TH3202A - How to remove wax from edible vegetable oil - Google Patents

Abstract

The process combines bleaching and dewaxing methods for vegetable oil, consisting of a bleaching step using sufficient amounts of bleaching clay and filtration aids at approximately 80-130°C for 15-60 minutes. This is followed by rapid cooling of the bleached oil (containing the bleaching clay) to approximately 0-15°C for 15 minutes to 4 hours to remove the wax. The used bleaching clay, wax, and other impurities are then separated and filtered at a low temperature of approximately 0-20°C to recover the bleached and dewaxed vegetable oil.

Claims (13)

1. A method for bleaching and dewaxing vegetable oil, performed in a single step, consists of: (a) removing gum from the vegetable oil by cooling it to 0-20°C and then mixing it with a sufficient amount of cold water while stirring to hydrate the gum, making the hydrated gum insoluble; (b) separating the oil from the hydrated gum by centrifugation and dewatering the oil, thus reducing the water content to less than approximately 0.1%; (c) bleaching the oil with a sufficient amount of bleaching clay and a filtration aid containing phosphoric acid at a concentration of approximately 75-85% and in an amount of 0.04 to approximately 0.12% by weight of the oil under vacuum and stirring at 100-110°C for approximately 30 minutes; (d) rapidly cooling the bleached oil containing the bleaching clay while stirring at a cooling rate. (e) The bleaching clay, wax-like material, and other impurities are separated from the oil by filtration at a temperature of approximately 0-20°C. (f) The bleached and dewaxed vegetable oil is recovered. 2. A method for bleaching and dewaxing vegetable oil, performed in a single step, consisting of: (a) removing gum from the vegetable oil by cooling it to 10-20°C and mixing it with 3% cold water while stirring to hydrate the gum, rendering it insoluble in the oil; (b) separating the oil from the hydrated gum by centrifugation and dewatering it, thus reducing the water content to less than approximately 0.1%; (c) bleaching the oil with a sufficient amount of bleaching clay and a filtration aid containing approximately 0.08 to 0.10% by weight of the oil, which is 85% phosphoric acid. (d) The bleached oil, which contains the bleaching clay, is rapidly cooled while being stirred at an average cooling rate of 10-2 °C per minute until it reaches a temperature of approximately 7-10 °C, and this temperature is maintained for approximately 1-2 hours, thus removing the wax from the oil. (e) The used bleaching clay, wax-like materials, and other impurities are separated from the oil by filtration at a temperature of approximately 10-15 °C, and (f) the bleached and dewaxed vegetable oil is recovered. 3. Method for bleaching and dewaxing corn oil, performed in a single step, consisting of: (a) Degumming of the corn oil by cooling it to approximately 10°C and mixing it with approximately 3% cold water while stirring for about 30 minutes to hydrate the gum present in the corn oil, making it insoluble; (b) Separating the oil from the hydrated gum by centrifugation and dewatering the oil to reduce the water level to less than approximately 0.1%; (c) Bleaching the oil with a sufficient amount of bleaching clay and a filtration aid containing approximately 85% concentrated phosphoric acid at approximately 0.08-0.10% by weight of the oil, under vacuum and stirring at approximately 100-105°C for about 20 minutes; (d) Rapidly cooling the bleached oil containing the bleaching clay while stirring at a cooling rate. (e) The bleached corn oil is then dewaxed at a rate of approximately 15°C per minute until the temperature reaches approximately 10°C and this temperature is maintained for about 1 hour to remove the wax from the oil. (f) The used bleaching clay, wax-like material, and other impurities are separated from the oil by filtration at a temperature of approximately 10-15°C. (f) The dewaxed corn oil is then recovered. 4. The method under claim 1, in which the vegetable oils are selected from a group comprising corn oil, Milo oil, rapeseed (canola) oil, rice bran oil, sunflower oil, and safflower oil. 5. The method under claim 1, which involves purifying the vegetable oil in lye before the bleaching step. 6. The method under claim 5, which involves dehydrating vegetable oil to a water content of less than approximately 0.1% by weight after purification in alkali. 7. The method under claim 1 in which the bleaching soil is altered by approximately 0.5-5% by weight of the vegetable oil. 8. The method under claim 1, in which the amount of facilitating agent varies from approximately 5-50 parts by weight per 100 parts by weight of bleaching clay. 9. The method under claim 8, in which the ratio of the filtration agent to the bleaching clay is approximately 1:3, respectively. 10. The method under claim 1, in which the bleaching step is performed in a vacuum and stirred for approximately 15-60 minutes. 11. The method under claim 1 cools the bleached oil at an average cooling rate of approximately 15°C per minute. 12. The method under claim 1, which uses the bleaching clay as a catalyst for the crystallization of wax. 13. The method under claim 1, which uses the aforementioned filtration aid to simultaneously remove the used bleaching clay and wax-like material.