3000 ppm. In some aspects, the thin film degasser 140 is configured to reduce the moisture content of the fry ing oil 202 to below 1000 ppm. In some aspects, the thin film degasser 140 is configured to reduce the moisture content of the frying oil 202 to less than 800 ppm, 400 ppm. 300 ppm, 200 ppm, 100 ppm, 80 ppm, 50 ppm, 40 ppm, or any range including and / or in between any two of the preceding values. In some aspects, the thin film degasser 140 is configured to reduce the moisture content of the fry ing oil 202 to more than 1 ppm, 10 ppm, or 50 ppm. In some aspects, the moisture content of the degassed frying oil 202 is between 80 ppm to 120 ppm.

[0060] Various parameters can contribute to the time required to sufficiently reduce the moisture content of the frying oil 202 in the thin film degasser 140 such as, for example, the thickness of the frying oil 202 on the rotating disk 144 of the thin film degasser 140, the residence time of the frying oil 202 on the disk 144, the rotation speed of the disk 144. the surface area of the disk 144, the temperature of the frying oil 202, and the vacuum pressure in the volume 142 of the thin film degasser 140. Generally, the thin film degasser 140 is configured to sufficiently degas a volume of frying oil 202 in the time it takes for the volume of frying oil 202 to spread radially outwardly across the rotating disk 144, which may be within 5 seconds or less, 3 seconds or less, or 1 second or less.

[0061] The feed rate of the thin film degasser 140 can be a function of the surface area of the rotating disk that is configured to receive and create the thin film of oil. The thin film degasser 140 can have a feed rate from about 100 L / hr-m2up to about 100,000 L / hr-m2. In some aspects the thin film degasser 140 can have a feed rate of about 1,000 L / hr-m2to about 6,000 L / hr-m2; about 7,000 L / hr-m2to about 14,000 L / hr-m2; or about 13,000 L / hr-m2to about 20,000 L / hr-m2, as examples.

[0062] V arious parameters can contribute to the time required to sufficiently reduce the moisture content of the frying oil 202 in the fry ing oil vat 210. Among other parameters, such as those described above, the volume of frying oil 202 in the flying oil vat 210 and the volumetric flow rate of the frying oil 202 through the degassing system 100 impacts the time required to reduce the moisture content of the frying oil 202 in the frying oil vat 210. Furthermore, the specific moisture content released into the frying oil 202 from the fried food, which is dictated by the amount offood being fried and the fry ing time, and the desired moisture content also dictate the time required to reduce the moisture content of the frying oil vat 210. In some aspects, the degassing system 100 is configured to maintain a flow rate of less than 10 gal / min (38 L / min), 5 gal / min (19 L / min), or 3 gal / min (11 L / min) through the thin film degasser 140. In some aspects, the degassing system 100 is configured to maintain a flow rate of less than 200 gal / min (757 L / min), 175 gal / min (662 L / min), or 150 gal / min (566 L / min) through the thin film degasser 140. In some aspects, the system 100 is configured to maintain a flow rate of greater than 0.25 gal / min (1 L / min), .5 gal / min (2 L / min), 1 gal / min (4 L / min), or 3 gal / min (11 L / min) through the thin film degasser 140. In some aspects, the degassing system 100 is configured to maintain a flow rate of greater than 50 gal / min (189 L / min), 75 gal / min (284 L / min), or 100 gal / min (379 L / min) through the thin film degasser 140. The size of frying oil vat 210 is generally not limited for purposes of the present technology' disclosed herein. In various aspects, the size of the frying oil vat 210 can range from 1 gal to 3000 gal.

[0063] In some aspects, the operation of the degassing system 100 is configured to operate in a batch mode. When the operation is under the batch mode, the frying oil 202 is pumped or suctioned from the frying oil vat 210 and delivered to the thin film degasser 140 for degassing. The degassed frying oil 202 can be held in a holding tank (not shown), for example, and then returned to the frying oil vat 210 after all of the frying oil 202 in the frying oil vat 210 has been removed and treated. During such degassing, the frying system 200 is not used to fry food during the degassing system operation period. In such examples, the frying oil vat 210 can be cleaned after degassing of the fry ing oil 202. After the degassing system operation, the frying oil 202 can be returned to the frying oil vat 210. In such embodiments, the frying oil 202 can be added to the frying oil vat 210 towards the base 230 of the frying oil vat to limit entrainment of ambient air in the frying oil 202.

[0064] In some aspects, the operation of the degassing system 100 is configured to operate in a continuous mode, which is consistent with the system depicted in FIG. 1. When the operation is in continuous mode, the frying oil 202 is continuously pumped or suctioned from the frying oil vat 210 through the vat outlet 114 to the degassing volume 142 of the thin film degasser 140 for degassing and returned back to the frying oil vat 210 through the inlet conduit 116 in a continuous cycle. Such a continuous operation occurs during frying operations, more specifically while the frying oil 202 within the frying oil vat 210 is being used to fry food.

[0065] In some aspects also consistent with FIG. 1, the operation of the thin film degasser 140 is configured to be semi-continuous. When the operation is semi- continuous, the frying oil 202 can be continuously pumped or suctioned from the frying oil vat 210 to the thin film degasser 140 and returned to the fr ing oil vat 210 within a treatment time interval. The treatment time interval may be 10 min, 30 min, 60 min. or the like. After the treatment time interval, there can be a waiting period during which the degassing system 100 does not operate. In such aspects the frying system 200 can be used to fry food during the treatment period, the waiting period, or both the treatment period and the waiting period.

[0066] Some aspects of systems consistent with the present technology include a liquid pump 130. The liquid pump 130 is configured for fluid communication with the fluid flow line 110. In some aspects, the liquid pump 130 is a high temperature liquid pump, to accommodate the relatively high temperature of the fry ing oil 202. The temperature of the liquid flowing through the liquid pump 130 can be consistent with the temperature of the frying oil 202 in the frying oil vat 210. The liquid pump 130 may define the volumetric flow rate of the frying oil 202 through the degassing system 100 and is not particularly limited. In some aspects, the liquid pump 130 has a pump capacity of at least 2 liters / minute. In some aspects, the liquid pump 130 has a pump capacity of at least 3 liters / minute, 5 liters / minute, or 10 liters / minute. In some embodiments, the liquid pump 130 has a pump capacity of no more than 200 liters / minute, 50 liters / minute, 30 liters / minute, or 20 liters / minute.

[0067] The type of liquid pump 130 is not limited. In some aspects, the liquid pump 130 is a positive displacement pump. In some aspects, the positive displacement pump is a rotary pump. In some aspects, the positive displacement pump is a reciprocating pump. In some aspects, the liquid pump 130 is a dynamic pump. In some aspects, the dynamic pump is a centrifugal pump. In some aspects, the dynamic pump is a jet ejector, reversible centrifugal, gas lift, hydraulic ram, or electromagnetic pump.

[0068] In some aspects, the system does not include a liquid pump 130. When the system does not include the liquid pump 130, the thin film degasser 140 can be configured to function as the liquid pump 130. For example, the vacuum generated by the vacuum pump 160 may be sufficient to elicit flow of the frying oil 202 from the vat outlet 114, through the degassing system 100, and to the vat inlet 112.

[0069] It is noted that the disclosed systems 100, 200 may include various check valves 147. relief valves, drain lines, control valves to facilitate system operation. In the cunent example, a check valve 147 is disposed along the fluid flow line 110 between the inlet conduit 116 and the degasser outlet 148 to prevent back-flow of degassed fry ing oil to the thin film degasser 140. Similarly, in the current example, a check valve 147 is disposed along the gas transmission line 180 between the knockout pot 150 and the vacuum pump 160.

[0070] A particle filter 170 is configured to be positioned upstream of the thin film degasser 140 along the fluid flow line 110. The particle filter 170 is generally configured to filter the frying oil 202. In some aspects, the particle filter 170 is configured to filter particle contaminants such as crumbs from the frying oil 202. Such a configuration may advantageously prevent particle contaminants from entering the thin film degasser 140. Such a configuration may also advantageously extend the frying lifetime of the frying oil 202 by preventing fouling of the frying oil 202 by the particle contaminants that may reduce the lifetime of the frying oil 202. In some aspects the particle filter 170 is configured to be positioned upstream of the liquid pump 130. In some other aspects, such as that depicted, the particle filter 170 can be positioned downstream of the liquid pump 130.

[0071] The particle filter 170 can be constructed of a variety of different materials and combinations of materials that accommodate particle filtration of the frying oil. In some aspects, the particle filter 170 is constructed of materials and combinations of materials that accommodate particle filtration of a high temperature frying oil. The particle filter 170 consistent with the technology disclosed herein can have a variety of configurations. In some embodiments, the particle filter 170 can be constructed of one or more layers of material, where each layer of material is a permeable substrate. In some aspects, the permeable substrate is fibrous. A fibrous substrate can be construction of cellulose fibers, metal fibers, polymeric fibers, and combinations thereof. In some aspects, the permeable substrate is a mesh screen such as a metal or plastic mesh screen. In various examples, the mesh screen is stainless steel. In some embodiments the mesh screen can have openings ranging from 20 microns to 1000 microns. The particle filter 170 may incorporate layers of material including support layers, particle filtration layers, chemical filtration layers, sorbent layers, and the like. Each of the layers of material can be coupled to abutting layers of material inembodiments. Alternatively, the particle filter 170 can include multiple filter elements that are arranged in series, which may be coupled or uncoupled along the fluid flow line 110.

[0072] It is noted that, in the current example schematic, there is a single degassing system 100, but in various implementations there may be multiple degassing systems consistent with the degassing system 100 already described herein. One or more degassing systems can be configured to be functionally parallel to a first degassing system 100 to increase the degassing capacity of the system. In some other embodiments, there may be a single degassing system 100 consistently with that described above, except that one or more additional thin film degassers (consistent with the thin film degasser 140 described above) can be incorporated in the degassing system 100. In such a system, each thin film degasser 140 can be configured to operate in parallel with other thin film degasser(s) 140 in the degassing system 100, which may advantageously increase the degassing capacity of the system. In such an example, the fluid flow line 110 may extend from the frying oil vat 210 to each of the thin film degassers in parallel. In such an example, the fluid flow line 110 would additionally extend from each of the thin film degassers back to the frying oil vat 210.

[0073] Some aspects of the present technology relate to a method of degassing frying oil. FIG. 2 depicts an example method 300 consistent with the technology disclosed herein. Consistent with some implementations of the present technology, a frying oil vat may be filled with frying oil and heated to an appropriate cooking temperature. Food can be placed in the frying oil vat and immersed in the heated frying oil for a frying operation. Either in parallel with the frying operation, or alternating with the frying operation, the heated frying oil can be degassed such as by the example method 300 in FIG. 2. The frying oil is pumped to a thin film degasser 310, the oil is exposed to a vacuum 330, and the oil is returned to a vat 340.

[0074] The frying oil is pumped to a thin film degasser 310, particularly through the vat outlet of the frying oil vat to the degassing volume of the thin film degasser. The frying oil is pumped to the thin film degasser 310 via the degasser inlet. In some embodiments the frying oil is pumped with a liquid pump. In some other aspects the frying oil is pumped via a vacuum pump that is in fluid communication with the degassing volume of the thin film degasser, as discussed above with reference to FIG. 1

[0075] In various aspects, the frying oil is heated when it is pumped to the thin film degasser 310. As discussed above, the frying oil may be heated by virtue of a frying operation where food is being fried by the heated oil. As such, the frying oil that is pumped to the thin film degasser 310 may be heated to a temperature at which food is being fried. Particular ranges of temperature of the heated frying oil are discussed in detail above.

[0076] The heated frying oil is exposed to a vacuum 330 of the thin film degasser. For example, as discussed in example systems disclosed above, a vacuum pump can be in fluid communication with the volume of the thin film degasser to create the vacuum. The heated frying oil can be drawn into the volume of the thin film degasser and deposited onto a rotating disk. The rotation of the rotating disk creates a thin film of the heated frying oil across its surface and the vacuum draws off the entrapped moisture and vapor. The vacuum can be configured to reduce the moisture content of the heated frying oil to amounts disclosed elsewhere herein, such as less than 1000 ppm or even less than 400 ppm. The vacuum can be consistent with vacuum pressures discussed in detail above.

[0077] The treated frying oil is returned to the frying oil vat 340 such as through the liquid flow line to the inlet conduit. In some aspects, the fry ing oil contained in the frying oil vat has a minimum height relative to the frying oil vat, and the inlet conduit is configured to be positioned vertically below the minimum height. Such a configuration may advantageously prevent the frying oil from making contact with ambient air and may limit moisture and vapor in the air from becoming entrained in the frying oil when it is returned to the frying oil vat via the vat inlet. In various aspects, returning the frying oil to the frying oil vat 340 is after exposing the frying oil to the vacuum 330.

[0078] In some aspects, the frying oil is filtered 320. The frying oil can be filtered 320 with a particle filter, in some aspects. The particle filter can be a metal screen in some aspects. In some aspects the frying oil can be filtered 320 with an adsorbent filter or a chemical filter. In such embodiments the frying oil can be filtered 320 prior to exposing the frying oil to a vacuum 330, such as upstream of the thin film degasser.

[0079] In some aspects, each of the pumping oil to the thin film degasser 310, exposing the oil to a vacuum 330, and returning the oil to the vat 340 is a substantially continuous cycle. In some such aspects the example method 300 is performed whilefood is fried in the fry ing oil in the frying oil vat. In some aspects the example method 300 is performed after the food is fried in the fry ing oil in the frying oil vat.

[0080] FIG. 3 depicts the predicted steady state moisture content of an example fry ing oil as a function of vacuum pressure and oil temperature based on thermodynamic calculations of partial pressure data. The plots are show n in FIG. 3 correspond to the moisture content of the same type of vegetable oil across a range of temperatures and vacuum pressures. Plot 410 corresponds to a fry ing oil temperature of 75°C, plot 420 corresponds to a frying oil temperature of 100°C, plot 430 corresponds to a fry ing oil temperature of 125°C, plot 440 corresponds to a frying oil temperature of 150°C, and plot 450 corresponds to a frying oil temperature of 175°C. In each plot, the steady state moisture content of the frying oil is predicted across a range of vacuum pressures. Generally, the data demonstrates that in each plot 410, 420, 430, 440, and 450 that the steady state moisture content of the heated fry ing oil decreases with decreasing vacuum pressure. Generally, the data demonstrates in each plot 410. 420, 430. 440, and 450 that the steady state moisture content of the frying oil decreases with increasing temperature.

[0081] While not wishing to be bound by theory , the higher the temperature, the higher kinetic energy of the moisture and / or vapor to escape into the environment that facilitate the vacuum draws off them from the heated frying oil. Generally, the lower the vacuum pressure, the higher driven force that the vacuum draws off the entrapped moisture and / or vapor.

[0082] The temperature of frying oil can thus dictate the particular vacuum pressure to which the frying oil is exposed to achieve the target moisture content of the frying oil. In various implementations, the temperature of the frying oil is dictated by the cooking temperature required to cook particular food to a particular specification. The temperature of the frying oil can also be dictated by the temperature drop in the frying oil after transmission of the frying oil from the frying oil vat to the thin film degasser. As discussed above, frying oil that is heated for cooking food may generally be heated to temperatures and temperature ranges that have been described in detail above.

[0083] A target moisture content of less than 1000 ppm of the frying oil can be achieved throughout the ranges and frying oil temperatures and vacuum pressures disclosed in FIG. 3. However, to achieve a target moisture content of less than, forexample 400 ppm, the vacuum pressure would be less than or equal to 100 mbar for frying oil temperatures greater than or equal to 100 °C, or at a frying oil temperature of 75 °C, a vacuum pressure of less than about 65 mbar would be needed. In some specific implementations, it may be desirable to achieve a moisture content of less than 100 ppm. In such implementations, in accordance with the data depicted in FIG. 3, a maximum vacuum pressure of about 80 mbar would be required across the disclosed frying oil temperature range.

[0084] Various implementations of the present technology, such as the methods and systems described above, may advantageously result in frying oil having a relatively high average composite age and a relatively low moisture content compared to known technologies. For example, in implementations where frying oil is cycled continuously between a fry ing vat and a thin film degasser for degassing during frying operations (or between frying operations), the frying oil may have an average composite age of at least 4 days, at least 6 days, at least 8 days, at least 10 days, at least 12 days, or at least 17 days. Such a frying oil may advantageously have a moisture content of less than 1000 ppm. less than 900 ppm. less than 800 ppm. less than 700 ppm, less than 300 ppm, or even less than 200 ppm. In some embodiments, the frying oil in the vat has a moisture content of 100 ppm to 300 ppm. This is contrary to known frying operations, where the frying oil contained in the frying oil vat is expected to have a moisture content of at least 1000 ppm at atmospheric pressure, which has been described above. Further, the present technology may advantageously facilitate the use of used frying oil for frying operations beyond an average composite age of 17 days, 20 days, or even 23 days.

[0085] The elimination of moisture in the frying oil may advantageously slow hydrolysis and the formation of FFA, monoglycerides and diglycerides in the frying oil over time. As such, used frying oil consistent with the present technology may have a relatively high average composite age and a relatively low FFA content. The frying oil may have an average composite age of at least 4 days, at least 6 days, at least 8 days, at least 10 days, at least 12 days, or at least 17 days. Such a frying oil may advantageously have an FFA content of less than 2.5 wt%, less than 2 wt%, less than 1.5 wt%, less than 1 wt%, less than 0.5 wt%, or even less than 0.3 wt%. In some aspects, the frying oil in the vat has an FFA content of 0.2 wt% to 0.5 wt%. The frying oil may have an FFA content of at least 0.05 wt%, 0.2 wt%, 0.3 wt% although the minimum value of FFA in the used frying oil is not particularly limited.

[0086] The elimination of moisture in the frying oil may advantageously slow the formation of TPM in the frying oil over time. As such, used frying oil consistent with the present technology may have a relatively high average composite age and a relatively low TPM content. The frying oil may have an average composite age of at least 4 days, at least 6 days, at least 8 days, at least 10 days, least 12 days, at least 17 days, or at least 20 days. Such a frying oil may advantageously have a TPM content of less than 25 wt%, less than 20 wt%, less than 15 wt%, or even less than 10 wt%. In some aspects, the frying oil in the vat has a TPM content of 5 wt% to 10 wt%. The flying oil may have a TPM content of at least 1 wt%, 2 wt%, or 3 wt% although the minimum value of TPM in the used fry ing oil is not particularly limited.

[0087] Thin film degassing consistent with the present technology may also remove some FFA from used frying oil. In some aspects, FFA having a carbon number CIO or C8 and lower (hereinafter “low molecular weight FFA”) within the used fry ing oil may be removed from the used frying oil via thin film degassing. As such, used frying oil consistent with the present technology may have a relatively high average composite age and a relatively loyv molecular weight FFA content. The frying oil may have an average composite age of at least 4 days, at least 6 days, at least 8 days, at least 10 days, at least 12 days, or at least 17 days. Such a frying oil may advantageously have a low molecular weight FFA content of less than 0.06 wt%, less than 0.05 wt%. less than 0.03 wt%, or about 0.0 wt%.Experimental Data

[0088] Technology consistent with the present disclosure is tested against existing approaches to reduce the moisture content of used frying oil. In the experiment, three identical fryers (Frymaster RE114TCSD, manufactured by Frymaster Corporation based on Schreveport, Louisiana, USA) are each filled to its 50-pound oil capacity with identical frying oil, which is soybean oil with polydimethylsiloxane (DMPS) additive. Each fryer filled with frying oil is used to fry 50 lbs (22.7 kg) of fresh cut fries per day over the course of at least 12 days. For frying the fries, the oil in each vat is heated to 350°F and 1.5-pound (0.7 kg) batches of fries are cooked for 5 minutes each until the 50 pounds of fries is cooked. Each vat had an average frying time of 2 hours / day. Each morning a 200-gram sample of oil from each vat is collected and recorded, which is analyzed for content. During frying the fries absorbed some oil and so the vats were topped off with equal amounts of oil daily.

[0089] The frying oil (“the control oil"’) from a first vat (“the control vat”) is purified using passive filtration. After the end of the frying operations on each day. the control oil within the control vat is removed from the control vat and passed through 70-micron filter paper positioned on a perforated stainless-steel screen with 2 mm circular openings to remove particulate contaminants. The control vat is cleaned, and then the filtered control oil is returned to the control vat.

[0090] The frying oil (“adsorbent treated oil”) from a second vat (“adsorbent treated vat”) is purified using Magnesol™ (product of the Dallas Group of America, Inc. based in Whitehouse, NJ, U.S.A.) according to manufacturer instructions. In particular, a recommended amount of Magnesol™ is sprinkled over a 70-micron filter paper positioned on a 2 mm perforated stainless-steel screen (with circular openings) in a filter pan, frying oil is removed from the adsorbent treated vat to the filter pan, and the frying oil is recirculated for 5-7 minutes in the filter pan. The adsorbent treated vat is then cleaned and the adsorbent treated frying oil is returned to the cleaned adsorbent treated vat.

[0091] The frying oil (“degassed oil”) from a third vat (“degassed oil vat”) is purified using a thin film degasser system consistent with that depicted and described with reference to FIG. 1. During the fr ing operation, the frying oil is removed from the degassed oil vat and passed through a strainer and then advanced to a thin film degasser. Frying oil is fed to the surface of a rotatable disk of the thin film degasser at a rate of 1 .5 to 1.7 L / min, which was limited by the particular thin film degasser used. The rotatable disk rotates at 5500 revolutions-per-minute (RPM), which creates a thin film of the frying oil on the surface of the disk. The rotatable disk is in chamber that is under an 80 mmgH (107 mbar) vacuum. Because it was observed that the particular degasser used under the presently described experimental conditions tended to accumulate some oil in the chamber (that was not expelled), every four minutes the chamber is drained of accumulated oil, which was returned to the degassed oil vat. After the end of the frying operations on each day, the frying oil within the degassed oil vat is removed from the vat and passed through a 2 mm perforated stainless-steel screen (with circular openings) that removes some particulate contaminants. The degassed oil vat is cleaned, and then the filtered degassed oil is returned to the degassed oil vat.

[0092] FIG. 4 depicts the weight percentage of moisture of the oil in each of the vats as a function of the number of days of frying. In addition, the weight percentageof moisture of the oil exiting the degasser (prior to reintroduction of the degasser oil into the degasser vat) was also measured. The weight percentage of oil was determined in accordance with AOCS Official Method Ca 2e-84, by titration with Karl Fischer reagent. The data demonstrates that moisture of the oil exiting the degasser was at least 80% less than moisture of the adsorbent vat and the control vat. Moisture content of the frying oil existing the degasser ranged between 0.01 and 0.02% compared to the control and adsorbent vat at 0.05 to 0.06%. After the degassed oil was reintroduced into the degasser vat, the moisture content in the degassed vat remained lower than both the control vat and the adsorbent treated vat. Such a configuration may advantageously result in a relative increase in the usable lifetime of the frying oil. Further, based on this data it is noted that using a degasser with an increased feed capacity is expected to further reduce the amount of moisture in the degassed oil vat.

[0093] FIG. 5 depicts test data reflecting diacylglycerol (DAG) content by lipid profile of the frying oil in each of the vats as a function of the number of days of frying. DAG was determined in accordance with The American Oil Chemists' Society (AOCS) Official Method Cd 22-91 using high performance liquid chromatography (HPLC). The data reflects that the frying oil in the degassed oil vat showed similar levels of DAG to the frying oil in the adsorbent treated vat, which, after 7 frying days, was notably lower than the frying oil in the control vat.

[0094] FIG. 6 depicts TPM content of the oil in each of the vats as a function of the number of days of frying. TPM content was determined in accordance with AOCS Official Method Cd 22-91 using HPLC. The data reflects that TMP generation in the frying oil in the degassed oil vat was similar to the frying oil in the adsorbent vat and the frying oil in the control vat for the first 7 days of frying. After the 7thday of frying, the frying oil in the degassed oil vat and the adsorbent vat had less TPM than the fry ing oil in the control vat.

[0095] FIG. 7 depicts the weight percentage of FFA of the oil in each of the vats as a function of the number of days of frying. The FFA content was determined in accordance with AOCS Official Method Ca 5a-40. The frying oil in the degassed oil vat had an FFA content that was generally lower than the frying oil in the control vat, which may advantageously extend the life of the frying oil relative to the control.

[0096] The test procedure described above, and the data resulting from that test procedure, was limited by the particular feed rate capacity of the particular degasserthat was obtained. It is noted that, in practice, a degasser having a much higher capacity may be desirable. For example, a feed rate of 4.9 L / min may allow degassing of all of the frying oil within a 50-pound (22.7 kg) capacity fryer vat within 5 minutes.Exemplary Aspects

[0097] Aspect 1. A method comprising: pumping frying oil through a vat outlet of a vat to a volume of a thin film degasser; exposing the frying oil to a vacuum in the volume of the thin film degasser; and returning the frying oil to the vat through an inlet conduit.

[0098] Aspect 2. The method of any one of aspects 1 and 3-34, wherein the frying oil contained in the vat has a minimum height, and the inlet conduit is positioned vertically below the minimum height.

[0099] Aspect 3. The method of any one of aspects 1-2 and 4-34, wherein the frying oil returned to the vat has a moisture content of less than 1000 ppm.

[0100] Aspect 4. The method of any one of aspects 1-3. and 5-34 wherein the frying oil returned to the vat has a moisture content of less than 400 ppm.

[0101] Aspect 5. The method of any one of aspects 1-4 and 6-34, wherein the frying oil returned to the vat has a moisture content of less than 200 ppm.

[0102] Aspect 6. The method of any one of aspects 1-5 and 7-34, wherein the frying oil has a temperature of at least 150°C at the vat outlet.

[0103] Aspect 7. The method of any one of aspects 1 -6 and 8-34, wherein the fiying oil has a temperature of less than 200°C at the vat outlet.

[0104] Aspect 8. The method of any one of aspects 1-7 and 9-34, wherein the pumping, exposing, and returning is a continuous cycle.

[0105] Aspect 9. The method of any one of aspects 1-8 and 10-34, further comprising frying a food product in the vat, wherein the continuous cycle is executed during the fry ing.

[0106] Aspect 10. The method of any one of aspects 1-9 and 11-34, wherein the thin film degasser is configured to remove oxygen and moisture from its volume.

[0107] Aspect 11. The method of any one of aspects 1-10 and 12-34, wherein the thin film degasser is configured to remove fatty acids.

[0108] Aspect 12. The method of any one of aspects 1-11 and 13-34, further comprising filtering the frying oil upstream of the thin film degasser.

[0109] Aspect 13. The method of any one of aspects 1-12 and 14-34, wherein the vacuum pressure in the volume of the thin film degasser is less than 80 mbar.

[0110] Aspect 14. The method of any one of aspects 1-13 and 15-34, wherein returning the frying oil to the vat is after exposing the frying oil to the vacuum.

[0111] Aspect 15. The method of any one of aspects 1-14 and 16-34, further comprising frying a food product in the fr ing oil in the vat.

[0112] Aspect 16. The method of any one of aspects 1-15 and 17-34. wherein the thin film degasser has a feed rate of 1,000 L / hr-m2to 6,000 L / hr-m2

[0113] Aspect 17. The method of any one of aspects 1-16 and 18-34, wherein the thin film degasser has a feed rate of 7,000 L / hr-m2to 14,000 L / hr-m2.

[0114] Aspect 18. The method of any one of aspects 1-17 and 19-34, wherein the thin film degasser has a feed rate of 13,000 L / hr-m2to 20,000 L / hr-m2.

[0115] Aspect 19. The method of any one of aspects 1-18 and 20-34, wherein the frying oil in the vat has an average composite age of at least 10 days and a moisture content of less than 1000 ppm.

[0116] Aspect 20. The method of any one of aspects 1-19 and 21-34. wherein the frying oil in the vat has an average composite age of at least 17 days.

[0117] Aspect 21. The method of any one of aspects 1-20 and 22-34, wherein the frying oil in the vat has a moisture content of less than 500 ppm.

[0118] Aspect 22. The method of any one of aspects 1-21 and 23-34, wherein the frying oil in the vat has a moisture content of less than 400 ppm.

[0119] Aspect 23. The method of any one of aspects 11-22 and 24-34 wherein the frying oil in the vat has an average composite age of at least 10 days and an FFA content of less than 2.5 wt%.

[0120] Aspect 24. The method of any one of aspects 1-23 and 25-34, wherein the frying oil in the vat has an average composite age of at least 17 days.

[0121] Aspect 25. The method of any one of aspects 1-24 and 26-34, wherein the frying oil in the vat has an FFA content of less than 1 wt%.

[0122] Aspect 26. The method of any one of aspects 1-25 and 27-34. wherein the frying oil in the vat has an FFA content of 0.2 - 0.5 wt%.

[0123] Aspect 27. The method of any one of aspects 1-26 and 28-34, wherein the frying oil in the vat has an average composite age of at least 10 days and an TPM content of less than 25 wt%.

[0124] Aspect 28. The method of any one of aspects 1-27 and 29-34, wherein the frying oil in the vat has an average composite age of at least 17 days.

[0125] Aspect 29. The method of any one of aspects 1-28 and 30-34, wherein the frying oil in the vat has an TPM content of less than 20 wt%.

[0126] Aspect 30. The method of any one of aspects 1-29 and 31-34, wherein the frying oil in the vat has an TPM content of 5 - 10 wt%.

[0127] Aspect 31. The method of any one of aspects 1-30 and 32-34. wherein the frying oil in the vat has an average composite age of at least 10 days and a low molecular weight FFA content of less than 0.01 wt%.

[0128] Aspect 32. The method of any one of aspects 1-31 and 33-34, wherein the frying oil in the vat has an average composite age of at least 17 days.

[0129] Aspect 33. The method of any one of aspects 1-32 and 34, wherein the frying oil in the vat has a low molecular weight FFA content of 0.0 wt%.

[0130] Aspect 34. The method of any one of aspects 1-33, wherein the thin film degasser removes light volatile aroma compounds from the frying oil.

[0131] Aspect 35. A system comprising: a fluid flow line having an inlet conduit configured to fluidly communication with an interior volume of a fr ing oil vat and an interface configured to fluidly couple to an outlet of the frying oil vat; a thin film degasser defining a volume configured for fluid communication with the fluid flow line; a particle filter configured to be positioned upstream of the thin film degasser along the fluid flow line; and a vacuum pump configured for fluid communication with the volume of the thin film degasser.

[0132] Aspect 36. The system of any one of aspects 35 and 37-42, further comprising a high temperature liquid pump configured for fluid communication with the fluid flow line.

[0133] Aspect 37. The system of any one of aspects 35-36 and 38-42. wherein the vacuum pump is configured to maintain a pressure of less than 300 mbar in the volume of the thin film degasser.

[0134] Aspect 38. The system of any one of aspects 35-37 and 39-42, wherein the liquid pump has a pump capacity of at least 2 liters / minute.

[0135] Aspect 39. The system of any one of aspects 35-38 and 40-42. wherein the interface is configured to be positioned vertically below the inlet conduit when coupled to the frying oil vat.

[0136] Aspect 40. The system of any one of aspects 35-39 and 41-42, further comprising a knockout pot in fluid communication with the thin film degasser and the vacuum pump, wherein the knockout pot is configured to be positioned between the thin film degasser and the vacuum pump.

[0137] Aspect 41. The system of any one of aspects 35-40 and 42, wherein the thin film degasser is configured to remove oxygen and moisture from its volume.

[0138] Aspect 42. The system of any one of aspects 35-41, wherein the thin film degasser is configured to remove fatty acids.

[0139] Aspect 43. A method of reducing hydrolysis in frying oil using the system of any one of aspects 35-42.

[0140] Aspect 44. A system comprising: a frying oil vat having an open interior volume, a vat inlet, and a vat outlet; a fluid flow line having an inlet conduit configured to be in fluid communication with the open interior volume and an interface configured to be fluidly coupled to the vat outlet; a thin film degasser defining a volume configured for fluid communication with the fluid flow line; a particle filter configured to be positioned upstream of the thin film degasser along the fluid flow' line; and a vacuum pump in fluid communication with the volume of the thin film degasser.

[0141] Aspect 45. The system of any one of aspects 44 and 46-52, further comprising a high temperature liquid pump configured for fluid communication with the fluid flow' line.

[0142] Aspect 46. The system of any one of aspects 44-45 and 47-52, where the frying oil vat comprises: a base and a sidewall, the sidewall having: a proximal end integrated with the base, a distal end, and a height between the proximal end and the distal end, the open interior volume extending from the base to the distal end of the sidewall.

[0143] Aspect 47. The system of any one of aspects 44-46 and 48-52, wherein the inlet conduit is vertically spaced from the base no more than half of the height of the sidewall.

[0144] Aspect 48. The system of any one of aspects 44-47 and 49-52. wherein the vat outlet is defined towards the proximal end of the sidewall.

[0145] Aspect 49. The system of any one of aspects 44-48 and 50-52, wherein the vacuum pump is configured to maintain a pressure of less than 300 mbar in the volume of the thin film degasser.

[0146] Aspect 50. The system of any one of aspects 44-49 and 51-52. wherein the liquid pump has a pump capacity of at least 2 liters / minute.

[0147] Aspect 51. The system of any one of aspects 44-50 and 52, wherein the interface is configured to be positioned vertically below the inlet conduit when coupled to the frying oil vat.

[0148] Aspect 52. The system of any one of aspects 44-51, further comprising a knockout pot in fluid communication with the thin film degasser and the vacuum pump, wherein the knockout pot is configured to be positioned between the thin film degasser and the vacuum pump.

[0149] Aspect 53. A method of reducing hydrolysis in frying oil using the system of any one of aspects 44-52.

[0150] Aspect 55. A method of using a thin film degasser to reduce hydrolysis in frying oil.

[0151] Aspect 56. The method of any one of aspects 55 and 57-82, wherein the degassed frying oil has a moisture content of less than 1000 ppm after use of the thin film degasser.

[0152] Aspect 57. The method of any one of aspects 55-56, and 58-82 wherein the degassed frying oil has a moisture content of less than 400 ppm.

[0153] Aspect 58. The method of any one of aspects 55-57 and 59-82, wherein the degassed frying oil has a moisture content of less than 200 ppm.

[0154] Aspect 59. The method of any one of aspects 55-58 and 60-82, wherein the fry ing oil has a temperature of at least 150°C when introduced to the thin film degasser.

[0155] Aspect 60. The method of any one of aspects 55-59 and 61-82, wherein the frying oil has a temperature of less than 200°C when introduced to the thin film degasser.

[0156] Aspect 61. The method of any one of aspects 55-60 and 62-82, further comprising frying a food product in the frying oil vat. wherein the frying oil is introduced to the thin film degasser from the frying oil vat.

[0157] Aspect 62. The method of any one of aspects 55-61 and 63-82, wherein the thin film degasser is configured to remove oxygen and moisture from its volume.

[0158] Aspect 63. The method of any one of aspects 55-62 and 64-82, wherein the thin film degasser is configured to remove fatty acids.

[0159] Aspect 64. The method of any one of aspects 55-63 and 65-82, further comprising filtering the frying oil upstream of the thin film degasser.

[0160] Aspect 65. The method of any one of aspects 55-64 and 66-82, wherein the vacuum pressure in the volume of the thin film degasser is less than 80 mbar.

[0161] Aspect 66. The method of any one of aspects 55-65 and 67-82, wherein the frying oil is returned to a frying oil vat after using the thin film degasser on the frying oil.

[0162] Aspect 67. The method of any one of aspects 55-66 and 68-82, wherein the thin film degasser has a feed rate of 1,000 L / hr-m2to 6,000 L / hr-m2

[0163] Aspect 68. The method of any one of aspects 55-67 and 69-82, wherein the thin film degasser has a feed rate of 7,000 L / hr-m2to 14,000 L / hr-m2.

[0164] Aspect 69. The method of any one of aspects 55-68 and 70-82, wherein the thin film degasser has a feed rate of 13,000 L / hr-m2to 20,000 L / hr-m2.

[0165] Aspect 70. The method of any one of aspects 55-69 and 71-82, wherein the frying oil has an average composite age of at least 10 days.

[0166] Aspect 71. The method of any one of aspects 55-70 and 72-82, wherein the frying oil has an average composite age of at least 17 days.

[0167] Aspect 72. The method of any one of aspects 55-71 and 73-82, wherein the degassed frying oil has a moisture content of less than 500 ppm.

[0168] Aspect 73. The method of any one of aspects 55-72 and 74-82, wherein the degassed frying oil has a moisture content of less than 400 ppm.

[0169] Aspect 74. The method of any one of aspects 155-73 and 75-82 wherein the degassed frying oil has an FFA content of less than 2.5 wt%.

[0170] Aspect 75. The method of any one of aspects 55-74 and 76-82, wherein the degassed frying oil has an FFA content of less than 1 wt%.

[0171] Aspect 76. The method of any one of aspects 55-75 and 77-82, wherein the degassed frying oil has an FFA content of 0.2 - 0.5 wt%.

[0172] Aspect 77. The method of any one of aspects 55-76 and 78-82, wherein the degassed frying oil has a TPM content of less than 25 wt%.

[0173] Aspect 78. The method of any one of aspects 55-77 and 79-82, wherein the degassed frying oil has an TPM content of less than 20 wt%.

[0174] Aspect 79. The method of any one of aspects 55-78 and 80-82, wherein the degassed frying oil has an TPM content of 5 - 10 wt%.

[0175] Aspect 80. The method of any one of aspects 55-79 and 81-82, wherein the degassed frying oil has a low molecular weight FFA content of less than 0.01 wt%.

[0176] Aspect 81. The method of any one of aspects 55-80 and 82, wherein the degassed frying oil has a low molecular weight FFA content of 0.0 wt%.

[0177] Aspect 82. The method of any one of aspects 55-81, wherein the thin film degasser removes light volatile aroma compounds from the frying oil.

[0178] It should also be noted that, as used in this specification and the appended claims, the phrase ‘'configured’’ describes a system, apparatus, or other structure that is constructed to perform a particular task or adopt a particular configuration. The word "configured" can be used interchangeably with similar words such as “arranged”, “constructed”, “manufactured”, and the like.

[0179] The term "about" as used herein can allow for a degree of variability in a value or range, for example, within 10%, within 5%, or within 1 % of a stated value or of a stated limit of a range and includes the exact stated value or range. The term "substantially" as used herein refers to a majority of, or mostly, as in at least about 50%. 60%. 70%. 80%. 90%. 95%. 96%. 97%. 98%. 99%. 99.5%. 99.9%. 99.99%, or at least about 99.999% or more, or 100%.

[0180] All publications and patent applications in this specification are indicative of the level of ordinary skill in the art to which this technology pertains. All publications and patent applications are herein incorporated by reference to the same extent as if each individual publication or patent application was specifically and individually indicated by reference. In the event that any inconsistency exists betw een the disclosure of the present application and the disclosure(s) of any document incorporated herein by reference, the disclosure of the present application shall govern.

[0181] This application is intended to cover adaptations or variations of the present subject matter. It is to be understood that the above description is intended to be illustrative, and not restrictive, and the claims are not limited to the illustrative embodiments as set forth herein.

Claims

ClaimsWhat is claimed is:

1. A method comprising: pumping frying oil through a vat outlet of a vat to a volume of a thin film degasser; exposing the frying oil to a vacuum in the volume of the thin film degasser; and returning the frying oil to the vat through an inlet conduit.

2. The method of claim 1, wherein the frying oil returned to the vat has a moisture content of less than 1000 ppm.

3. The method of claim 1, wherein the frying oil has a temperature of at least 150°C at the vat outlet.

4. The method of claim 1, wherein the pumping, exposing, and returning is a continuous cycle.

5. The method of claim 1, further comprising filtering the frying oil upstream of the thin film degasser.

6. The method of claim 1, wherein the vacuum pressure in the volume of the thin film degasser is less than 80 mbar.

7. The method of claim 1, wherein returning the frying oil to the vat is after exposing the frying oil to the vacuum.

8. The method of claim 1, further comprising frying a food product in the frying oil in the vat.

9. The method of claim 1, wherein the frying oil in the vat has an average composite age of at least 10 days and a moisture content of less than 1000 ppm.

10. The method of claim 1, wherein the frying oil in the vat has an average composite age of at least 17 days.

11. The method of claim 1, wherein the frying oil in the vat has an average composite age of at least 10 days and a FFA content of less than 2.5 wt%.

12. The method of claim 1, wherein the frying oil in the vat has an average composite age of at least 10 days and a TPM content of less than 25 wt%.

13. A system comprising:a fluid flow line having an inlet conduit configured to fluidly communication with an interior volume of a frying oil vat and an interface configured to fluidly couple to an outlet of the frying oil vat; at least one thin film degasser defining a volume configured for fluid communication with the fluid flow line; a particle filter configured to be positioned upstream of the at least one thin film degasser along the fluid flow line; and a vacuum pump configured for fluid communication with the volume of the at least one thin film degasser.

14. A system comprising: a frying oil vat having an open interior volume, a vat inlet, and a vat outlet; a fluid flow line having an inlet conduit configured to be in fluid communication with the open interior volume and an interface configured to be fluidly coupled to the vat outlet; at least one thin film degasser defining a volume configured for fluid communication with the fluid flow line; a particle filter configured to be positioned upstream of the at least one thin film degasser along the fluid flow line; and a vacuum pump in fluid communication with the volume of the thin film degasser.

15. A method of using a thin film degasser to reduce hydrolysis of frying oil.

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