A kind of refining processing method of millet cavings nutritional oil
Technical field
The present invention relates to the edible oil processing method, specifically be a kind of be the method for raw material refining processing millet cavings nutritional oil with millet cavings crude oil.
Background technology
The millet cavings is the accessory substance of millet processing millet process, is made up of pericarp, kind skin, aleurone and the rice plumule of millet.Discover: contain grease 14-16% in the millet ravine chaff.In millet cavings crude oil, unrighted acid accounts for 89.26% of total fatty acid content, and wherein linoleic acid content surpasses 70%, and oleic acid content is 14%, and alpha-linolenic acid content is 3-4%; In addition, also contain vitamin E 66-80 mg/100g, sterol 1.1-1.5%, oryzanol 0.3-0.5%.Oryzanol has the serum cholesterol of reduction, prevents physiological functions such as lipid oxidation, angiocardiopathy preventing, is soluble in alkalescence and neutral non-polar solution.Vitamin E is the necessary liposoluble vitamin of human body, also is natural food antioxidant.Therefore, edible millet cavings oil not only can satisfy the nutritional need of human body to necessary aliphatic acid and vitamin E, and has potential removing interior free yl, anti-oxidant and antilipemic healthy effect, has the excellent development prospect.
There are phosphatide and free fatty in the millet cavings crude oil, for guaranteeing the quality stability of product oil, must be through coming unstuck and deacidification process.Remove nonhydratable phosphatide and generally be employed under the normal pressure and add phosphoric acid or methods of citric acid, and come unstuck with deacidification in the normal pressure stir process can sneak into a large amount of oxygen, very easily cause the oxidation to the oxygen sensitive materials such as vitamin E, sterol, unrighted acid.For this reason, unit such as Henan Province's grain engineering designing institute adopts full negative pressure continued operation to produce salad oil in fat degumming, alkali refining, decolouring and deodorization refining; Also the someone adopts vacuum vaporization depickling (CN14689484) under the hot conditions.Yet, the destruction of causing heat-sensitive substances such as vitamin E under the hot conditions easily; In the refining overall process, full negative-pressure operation can strengthen power consumption and production cost.
Acid stripping method on the commercial production has methods such as alkali refining, distillation, solvent extraction and esterification, extensively adopt be alkali-refining deacidification method and steam distillation depickling method (being the physical refining method).The advantage of alkali refining method is simple to operate.Shortcoming is:
1.Soap stock can be taken most oryzanol in the oil out of, causes the loss of a large number of nutrients;
2.The affiliation that adds of alkali lye causes vitamin E and oryzanol isoreactivity material damage;
3.Contain a large amount of neutral oil in the soap stock that forms, cause the loss of neutral oil excessive.The physics way of distillation is utilize free fatty (FFA) and triglyceride relative volatility different, under high temperature, condition of high vacuum degree condition, carries out stripping by open steam, and overflows by the ratio of its dividing potential drop, to reduce a kind of technology of the FFA in the oil.The advantage of the method is: improved the grease yield.Shortcoming is;
1.Requirement to equipment and raw material is high, has high input;
2.Too high temperature is bigger to the destruction of some active materials such as vitamin E.
For avoiding the shortcoming of alkali-refining deacidification method and steam distillation depickling method, having patent (CN 101343593A) to adopt absolute methanol is that solvent carries out the depickling processing to the rice bran crude oil, when promoting oil quality, has increased oily yield again.The ethanol extraction depickling tea oil (CN101717689) of employing is also arranged, reduced the acid value of tea oil.The advantage of this extraction be neutral oil loss little, reduced of the pollution of salkali waste wash water to environment.But,, under normal pressure and PH neutrality or alkali condition,, still can cause a large amount of losses of bioactive ingredients such as oryzanol, vitamin E and sterol with methyl alcohol, ethanol equal solvent extraction depickling owing to contain enzymatic oxidation metal ions such as iron, copper ion in the crude oil.Through measuring, in the millet cavings oil with normal pressure solvent depickling method and the processing of steam distillation depickling method, oryzanol has only 60-70% with the storage rate of total vitamin E.
Vitamin E under acid condition to thermally-stabilised, unstable under alkaline aerobic conditions.In traditional alkali-refining deacidification process, the adding of alkali lye causes vitamin E and oryzanol to lose in a large number; And the destruction that high-temperature vapor distillation depickling meeting causes nutritional labelings such as vitamin E and sterol.
Summary of the invention
The object of the present invention is to provide a kind of nutritional labelings such as protection oryzanol, vitamin E and unrighted acid that have, effectively reduce the millet cavings nutritional oil refining processing method of acid value.
The refining processing method of a kind of millet cavings nutritional oil provided by the invention comprises the steps:
The first step: come unstuck: millet cavings crude oil is preheated to 55-65 ℃; The mass concentration that under 0.080-0.088MPa vacuum, adds the heavy 0.2-0.4% of crude oil then is 20% citric acid solution, stirs after the 3-5min, under 0.074-0.086MPa vacuum; Add while stirring phosphatide quality 0.4-1.0 in the crude oil doubly with hot water oily equality of temperature; Behind the vacuum stirring 20-40min,, remove the colloid of sub-cloud with the static insulation of normal pressure 5-7h;
Second step: depickling: the crude oil that comes unstuck is extracted depickling with ethanol-isopropyl alcohol mixed extractant; Condition: the mixed extractant consumption is the heavy 1-2 of crude oil times; Extraction temperature 25-35 ℃, vacuum 0.078-0.084MPa, mixing time 10-30min; The normal pressure standing demix separates and removes ethanol-isopropyl alcohol extraction phase afterwards; Above-mentioned deacidification repeats 2-4 time; Whipping process is controlled vacuum well, avoids the extractant boiling.
Described ethanol-isopropyl alcohol mixed extractant, its mass concentration are 85-95%, and wherein the mass ratio of isopropyl alcohol and ethanol is 1: 8~12; The pH value of said mixed extractant is adjusted to pH 5.0-6.5 with the citric acid-sodium citrate buffer solution;
The 3rd step: clean: with the sodium citrate solution of mass percentage concentration 0.05-0.15% to come unstuck, the cavings oil of depickling cleans 1-2 time, at every turn the consumption of sodium citrate solution be crude oil heavy 1/3~1/5; After washing, sodium citrate solution is washed till wash water pH 6.8-7.2 with clear water again;
The 4th step: dry and dewaxing:, the Water in oil amount is reduced to below 0.10% in 0.09-0.095MPa vacuum, 80-100 ℃ following vacuum drying; More than the 40h of normal pressure winterization below 4 ℃, centrifugal removal wax obtains millet cavings nutritional oil product.Its acid value below the 2mgKOH/g, the storage rate of vitamin E and oryzanol is respectively more than 85% and 75%.
Compared with prior art, the invention has the advantages that:
1., the present invention is coming unstuck, adopting vacuum condition in the whipping process of depickling, in non-whipping process, adopts condition of normal pressure, can reduce the oxidational losses of vitamin E, oryzanol and unrighted acid, can reduce energy resource consumption again.
2., adopt ethanol-isopropyl alcohol mixed extractant, deacidification effect is good.Discover, because the polarity of ethanol and isopropyl alcohol is different, after ethanol and isopropyl alcohol are with the certain proportion mixing; And be diluted with water to the mass concentration of 80-95% at a certain temperature; Can effectively extract the free fatty in the neutral oil, this deacidifying process is simple, and deacidification efficiency is high.Adopt subacidity ethanol-isopropyl alcohol extractant of pH 5.0-6.5, also help protecting vitamin E and oryzanol.
3., adopt sodium citrate solution that depickling oil is cleaned, in neutralization oil in the residual acid, can also play the effect that huge legendary turtle is closed metal ions such as iron in the oil, and can reduce the washing water consumption.
This method also can be used for the refining processing of other nutritive vegetable oil.
The specific embodiment
Embodiment 1:
Get the millet cavings crude oil 500g that the solvent lixiviation process obtains, acid value is 9mgKOH/g, and the content of vitamin E and oryzanol is respectively 765mg/kg and 0.35%, content of phospholipid 1.5%.After crude oil injected purifier heated sealed to 55 ℃, be evacuated down to 0.086MPa vacuum, add 20% citric acid solution
2G behind the stirring 3min, adds 55 ℃ of hot water of 3g (content of phospholipid is 0.4 times in the oil), under 0.080MPa vacuum, stirs 35min; 5h is left standstill in the normal pressure insulation, removes the colloid of sub-cloud.Degummed oil adds that the pH value is 6.0, concentration is that (ethanol: isopropyl alcohol=9: 1), 35 ℃ of following vacuum hydro-extraction depicklings 2 times, vacuum remains on 0.078-0.080MPa for ethanol-isopropyl alcohol extractant of 85%; It is 900 g that the extractant of each depickling adds weight, and the vacuum stirring time of each extraction is 30min; Stir end back normal pressure and leave standstill about 1 hour, separate and remove the sub-cloud extraction phase.Oil phase after the depickling cleans 1 time with the natrium citricum washing lotion of 150g mass concentration 0.15%; Be washed till wash water pH 7.0-7.2 with clear water again; Cavings oil behind the separation removal wash water layer is reduced to below 0.10% the Water in oil amount in 0.09-0.095MPa vacuum and 95-100 ℃ of following vacuum drying.Behind the dried millet cavings winterizing 50-60h, centrifugal removal wax, the millet cavings nutritional oil finished product that obtains.Compare with crude oil, the product oil outward appearance is limpid bright, and acid value is 0.90 mgKOH/g, and vitamin E and oryzanol content are respectively 697mg/kg and 0.29%.
Embodiment 2:
Get CO
2The millet cavings crude oil 800g that supercritical extraction obtains, acid value is 14mgKOH/g, the content of vitamin E and oryzanol is respectively 883mg/kg and 0.42%, content of phospholipid 0.8%.Millet cavings crude oil is injected equipment for vacuum refining; Suction is to 0.080 MPa after being heated to 65 ℃; Adding 3.0g concentration is 20% citric acid solution, adds 65 ℃ of hot water of 5.1g (content of phospholipid is 0.8 times in the crude oil) behind the stirring 4min, under 0.074MPa vacuum, stirs 20min; After 6h is left standstill in the normal pressure insulation, remove the sub-cloud colloid; The crude oil that comes unstuck adds that the pH value is 5.5, concentration does
9(ethanol: isopropyl alcohol=12: 1), the extraction depickling is 3 times under 25 ℃, 0.080-0.082MPa vacuum, and it is 1200g that each extractant adds weight for 5% ethanol-isopropyl alcohol extractant; 20min is stirred in each extraction, and after the extraction, normal pressure leaves standstill, and removes lower floor's extraction phase after the layering.Oil phase after the depickling cleans 2 times with the natrium citricum washing lotion 250g of mass concentration 0.10%, uses clear water to be washed till wash water pH again and is 6.8-7.0.Cavings oil behind the separation wash water is reduced to below 0.10% the Water in oil amount in 0.095MPa vacuum and 92-96 ℃ of following vacuum drying.Dried millet oil extracted from rice husks winterization 60-70h, centrifugal removal wax obtains as clear as crystal millet cavings nutritional oil finished product.This product oil acid value is 1.2mgKOH/g, and vitamin E and oryzanol content are respectively 805mg/kg and 0.35%.