WO2023108366A1

WO2023108366A1 - A method for delaying clouding of palm-containing oil and an edible oil prepared according thereto

Info

Publication number: WO2023108366A1
Application number: PCT/CN2021/137548
Authority: WO
Inventors: Zhenyu Zhao; Zhukun MA; Weilin XUE; Junyin CHEN
Original assignee: Cargill, Incorporated
Priority date: 2021-12-13
Filing date: 2021-12-13
Publication date: 2023-06-22

Abstract

The method for delaying clouding of an oil comprising palm oil and/or a palm oil derivative. The method includes: providing the oil comprising palm oil and/or a palm derivative; providing a mineral adsorbent, wherein the mineral adsorbent is white clay; adding, to the oil, equal to or greater than about 0.6wt% and less than about 1.0wt% the mineral adsorbent, by weight of the oil; bleaching the oil in the presence of the mineral adsorbent at from about 100 ℃ to about 110 ℃ for about 30-50 minutes at a pressure of about less than about 100 mbar; removing the mineral adsorbent from the bleached oil; deodorizing the bleached oil at from about 220 ℃ to about 245 ℃ for from about 25 to about 45 minutes at a pressure of about less than 10 mbar, wherein the deodorized oil has a color of between Y13R1.3 and Y35R3.5 by Lovibond ^TM Colorimeter with a cuvette unit size of 133.4 mm.

Description

A Method for Delaying Clouding of Palm-containing Oil and an Edible Oil Prepared According Thereto

Field of the Invention

The present invention generally relates to the technical field of edible oils, and more specifically to a method for improving the clouding of an edible oil comprising palm oil or a palm oil derivative.

Background of the Invention

Palm oil is the oil extracted from the fruit of the oil palm tree. It is the most widely consumed oil in the world, and finds its applications in various technical fields, from food and personal-care products to biofuel.

Palm oil has a unique fatty acid profile, having approximately 50%saturated fatty acids and 50%unsaturated fatty acids. Due to such a fatty acid profile, palm oil has a high smoke point and is naturally stable against oxidative deterioration. Furthermore, it does not have a strong flavor. As such, it is particularly suitable for use as a cooking or frying oil. However, due to the presence of a high amount of saturated fatty acids, palm oil is prone to clouding when stored at room temperature in cold weather, which affects consumer perception of the oil’s quality.

Clouding of palm oil or a palm oil derivative refers to the process of crystallization and precipitation of high melting saturated fatty acids and derivatives thereof contained in the oil. The precipitated crystals result in a hazy or cloudy appearance of the oil, which consumers may perceive as an indication of quality deterioration. As such, extensive research has been done to study the crystallization behavior of palm oil, to prevent or delay the clouding of palm oil or its derivative during storage for quality control purposes.

For instance, scientists found that the presence of diacylglycerols in high concentration inhibits nucleation and slows down crystal growth of certain ingredients in palm oil. Also, sorbitan esters as additives were found to inhibit palm oil crystallization.

Scientists also conducted studies on the impact of the refining process has on the crystallization behavior of palm oil. In a study on 10 degree palm oil, scientists found that many parameters for the refining process play a key role in the crystallization behavior of 10 degree palm oil. Specifically, deodorization temperature, deodorization duration and the amount of white clay for the bleaching step were all found to be relevant factors.

The degree of palm oil refers to its melting point. The term “10 degree palm oil” refers to palm oil which is liquid at 10 ℃ or higher and solidifies below 10 ℃. In the food industry, palm oil of 24 degree or below is usually used as cooking oil or raw material for food products such as cookies and instant noodles. In general, the lower the degree of palm oil is, the higher the cost will be. As such, 14 degree and 18 degree palm oil are more often used given the balance between their melting points and production costs in the food industry.

The crystallization behavior of palm oil is expected to vary as its melting point changes, due to the changes in palm oil’s composition.

Currently, the measures taken to prevent or delay the clouding of 14 degree or 18 degree palm oil or a palm oil containing blended oil includes: reducing the content of 14 degree and/or 18 degree oil in the blended oil; increasing the content of non-palm oil in the blended oil; using palm oil of lower degrees instead; maintaining storage temperature above clouding points; suspending delivery at low temperature; and/or increasing stock turnover rate. However, these measures either increase costs, or depend on the coordination of the purchasing side, which the supplying side of oils has little or no control.

As such, there still exists the need for methods of inhibiting or delaying the clouding of 14 degree, 18 degree palm oil and/or a derivative thereof.

Summary of the Invention

An aspect of the present invention relates to a method for delaying clouding of an oil comprising palm oil and/or a palm oil derivative. The method includes: providing the oil comprising palm oil and/or a palm derivative; providing a mineral adsorbent, wherein the mineral adsorbent is white clay; adding, to the oil, equal to or greater than about 0.6wt%and less than about 1.0wt%the mineral adsorbent, by weight of the oil; bleaching the oil in the presence of the mineral adsorbent at from about 100 ℃ to about 110 ℃ for about 30-50 minutes at a pressure of about less than about 100 mbar; removing the mineral adsorbent from the bleached oil; deodorizing the bleached oil at from about 220 ℃ to about 245 ℃ for from about 25 to about 45 minutes at a pressure of less than about 10 mbar to produce a deodorized oil, wherein the deodorized oil has a color of between Y13R1.3 and Y35R3.5 by LovibondTM Colorimeter with a unit cuvette size of 133.4 mm.

Another aspect of the present invention relates to an edible oil prepared by a method according to the present invention.

A further aspect of the present invention relates to use of an edible oil prepared according to the present invention. Such use includes, but not limited to, cooking, baking and/or mixing with another edible ingredient.

A yet further aspect of the present invention relates to the use of bleaching in the presence of equal to or greater than 0.6wt%and less than 1.0wt%white clay followed by deodorization at 220 ℃ to about 245 ℃ for delaying the clouding of palm oil or a palm oil derivative.

Without intending to be bound by theory, it is believed that the present invention provides a method of effectively delaying clouding of palm oil or a palm oil derivative. Such a method may be readily applicable to the current production line of palm oil or a palm oil derivative without requiring modifications to the production equipment. As such, the present invention is believed to be capable of improving the quality of palm oil or a derivative thereof while maintaining the production costs low.

Detailed Description of the Invention

Unless otherwise noted, all measurements, weights, lengths etc. are in metric units, and all temperatures are in degrees Celsius. It is understood that unless otherwise specifically noted, the materials compounds, chemicals, etc. described herein are typically commodity items and/or industry-standard items available from a variety of suppliers and sources worldwide.

As used herein, the term “palm oil derivative” refer to any acid, ester or alcohol derived from palm oil in pure form or in mixture. They include, but not limited to, palm stearin and/or palm olein.

As used herein, the term “X degree palm oil” refers to palm oil having a melting point of X ℃. For instance, “14 degree palm oil” refers to palm oil with a melting point of 14 ℃.

As used herein, the term "white clay" refers to any substance having the mineral montmorillonite as the main component. It includes naturally occurring acidic white clay and acid activated white clay, which is produced by treating acidic white clay with an inorganic acid such as sulfuric acid.

As used herein, the term “cloud point” refers to the temperature at which the first crystal formation starts in an oil. To delay clouding in the context of the present invention refers to postponing the onset of crystal formation and/or decrease the amount of crystals formed at or below cloud point.

An aspect of the present invention relates to a method for delaying clouding of an oil comprising palm oil and/or a palm oil derivative. The method includes: providing the oil comprising palm oil and/or a palm derivative; providing a mineral adsorbent, wherein the mineral adsorbent is white clay; adding, to the oil, equal to or greater than about 0.6wt%and less than about 1.0wt%the mineral adsorbent, by weight of the oil; bleaching the oil in the presence of the mineral adsorbent at from about 100 ℃ to about 110 ℃ for about 30-50 minutes at a pressure of about less than about 100 mbar; removing the mineral adsorbent from the bleached oil; deodorizing the bleached oil at from about 220 ℃ to about 245 ℃ for from about 25 to about 45 minutes at a pressure of less than about 10 mbar to produce a deodorized oil, wherein the deodorized oil has a color of between Y13R1.3 and Y35R3.5 by Lovibond ^TM Colorimeter with a unit cuvette size of 133.4 mm.

In general, a refined palm oil should have a color of between Y13R1.3 and Y35R3.5 by Lovibond ^TM Colorimeter with a unit cuvette size of 133.4 mm for visual appeal to consumers. Preferably, the palm oil may have a color of Y13R1.3 and Y33R3.3.

To quantify the cloudiness of the refined palm oil, the respective solid fat content (SFC) is tested at various time points during a cold-water bath experiment at 5℃. A refined oil obtained with the method of the present invention shows no SFC content at 5℃ after 5 minutes. The cloudiness delay can be followed by measuring the SCF content at 5℃ after 10 minutes, 15 minutes, 20℃ and 25℃.

In a specific example, the mineral adsorbent is removed by filtration. A person skilled in the art would understand that other techniques may be utilized for the removal of the mineral adsorbent, such as centrifugation.

In an aspect of the present invention, the white clay has a pH of about 2.2-4.8. The white clay may be naturally occurring acidic white clay or acid activated white clay. In certain situations, it is believed that acid activated white clay is preferable to naturally occurring acidic white clay, in terms of, for instance, pigment removal and impurity adsorption.

In another aspect, the white clay is added in an amount of from about 0.65wt%to about 0.95wt%; or from about 0.7wt%to about 0.9wt%, by weight of the oil. Specifically, the white clay may be added in an amount of about 0.60wt%, 0.65wt%, 0.70wt%, 0.75wt%, 0.80wt%, 0.85wt%, 0.90wt%or 0.95wt%, by weight of the oil.

Without intending to be bound by theory, it is believed that the amount of white clay used in the bleaching step impacts the clouding behavior of palm oil and its derivatives. Specifically, it is believed that the more white clay is used in the bleaching step, the more likely the palm oil or a derivate thereof is to cloud at a given temperature equal to or below its cloud point. The inventors of the present invention believe this is because the residual white clay in the palm oil or its derivative could serve as crystal nuclei at the onset of crystal formation, thereby accelerating precipitation of crystals to bring about cloudiness.

In an aspect of the present invention, the bleaching step is conducted at from about 100 ℃ to about 109 ℃; or is conducted at from about 100 ℃ to about 107 ℃; or is conducted at from about 100 ℃ to about 106 ℃; or is conducted at from about 100 ℃ to about 105 ℃. In another aspect, the bleaching step is conducted for a period of from about 15 minutes to about 45 minutes; or from about 20 minutes to about 40 minutes.

Without intending to be limited by theory, it is believed that a bleaching temperature and bleaching duration within the aforementioned ranges do not have a substantial impact on the clouding behavior of the palm oil or palm oil derivative. However, bleaching conducted at a higher temperature for a longer period of time may lead to increased formation of trans fatty acids, which is believed to contribute to the clouding of palm oil or a palm oil derivative due to their high melting points. It is also believed that higher temperature and longer duration could lead to reduced oxidative stability. As such, it is preferable for the bleaching step to take place at the aforementioned temperature range for the aforementioned duration.

In an aspect of the present invention, the deodorizing step is conducted at from about 230 ℃ to about 240℃; or is conducted at from about 233 ℃ to about 237 ℃. In another aspect of the present invention, the deodorizing of the bleached oil is conducted for a period of from about 30 minutes to about 40 minutes; or from about 33 minutes to 37 minutes.

Without intending to be bound by theory, it is believed that the temperature and duration of the deodorizing step impact the clouding behavior of palm oil or a palm oil derivative. Specifically, it is believed that for a given deodorizing duration, the higher the deodorizing temperature is, the more likely the palm oil or palm oil derivative is to cloud at a given temperature around or below its cloud point. It is also believed that at a given deodorizing temperature, the longer the deodorizing duration is, the more likely the palm oil or palm oil derivative is to cloud around or below its cloud point. This is because heating at a high temperature for a long period of time will increase the formation of trans fatty acids, which tend to crystallize and precipitate due to their high melting points. However, a balance should be drawn between the removal of the volatile ingredients, preventing formation of trans fatty acids and maintaining production costs low. It is believed that such a balance is struck by the aforementioned ranges of the deodorizing temperature and duration.

In an aspect of the present invention, the oil subject to the refining process according to the present invention is palm oil, palm stearin, palm olein or a combination thereof. In a specific example, the palm oil is 14 degree palm oil, 18 degree palm oil, or a combination thereof. It is believed that the present invention is particularly suitable for refining 14 degree palm oil and/or 18 degree palm oil, effectively delaying the clouding thereof.

In an aspect of the present invention, the obtained oil obtained according to the present invention is blended with an additional oil that is not palm oil. For instance, the additional oil may be derived from a plant source, from an animal source, and/or from a microorganism source.

Specifically, the additional oil derived from a plant source may be selected from the group consisting of coconut oil, corn oil, canola oil, cottonseed oil, olive oil, palm oil, peanut oil, rapeseed oil, safflower oil, sesame oil, soybean oil, sunflower oil, almond oil, beech nut oil, brazil nut oil, cashew oil, hazelnut oil, macadamia oil, mongongo nut oil, pecan oil, pine oil, pistachio oil, walnut oil, pumpkin seed oil, grapefruit seed oil, lemon oil, orange oil, bitter gourd oil, bottle gourd oil, buffalo gourd oil, butternut squash seed oil, egusi seed oil, watermelon seed oil, acai oil, black seed oil, blackcurrant seed oil, borage seed oil, evening primrose oil, flaxseed oil, amaranth oil, apricot oil, apple seed oil, argan oil, avocado oil, babassu oil, ben oil, borneo tallow nut oil, cape chestnut oil, carob pod oil, cocklebur oil, cohune oil, coriander seed oil, date seed oil, dika oil, false flax oil, grape seed oil, kapok seed oil, kenaf seed oil, lallemantia oil, mafura oil, marula oil, meadowfoam seed oil, mustard oil, niger seed oil, nutmeg butter, okra seed oil, papaya seed oil, perilla seed oil, persimmon seed oil, pequi oil, pili nut oil, pomegranate seed oil, poppyseed oil, pracaxi oil, virgin pracaxi oil, prune kernel oil, quinoa oil, ramtil oil, rice bran oil, royle oil, sacha inchi oil, sapote oil, seje oil, shea butter, taramira oil, tea seed oil, thistle oil, tigernut oil, tobacco seed oil, tomato seed oil, wheat germ oil and a combination of two or more thereof. More specifically, the obtained oil may be blended with one or more oils selected from soybean oil, rapeseed oil, corn oil and sunflower oil.

The additional oil derived from an animal source may be derived from a fish, a pig, a chicken, a cow, a duck, a goose, and a combination thereof; or from cheese, butter, milk and a combination thereof.

The additional oil derived from a microorganism source may be derived from a bacteria, a yeast, a fungus and/or an algae, and a combination of two or more thereof. For instance, oils produced by Mortierella alpina, Crypthecodinium cohnii and Schizochytrium spp may be used.

In a specific example, the obtained oil may be blended with rapeseed oil, sunflower oil, and/or soybean oil for frying. It may also be blended with one or more other high smoke point oils for serving as cooking or frying oils. The refined oil may also be blended with one or more non-palm oils in solid state for formulation of margarine. Furthermore, the refined oil may also be blended with an oil of an animal source, such as fish oil, as animal feeds.

Another aspect of the present invention relates to an edible oil prepared by a method according to the present invention. In an aspect, the edible oil is blended with an additional oil that is not palm oil. As discussed above, the non-palm oil may be an oil derived from a plant source, an animal source and/or a microorganism source. Specific examples include one or more oils selected from soybean oil, rapeseed oil, corn oil and sunflower oil.

A further aspect of the present invention relates to use of an edible oil prepared according to the present invention, for instance, for cooking, baking and/or mixing with another edible ingredient.

A yet further aspect of the present invention relates to use of bleaching in the presence of equal to or greater than 0.6wt%and less than 1.0wt%white clay followed by deodorization at 220 ℃ to about 245 ℃ for delaying the clouding of palm oil or a palm oil derivative. Such an oil is preferably palm oil.

Without intending to be bound by theory, it is believed that the present invention may be readily applied to the production line of palm oil or a palm oil derivative, without the need for modifying existing apparatus. For instance, the present invention may be easily incorporated into a production line comprising one or more following steps: degumming the oil before bleaching; neutralizing the oil before the bleaching step; centrifugation before the bleaching step; water-wash before the bleaching step; and drying before the bleaching step.

It is found that palm oil of 14 degree or 18 degree refined according to the present invention may remain clear after one week storage at 25 ℃ (indoor, air conditioned) in the summer time. It is also found that such oil may remain clear after one week of storage at 14 ℃ (outdoor) in the winter time.

Without intending to be bound by theory, it is believed that the present invention can increase the amount of palm oil and/or derivative thereof in blended oils without compromising consumer satisfaction. The current practice is to decrease the use of palm oil and/or derivative thereof in order to avoid consumer complaints on cloudiness, especially in winter time. By way of the present invention, it is believed that more palm oil and/or derivative thereof may be added to blended oil even in the winter time, thereby substantially lowering the production costs of blended oils.

Indeed, it is found that a blended oil may contain as much as 99wt%palm oil or derivative according to the present invention in the summer time without increasing the cloudiness tendency of the blended oil. It is also found that more palm oil (e.g., 50wt%-86wt%) according to the present invention may be added to a blended oil in the winter time without causing clouding.

EXAMPLES

Experiments are conducted to investigate the impact of various parameters for the refining process of 14 degree and 18 degree palm oil. In all experiments, the color of the refined oil is assessed by Lovibond ^TM Colorimeter after refinement and before bringing the oil in a cold water bath for measurement of clouding behavior. The refined palm oil is subject to cold water bath for testing its clouding behavior.

Example 1

Experiments are conducted to test the effects of the amount of white clay, the deodorizing temperature and deodorizing duration on the clouding behavior of 18 degree palm oil. The experimental results are summarized as follows.

Table 1. Clouding Study of 18 Degree Palm Oil

It can be seen from the above that the 18 degree palm oil refined according to the refining process of the present invention only starts to display cloudiness after being placed in the cold water bath for 15 minutes.

Example 2

Further experiments are conducted to investigate the impact of various white clay amounts on the clouding tendency of 18 degree palm oil where the deodorizing temperature and duration are the same

Table 2. Clouding Study on Impact of Various White Clay Amounts

It can be seen from the above that batch B delivers the best performance in delaying clouding compared to comparative example 1 and batch C. It can be determined that where other bleaching and deodorization parameters are the same, the more white clay used for bleaching, the more likely the deodorized palm oil is to cloud. Both batches B and C deliver better performance than the comparative example 1 in terms of delayed cloudiness.

Example 3

Further experiments are conducted to explore the impact of deodorization duration and white clay amount on the clouding tendency of 14 degree palm oil.

Table 3. Clouding Study of 14 Degree Palm Oil

It can be seen from the above that batch D only becomes slightly hazy after being placed in the cold water bath for 20 minutes. As is the case with 18 degree palm oil, the refining process of the present invention effectively delays the clouding of 14 degree palm oil as well.

Example 4

Further experiments are conducted to study the impacts of various experimental parameters of the refining process on the clouding behavior of 18 degree palm oil. The results are summarized below in Table 4.

Table 4. Clouding Study on Impacts of Various Experimental Parameters

It can be seen from the above that batch F performs the best in terms of cloudiness delay, and the comparative example 2 is the cloudiest among all three samples throughout the cold water bath experiment. To quantify the cloudiness of the samples, their respective solid fat content (SFC) is tested at various time points during the same cold water bath experiment, and the results are summarized in Table 5.

Table 5. SFC of Comparative Example 2, Batch E and F during Cold Water Bath Experiment

As shown by the SFC content of comparative example 2, batch E and batch F throughout the 5 ℃ cold water bath experiment, the comparative example 2 displays solid fat precipitates after being placed in the cold water bath for 5 minutes, whilst batches E and F have no precipitates at all at the same time point. Further, both batches E and F have SFC values substantially smaller than those of the comparative example throughout the cold water bath experiment. As such, both bathes E and F, which are refined according to the refining process of the present invention, perform substantially better in terms of cloudiness delay than the comparative example 2.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the embodiments of the invention belong. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

While the disclosure has been described with reference to an exemplary embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the disclosure. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the disclosure without departing from the essential scope thereof. Therefore, it is intended that the disclosure not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this disclosure, but that the disclosure will include all embodiments falling within the scope of the appended claims.

All references specifically cited herein are hereby incorporated by reference in their entireties. However, the citation or incorporation of such a reference is not necessarily an admission as to its appropriateness, citability, and/or availability as prior art to/against the present invention.

Claims

A method for delaying clouding of an oil comprising palm oil and/or a palm derivative, comprising:

(A) providing the oil comprising palm oil and/or a palm derivative;

(B) providing a mineral adsorbent, wherein the mineral adsorbent is white clay;

(C) adding, to the oil, equal to or greater than about 0.6wt%and less than about 1.0wt%the mineral adsorbent, by weight of the oil;

(D) bleaching the oil in the presence of the mineral adsorbent at from about 100 ℃ to about 110 ℃ for about 30-50 minutes at a pressure of about less than about 100 mbar;

(E) removing the mineral adsorbent from the bleached oil;

(F) deodorizing the bleached oil at from about 220 ℃ to about 245 ℃ for from about 25 to about 45 minutes at a pressure of less than about 10 mbar to produce an deodorized oil,

wherein the deodorized oil has a color of between Y13R1.3 and Y35R3.5 as measured by Lovibond Colorimeter with a unit cuvette size of 133.4 mm.
The method according to claim 1, wherein the white clay has a pH of from about 2.2 to about 4.8.
The method according to claim 1 or 2, wherein the mineral adsorbent is from about 0.65wt%to about 0.95wt%; or from about 0.7wt%to about 0.9wt%, by weight of the oil; or in an amount of about 0.60wt%, 0.65wt%, 0.70wt%, 0.75wt%, 0.80wt%, 0.85wt%, 0.90wt%or 0.95wt%, by weight of the oil.
The method according to any one of the preceding claims, wherein the bleaching step is conducted at from about 100 ℃ to about 109 ℃; or is conducted at about 100 ℃ to about 108 ℃; or is conducted at about 100 ℃ to about 107 ℃; or is conducted at about 100 ℃ to about 106 ℃; or is conducted at about 100 ℃ to about 105 ℃.
The method according to any one of the preceding claims, wherein the bleaching of the oil is conducted for a period of from about 15 minutes to about 45 minutes; or from about 20 minutes to about 40 minutes.
The method according to any one of the preceding claims, wherein deodorizing step is conducted at from about 230 ℃ to about 240℃; or is conducted at from about 233 ℃ to about 237 ℃.
The method according to any one of the preceding claims, wherein the deodorizing of the bleached oil is conducted for a period of from about 30 minutes to about 40 minutes; or from about 33 minutes to 37 minutes.
The method according to any one of the preceding claims, wherein the oil is selected from the group consisting of palm oil, palm stearin, palm olein and a combination thereof; or the oil is palm oil; or the oil is selected from the group consisting of 14 degree palm oil, 18 degree palm oil and a combination thereof.
The method according to any one of the preceding claims, further comprising the step of blending the obtained oil with an additional oil, wherein the additional oil is not palm oil.
An edible oil prepared by a method according to any one of the preceding claims.
The edible oil according to claim 10, wherein the obtained oil remains clear after being stored at a temperature of about 14 ℃ for a week.
Use of an edible oil according to claim 10 or 11, wherein the use is selected from the group consisting of cooking, baking, mixing with another edible ingredient and a combination thereof.
Use of bleaching in the presence of equal to or greater than 0.6wt%and less than 1.0wt%white clay followed by deodorization at 220 ℃ to about 245 ℃ for delaying the clouding of palm oil or palm oil derivatives, preferably palm oil.
The use according to claim 13, wherein the palm oil or palm oil derivative remain clear after being stored at a temperature of about 14 ℃ for a week.