Method of refining liquid oils

Abstract

The present invention relates to a method for refining liquid oil comprising a bleaching step of the liquid oil and the bleaching is taking place in presence of a bleaching agent wherein the bleaching agent is a combination of white clay and silica, wherein the white clay is acidic; the white clay and silica are added in a weight ratio of 2:0.6 to 4.5:6; and the white clay is added in an amount of from 1.5 to 4.5 wt.%, and the silica is added in an amount of from 0.5 to 5 wt.%; and the bleached oil obtained in this method. It relates to the use of a combination of white clay and silica as bleaching agent in a bleaching step of a liquid oil for improving the flavor of the liquid oil, preferably canola oil.

Description

PT-2314-WO[2]-PCTMETHOD OF REFINING LIQUID OILSCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of PCT Application No. PCT / CN2025 / 081720 filed March 11, 2025 which is incorporated by reference herein in its entirety.FIELD OF THE INVENTION

[0002] The present invention relates to a method of refining liquid oils.BACKGROUND

[0003] Crude oils, as extracted from their original source, are not suitable for human consumption due the presence of high levels of contaminants - such as free fatty acids, phosphatides, soaps and pigments - which may be toxic or may cause an undesirable colour, odour or taste. Crude oils are therefore refined before use. The refining process typically consists of three major steps: degumming, bleaching and deodorizing. An oil obtained after completion of the refining process (called a "refined oil") is normally considered suitable for human consumption and may therefore be used in the production of any number of foods and beverages.

[0004] There is still a need in the industry for developing a refining method that provides in liquid oils with improved flavor.

[0005] The current invention provides in such a method and the resulting product.SUMMARY

[0006] The present invention relates to a method for refining liquid oil comprising a bleaching step of the liquid oil and the bleaching is taking place in presence of a bleaching agent wherein the bleaching agent is a combination of white clay and silica, wherein the white clay is acidic; the white clay and silica are added in a weight ratio of 2:0.6 to 4.5:6; and the white clay is added in an amount of from 1.5 to 4.5 wt.%, and the silica is added in an amount of from 0.5 to 5 wt.%.

[0007] It further relates to a bleached liquid oil obtainable by the method of the present invention.PT-2314-WO[2]-PCT

[0008] Finally, it relates to the use of a combination of white clay and silica as bleaching agent in a bleaching step of a liquid oil for improving the flavor of the liquid oil.DETAILED DESCRIPTION

[0009] The present invention relates to a method for refining liquid oil comprising a bleaching step of the liquid oil and the bleaching is taking place in presence of a bleaching agent wherein the bleaching agent is a combination of white clay and silica wherein the white clay is acidic; the white clay and silica are added in a weight ratio of 2:0.6 to 4.5:6; and the white clay is added in an amount of from 1.5 to 4.5 wt.%, and the silica is added in an amount of from 0.5 to 5 wt.%.Bleaching Step

[0010] In the present invention, the bleaching step involves adding the bleaching agent to the liquid oil, followed by the bleaching in presence of the bleaching agent and subsequent removing the bleaching agent from the bleached liquid oil.

[0011] Bleaching is a process whereby impurities are removed to improve the color and flavor of the oil. It is typically performed prior to deodorization. The nature of the bleaching step will depend, at least in part, on the nature and quality of the oil being bleached. Generally, a crude or partially refined oil will be mixed with a bleaching agent which combines with oxidation products (e.g. peroxides), trace phosphatides, trace soaps, pigments and other compounds to enable their removal.

[0012] In an aspect of the invention, the bleaching is conducted at a temperature of from 95°C to 115°C, preferably from 100 to 110°C.

[0013] In an aspect of the invention, the bleaching is conducted for a time of 5 minutes to 60 minutes, preferably from 10 to 40 minutes.Liquid oil

[0014] In the present invention, the liquid oil is selected from the group consisting of cottonseed oil, corn oil, groundnut oil, linseed oil, olive oil, rapeseed oil, rice bran oil, sesame oil, safflower oil, soybean oil, sunflower oil, their corresponding high oleic varieties, and mixture of two or more thereof. More preferably, the vegetable oil is selected from the group consisting of rapeseed oil, sunflower oil, com oil, soybean oil, their corresponding high oleic varieties, and mixture of two or more thereof. The high oleic varieties are containing at leastPT-2314-WO[2]-PCT40%, at least 50%, at least 60%, at least 70% and preferably at least 80% oleic acid in respect of the fatty acid profile.

[0015] In an aspect of the invention, the liquid oil is selected from soybean oil, sunflower oil, canola oil, and a combination of two or more thereof; preferably the liquid oil is canola oil.

[0016] The term “canola oil” is also encompassing rapeseed oil (low erucic) and visa versa.

[0017] In one aspect, the liquid oil before being treated by the method of the present invention goes through a degumming, and neutralizing process. In one aspect, the liquid oil before being treated by the method of the present invention is a degummed and neutralized oil which has never gone through a previous bleaching step or a previous deodorizing step.Bleaching agent

[0018] In the present invention, white clay is used as part of the bleaching agent to adsorb and remove impurities, for example colouring matters from liquid oils.

[0019] In the present invention, beyond the white clay, also silica is used in the bleaching of liquid oils.

[0020] Silica is likewise used as the white clay as an adsorbent to remove impurities such as free fatty acids, trace metals, phospholipids, color bodies (like chlorophyll and carotene), and oxidation products from the oil.

[0021] The silica may amongst others also enhance the filtration performance when removing the bleaching agent from the bleached liquid oil.

[0022] The white clay is an acid activated clay. The white clay is acidic.

[0023] The white clay and silica are added in a weight ratio of 2:0.6 to 4.5:6.

[0024] The white clay is added in an amount of from 1.5 to 4.5 wt.%, preferably in an amount of from 2.0 to 4.0 wt.%, more preferably in an amount of from 2.5 to 3.0 wt.%.

[0025] The silica is added in an amount of 0.5 to 5 wt.%, more preferably the silica is added in an amount of from 0.75 to 4.5 wt.%, more preferably the silica is added in an amount of from 1.0 to 4.0 wt.%.

[0026] In an aspect of the invention, the white clay is added in an amount of from 2.5 to 3 wt.% and the silica is added in an amount of 0.8 to 4 wt.%.PT-2314-WO[2]-PCTDeodorization Step

[0027] In an aspect of the invention, the bleaching step of the claimed method is followed by a deodorization step.

[0028] Deodorization is a process whereby free fatty acids (FFAs) and other volatile impurities are removed by treating (or "stripping") a crude or partially refined oil with steam, nitrogen or other inert gases. The deodorization process and its many variations and manipulations are well known in the art.

[0029] For instance, deodorizers may be selected from any of a wide variety of commercially available systems, including both multi-chamber deodorizers (such as those sold by Krupp; De Smet Group; Gianazza Technology; Alfa Laval, or others) and multi-tray deodorizers (such as those sold by Krupp, DeSmet Group, S.A., and Crown Ironworks of the United States), and the like.

[0030] Deodorization is typically carried out at elevated temperatures and reduced pressure to better volatilize the FFAs and other impurities. The pressure, for instance, will preferably be no greater than 10 mm Hg but certain aspects may benefit from a pressure below or equal to 5 mm Hg, e.g. 1-4 mm Hg.

[0031] In an aspect of the invention, the deodorization step is conducted at a temperature of from 240°C to 270°C, preferably the deodorization is conducted at a temperature of from 245°C to 260°C.

[0032] In an aspect of the invention, the deodorization step is conducted for a time of from 30 minutes to 120 minutes, preferably the time is from 40 minutes to 60 minutes.Other Steps

[0033] In one aspect of the invention, the method comprises: a) optionally de-gumming liquid oil; b) neutralizing the degummed oil; c) bleaching the neutralized oil with the bleaching agent; and d) deodorizing the bleached oil.

[0034] It is to be understood that degumming an neutralization are process steps commonly known and performed in the refining of edible oils.Bleached liquid oil

[0035] The present invention related to a bleached liquid oil obtainable by the claimed method; preferably the bleached liquid oil is bleached canola oil.PT-2314-WO[2]-PCT

[0036] Without being bound by any explanation and / or theory, the bleached liquid oil is having an improved flavor compared with a bleached liquid oil obtainable by a common bleaching process.

[0037] In an aspect of the invention, the bleached oil is deodorized.

[0038] In an aspect of the invention, the bleached, deodorized liquid oil, preferably bleached, deodorized canola oil is having an improved flavor compared with a bleached, deodorized liquid (canola) oil obtainable by a common bleaching process.

[0039] It has been shown that the claimed product has a better flavor in respect of astringency, oiliness, oxidized flavor and / or grassy flavor.

[0040] Astringency relates to the astringent sensation on the mouth surface upon contacting the product, and described as commonly found in raw bananas, persimmons, tea and the like.

[0041] Oiliness relates to the fresh or heat-process fat / oil aroma, excluding the rancid odor.

[0042] Oxidized flavor involves the unpleasant flavor obtained by oxidation of the oil.

[0043] Grassy flavor relates to the flavor of green leaves, freshly cut grass, vegetables such as edamame beans.Food Product

[0044] A food product comprising the claimed bleached liquid oil.

[0045] In an aspect of the invention the food product is comprising the claimed bleached, deodorized oil, preferably canola oil.

[0046] In an aspect of the invention, the claimed food product is having an improved flavor due to the presence of the claimed liquid oil, preferably the claimed canola oil.

[0047] In an aspect the claimed oil is present in an amount of from 5 to 90 wt.% based upon the weight of the food product.Use

[0048] The present invention relates to the use of a combination of white clay and silica as bleaching agent in a bleaching step of a liquid oil for improving the flavor of the liquid oil, preferably the liquid oil is canola oil.

[0049] The white clay and silica are added in a weight ratio of 2:0.6 to 4.5:6.PT-2314-WO[2]-PCT

[0050] In an aspect of the invention, the white clay is used in an amount of from 2.5 to 3 wt.% and the silica is added in an amount of 0.8 to 4 wt.%.AdvantagesThe combination of white clay and silica in the bleaching step of liquid oil, preferably canola oil is beneficial for the flavor of the liquid oil.The best results are obtained with combining acidic white clay and silica.The subsequent deodorization can help improving the flavorthe temperature of the deodorization step is selected to improve the flavor and reducing / avoiding and / or keeping controlled the formation of trans fatty acids.EXAMPLESSensory Panel

[0051] A panel of 14 trained and qualified members was used for the evaluation of the different samples. They have been trained with different training techniques, such as quantitative descriptive analysis (QDA), temporal dominance of sensations (TDS) and discrimination tests.

[0052] The following descriptive terms were used to qualify the sensory properties of the samples.Table 1PT-2314-WO[2]-PCTBleaching Conditions:

[0053] The bleaching was conducted at 105°C for 30 minutes. The starting material for each of the bleaching tests was neutralized canola oil. The used bleaching agent is shown in Table 2.Table 2Deodorization conditions

[0054] After the bleaching step, the samples were deodorized in presence of 1% of nitrogen, at a temperature of 250°C for 45 minutes.PT-2314-WO[2]-PCTExamples 6 & 7

[0055] The influence of the deodorization temperature was tested by conducting the deodorization at temperatures 240°C, 250°C and 260°C.

[0056] Prior to these tests, the neutralized canola oil was bleached at 105°C for 30 minutes in presence of 3% acidic white clay (yu shan) and 4% silica.Table 3

[0057] The sensory evaluation of the examples and comparative examples as well as the content of trans fatty acids is provided in tables 4 to 9.Table 4: Overall PurityPT-2314-WO[2]-PCT

[0058] Overall flavor: (Oils with the cleanest flavor are rated 10, while those with the richest oil flavor are rated 0).Table 5: Overall Flavor IntensityTable 6: astringencyPT-2314-WO[2]-PCTTable 7: oxidized flavorTable 8: OilinessPT-2314-WO[2]-PCTTable 9

Claims

PT-2314-WO[2]-PCTCLAIMS1. A method for refining liquid oil comprising a bleaching step of the liquid oil and the bleaching is taking place in presence of a bleaching agent wherein the bleaching agent is a combination of white clay and silica,wherein the white clay is acidic;the white clay and silica are added in a weight ratio of 2:0.6 to 4.5:6; andthe white clay is added in an amount of from 1.5 to 4.5 wt.%, and the silica is added in an amount of from 0.5 to 5 wt.%.

2. The method according to anyone of the preceding claims wherein the bleaching is conducted at a temperature of from 95°C to 115°C.

3. The method according to anyone of the preceding claims wherein the bleaching is conducted for a time of from 5 minutes to 60 minutes.

4. The method according to anyone of the preceding claims wherein the bleaching step is followed by a deodorization step.

5. The method according to claim 4 wherein the deodorization step is conducted at a temperature of 240°C to 270°C.

6. The method according to claim 4 or 5 wherein the deodorization step is conducted for a time of from 30 minutes to 120 minutes.

7. A bleached liquid oil obtainable by the method according to anyone of the preceding claims.

8. The liquid oil according to claim 7 wherein the bleached oil is deodorized.

9. The liquid oil according to claim 7 or claim 8 wherein the liquid oil is canola oil.PT-2314-WO[2]-PCT10. A food product comprising the bleached liquid oil according to anyone of claims 7 to 9.

11. Use of a combination of white clay and silica as bleaching agent in a bleaching step of a liquid oil for improving the flavor of the liquid oil.

12. The use wherein the liquid oil is canola oil.

Images