Title of Invention	A NEW ADSORBENT FOR REGENERATION OF USED EDIBLE FRYING OIL, METHOD OF PREPARING THE SAME AND METHOD OF REGENERATION BY THE NEW ADSORBENT
Abstract	The invention relates to a new adsorbent, method of preparing the same and method for regeneration of used edible frying oil by treating it with the new adsorbent. The used edible frying oil is regenerated by removing and/or decreasing contaminants, like free fatty acid, viscosity, colour, density, moisture and suspended materials. The regeneration"is achieved by treating the used edible frying oil with the new adsorbent containing effective amount of Magnesium tri silicate, Sodium sulphate, Alum, Marble, Citric acid, Fuller"s earth and Silica gel. Removal of the contaminants from the used edible frying oil by the new adsorbent and according to the method regenerates and maintains the nutrient value of used edible frying oil.

Title of Invention

A NEW ADSORBENT FOR REGENERATION OF USED EDIBLE FRYING OIL, METHOD OF PREPARING THE SAME AND METHOD OF REGENERATION BY THE NEW ADSORBENT

Abstract

The invention relates to a new adsorbent, method of preparing the same and method for regeneration of used edible frying oil by treating it with the new adsorbent. The used edible frying oil is regenerated by removing and/or decreasing contaminants, like free fatty acid, viscosity, colour, density, moisture and suspended materials. The regeneration"is achieved by treating the used edible frying oil with the new adsorbent containing effective amount of Magnesium tri silicate, Sodium sulphate, Alum, Marble, Citric acid, Fuller"s earth and Silica gel. Removal of the contaminants from the used edible frying oil by the new adsorbent and according to the method regenerates and maintains the nutrient value of used edible frying oil.

Full Text	The present invention relates to a new adsorbent, method of preparing the same and method of regeneration of used edible frying oil by the new adsorbent. More particularly the invention relates to a new adsorbent in two parts of adsorbent A and adsorbent B for regeneration of used edible frying oil for reducing impurity content of the used frying oil. BACKGROUND OF THE INVENTION Edible oils (e.g. palm oil, soybean oil or vegetable oil) which are continuously used for deep-fat frying of savouries and snacks for 12 to 40 hours at temperatures of about 200 degree centigrade, can decompose over time with use due to generation of various contaminants during frying. Contaminants such as free fatty acids, polar compounds, moisture, colour bodies and saponification value alter the iodine value, density, viscosity in the edible oil is built-up over time and contribute to the degradation and increased instability of the edible oil. As these contaminants build up in the edible oil, the edible oil can become discoloured, develop a displeasing smell and taste, begin to foam, produce heavy smoke at normal cooking temperatures, and quickly become rancid and unusable. Without treatment this degeneration typically occurs rapidly, requiring complete replacement of the used frying oil with fresh oil as often as every 2 or 3 days, thereby significantly raising the cost of production of fried foods. However, the amount of time frying oils may be used for frying varies, depending upon a number of factors, such as the type and volume of savouries and snacks, the temperature, the quantity of new edible oil added and the frequency of addition of new edible oil, as well as the treatment used for decontamination of the oil. The properties of edible frying oil (palm oil, soybean oil or vegetable oil) change when heated or frying food containing water. The changes can be in both physical and chemical properties, e.g., polymerization causing high viscosity. The other changes that occur are the refractive index, specific gravity, colour, viscosity, saponification value, and free fatty acids of edible oil increases with frying temperature. Appearance of dark colour in edible frying oil samples is due to the decomposition of free fatty acid to triglyceride at high temperatures of about 200 to 220° C. In addition, oil characteristics especially flavour and colour also changes when the edible oil is used for frying several times. That directly affects food characteristics and quality of the used edible oil for frying. Repeated use of edible frying oils for frying produces undesirable constituents that may pose health hazards. During deep frying, fats and oils are repeatedly used at elevated temperatures in the presence of atmospheric oxygen and receive maximum oxidative and thermal abuse. Heating in the presence of air causes partial conversion of fats and edible oils to volatile chain-scission products, non-volatile oxidized derivatives, and dimeric, polymeric, or cyclic substances. Investigations of commercial frying have generally indicate that these oils nutritional value of frying fats is affected by loss of polyunsaturated fatty acids (PUFA), which supplement the essential fatty acids' requirement in human metabolism. Used edible frying oil after multiple frying showed increase in peroxide content which is an indicator of the oxidative changes. Similarly changes in free fatty acid content is indicative of hydrolytic changes occurring due to high temperature. Lowering in Iodine value is indicative of decrease in polyunsaturated content in the used oil samples. PRIOR ART It is known from the prior art the use of calcium silicate for treating contaminant cooking oil for removal of free fatty acid from the contaminant cooking oil. The US Patent No. 5391385 discloses the treatment of contaminant cooking oil with a combination of alumina and amorphous silica. According to the said granted US patent, it reduces contaminants by heating the contaminated cooking oil to a temperature of 180° F to 400° F and subsequently contacting said oil with a composition consisting of a mixture of 60% to 80% amorphous silica and 20 to 40% alumina for a time sufficient to remove contaminants from said oil. The US patent application 323663 and 323866 discloses a procedure for removing free fatty acids from cooking oil or fat employed in restaurant frying operations or in industrial frying operations by utilising a mixture of sodium magnesium aluminosilicate and calcium silicate. The US patent application 646123 discloses a method for treatment of used cooking oil or fat with precipitated silica material for removal of decent amount of free fatty acids. In another prior material, a metal doped precipitated silica type in which a magnesium doped precipitated silica material has proven effective in filtering used oils and/or fats; however, generally, such materials exhibit a pore size between 50 and 200 .AIMG., and BET surface area (as measured by nitrogen absorption) of 535 m2/g, and the particle size is above about 40 urn. In essence, there is a large amount of surface area, with an appreciable amount taken up by pores that are of a critical size. This, in turn, delivers efficient utilization of the available pores within the silica materials, but the very high pore volume coupled with the need to dope the materials, adds to manufacturing cost. Also known in the prior art is a synthetic calcium silicate, which has been utilized as a proper filter media because it is very effective in lowering free fatty acid concentration. Synthetic calcium silicate lowers the free fatty acid (FFA) concentration of the oil by a combination of adsorption and neutralization. The use of such a material, however, often darkens the oil to a suspect level. In addition, the product of the neutralization of a fatty acid with an alkaline metal is a fatty acid soap. The amount of soap formed is dependent on the amount of alkaline metal present, and the initial percentage of free fatty acids in the oil. When the soap level is high, the oil foams. The use of synthetic calcium silicate in order to lower the free fatty acid concentration sometimes results in uncontrollable foaming. U.S. Patent No. 5,597,600, issued to Munson et al., utilizes magnesium silicate of certain particle size to filter used oils and/or fats as well. Such magnesium silicate materials provide effective filtering of such cooking oils and fats; however, there are limitations to free fatty acid removal levels as well as the need for relatively large amounts of extra oils and/or fats to be added to the used sources in order to attain acceptable frying conditions. Moreover, the magnesium silicate acts as a bleaching agent to change the colour of the colour bodies within the oil, thereby lightening the colour of the oil. However, the disadvantage to this method is that the magnesium silicate creates polar compounds as a by product of the neutralization process. The presence of additional polar compounds reduces the smoke point of the oil and increases the oxidation of the oil, which accelerates spoiling and may give the oil an unpleasant taste and/or odour. The WIPO application PCT/US 2003/006492 ( WO/2003/075671) discloses a composition and a process for removing contaminants from degraded edible oils used for cooking. The invention teaches a process for treating edible cooking oil with a composition of silica, acidic alumina, clay and citric acid. The edible oil is contacted with the composition, heated, and then separated from the composition. The disclosed methods and compositions have not adequately removed the contaminants that contribute to the degradation of the edible oil, but have instead individually attacked the particular contaminant perceived to be the greatest concern in a particular system. Moreover, these treatments fail to significantly extend the life of the oil by eliminating enough of each contaminant. Thus, what is needed in the art are compositions and methods for quickly and effectively reducing the amount of several contaminants such as colour bodies, free fatty acids, saponification value, refractive index, specific gravity, viscosity and trace metals, such that regular treatment with the adsorbent and method significantly extends the useable life of the edible oil, thereby reducing health risks and costs of fried food operations. There exists thus a definite need to improve each of these prior developments within the cooking oil/fat filtering area with less costly materials. A new adsorbent and method that provide improved levels of free fatty acid reduction, improved colour, and/or a significant reduction in the needed amount of added fresh edible oil to be added to the used edible oil will provide a much sought after advancement to the restaurant and/or industrial frying markets. Summary of the invention The invention relates to a new adsorbent and method for reducing the contaminants in edible frying oils used for cooking food products and enables recycling of the used edible oil while preserving the taste and quality of the edible oil and food cooked in the oil. Such contaminants include changes in both physical and chemical properties, e.g., polymerization causing high viscosity. The other changes that occur are the refractive index, specific gravity, colour, viscosity, free fatty acids and saponification value of edible frying oil that increases with frying temperature. In its broad aspects, the invention relates to a new adsorbent in two parts comprising adsorbent A and adsorbent B, a process for preparing the adsorbent and treating used edible frying oil with the new adsorbent and then separating the regenerated edible oil from the adsorbent and contaminants. The invention provides new adsorbent and method for significantly reducing the accumulation of undesirable contaminants in used edible frying oil and improving the shelf life of the used edible oil. In its broad aspects, the new adsorbent constitute in two parts, adsorbent A and adsorbent B wherein the adsorbent A comprising the ingredients, Magnesium tri silicate, Sodium sulphate, Alum, Marble and Citric acid and the adsorbent B comprises the ingredients Fuller's earth and Silica gel. The new adsorbent contains these ingredients in amounts effective to remove contaminants of the used edible frying oil. The used edible oil is heated to a temperature of 100° C and subsequently the new adsorbent is mixed with the heated used edible oil and left for a certain time period and filtered by filter paper. The new adsorbent and the method of regenerating the used edible frying oil are more effective than that known in the art for purification and maintenance of nutrient value of used edible frying oil. DESCRIPTION OF THE INVENTION It is therefore an advantage of the present invention to provide a new adsorbent and a more efficient method for more effective regeneration of used edible frying oil by removing various contaminants. In the present invention the new adsorbent for regeneration of edible frying oil comprises two parts, that is, adsorbent A and adsorbent B. The weight percentages of various reagents of adsorbent A are Magnesium tri silicate 49.5 %, Sodium sulphate 11.3%, Alum (Aluminium potassium sulphate) 18.4%, Marble 19.9% and Citric acid 0.99%. The reagents of adsorbent B are 2g of Fuller's earth and 3g of Silica gel for every 100ml of used edible frying oil. The reagents of Adsorbent A and Adsorbent B, after treatment with used edible frying oil, effectively regenerates the said edible oil. The various reagents of the new adsorbent, comprising Adsorbent A and Adsorbent B, interact with the contaminants present in the used edible frying oil when the said oil is treated with the new adsorbent and the reagents adsorbs the contaminants. The contaminants are then removed from the edible oil upon filtering the treated edible frying oil. The new adsorbent contains each of the ingredients in an amount effective to remove and/or decreases contaminants, like free fatty acid, viscosity, colour, density, moisture and trap suspended materials of the used edible frying oil. It is observed that 7% by w/v of adsorbent A and 5% by w/v of adsorbent B is found to be most suitable for regeneration of used edible frying oil. The preparation of the new adsorbent and method of regeneration of used edible frying oil is described by way of an exemplary embodiment. All the ingredients for the adsorbent A and adsorbent B are accurately weighed as per data provided in Table 1 and Table 2. 50g of Magnesium tri silicate and 20g of Marble are mixed and then 15ml deionised water is added to it to form a paste. This paste is heated to a temperature of approximately 100°C until it is dried. Subsequently 18.6g of Alum and 11.4g of Sodium sulphate are uniformly blended and steadily added in 10 ml of deionised water while constantly stirring with addition of lg Citric acid. After thorough stirring, dried magnesium tri silicate and marble mixture is added to it. The resultant paste of all ingredients is heated to a temperature between 90°C to 100°C until it is dry and then sieved in a mesh size of 200-300 to get uniform mixture of adsorbent A and kept in desiccators. Subsequently, 2gm of Fuller's earth and 3gm of silica gel were mixed and sieved in mesh size of 200-300 to get uniform mixture of Adsorbent B. It is to be noted that the weight of each of the ingredients are for treating 100ml of used edible frying oil, hence various weights of the ingredients will proportionately be decided according to the volume of the used edible frying oil. TABLE 1 Adsorbent A: Magnesium tri silicate, Sodium sulphate, Alum, Marble and Citric acid (Table Removed) TABLE 2 Adsorbent B- Fuller's earth and silica gel (Table Removed) Method-I for regenerating of used edible frying oil According to a first method (Method-I) of treating used edible frying oil for regeneration: 100 ml of used edible oil was taken in 250 ml conical flask and heated to 100°C. 7% w/v of adsorbent A, as prepared above, is added to the said heated oil and shaken thoroughly for proper blending and the oil is pre-treated. The adsorbent B, containing 3g silica gel and 2g fuller's earth as prepared above, is poured into a narrow cylindrical column with tapered bottom. The pre treated used edible frying oil sample is subsequently poured into the cylindrical column and is allowed to settle on the adsorbent B. The pre treated oil passes through the adsorbent B and the contaminants in the pre treated oil get adsorbed in the adsorbent B. It takes 15-30 min. to filter through the adsorbent B. The treated edible frying oil coming out of the cylindrical column is filtered through a filter paper and thus the edible oil is regenerated while removing the various contaminants as described above. Method-II for regenerating of used edible frying oil According to a second method ( Method-II) of treating used edible oil for regeneration: 100 ml of used edible oil was taken in 250 ml conical flask and heated to 100°C and then 7% w/v of adsorbent A was added to it and shaken rigorously for 2 minutes. Subsequently adsorbent B, containing 3g silica gel powder and 2g fuller's earth powder, was added to the treated edible oil sample. Thus treated oil sample was left idle for 5 minutes and thereafter filtered by filter paper and the used edible frying oil is regenerated while removing the various contaminants as described above. The regenerated edible frying oil samples collected after treatment with the new adsorbent by the method-I and method-II were analyzed for various parameters, for example, the iodine value, peroxide value, carbonyl value, etc. and compared with that of the unused edible frying oil and used edible frying oil, as shown in Table 3 and Table 4. It is observed that sample of edible frying oil treated by Method-I is better,than the samples treated by Method-II in the evaluated parameters viz. viscosity, peroxide value, iodine value, etc. In the methods for treatment of used edible frying oil, magnesium tri silicate reduces acid value and Fuller's earth was good agent for reduction of Free Fatty Acid( FFA) by providing sufficient retention time( 10-30 mins. ) for the used edible frying oil. This retention time plays significant role for removal of impurities. Surface area and porosity of Fuller's earth is rightly suited for the purification of edible oil. Table- 3 : Change in Density and Viscosity of Edible oil after different Treatments (Table Removed) Table-4: Results of Different parameters before and after Regeneration of Edible Oil (Table Removed) Although the invention has been described with reference to particular illustrative embodiments, many changes and modifications of the invention may become apparent to those skilled in the art without departing from the spirit and scope of the invention. Therefore, included within the patent hereon are all such changes and modifications as may reasonably and properly be included within the scope of this contribution to the art. I Claim: 1. A new adsorbent for regeneration of used edible frying oil comprising adsorbent A and adsorbent B, were used to remove the contaminants from the edible oils (e.g. palm oil, soybean oil or vegetable oil) by a) contacting the oil with the compositionally fixed and prepared adsorbents comprising of 7 ingredients- Magnesium tri silicate, Sodium sulphate, Alum (Aluminium potassium sulphate), Marble and Citric acid, Fuller's earth and Silica gel; and b) separating the adsorbent from the oil to recover the oil. 2. The process of claim 1, wherein adsorbent A comprises 49.5 % of Magnesium tri silicate, 11.3% of Sodium sulphate, 18.4% of Alum, Marble 19.9% and Citric acid 0.99% and the reagents of adsorbent B are 2% of Fuller's earth and 3% of Silica gel for 100ml of used edible oil, have been chosen in an effective amount to treat selectively and specifically polar compounds, free fatty acids, colour bodies and soaps. 3. The process of claim 1, wherein in the method of preparing the new adsorbent A for regeneration of used edible frying oil, comprises of the step of uniformly mixing 50g of Magnesium tri silicate with 20g of Marble and then 30ml deionised water to form a paste which has pH 9.2-9.5. 4. The process of claim 1, wherein in the method of preparing the new adsorbent A for regeneration of used edible frying oil, comprises of the step of uniformly mixing Magnesium tri silicate with Marble in deionised water to form a paste, which was heated to a temperature of 100°C-120°C until it dried completely. 5. The process of claim 1, wherein in the method of preparing the new adsorbent A for regeneration of used edible frying oil, comprises of the step of uniformly mixing 18.6g of Alum (Aluminium potassium sulphate) and 11.4g of Sodium sulphate in 8 ml of deionised water for perfect blending the mixture is constantly stirred, subsequently addition of lg Citric acid to form a gel. 6. The process of claim 5, wherein in the method of preparing the new adsorbent A for regeneration of used edible frying oil, comprises of the step of uniformly mixing Alum (Aluminium potassium sulphate), Sodium sulphate and Citric acid to form a gel having a pH 3.0-3.2. 7. The process of claim 4 wherein for the preparation of dry mixture of magnesium tri silicate and marble was added to the gel prepared as in (claim 5). 20 ml of deionised water was added. The pH of the resultant paste should be in the range of 6.1-6.2. 8. The process of claim 7, wherein the above mentioned paste of all reagents were further heated at a temperature between 100°C-120°C until it was dry. 9. The process of claim 8, wherein the dried mixture was subsequently sieved in a mesh (mesh size of 200-300) to get uniform mixture of adsorbent A. 10. The process of claim 1 wherein 2gm of Fuller's earth and 3gm of silica gel, for treating 100ml of used edible frying oil, were uniformly blended. 11. The process of claim 10, wherein silica gel that is the chosen is of mesh size 100-200 (column chromatography grade). 12. The process of claim 10, wherein Fuller's earth and silica gel blended uniformly, were sieved in mesh size of 200-300 to get uniform mixture of Adsorbent B. 13. The process of Claim 1, wherein the method of regenerating used edible frying oil by treating with the new adsorbent with used edible oil comprises the steps of : (i) heating 100 ml of used edible frying oil in a 250 ml conical flask to 100°C- 150°C; (ii) 7% w/v of adsorbent A is added to the heated edible frying oil and shaken thoroughly for uniform blending or adsorbent A; (iii) a cylindrical tube with tapered bottom is filled with the adsorbent B containing 3g silica gel and 2g fuller's earth; (iv) The treated edible oil sample from step (ii) is poured in the cylindrical tube and filtered through the column filled with adsorbent B; (v) The treated edible frying oil from step (iv) is subsequently passed through a filter paper thereby regenerating the used edible frying oil by removing the various contaminants. 14. A method of regenerating used edible frying oil by treating with the new adsorbent as claimed in claim 1 comprises the steps of : (i) 100 ml of used edible frying oil was taken in 250 ml conical flask and heated to 100°C-150°C; (ii) 7% w/v of adsorbent A was added to it and shaken rigorously; (iii) Adsorbent B, containing 3g silica gel powder and 2g fuller's earth powder, was added to the edible frying oil sample treated with adsorbent A; (iv) The treated oil sample was left idle for certain time period and thereafter filtered by filter paper and the used edible frying oil is regenerated while removing the various contaminants.

Full Text

The present invention relates to a new adsorbent, method of preparing the same and method of regeneration of used edible frying oil by the new adsorbent. More particularly the invention relates to a new adsorbent in two parts of adsorbent A and adsorbent B for regeneration of used edible frying oil for reducing impurity content of the used frying oil.
BACKGROUND OF THE INVENTION
Edible oils (e.g. palm oil, soybean oil or vegetable oil) which are continuously used for deep-fat frying of savouries and snacks for 12 to 40 hours at temperatures of about 200 degree centigrade, can decompose over time with use due to generation of various contaminants during frying. Contaminants such as free fatty acids, polar compounds, moisture, colour bodies and saponification value alter the iodine value, density, viscosity in the edible oil is built-up over time and contribute to the degradation and increased instability of the edible oil. As these contaminants build up in the edible oil, the edible oil can become discoloured, develop a displeasing smell and taste, begin to foam, produce heavy smoke at normal cooking temperatures, and quickly become rancid and unusable.
Without treatment this degeneration typically occurs rapidly, requiring complete replacement of the used frying oil with fresh oil as often as every 2 or 3 days, thereby significantly raising the cost of production of fried foods. However, the amount of time frying oils may be used for frying varies, depending upon a number of factors, such as the type and volume of savouries and snacks, the temperature, the quantity of new edible oil added and the frequency of addition of new edible oil, as well as the treatment used for decontamination of the oil.
The properties of edible frying oil (palm oil, soybean oil or vegetable oil) change when heated or frying food containing water. The changes can be in both physical and chemical properties, e.g., polymerization causing high viscosity. The other changes that occur are the refractive index, specific gravity, colour, viscosity, saponification value, and free fatty acids of edible oil increases with frying temperature.
Appearance of dark colour in edible frying oil samples is due to the decomposition of free fatty acid to triglyceride at high temperatures of about 200 to 220° C. In addition, oil characteristics especially flavour and colour also changes when the edible oil is used for frying several times. That directly affects food characteristics and quality of the used edible oil for frying.
Repeated use of edible frying oils for frying produces undesirable constituents that may pose health hazards. During deep frying, fats and oils are repeatedly used at elevated temperatures in the presence of atmospheric oxygen and receive maximum oxidative and thermal abuse. Heating in the presence of air causes partial conversion of fats and edible oils to volatile chain-scission products, non-volatile oxidized derivatives, and dimeric, polymeric, or cyclic substances. Investigations of commercial frying have generally indicate that these oils nutritional value of frying fats is affected by loss of polyunsaturated fatty acids (PUFA), which supplement the essential fatty acids' requirement in human metabolism.
Used edible frying oil after multiple frying showed increase in peroxide content which is an indicator of the oxidative changes. Similarly changes in free fatty acid content is indicative of hydrolytic changes occurring due to high temperature. Lowering in Iodine value is indicative of decrease in polyunsaturated content in the used oil samples.
PRIOR ART
It is known from the prior art the use of calcium silicate for treating contaminant cooking oil for removal of free fatty acid from the contaminant cooking oil.
The US Patent No. 5391385 discloses the treatment of contaminant cooking oil with a combination of alumina and amorphous silica. According to the said granted US patent, it reduces contaminants by heating the contaminated cooking oil to a temperature of 180° F to 400° F and subsequently contacting said oil with a composition consisting of a mixture of 60% to 80% amorphous silica and 20 to 40% alumina for a time sufficient to remove contaminants from said oil.
The US patent application 323663 and 323866 discloses a procedure for removing free fatty acids from cooking oil or fat employed in restaurant frying operations or in industrial frying operations by utilising a mixture of sodium magnesium aluminosilicate and calcium silicate.
The US patent application 646123 discloses a method for treatment of used cooking oil or fat with precipitated silica material for removal of decent amount of free fatty acids.
In another prior material, a metal doped precipitated silica type in which a magnesium doped precipitated silica material has proven effective in filtering used oils and/or fats; however, generally, such materials exhibit a pore size between 50 and 200 .AIMG., and BET surface area (as measured by nitrogen absorption) of 535 m2/g, and the particle size is above about 40 urn. In essence, there is a large amount of surface area, with an appreciable amount taken up by pores that are of a critical size. This, in turn, delivers efficient utilization of the available pores within the silica materials, but the very high pore volume coupled with the need to dope the materials, adds to manufacturing cost.
Also known in the prior art is a synthetic calcium silicate, which has been utilized as a proper filter media because it is very effective in lowering free fatty acid concentration. Synthetic calcium silicate lowers the free fatty acid (FFA) concentration of the oil by a combination of adsorption and neutralization. The use of such a material, however, often darkens the oil to a suspect level. In addition, the product of the neutralization of a fatty acid with an alkaline metal is a fatty acid soap. The amount of soap formed is dependent on the amount of alkaline metal present, and the initial percentage of free fatty acids in the oil. When the soap level is high, the oil foams. The use of synthetic calcium silicate in order to lower the free fatty acid concentration sometimes results in uncontrollable foaming.
U.S. Patent No. 5,597,600, issued to Munson et al., utilizes magnesium silicate of certain particle size to filter used oils and/or fats as well. Such magnesium silicate materials provide effective filtering of such cooking oils and fats; however, there are limitations to free fatty acid removal levels as well as the need for relatively large amounts of extra oils and/or fats to be added to the
used sources in order to attain acceptable frying conditions. Moreover, the magnesium silicate acts as a bleaching agent to change the colour of the colour bodies within the oil, thereby lightening the colour of the oil. However, the disadvantage to this method is that the magnesium silicate creates polar compounds as a by product of the neutralization process. The presence of additional polar compounds reduces the smoke point of the oil and increases the oxidation of the oil, which accelerates spoiling and may give the oil an unpleasant taste and/or odour.
The WIPO application PCT/US 2003/006492 ( WO/2003/075671) discloses a composition and a process for removing contaminants from degraded edible oils used for cooking. The invention teaches a process for treating edible cooking oil with a composition of silica, acidic alumina, clay and citric acid. The edible oil is contacted with the composition, heated, and then separated from the composition.
The disclosed methods and compositions have not adequately removed the contaminants that contribute to the degradation of the edible oil, but have instead individually attacked the particular contaminant perceived to be the greatest concern in a particular system. Moreover, these treatments fail to significantly extend the life of the oil by eliminating enough of each contaminant.
Thus, what is needed in the art are compositions and methods for quickly and effectively reducing the amount of several contaminants such as colour bodies, free fatty acids, saponification value, refractive index, specific gravity, viscosity and trace metals, such that regular treatment with the adsorbent and method significantly extends the useable life of the edible oil, thereby reducing health risks and costs of fried food operations.
There exists thus a definite need to improve each of these prior developments within the cooking oil/fat filtering area with less costly materials. A new adsorbent and method that provide improved levels of free fatty acid reduction, improved colour, and/or a significant reduction in the needed amount of added fresh edible oil to be added to the used edible oil will provide a much sought after advancement to the restaurant and/or industrial frying markets.
Summary of the invention
The invention relates to a new adsorbent and method for reducing the contaminants in edible frying oils used for cooking food products and enables recycling of the used edible oil while preserving the taste and quality of the edible oil and food cooked in the oil. Such contaminants include changes in both physical and chemical properties, e.g., polymerization causing high viscosity. The other changes that occur are the refractive index, specific gravity, colour, viscosity, free fatty acids and saponification value of edible frying oil that increases with frying temperature.
In its broad aspects, the invention relates to a new adsorbent in two parts comprising adsorbent A and adsorbent B, a process for preparing the adsorbent and treating used edible frying oil with the new adsorbent and then separating the regenerated edible oil from the adsorbent and contaminants.
The invention provides new adsorbent and method for significantly reducing the accumulation of undesirable contaminants in used edible frying oil and improving the shelf life of the used edible oil.
In its broad aspects, the new adsorbent constitute in two parts, adsorbent A and adsorbent B wherein the adsorbent A comprising the ingredients, Magnesium tri silicate, Sodium sulphate, Alum, Marble and Citric acid and the adsorbent B comprises the ingredients Fuller's earth and Silica gel. The new adsorbent contains these ingredients in amounts effective to remove contaminants of the used edible frying oil. The used edible oil is heated to a temperature of 100° C and subsequently the new adsorbent is mixed with the heated used edible oil and left for a certain time period and filtered by filter paper. The new adsorbent and the method of regenerating the used edible frying oil are more effective than that known in the art for purification and maintenance of nutrient value of used edible frying oil.
DESCRIPTION OF THE INVENTION
It is therefore an advantage of the present invention to provide a new adsorbent and a more efficient method for more effective regeneration of used edible frying oil by removing various contaminants.
In the present invention the new adsorbent for regeneration of edible frying oil comprises two parts, that is, adsorbent A and adsorbent B. The weight percentages of various reagents of adsorbent A are Magnesium tri silicate 49.5 %, Sodium sulphate 11.3%, Alum (Aluminium potassium sulphate) 18.4%, Marble 19.9% and Citric acid 0.99%. The reagents of adsorbent B are 2g of Fuller's earth and 3g of Silica gel for every 100ml of used edible frying oil.
The reagents of Adsorbent A and Adsorbent B, after treatment with used edible frying oil, effectively regenerates the said edible oil. The various reagents of the new adsorbent, comprising Adsorbent A and Adsorbent B, interact with the contaminants present in the used edible frying oil when the said oil is treated with the new adsorbent and the reagents adsorbs the contaminants. The contaminants are then removed from the edible oil upon filtering the treated edible frying oil. The new adsorbent contains each of the ingredients in an amount effective to remove and/or decreases contaminants, like free fatty acid, viscosity, colour, density, moisture and trap suspended materials of the used edible frying oil.
It is observed that 7% by w/v of adsorbent A and 5% by w/v of adsorbent B is found to be most suitable for regeneration of used edible frying oil.
The preparation of the new adsorbent and method of regeneration of used edible frying oil is described by way of an exemplary embodiment.
All the ingredients for the adsorbent A and adsorbent B are accurately weighed as per data provided in Table 1 and Table 2. 50g of Magnesium tri silicate and 20g of Marble are mixed and then 15ml deionised water is added to it to form a paste. This paste is heated to a temperature of approximately 100°C until it is dried. Subsequently 18.6g of Alum and 11.4g of Sodium sulphate are uniformly blended and steadily added in 10 ml of deionised water while constantly stirring with addition of lg Citric acid. After thorough stirring, dried magnesium tri silicate and marble mixture is added to it. The resultant paste of all ingredients is heated to a temperature between 90°C to 100°C until it is dry and then sieved in a mesh size of 200-300 to get uniform mixture of adsorbent A and kept in desiccators. Subsequently, 2gm of Fuller's earth and 3gm of silica
gel were mixed and sieved in mesh size of 200-300 to get uniform mixture of Adsorbent B.
It is to be noted that the weight of each of the ingredients are for treating 100ml of used edible frying oil, hence various weights of the ingredients will proportionately be decided according to the volume of the used edible frying oil.
TABLE 1
Adsorbent A: Magnesium tri silicate, Sodium sulphate, Alum, Marble and Citric acid

(Table Removed)
TABLE 2 Adsorbent B- Fuller's earth and silica gel

(Table Removed)
Method-I for regenerating of used edible frying oil
According to a first method (Method-I) of treating used edible frying oil for regeneration:
100 ml of used edible oil was taken in 250 ml conical flask and heated to 100°C. 7% w/v of adsorbent A, as prepared above, is added to the said heated oil and shaken thoroughly for proper blending and the oil is pre-treated. The adsorbent B, containing 3g silica gel and 2g fuller's earth as prepared above, is
poured into a narrow cylindrical column with tapered bottom. The pre treated used edible frying oil sample is subsequently poured into the cylindrical column and is allowed to settle on the adsorbent B. The pre treated oil passes through the adsorbent B and the contaminants in the pre treated oil get adsorbed in the adsorbent B. It takes 15-30 min. to filter through the adsorbent B. The treated edible frying oil coming out of the cylindrical column is filtered through a filter paper and thus the edible oil is regenerated while removing the various contaminants as described above.
Method-II for regenerating of used edible frying oil
According to a second method ( Method-II) of treating used edible oil for regeneration:
100 ml of used edible oil was taken in 250 ml conical flask and heated to 100°C and then 7% w/v of adsorbent A was added to it and shaken rigorously for 2 minutes. Subsequently adsorbent B, containing 3g silica gel powder and 2g fuller's earth powder, was added to the treated edible oil sample. Thus treated oil sample was left idle for 5 minutes and thereafter filtered by filter paper and the used edible frying oil is regenerated while removing the various contaminants as described above.
The regenerated edible frying oil samples collected after treatment with the new adsorbent by the method-I and method-II were analyzed for various parameters, for example, the iodine value, peroxide value, carbonyl value, etc. and compared with that of the unused edible frying oil and used edible frying oil, as shown in Table 3 and Table 4. It is observed that sample of edible frying oil treated by Method-I is better,than the samples treated by Method-II in the evaluated parameters viz. viscosity, peroxide value, iodine value, etc.
In the methods for treatment of used edible frying oil, magnesium tri silicate reduces acid value and Fuller's earth was good agent for reduction of Free Fatty Acid( FFA) by providing sufficient retention time( 10-30 mins. ) for the used edible frying oil. This retention time plays significant role for removal of impurities. Surface area and porosity of Fuller's earth is rightly suited for the purification of edible oil.

Table- 3 : Change in Density and Viscosity of Edible oil after different Treatments

(Table Removed)
Table-4: Results of Different parameters before and after Regeneration of Edible Oil

(Table Removed)
Although the invention has been described with reference to particular illustrative embodiments, many changes and modifications of the invention may become apparent to those skilled in the art without departing from the spirit and scope of the invention. Therefore, included within the patent hereon are all such changes and modifications as may reasonably and properly be included within the scope of this contribution to the art.

I Claim:
1. A new adsorbent for regeneration of used edible frying oil comprising
adsorbent A and adsorbent B, were used to remove the contaminants from the edible oils (e.g. palm oil, soybean oil or vegetable oil) by a) contacting the oil with the compositionally fixed and prepared adsorbents comprising of 7 ingredients- Magnesium tri silicate, Sodium sulphate, Alum (Aluminium potassium sulphate), Marble and Citric acid, Fuller's earth and Silica gel; and b) separating the adsorbent from the oil to recover the oil.
2. The process of claim 1, wherein adsorbent A comprises 49.5 % of
Magnesium tri silicate, 11.3% of Sodium sulphate, 18.4% of Alum, Marble 19.9% and Citric acid 0.99% and the reagents of adsorbent B are 2% of Fuller's earth and 3% of Silica gel for 100ml of used edible oil, have been chosen in an effective amount to treat selectively and specifically polar compounds, free fatty acids, colour bodies and soaps.
3. The process of claim 1, wherein in the method of preparing the new
adsorbent A for regeneration of used edible frying oil, comprises of the step of uniformly mixing 50g of Magnesium tri silicate with 20g of Marble and then 30ml deionised water to form a paste which has pH 9.2-9.5.
4. The process of claim 1, wherein in the method of preparing the new
adsorbent A for regeneration of used edible frying oil, comprises of the step of uniformly mixing Magnesium tri silicate with Marble in deionised water to form a paste, which was heated to a temperature of 100°C-120°C until it dried completely.
5. The process of claim 1, wherein in the method of preparing the new
adsorbent A for regeneration of used edible frying oil, comprises of the step of uniformly mixing 18.6g of Alum (Aluminium potassium sulphate) and 11.4g of Sodium sulphate in 8 ml of deionised water for
perfect blending the mixture is constantly stirred, subsequently addition of lg Citric acid to form a gel.
6. The process of claim 5, wherein in the method of preparing the new
adsorbent A for regeneration of used edible frying oil, comprises of the step of uniformly mixing Alum (Aluminium potassium sulphate), Sodium sulphate and Citric acid to form a gel having a pH 3.0-3.2.
7. The process of claim 4 wherein for the preparation of dry mixture of
magnesium tri silicate and marble was added to the gel prepared as in (claim 5). 20 ml of deionised water was added. The pH of the resultant paste should be in the range of 6.1-6.2.
8. The process of claim 7, wherein the above mentioned paste of all reagents
were further heated at a temperature between 100°C-120°C until it was dry.
9. The process of claim 8, wherein the dried mixture was subsequently
sieved in a mesh (mesh size of 200-300) to get uniform mixture of adsorbent A.
10. The process of claim 1 wherein 2gm of Fuller's earth and 3gm of silica gel, for treating 100ml of used edible frying oil, were uniformly blended.
11. The process of claim 10, wherein silica gel that is the chosen is of mesh size 100-200 (column chromatography grade).
12. The process of claim 10, wherein Fuller's earth and silica gel blended uniformly, were sieved in mesh size of 200-300 to get uniform mixture of Adsorbent B.
13. The process of Claim 1, wherein the method of regenerating used edible frying oil by treating with the new adsorbent with used edible oil comprises the steps of :
(i) heating 100 ml of used edible frying oil in a 250 ml conical flask to 100°C- 150°C;
(ii) 7% w/v of adsorbent A is added to the heated edible frying oil and shaken thoroughly for uniform blending or adsorbent A;
(iii) a cylindrical tube with tapered bottom is filled with the adsorbent B containing 3g silica gel and 2g fuller's earth;
(iv) The treated edible oil sample from step (ii) is poured in the cylindrical tube and filtered through the column filled with adsorbent B;
(v) The treated edible frying oil from step (iv) is subsequently passed through a filter paper thereby regenerating the used edible frying oil by removing the various contaminants.
14. A method of regenerating used edible frying oil by treating with the new adsorbent as claimed in claim 1 comprises the steps of :
(i) 100 ml of used edible frying oil was taken in 250 ml conical flask and heated to 100°C-150°C;
(ii) 7% w/v of adsorbent A was added to it and shaken rigorously;
(iii) Adsorbent B, containing 3g silica gel powder and 2g fuller's earth powder, was added to the edible frying oil sample treated with adsorbent A;
(iv) The treated oil sample was left idle for certain time period and thereafter filtered by filter paper and the used edible frying oil is regenerated while removing the various contaminants.

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Patent Number

270624

Indian Patent Application Number

1122/DEL/2009

PG Journal Number

02/2016

Publication Date

08-Jan-2016

Grant Date

05-Jan-2016

Date of Filing

02-Jun-2009

Name of Patentee

DR. PADMA S VANKAR

Applicant Address

302, SOUTHERN BLOCK LABORATORY, FACILITY FOR ECOLOGICAL ANALYTICAL TESTING, INDIAN INSTITUTE OF TECHNOLOGY, KANPUR, U.P.-208 016

Inventors:

#	Inventor's Name	Inventor's Address
1	DR. PADMA S VANKAR	302, SOUTHERN BLOCK LABORATORY, FACILITY FOR ECOLOGICAL ANALYTICAL TESTING, INDIAN INSTITUTE OF TECHNOLOGY, KANPUR, U.P.-208 016
2	RAMA SHANKER SAHU	302, SOUTHERN BLOCK LABORATORY, FACILITY FOR ECOLOGICAL ANALYTICAL TESTING, INDIAN INSTITUTE OF TECHNOLOGY, KANPUR, U.P.-208 016

PCT International Classification Number

A47J 37/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA