Title of Invention

"A PROCESS FOR THE PRODUCTION OF DEGUMMED AND DEWAXED RICE BRAN OIL FOR PHYSICAL REFINING"

Abstract

This invention relates to a process for the production of degummed & dewaxed rice ban oil suitable for physical refining. Rice Bran Oil is one of the nutritious healthy edible oil. Physical refining of RBO is difficult due to high gum and wax content. For physical refining of Phospholipids, in term of phosphorous (p-Value) and wax were need to brought down lower than 5 ppm and 0.2 % respectively. In this process degumming agent is 1 % aqueous solution of CaCl2 (6%). Simultaneous degumming and dewaxing followed by bleaching gave oil with less than 5 ppm phosphorous and 0.2% wax which make oil fit for physical refining

Full Text

The present invention relates to a process for the production of degummed and dewaxed rice bran oil for physical refining. The oil content with Novelty of this process is the simultaneous removal of phospholipids and wax through a single degumming and, dewaxing steps followed by bleaching. India is the second largest producer of rice in the world, with an annual production of 118.6 MMT paddy corresponding to 80 MMT rice. Against the potential for the production of 10 MMT rice bran, which correspond tol.5 MMT of rice bran oil, only about 0.42 MMT RBO is produced per annum. The crude rice bran oil (CRBO) produced currently is of poor quality with high FFA and colour value which makes it not suitable for economic refining and result in only about 10 % of CRBO is refined for edible use and the remaining is used in vanaspathy and soap. Lack of standardized process technology has been the impediment leading to the present situation. Rice Bran Oil is one of the nutritious healthy edible oil, owing to the presence of natural bioactive phytochemicals like Orizanols, tocotrienols, and tocopherol etc. Hence it is of paramount importance to exploit this naturally rich RBO to its larger benefits. Chemical refining and physical refining are the two major methods to refine the oil for edible purpose. Eventhough chemical refining also provides good quality oil, this process unviable. Moreover all the nutritive micronutrients are also lost in the process . It is in this context physical refining process holds supremacy over chemical refining process. But the wax and the phospholipids level need to brought to much lower level to make the oil fit for physical refining, otherwise these constituents impart colour, haziness and bad taste to the final product Rice bran oil being rich in wax and phosphatides, it is a prerequisite to bring down the phosphatides and wax content to less than 125 ppm and 0.2% respectively. A process to super degumming and dewaxing Rice bran oil to meet the above parameters to make it fit for physical refining. . The comparative study of the refining study of refining of RBO either by chemical or by solvent or physical refining techniques revealed that physical refining is the most favored method for RBO [Sun Ki Kim, Chul Jin Kim, Hong Sik Cheigh and Suk Hoo Yoon, Effect of Caustic Refining, solvent Refining and steam Refining on the Deacidification and Color of Rice Bran Oil, Division of Biological Science and Engineering, Korea Advanced Institute of Science and Technology, P.O. Box 131, Dongdaemun, Seoul, Korea, JAOCS, Vol.62 no. 10 October 1985] In this study the authors showed physical refining as the most suitable method for refining of RBO, colour value is also higher in chemically and solvent refined oil. In another report degumming and dewaxing of RBO for physical refining was carried out [A.C. Bhattacharyya and DK Bhattacharyya, Degumming of Rice Bran Oil, Journal of Oil Technology Association of India April- June 1998], using water 20 kg /tone of oil containing inorganic acids (Each1 kg/ tone) at 70° C for 25 min. and also with surface active compound in water (20 kg/tone of oil). According to this study most effective treatment was phosphoric acid and Sulphuric acid at 1:1 ratio. But residual phospholipid content is 0.13%, which is much higher for physical refining. In this new process reported here residual Phospholipid could be brought down to as low as 0.02 % after degumming and dewaxing. Another physical refining study of RBO [B.K. De and D.K Bhattacharya, Physical refining of Rice Bran Oil In relation to Degumming and Dewaxing, JAOCS .Vol .75.No 11(1998)], degumming and dewaxing done with water and phosphoric acid. After water degumming and water dewaxing at 10° C the residual wax and gum was 0.48, 0.57 and 0.53 %, for three oil samples with FFA 4.0, 9.5, and 12.4 % respectively. High temperature Phosphoric acid degumming followed by low temperature water dewaxing at 10 °C and water degummed at 17 °C contained 0.60 % and 0.69 % of wax and gum. It is also significantly higher compare to new process and further reduction of gum and wax required for physical refining of RBO. In another study [Nasirullah and Ramtham. Physical refining of Rice Bran and Soybean Oils. J.FoodSci.Technol.2000.vol.37, N0.2:135-138], to remove nonhydratable phospholipids, water degummed RBO was treated with 1% aqueous Kcl solution to convert nonhydratable bivalent salt of phospholipid to monovalent salts with K+ ions. Even here the residual phospholipid content was 0.10 %. In another study [Pradeep Nalewade, Latest technology of physical refining of edible Rice Bran Oil. Alpha Laval Ltd, Pune 411012, National Seminar on Edible Rice Bran Oil Goa 3rd June 2000], it was reported that acid degumming followed by water washing has become regular operandi to reduce the phosphorus level and trace metal content. After lye washing dewaxing and bleaching residual phosphorus content was 17 ppm, which is the lowest value obtained in this study. By using membrane for the degumming & dewaxing [R.Subramanian,,M.Nakajima, A.yasui H.Nebethani.T.Kimura, and T.Maekawa . Evaluation of Surfactant-Aided Degumming of Vegetable oils by Membrane Technology, JAOCS Vol.76.No.10 (1999)], the phosphorus content in the permeate ranged from 20 to 50 mg/Kg in soybean and 63-94 mg/Kg for rapeseed oil. Furt her reduction of phosphorus content is required for physical refining of oil. Furthermore since membrane technology is still under R&D stage and is not economical to use it commercially. In another process for the refining of vegetable oils [Rohdenburg,, Herbert L, (Hamburg, De); Csernitzky; Karoly (Szolnok, HU); Chikany; Belu (Budapest .HU) Peredi;Jozsef (Budapest.HU); Borodi; Attila (Budapest,HU); Ruzics; Anna F. (Budapest.HU); Degumming process for plant oils. US Patent No.US.5239 096(1993)] sunflower Oil was degummed first and then heated to 50° C and fed continuously with a 10% citric acid solution in a tank provide with a Stirrer, and for each 1000 kg oil, 700 g acid were added. The oil, acid mixture was stirred for 15 min in a tank and then cooled to 30°C. To this mixture was added 4% aqueous NaOH solution corresponding to the amount stoichiometrically required to neutralize all of the citric acid. The resulting mixture was slowly stirred for 2 hrs in the tank and then suddenly heated to 80° C .The oil phase recovered is washed with 10 % soft water and dried. Here phosphorus content of the oil after water degumming was 75 ppm, and after above process it was reduced to 2.5 ppm. And after bleaching it was reduced to From the above reports it could be reasonably assumed that an economic method suitable for commercial use for degumming and dewaxing of CRBO is currently not available. The main object of the present invention therefore is to provide a process for the Production of degummed and dewaxed rice bran oil suitable for physical refining. Another objective of the present invention is to reduce neutral oil loss compared to conventional process., through simultaneous degumming and dewaxing , so that the . process is economical. Still another objective of the present invention is to obtain sludge with less Contamination, unlike in acid-water degumming, to enable recovery of lecithin easily. Yet another objective of the present invention is to make economical dewaxing and degumming through use of cheaper chemicals like CaCl2 that can be removed from the oil easily. In the present invention, stirring time and cooling time is short with no settling time, for wax and gum and therefore it is less time consuming process. Novelty of this process is the simultaneous removal of phospholipids and wax through a single degumming and dewaxing steps followed by bleaching The economical dewaxing and degumming is done through use of cheaper chemicals like CaC12 that can be removed from the oil easily. Accordingly, the present invention provides a process for the production of degummed & dewaxed rice ban oil suitable for physical refining comprising; i) heating the crude rice bran oil at temperature range of 50-95 deg C and hydrating by adding 2 % water and stirring for a period of 20-40 minutes, ii) characterized in adding 0.5 to 3% volume of aqueous Ca Cl2 solution 1 to 10% with continuous stirring for a period of 20-40 minutes, iii) cooling the mixture of step ii) to 5-20 deg C at the cooling rate of 0.1 to 2 deg C /minute to facilitate crystallization of wax and gum from the oil, iv) removing sludge(gum and wax) by centrifugation at 6000-10000 rpm at a temperature range of 10-20 deg C for a period of 10-30 minutes, v) bleaching the oil obtained in step iv) with bleached earth 4 to 5% containing tonsil:Indian earth in a ratio of 1:3 and 0.4 % activated carbon in presence of 0.05 % citric acid at a temperature range of 100- 110 deg C for a period of 10-20 minutes and filtering, vi) holding bleached oil of step vi) at 10-20 deg C for a period of 24 hours, filtering to obtain degummed and dewaxed oil. In an embodiment of the present invention, crude rice bran oil contains free fatty acid 3 to 7 %, phosphorous 370-700 ppm. In another embodiment of the present invention, in step iv) removal of sludge is by batch or continuous centrifugation. In yet another embodiment of the present invention in step iv), centrifugation is carried out preferably at 8000 rpm and for a period of 20 minutes. In another embodiment of the present invention, the said process brings down the phosphorus content of oil to DETAILED DESCRIPTION OF THE INVENTION Crude rice bran oil contains approximately 1% suspended particles and moisture as Impurities, Suspended matters are, fine particles, high melting hard wax, solid oil insoluble particles etc. Which give more turbidity to the oil, which will affect the quality of the oil and processing as well. The impurities combine with wax and gum leading to increased oil loss during degumming and dewaxing steps. Removal of this suspended particle therefore is an important step in rice bran oil refining. Crude RBO is heated to 75° C and filtered. By this way fine particles and high melting solids like hard wax molecules were separated which will facilitate down stream processing. Crude rice bran oil contains about 1.0 to 2.5 % of phosphotides and 2.0 to 6.0 % wax. As a result the crude rice bran oil is viscous and most difficult to refine. Phosphatides are classified in to two types hydratable and nonhydratable. The principal component of hydratable phospholipids are phosphotidylcholine (PC) where as the nonhydratable phospholipids are the bivalent salts of phosphatidicacid (PA), phosphatydylethanolamine (PE). Hydratable and nonhydratable phosphatides are approximately in the ratio of 80:20. Wax present in the crude rice bran oil also is classified as soft wax and hard wax depending on their melting points. This complexity coupled with high contents makes refining of CRBO an extreme difficult task and a R&D challenge. Hence dewaxing and degumming to meet with the standard requirements are important step in rice bran oil processing. Both hydratable and nonhydratable phospholipids are precipitated at 75°C with water and aqueous solution of CaCl2. Hydration of phospholipids takes place by the interaction of water molecules with nitrogen center and makes the phospholipid molecule coagulate out the oil medium. Water required for hydration was optimized by carried many trials. Better precipitation observed with 2% of water. More water may lead to the formation of water, oil emulsion during mixing. The filtered oil was heated to 75°C and 2% WA/ of water was sprayed on it and stirred for 30 minutes to ensuring thorough mixing of oil and water, Temperature of the mixture was maintained at 75°C, throughout precipitation of hydratable and nonhydratable phospholipids with a single step is difficult and therefore sequential steps were followed. The addition of bivalent cations like calcium or aluminium produces water crystals of nonhydratable phospholipids called liposomes by way of decreasing the transition temperature of the phospholipids, and water droplets an bind the same. To this water treated oil 1% WA/ of 6% aqueous CaCl2 solution was sprayed and stirred for 30 minutes. Quantity of the CaCI2 requirement was optimized with different trials. Thorough mixing of aqueous CaCl2 solution should be ensured to achieve complete precipitation of the non-hydratable phospholipids. Temperature of the mixture maintained at 75°C throughout this step. Rate of cooling is very important in this process of combined degumming and dewaxing. Slower or faster cooling may affect the crystal formation and leads to incomplete removal of wax and gum or increase the oil loss. Rate of cooling was optimized through different trials and it was observed cooling of the mixture from 75°C - 20°C @ 0.4°C/ minute was the optimal cooling rate to achive the desirable results. The oil was cooled to 10°C and also it was noticed that the phospholipid removal is better but oil loss was relatively higher compared to that at 20°C. However the phospholipid content at 20°C could be brought to the desired levels during bleaching and second winterization steeps. During winterization (crystallization) the phospholipids appear to form nucleus that facilitate to instabilization of wax and precipitation of gums and wax together. Centrifugation was adopted to separate precipitated gums and wax variables such as speed, time and temperature were varied and there effect on separation was studied. It was found out that a speed of 8000 rpm for 20minutes at 20°C is the most suitable condition for better separation of precipitate under these situations. The supernatant oil was clear and free from wax and gum. The residual wax and gum in the supernatant oil varied from 0.02-0.09 % and wax content from 0.1 -0.7 % respectively for different trials using crude oils from different sources. Moisture is removed by vacuum drying before bleaching. The degummed and dewaxed oil was mixed with 0.05% citric acid as 25 % aqueous solution and oil is heated to 90°C under I torr vacuum to remove the moisture. Degummed, dewaxed and dried oil was heated to 100-110 °C and mixed with 4.4% W/W bleaching earth [Tonsil: Indian earth 1:3 and 0.4% activated carbon] for 20 minutes under vacuum and filtered. This gave better result in terms of colour reduction and also reduced residual phospholipids. Trace metals like copper and iron, trace calcium etc chelated with citric acid also removed with sludge. Bleached oil was cooled to 20°C and stored for 24 hrs, for crystallization of residual wax. Winterization followed by filtration of the oil before deacidification increase the clarity of the oil and also prevents the haziness on storage. The presence of trace wax was found to also affect the colour of the oil during physical refining and hence requirement for a second winteriztion step. (Figure Removed) Example-1 10 kg of crude RBO with FFA 3.09%, and phosphorus content is 645 ppm is heated to 75° C and added 2 % of water and stirred for 30 min at 200 rpm in pilot plant and at the end added 1% of CaCl2 (6 % solution). Continued stirring for further 30 min. Then oil, water, CaCl2 mixture cooled to 20° C @ 0.4 °C to crystallize gums and wax. After cooling the mixture was centrifuged in refrigerated centrifuge at 20° C at 8000 rpm for 20 min. 90 % oil having 0.09 % phospholipids and 0.77 % wax was recovered. This degummed and dewaxed oil was mixed with 0.05 % citric acids (25 % aqueous solution) dried under vacuum subsequently the oil was bleached with 4.4 % bleaching earth [3% Indian clay and 1% tonsil, 0.4% activated charcoal] and filtered. Oil recovered had colour value 15 units in 1 /4 inch cell (5R+Y) 0.18 % wax. Residual phosphorus content was 2.87 ppm. This recovered oil was subjected to a second winterization by keeping overnight at 20°C and filtered. (Table 1) Example: 2 20 kg crude RBO with FFA 6.12 % and phosphorus content 385 ppm was heated to 75° C in a pilot plant and added 400 ml water stirred for 30 min at this temperature. Subsequently 200 ml of 6 % CaCb solution was added stirring continued for further 30 Min. And cooled to 20° C @ 0.4 C /min. The mixture was centrifuged in a refrigerated centrifuge at 20° C at 8000 rpm for 20 min. The degummed and dewaxed supernatant oil was collected. The recovered of the oil of 18 kg was mixed with 0.05 % citric acid as 25% aqueous solution and dried under vacuum. The oil was bleached in a bleaching unit with 4.4% bleaching earth [3% Indian earth, 1% tonsil, and activated charcoal 0.4 %]. The and wax content of the recovered oil was 0.1 % and residual phosphorus content was Example: 3 25 kg of crude RBO with 6.68 % FFA and phosphorus content of 645 ppm was heated to75° C followed by addition of 500 ml of water and stirred for 30 min at the same temperature. At the end 250 ml of 6% CaCI 2 solution was added continued stirring for further 30 min. After this mixture was cooled to 20° C at the rate of 4°C/min. and centrifuged at 8000 rpm for 20 min. The recovery was 91%. Oil containing 0.22 wax and 11.5 ppm phosphorus content. After bleaching with 4.4 % bleaching earth, [3 % Indian clay 1 % tonsil and 0.4 % activated charcoal] in presence of citric acid 0.05% the oil was filtered which contained 1% wax and residual phosphorus Table-1 (Table Removed) The main advantages of the present invention are the following: 1. This process is cost effective for refining crude RBO into value added Physically refined edible RBO, hitherto not developed. 2. Conventional water and acid degumming and dewaxing requires further neutralization and washing steps resulting in high neutral oil and oryzanol loss. 3. Degumming and dewaxing in the present process is single step hence oil loss is less. 4. Unlike in the conventional process no neutralization step is required therefore no loss of oryzanol 5. Colour value is reduced after bleaching to the commercially acceptable level. 6. Reduction of phosphorus content to less than 5 ppm to meet the requirement for physical refining. 7. After degumming and dewaxing followed by bleaching the oil recovered is superior quality suitable for Physical refining. 8. Effective dewaxing reduces wax content to lowest level so that no haziness in the refined RBO on storage. We claim : 1. A process for the production of degummed & dewaxed rice ban oil suitable for physical refining comprises; i) heating the crude rice bran oil at temperature range of 50-95 deg C and hydrating by adding 2 % water and stirring for a period of 20-40 minutes, ii) characterized in adding 0.5 to 3% volume of aqueous Ca Cl2 solution 1 to 10% with continuous stirring for a period of 20-40 minutes, iii) cooling the mixture of step ii) to 5-20 deg C at the cooling rate of 0.1 to 2 deg C /minute to facilitate crystallization of wax and gum from the oil, iv) removing sludge(gum and wax) by centrifugation at 6000-10000 rpm at a temperature range of 10-20 deg C for a period of 10-30 minutes, v) bleaching the oil obtained in step iv) with bleached earth 4 to 5% containing tonsihlndian earth in a ratio of 1:3 and 0.4 % activated carbon in presence of 0.05 % citric acid at a temperature range of 100- 110 deg C for a period of 10-20 minutes and filtering, vi) holding bleached oil of step vi) at 10-20 deg C for a period of 24 hours, filtering to obtain degummed and dewaxed oil. 2. A process as claimed in claim 1 wherein crude rice bran oil contains free fatty acid 3 to 7 %, phosphorous 370-700 ppm. 3. A process as claimed in claim 1, wherein in step iv) removal of sludge is by batch or continuous centrifugation. 4. A process as claimed in claim 1, wherein in step iv), centrifugation is carried out preferably at 8000 rpm and for a period of 20 minutes. 5. A process as claimed in claim 1, wherein the said process brings down the phosphorus content of oil to 6. A process for the production of degummed & dewaxed rice ban oil suitable for physical refining substantially as herein described with reference to the examples.

Documents:

1889-DEL-2004-Abstract-(03-03-2011).pdf

1889-del-2004-abstract.pdf

1889-DEL-2004-Claims-(03-03-2011).pdf

1889-del-2004-claims.pdf

1889-DEL-2004-Correspondence-Others-(03-03-2011).pdf

1889-del-2004-correspondence-others.pdf

1889-DEL-2004-Description (Complete)-(03-03-2011).pdf

1889-del-2004-description (complete).pdf

1889-del-2004-form-1.pdf

1889-del-2004-form-18.pdf

1889-DEL-2004-Form-2-(03-03-2011).pdf

1889-del-2004-form-2.pdf

1889-DEL-2004-Form-3-(03-03-2011).pdf

1889-del-2004-form-3.pdf

1889-del-2004-form-5.pdf