DESC:

3. PREAMBLE TO THE DESCRIPTION
COMPLETE SPECIFICATION
The following specification describes the invention and the manner in which it is to be performed.

A PROCESS FOR THE TREATMENT OF VEGETABLE OILS
Technical field
[0001] The invention is in relation to oil refining technology. The invention in particular provides a process for the treatment of vegetable oils in the presence of a combination of enzymes to obtain refined vegetable oils in higher yields and with reduced impurities.
Background of the invention
[0002] Crude vegetable oils contain gums, color, metals, oxidized fatty acids, waxes and free fatty acids as impurities and all of these impurities need to be removed to produce shelf stable vegetable oils. Phospholipids or Phosphatides, also known as gums, are natural emulsifiers and they are known to be one of the factors contributing to reduced shelf-stability in refined vegetable oils and hence these gums are removed from the oil, as a first step in the refining process of vegetable oils.
[0003] Vegetable oils are traditionally refined by two different ways. The most predominant way is called “Chemical Refining” and the second way is called “Physical Refining”. “Chemical refining” suffers from drawbacks of oil losses and effluent generation while producing very stable refined vegetable oil. “Physical refining” is the ideal way of refining all the oils that carry high levels of free fatty acids in crude oils; examples include rice bran oil and palm oil. Successful physical refining needs more complete removal of gums from crude oils and this is being done by a large range of treatments.
[0004] The two major byproducts or impurities from refining process are Soap Stock from chemical refining and Gums (Lecithin) from degumming process in physical refining - prior to the refining stage. For certain oils, it may be desirable to degum the crude oil prior to alkali refining. Degumming and alkali refining generally remove phosphatides, soaps, and other impurities such as metals. Degumming generally refers to the process of removing phospholipids from crude vegetable oils. These phospholipids can be classified into hydratable and non-hydratable phospholipids. Hydratable Phospholipids can be easily removed with the help of hot water; however, non-hydratable phospholipids can only be removed by using acid, alkali or enzymes.
[0005] There are several degumming processes in the known art and one such process is known as water degumming and involves mixing of water with vegetable oil and separating the resulting composition into hydratable gums and oil containing non-hydratable gums. This process is usually followed by either physical refining or chemical refining. In the chemical refining, the oil containing non-hydratable gums is subjected to neutralization of free fatty acids by using an alkali such as sodium hydroxide. Sodium hydroxide reacts with free fatty acids and forms sodium salt of fatty acids, causing precipitation of a semisolid material known as soap stock. This precipitate is separated from the oil by centrifugation. Together with the soaps, the phospholipids are also precipitated and removed from the oil. The soap also carries good amount of oil and water insoluble gums along with it. This results in loss of oil in soap, loss of fatty acids in soap and loss of water insoluble gums. In contrast, in the physical refining the free fatty acids are distilled off after the bleaching and/or de-waxing during the deodorization step, but the phospholipids have to be removed prior to the bleaching by a process step especially designed for this task, which might be called full degumming.
[0006] Although, water degumming is the oldest and simplest process for removing Gums (phospholipids/phosphatides/lecithin) from vegetable oils and also forms the basis of the production of commercial lecithin (Lecithin as obtained by drying the gums resulting from the water degumming process contains a mixture of different phosphatides). Only hydratable phospholipids can be removed during water degumming, leaving large amount of phosphorus in the oil, depending on the type and the quality of the crude oil.
[0007] In more useful in connection with physical (as opposed to alkali) refining, phospholipids content is further reduced by other degumming processes, such as enzymatic degumming. However, in all the current known enzymatic degumming processes there is still considerable amount of oil lost in gum phase and some fatty acids too are lost as a part of un-hydrolyzed gums. Moreover, none of the prior art provides to recover the fatty acids present in gum molecules completely and at the same time eliminate the use of centrifuges to separate the gums- saving oil loss, electrical power and preventing effluent generation.
[0008] Enzymatic degumming was initially reported by Roehm and Lurgi and was known as Enzymax Process. In this invention Phospholipase A 2 was used to hydrolyze the non-hydratable phospholipids to their hydratable lyso-compounds. Though this is efficient in removing gums from vegetable oils to satisfactory level, it does not focus on (a) Saving oil losses, (b) elimination of use of centrifuges to separate gums from oil.
[0009] Fangyan Jiang etal.,( Bioresource Technology, 102, (17), 8052 – 8056, 2011) reported.
[0010] Degumming of vegetable oils by a novel phospholipase B from Pseudomonas fluorescence BIT-18. It describes use of a novel enzyme that is capable of hydrolyzing both C1 and C2 position ester bonds in phospholipids leading to good degumming results. However, the work focuses only on removing gums from the oil by standard degumming process and there is no mention of special need to hydrolyze both C1 and C2 positions and the potential benefits of hydrolyzing both C1 and C2 positions. The hydrolysis of both C1 and C2 positions by choosing appropriate enzymes – alters the properties of hydrolyzed gum molecules and these altered properties enable us to derive additional benefits such as substantially reduced oil losses, possibility of eliminating use of centrifuge to remove hydrolyzed gums and higher yield of fatty acids from gums as byproducts. None of these possibilities have been mentioned in this paper. The paper also does not talk about using a mixture of phospholipase and lyso-phospholipase to derive special benefits in addition to removal of gums from the oil.
[0011] In US Patent No 6001640, Loeffler et al., mention about the use of mixture of phospholipase and lysophospholipase for degumming of vegetable oils. The main characteristic of the invention is indicated as “Use of phospholipase from Aspergillus strain. However, no specific purpose for use of lysophospholipse was mentioned in the patent. Lysophospholipase happened to be present as a side activity in phospholipase activity, and since this phospholipase from Aspergillus was being used for degumming of vegetable oils, the side activity got added in to process automatically without producing any unwanted effects. The main drawback of this invention is that the process was carried out at or below a pH of 4.0, while the present invention talks about using a mixture of citric acid and NaOH as a buffer to get a pH of 4.8 to 5.0 for efficient enzyme reaction. In addition, in the instant invention any commercially available enzymes can be used unlike this invention. Furthermore, the invention does not avoid the usage of centrifuge for separation unlike the instant invention and is not eco-friendly. The invention also does not focus on preventing oil losses and recovery of fatty acids from gums – during degumming process.
[0012] In EP0869167 A2: Borch Kim et. al., reported reduction of phosphorous containing components in edible oils comprising a high amount of non-hydratable phosphorous by means of a phospholipase, a phospholipase from a filamentous fungus having phospholipse A and / or B activity. The drawback in this invention is that it cannot eliminate effluent generation and the centrifugation steps. It is also silent on elimination of oil losses.
[0013] Further, in US 5558781, Buchold et.al., mentions about use of Phospholipase B (lysophospholipase) for degumming, but their objective is to recycle part of the enzyme and the process still uses centrifuge and still produces liquid gum effluent. Similarly, in US 6127137, Hasida Miyoko et al., have used an enzyme that has both phospholipase and lysophospholipase activities primarily for removal of gums under acidic conditions from vegetable oils that are preferably treated with water prior to enzyme degumming. This patent focuses on the novelty of using acidic conditions for enzyme degumming and the strain Hyphozyma. It does not talk about eliminating degumming losses, recovery of fatty acids, eliminating effluent and elimination of use of centrifuges.
[0014] WO2008/036863 A2: by Verenium Corporation discloses enzymatic degumming of vegetable oils. Its principal objective is to use phospholipase C either alone or in combination with PI specific phospholipase C or phosphatase to convert phsopholipids in to 1, 2 diglyceride and phosphate esters. This also mentions the use of Phospholipase C and its blends in alkali refining or in soap stock again to produce diglycerides from gums. Though this process increases the oil yield and eliminates oil losses completely, the principal drawback of this process is that the gums are converted in to Di-acyl glycerol which moves in to oil phase. Di-acyl glycerol has been implicated in undesirable effects on human health and hence any increase in Di-acyl glycerol content in vegetable oils is not desirable.
[0015] Therefore, all these gum treatments –suffer from either one or more of (a) loss of valuable oil along with the gums and (b) loss of valuable fatty acids which are present within the gum molecules, (c) generation of liquid lyso-gums which are difficult to handle or process further, (d) use of centrifuge to separate gums from the oil and (e) increase in level of Di-acyl glycerol in degummed oil. It is typical for all these degumming processes that only purely mechanical or physical-chemical processes are applied, and these are not always optimally suited for all oil qualities. The apparatus requirement and the energy expenditure of all these processes are great, and in addition, there is no guarantee that the low phosphorus contents required for subsequent de-acidification by distillation will be achieved in some cases especially with rice bran oil.
[0016] Further, all the enzymatic processes have in common the reduction of the phosphorous content only.
Objects of the present invention
[0017] The primary object of the present invention is to provide a process for the treatment of vegetable oils to reduce the content of impurities, such as various phospholipids i.e. gums and to eliminate the loss of valuable oil.
[0018] An object of the present invention is to provide a process for the treatment of vegetable oil to efficiently remove the phospholipids and recover the fatty acids present in gum molecules completely and at the same time eliminating the use of centrifuges to separate the gums which results in saving of electrical power
[0019] Another object of the present invention is to provide a process for the treatment of vegetable oil to substantially reduce the generation of effluent and, to prepare refined vegetable oil with high shelf-stability.
[0020] Yet another object of the invention is to provide a process for hydrolyzing all phospholipids into glycerophophosphatesand free fatty acids, by subjecting the gums to enzyme treatment and recovering high quality edible oil therefrom.
Summary of the invention
[0021] The subject matter disclosed herein describes a process for the treatment of vegetable oil. The method comprises of efficiently removing the phospholipids and to recover the fatty acids present in gum molecules completely and at the same time eliminating the use of centrifuges to separate the gums and to substantially reduce the generation of effluent. The subject matter disclosed herein further describes the process of hydrolysing all phospholipids into glycerophophospatesand free fatty acids by subjecting the gums to enzyme treatment and recovering high quality edible oil therefrom.
[0022] These and other features, aspects, and advantages of the present subject matter will become better understood with reference to the following description and appended claims. This summary is provided to introduce a selection of concepts in a simplified form. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
Brief description of drawings
[0023] FIG.1 is flow-drawing depicting process steps of the present invention
Detailed description of the invention
[0024] During the process of removal of gums from the oil, due to their natural emulsification ability, the gums always carry some amount of oil along with them. Gums obtain their emulsifier character from the long fatty acid chains present in their molecules and the phosphate groups plus functional groups. The fatty acid chains form strong hydrophobic part, while the rest of the gum molecule has hydrophilic nature. The hydrophobic parts of gums i.e., fatty acid chains are responsible for oil carrying capacity of gums. Therefore, if the gums are hydrolyzed completely by using enzymes and separate the fatty acid chains from gum molecules, the remaining gum molecule, which is called glycerophosphates, loses the ability to act as emulsifier and carry oil with it and hence these hydrolyzed gums can be easily separated from the oil either by simple water extraction or by adsorbing on to bleaching earth, which is used for removing natural pigments from vegetable oils, as a part of standard vegetable oil refining process. Since, the glycerophosphates do not carry any oil with them, this leads to following benefits: (a) there will be no oil losses while removing gums, (b) the fatty acids present in gums are recovered as valuable by-products instead of loosing as a part of gum and (c) since the hydrolyzed gums can be removed by adsorption on to bleaching earth, there is no need to use centrifuge to remove gums from the oil and hence there is a saving in electrical power consumption and no effluent is generated.
[0025] Accordingly, in the present invention a combination of enzymes selected from phospholipase A1 orA2 and Lysophospholipase is used for the treatment of vegetable oils. The process steps of the present invention for the treatment of vegetable oils is used to convert all the phospholipids into glycerophosphates in vegetable oils including soybean oil, rapeseed oil, sunflower oil, mustard oil, linseed oil and rice bran oil.
[0026] These gums can be hydrolyzed completely by using a mixture of the aforementioned enzymes and converted into free fatty acids and glycerophosphatesThe process of the present invention converts original gums completely into lysophospholipids first and then converts the lysophospholipidsinto glycerophosphates and free fatty acids.
[0027] Schematic representation of the reaction scheme of the present invention is as follows:

[0028] Wherein, R1-COOH & R2- COOH represent fatty acid moieties on C1 and C2 carbons of glycerol backbone of phospholipid.
[0029] X – Represents functional group attached to phosphate group which could be as follows with different types of phospholipids.
X = H – Phosphatidic acid (PA)
X= Inositol Phosphatidyl inositol (PI)
X= Choline Phosphatidyl choline (PC)
X= Serine Phosphatidyl Serine (PS)
X= Ethanol amine Phosphatidyl ehthnol amine (PE)
[0030] In the process of the present invention, initially a crude vegetable oil is treated with at least a mixture of two or more enzymes, selected from phospholipase A1 or Phospholipase A2 and lysophospholipase, and the gums thus obtained (Lecithin/Phosphatides/Phospholipids) are converted to glycerophosphosphates and free fatty acids, to obtain a refined vegetable oil with substantially reduced impurities.
[0031] The process steps of the present invention are now described, by referring to FIG.1, which is a flow-drawing, depicting the process steps of the present invention.
[0032] Vegetable oil, which is required to be treated is sourced and heated to a temperature in the range of about 50-550C, in the presence of a pH regulating agent such as citrate buffer, to regulate pH in the range of about 4.0 to 5.5. A suitable amount of water in the range of about 1.0 to 5 wt. % of oil is added to the oil. In the process of the present invention, as an exemplary embodiment, crude rice bran oil, soybean oil and sunflower oil is used for the purpose of refinement. It is understood here that other vegetable oils such as rapeseed oil, mustard oil, canola oil can also be used in conjunction with the process of the present invention.
[0033] The gums in the oil are then hydrolyzed, in the presence of an enzyme selected from phospholipase A1 or phospholipase A2, in desired quantities.Further, phospholipase A1 such as commercially available Lecitase Ultra from AB Enzymes is added in the quantity of about 25-75 gm per ton of the oil and the enzyme having an activity of 10 KLU/gm.
[0034] Alternately, the hydrolyzing step can also be performed in the presence of the enzyme phospholipase A2 such as commercially available Lecitase PLXtra from AB Enzymes, in the range of about 15-75 gm/ton of oil having the activity levels in the range of 5 to 10 KLU/gm. Simultaneous to the partial hydrolysis of the gums in the oil, the reaction mixture containing the said enzyme is subjected to another step of hydrolysis, in a high-shear mixer, in the presence of an enzyme, to obtain a corresponding glycerophosphosphates. In this step, the preferred enzyme that is used is lysophospholipase (Such as Rohalase F from AB Enzymes), in the quantity of about 50-200 gm/ton of oil, having the enzyme activity in the range of about 5 to 20 KLU/gm. The enzymatic reaction is carried out in a retention tank with constant mild mixing for about 4-8 hrs. The temperature of oil is raised to about 75 - 80°C, in a heat exchanger and filter aid is added to the oil at a level of about 0.1% - 0.5% by weight of oil and mixed for 10 minutes. The filter aid can be any standard filter aid commonly used such as Hyflo-supercel, Diatomite, Perlite and the like. The Oil is then dried using vacuum dryer to get a moisture content of less than or equal to 0.1% in the oil. The dried oil is filtered through filter bed containing spent bleaching earth, which is obtained by filtering bleached oil. This filtration removes substantially, the presence of gums, sediments, polymerized fatty material and large-colored bodies. The filtered oil is bleached using fresh bleaching earth and can be subjected to de-waxing in case of oils containing waxes. The cleaned oil is deodorized to obtain a refined oil having desired shelf-stability.
[0035] In an aspect of the present invention, the step of centrifugation is avoided, since the glycerolphosphates are adsorbed on to the filter aid and are removed from the oil together with filter aid by filtering the oil through spent filter bed. Avoiding the step of centrifugation results in reduced power consumption and elimination of undesirable effluents. Additionally, the avoidance of centrifugation step helps in reducing oil losses.
[0036] The preferred embodiments of the process of the present invention are now described by the following examples. These examples are illustrative in nature and shall not be considered as limiting the scope of the invention.
Example 1
[0037] Different samples of Crude rice bran oil of different levels of free fatty acids and phosphorous content as mentioned in the following Sets a) SET 1: 6% FFA, 500 ppm phosphorous, b) SET 2: 5% FFA , 350 ppm phosphorous and c) SET 3: 22%FFA and 225 ppm phosphorous, is degummed in a commercial plant using continuous degumming process as follows: The oil is heated to 50oC through a heat exchanger and taken to a high shear mixer in which the following are added to the oil: (a) a commercial phospholipase A1, such as Lecitase Ultra is used at 55 gm per ton of oil (b) a commercially available Lysophospholipase, such as Rohalase F is used at 100 gm per ton of oil and (c) 2.5% on weight of oil of citrate buffer of pH 4.8–5.0. Both the enzymes and citrate buffer can also be mixed as single solution prior to addition to oil and added to the oil. The enzymes and the buffer are mixed with oil in the high shear mixer to provide intimate contact between oil and aqueous phase by dispersing the aqueous phase in the form of very fine droplets within oil phase. The enzyme containing oil is passed through a retention tank in a continuous flow to provide a reaction time of 6 hrs at 50oC. The temperature of the oil is then raised to 80oC and taken to a second retention tank to provide a retention time of 20 min, in a continuous flow. The oil is then passed through an Alfa Laval SRG 610 separator to separate aqueous phase, containing gums, from the oil and is subjected to the analysis of (a) phosphorous content of degummed oil, (b) phosphorous content of degummed and water washed oil (c) degumming losses, by collecting aqueous phase for 6 hours, stirring it well, taking representative samples, drying the samples, estimating the dry solid content of samples and (d) acetone soluble content of gum phase on dry basis. The results of analysis are tabulated and provided in the following Table 1.

Table 1
PARAMETER SET 1 SET 2 SET 3
FFA of crude Rice bran Oil (%) 6 5 22
Phosphorous content of crude rice bran oil (ppm) 500 350 225
Sediments (%) on dry basis. 0.1 0.1 0.2
STANDARD ENZYME DEGUMMING: (CONTROL)
Phosphorous content in degummed oil (ppm) 65-70 65-70 70-75
Phosphorous content in degummed and water washed oil (ppm) 40 35-40 45-50
Degumming Losses (% wt/wt of oil) 2.25 1.64 1.32
Acetone soluble content of gums on dry basis (%) 48-50 45-50 45-50
INSTANT INVENTION: (SAMPLE)
Phosphorous content of degummed oil (ppm) 40-45 35-40 45
Acetone soluble content of gums on dry basis (%) 35 30 30
Degumming losses (% wt/wt of oil) 1.28 0.84 0.71
Savings in oil losses (% wt/wt of oil) 0.97 0.8 0.61
Savings in effluent (lit/ton of oil) 75-100 75-100 75-100

[0038] In the above example, water wash is not performed thereby reducing the effluent flow and the resultant degumming losses.

Example 2
[0039] Crude rice bran oil of different levels of free fatty acids and phosphorous content as indicated in different samples viz., set1, set 2, set 3 and set 4 of table 2.0 is degummed in a commercial plant using continuous degumming process as follows: The oil is heated to 50oC through a heat exchanger and taken to a high shear mixer in which the following are added to the oil: (a) a commercial phospholipse A1, (Lecitase Ultra) at 55 gm per ton of oil (b) a commercially available Lysophospholipase, (Rohalase F) at 100 gm per ton of oil and (c) 2.5% on weight of oil of citrate buffer of pH 4.8 – 5.0. Both the enzymes and citrate buffer can also be mixed as single solution prior to addition to oil and added to the oil. The enzymes and the buffer are mixed with oil in the high shear mixer to provide intimate contact between oil and aqueous phase by dispersing the aqueous phase in the form of very fine droplets within oil phase. The enzyme containing oil is passed through a retention tank in a continuous flow to provide a reaction time of 6 hrs at 500C. The temperature of the oil is then raised to 80oC and taken to a second retention tank to provide a retention time of 20 min, in a continuous flow. Diatomite Filter aid manufactured by E.P.Minerals, is added to the oil at a dose of 0.25%. The oil is dried by passing through vacuum dryer and a spare bleacher available in the plant, to a moisture level of 0.1%. The oil is then filtered through filter containing spent bleaching earth obtained through bleaching of oil coming out of spent filter, by using fresh bleaching earth and carbon. The oil is then subjected to bleaching in a continuous bleacher at 95 0C for 30 min using 4.0% neutral bleaching earth and 0.2% activated carbon. Phosphoric acid (85%) is added in the bleacher at a level of 0.5 kg per ton of oil. The following analyses is done: (a) phosphorous content of degummed oil, (b) phosphorous content of degummed and water washed oil, (c) phosphorous content of bleached oil, (d) degumming losses - by collecting aqueous phase for 6 hr, stirring it well, taking representative samples, drying the samples and estimating the dry solid content of samples and (d) acetone soluble content of gum phase on dry basis. Degumming losses is calculated as the sum of (i) quantity of un-hydrolyzed gums (ii) sediments and (iii) quantity of oil adsorbed by filter aid. The results are tabulated in provided in the following Table 2.
Table 2
PARAMETER SET 1 SET 2 SET 3 SET 4
FFA of crude rice bran oil (%) 37 12 6 5
Phosphorous content of crude rice bran oil (ppm) 120 300 500 350
Sediments (%) on dry basis. 0.07 0.1 0.1 0.1
STANDARD ENZYME DEGUMMING (CONTROL):
Phosphorous content of degummed oil (ppm) 70 65-70 65-70 65-70
Phosphorous content of degummed and water washed oil (ppm) 50 35-40 35-40 35-40
Phosphorous content of bleached oil (ppm) 18 14 12 12
Degumming losses (% wt/wt of oil) 0.63 1.23 2.25 1.64
Acetone soluble content of gums on dry basis (%) 50 45-50 45-50 45-50
CURRENT INVENTION: (SAMPLE)
Phosphorous content of bleached oil (ppm) <3 <3 <3 <3
Degumming losses (% wt/wt of oil). 0.32 0.47 0.89 0.65
Savings in Oil loss (%) 0.32 0.76 1.36 0.98
Savings in Effluent (Lit / ton of oil) 175-200 175-200 175-200 175-200

Example 3
[0040] In the current invention, crude soybean oil and sunflower oils of different levels of free fatty acids and phosphorous content as shown in Table 3 are degummed in a commercial plant using continuous degumming process as follows: The oil is heated to 50 oC through a heat exchanger and taken to a high shear mixer in which the following are added to the oil: (a) a commercial phospholipse A1, Lecitase Ultra at 30 gm per ton of oil (b) a commercially available Lysophospholipase, Rohalase F at 50 gm per ton of oil and (c) 2.5% on weight of oil of citrate buffer of pH 4.8 – 5.0. Both the enzymes and citrate buffer can also be mixed as single solution prior to addition to oil and added to the oil. The enzymes and the buffer are mixed with oil in the high shear mixer, supplied by Kunal consultancy, to provide intimate contact between oil and aqueous phase by dispersing the aqueous phase in the form of very fine droplets within oil phase. The enzyme containing oil is passed through a retention tank in a continuous flow to provide a reaction time of 6 hrs at 50 0C. The temperature of the oil is then raised to 75 oC and taken to a second retention tank to provide a retention time of 20 min, in a continuous flow. Diatomite Filter aid manufactured by E.P.Minerals, is added to the oil at a dose of 0.25%. The oil is dried by passing through vacuum dryer and a spare bleacher available in the plant, to a moisture level of 0.1%. The oil is then filtered through filter containing spent bleaching earth obtained through bleaching of oil coming out of spent filter, by using fresh bleaching earth and carbon. The oil is then subjected to bleaching in a continuous bleacher at 95 0C for 30 min using 2.0% activated bleaching earth and 0.4% activated carbon. Phosphoric acid (85%) is added in the bleacher at a level of 0.5 kg per ton of oil.
[0041] The following analyses are done: (a) phosphorous content of bleached oil and (b) degumming losses, calculated as the sum of (i) quantity of left behind after hydrolysis and (iii) quantity of mass adsorbed by filter aid. The results are presented in Table 3.
Table 3
PARAMETER SOYBEAN OIL SUNFLOWER OIL
FFA of crude oil (%) 0.55 0.55 0.6 0.6 0.6
Phosphorous content of oil (ppm) 150 180 225 60 100
STANDARD ENZYME DEGUMMING (CONTROL):
Phosphorous content of degummed oil (ppm) 11 12 12 12 11
Acetone soluble content of gums on dry basis (%) 35-40 35-40 35-40 35-40 35-40
Degumming losses (% wt/wt of oil) 0.5 0.58 0.75 0.21 0.37
Phosphorous content of bleached oil (ppm) NIL NIL NIL NIL NIL
CURRENT INVENTION: (SAMPLE)
Phosphorous content of bleached oil (ppm) NIL NIL NIL NIL NIL
Adsorption losses through filter aid (%) 0.25 0.25 0.25 0.25 0.25
Savings in Oil loss (%) 0.25 0.32 0.50 NIL NIL
Savings in Effluent (Lit / ton of oil) 100-125 100- 125 100-125 100-125 100-125

Advantages of the present invention
[0042] By adopting the process steps of the present invention valuable fatty acids are recovered from gum molecules as high value byproducts, which are otherwise lost in traditional degumming processes; at least one molecule of fatty acid is lost from every gum molecule in standard enzyme degumming using either phospholipase A1 or phospholipase A2.
[0043] In the process steps of the present invention there are no oil losses during degumming.
[0044] In the process steps of the present invention Glycerophosphosphates are completely removed from the oil by adsorption on to filter aid and bleaching earth – even if the original gum content of the oil is 1.5%, on account of their extreme hydrophilicity and the resulting affinity to bleaching earth and filter aid. This will ensure that the degumming losses are substantially reduced and limited to the extent of oil absorbed by filter aid, there will be no liquid effluent coming out of refining process and there is no need to install or run expensive centrifuges, resulting in reduced power consumption, capital cost and operating cost.
[0045] The reduced oil losses in the degumming process of the present invention are in the range of 50-60%.
[0046] The effluent generation in degumming process is eliminated completely and at the same time, produces refined vegetable oil with high shelf stability.
[0047] In the light of the description of the preferred embodiments of the process of the present invention, it will be apparent to the experts in the art that many other features or improvements can be made, which can be considered within the scope of invention as determined by the following claims.

,CLAIMS:1. A process for the treatment of crude vegetable oil, comprising the steps of:
(a) hydrolyzing selected crude vegetable oil in the presence of an enzyme, in an aqueous medium, at a temperature, to remove phospholipids from the vegetable oil; and
(b) hydrolysing further in the presence of an enzyme and the use of filter aid to remove glycerophosphates, to obtain a refined vegetable with substantially reduced impurities.
2. The process as claimed in claim 1, wherein the vegetable oil is selected from the group consisting of rice bran oil, sunflower oil, soybean oil , mustard oil
3. The process as claimed in claim 1, wherein the initial hydrolysis is performed with pH in the range of about 4.5 to about 5.5.
4. The process as claimed in claim 1, wherein the temperature of the initial hydrolysis is in the range of 50-550C.
5. The process as claimed in claim 1, wherein the enzyme for the initial hydrolysis is selected from Phospholipase A1, Phospholipase A2 or a mixture thereof.
6. The process as claimed in claim 1, wherein the enzyme for further hydrolysis, is lysophospholipase.
7. The process as claimed in claim 1, wherein the temperature for the addition of filter aid is in the range of 75-800C.
8. The process as claimed in claim 1 or any one of the preceding claims, wherein the separation of gums/impurities from crude vegetable oil is performed without centrifugation.
9. The process as claimed in claim 1, wherein the phosphorous impurity in the refined vegetable oil is in the range of 0 to 3ppm.