Organic compounds -- part of the class 532-570 series – Organic compounds – Fatty compounds having an acid moiety which contains the...
Reexamination Certificate
1999-08-09
2001-10-23
Carr, Deborah D. (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Fatty compounds having an acid moiety which contains the...
C554S211000
Reexamination Certificate
active
06307077
ABSTRACT:
FIELD OF THE INVENTION
This invention generally relates to a method of purifying oils. More specifically this invention is directed to a method of purifying a vegetable oil to provide a clarified vegetable oil.
BACKGROUND OF THE INVENTION
Vegetable oils find a wide variety of uses in consumer products including use as food additives, lubricants, solvents and coating additives. Most applications require refined vegetable oil that is essentially colorless to light yellow and free from insoluble material. Generally, vegetable oil is obtained by dry extruding vegetables, for example, vegetable seeds, in a friction extruder-usually at a temperature of greater than 130° C. to provide a semi-fluid extrudate. Then the semi-fluid extrudate is processed in a screw press to yield a crude vegetable oil and a solid or semi-solid vegetable meal, which is separated from the crude vegetable oil. Despite this initial separation, the crude vegetable oil still contains a variety of suspended insoluble solids. The suspended insoluble solids include semi-solid or gummy material that can be particularly difficult to remove by typical mechanical separation means. The insoluble solids do not readily precipitate from the crude oil. Attempts to filter out the insoluble solids present problems because the semi-solid and/or gummy material clogs the filter medium.
In an effort to address these problem, in the past crude oil has been refined using a solvent extraction process. In a solvent extraction process the crude oil is extracted with an organic solvent, for example, a mixture of hexanes. The organic solvent absorbs greater than 90% of the seed oils. The extract can be filtered, if necessary, to remove any particulate and/or insoluble matter. After filtering, the solvent is removed, typically by evaporation, to provide a partially refined vegetable oil, which can be used in many commercial products or further processed if desired.
While solvent extraction provides a process for refining vegetable oil, this process presents some significant problems. Along with the insoluble material, many of the beneficial, natural nutrients such as antioxidants and vitamins are removed from the vegetable oil. Both the extracted oil and solid material inevitably contain residual hexanes. Hexanes are toxic to humans and other animals and must be removed before the resulting oil and solid material are suitable for consumption by humans and other animals. While the hexanes are recycled for reuse, inevitably a significant amount of hexanes escape into the atmosphere and contribute to environmental pollution. In addition, hexane is an extremely flammable solvent and, therefore, presents a significant risk to fire and explosions. It is desirable to provide an alternative process for purifying vegetable oil.
Thus, there is a need to provide a process for purifying vegetable oils that avoids the problems described above. The present invention addresses this need in a novel and nonobvious way.
SUMMARY OF THE INVENTION
Accordingly, there is provided in accordance with the present invention a novel process for purifying a vegetable oil. In one form, the process removes insoluble material from crude vegetable oil. The process comprises the steps of maintaining the crude oil at a temperature below about 10° C.; heating the crude oil to a temperature sufficient to provide an amount of substantially clarified oil; and drawing off the substantially clarified oil. In preferred embodiments the vegetable oil is cooled to a temperature to induce the insoluble material to agglomerate and to form larger masses of insoluble material. More preferably, the crude oil is cooled to a temperature between about 5° C. and about 0° C. The vegetable oil may be maintained at this cold temperature for a selected amount of time, preferably between about 1 hour and about 8 hours. After the vegetable oil has been cooled, typically the oil is rapidly heated to induce the insoluble material to precipitate. In preferred embodiments, the vegetable oil is heated to a temperature between about 50° C. and about 80° C. A wide variety of crude vegetable oils can be processed according to this invention. For example, the vegetable oil can be selected from soybean oil, sunflower oil, safflower oil, corn oil, sesame oil, rapeseed oil, linseed oil, cottonseed oil, rice bran oil, perilla oil, castor oil, olive oil, tsubaki oil, coconut oil, palm oil, perilla oil, hemp seed oil, tung oil, kapok oil, tea seed oil and mixtures thereof This invention provides a clarified vegetable oil, which can be readily separated from the solid particles.
In yet another embodiment of the present invention, there is provided a process for purifying a vegetable oil composition containing insoluble matter. The process comprises cooling the vegetable oil to a temperature below about 10° C.; maintaining for a time to obtain agglomeration; heating to a temperature above about 50° C. to provide a clarified vegetable oil capable of being separated from the insoluble material; and drawing off the substantially clarified vegetable oil.
Further objects, features, aspects, forms, advantages and benefits shall become apparent from the description contained herein.
DETAILED DESCRIPTION OF THE INVENTION
For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated herein and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended. Any alterations and further modifications in the described processes, systems or devices, and any further applications of the principles of the invention as described herein, are contemplated as would normally occur to one skilled in the art to which the invention relates.
In general the present invention provides an improved process for purifying vegetable oil. The process provides clarified oil that is substantially free of insoluble material. The resulting clarified oil is useful for a variety of applications and can be included in a food additive, a solvent, a lubricant, a diluent, a coating additive or further purified in a subsequent downstream process. In one form, the process provides the clarified oil without requiring solvent extraction of the crude oil. In another form, the present invention refines the oil by removing insoluble material. This process uses minimal mechanical manipulations, and decreases production time, cost, and harm to the environment, while still providing a refined oil that is substantially free of insoluble material.
The process is useful to purify a wide variety of oils, including oils obtained from vegetables, preferably seed vegetables. Typically, but not required, the crude oil processed using the present invention is received directly from an extractor and/or extruding process. The vegetable oil can be crude oil or it can be partially processed oil in need of further refining. It is to be understood that oil from any source is potentially useful with the present invention.
As has been mentioned, the vegetable oil for use in the present invention can be derived from a wide variety of vegetables, primarily, but not exclusively vegetable seeds. Typical examples of vegetable oils for use with this invention include soybean oil, sunflower oil, safflower oil, corn oil, sesame oil, rapeseed oil, linseed oil, cottonseed oil, rice bran oil, perilla oil, castor oil, olive oil, tsubaki oil, coconut oil, palm oil, hemp seed oil, tung oil, kapok oil, tea seed oil and mixtures of these oils.
The insoluble material in the crude oil may be of any form such is commonly found in vegetable oil and may appear as particulate, flocculent, or waxy material. The insoluble material can cause the crude oil to appear turbid, cloudy or discolored. The crude vegetable oil can include seed debris, lecithins, phospholipids (phosphatides), free fatty acids, sterols, and unsaponified matter as well as a variety of other insoluble material. The insoluble material can originate from a variety o
Carr Deborah D.
Woodard Emhardt Naughton Moriarty & McNett
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