CN101906351A - Method for preparing low-acid value rice bran crude oil - Google Patents

Abstract

The invention relates to a method for preparing low-acid value rice bran crude oil. The method comprises the following steps of: (1) screening fresh rice bran to remove impurities and sieving the fresh rice bran through a 30-mesh screen; (2) adding food-grade calcium carbonate dry powder which is sieved through a 100-mesh sieve and accounts for 2 to 5 percent of the total weight of the rice bran into the rice bran pretreated by the step (1), uniformly mixing the rice bran and the food-grade calcium carbonate dry powder, putting the mixture into a jacketed kettle, introducing high-temperature steam of which the temperature is more than or equal to 150 DEG C into the interlayer of the kettle, heating the mixture to 80 to 90 DEG C, preserving heat for 20 to 30 minutes and continuously stirring the mixture; (3) lowering the temperature of the rice bran to be between 70 and 75 DEG C, adding liquid cellulase which accounts for 0.1 to 0.5 percent of the weight of the rice bran and continuously stirring the mixture at the temperature of between 70 and 75 DEG C for 20 to 30 minutes; and (4) putting the rice bran which is subjected to enzyme treatment in the step (3) into the conventional oil pressing equipment, pressing to obtain oil by the conventional general oil pressing method and filtering the oil to remove impurities.

Description

A kind of preparation method of low-acid value rice bran crude oil

Technical field

The present invention relates to a kind of preparation method of rice bran crude oil, especially relate to a kind of method that is equipped with rice bran crude oil with the physical squeezing legal system.

Background technology

Rice pollard oil is a kind of fine vegetables oil, contain multiple unsaturated fatty acidss such as linolic acid, also contain multiple compositions such as thiaminogen, vitamin-E, sterol to the human body beneficial, modern rich man diseases such as prevention of arterial sclerosis, blood fat reducing total cholesterol, preventing hypertension had good effect, therefore, be recommended as the high-quality edible oil by international cereal association, WHO and food and agricultural organization.

The quality of rice finished product oil extracted from rice husks, closely related with the quality of rice bran crude oil.Rice bran crude oil be meant with physical squeezing or chemical leach extraction method make without purified rice bran crude oil.

In the Rice pollard oil production process, one of maximum difficult problem is that acid number is difficult to control.According to the national standard requirement, finished product one-level edible rice bran oil acid number (KOH) is necessary≤0.2mg/g, and the acid number of rice bran crude oil (KOH) is necessary≤4.0mg/g.Acid number is low more in the crude oil, with regard to easy more acid number is lowered during refining.

At present, the method for production rice bran crude oil mainly contains two kinds: a kind of is the physical squeezing method, and a kind of is the organic solvent chemical extraction method.Existing physical squeezing method is after rice bran is passed through heating, to put into the press apparatus squeezing and get oil, and its advantage is a less investment, and operational safety is few to nutritive ingredient destruction in the crude oil, does not have organic solvent residual, so edible comparatively safe; Shortcoming is that yield is lower, and generally speaking, yield only is 8-10%, promptly the grease about half in the rice bran can only be extracted at most.The advantage of organic solvent chemical extraction method is that yield is higher, the highlyest can reach 15-18%; Shortcoming is that investment is big, and operational requirement height security incidents such as (misoperation) will setting off an explosion may have organic solvent residual.

China is paddy production and consumption big country, and the world's average paddy gross annual output amount accounts for 38%～40% of total output of grain at 5～600,000,000 tons, is the main food of half population in the world, is human 23% heat supplier.Paddy is the principal item of China food crop, accounts for 40% of national total output of grain, and China's paddy annual production accounts for about 37% of world's paddy ultimate production, occupies first place in the world.In the paddy processing of the whole nation, have every year the rice bran about 2,000 ten thousand tons not have fine utilization, part is made feed, has part almost completely not utilize, and wastes quite big.The rice bran whole body is precious, wherein contains oil extracted from rice husks about 20%.If whole utilization of 2,000 ten thousand tons rice brans produced Rice pollard oil, the ultimate production of China's Rice pollard oil will maintain an equal level with domestic peanut oil ultimate production.Therefore, utilize prospect boundless.

At present, China has more than tens thousand of families of husk rice producer, and major part is middle-size and small-size rice mill, handle paddy day about 100 tons, these rice brans are focused on, difficulty is very big, because the rice bran after shelling is very easy to become sour, often have little time to transport to centralized system oil together, just may become sour.

Summary of the invention

The object of the present invention is to provide a kind of operational safety, production cost is low, does not have any organic solvent residual, edible safety, and acid number is low, and the preparation method of the higher rice bran crude oil of yield.

Purpose of the present invention is achieved by the following technical programs, and it may further comprise the steps:

(1) raw materials pretreatment: foreign material are removed in fresh rice bran screening, crossed 30 mesh sieves;

(2) lime carbonate thermal treatment: toward the dry powder of the food grade lime carbonate that in the pretreated rice bran of step (1), adds mistake 100 mesh sieves that are equivalent to the heavy 2-5% of rice bran, mix, put into jacketed kettle, 〉=150 ℃ high-temperature steams are fed in the interlayer of pot, be heated to 80-90 ℃, be incubated 20-30 minute, and constantly stir;

(3) enzyme is handled: reduce the steam flux, the rice bran temperature is dropped to 70-75 ℃, add the liquid cellulase that is equivalent to the heavy 0.1-0.5% of rice bran in the atomizers spray mode, spray on the limit, rice bran is stirred on the limit, after cellulase is added, continues to stir 20-30 minute under 70-75 ℃ of temperature;

(4) squeezing: will put into existing oil equipment through the rice bran that step (3) enzyme was handled, and get oil by at present common oil expression method squeezing, going into to press temperature is 40 ℃～75 ℃, control screw speed 20-35r/min, refilter, remove foreign material, promptly get rice bran crude oil.

The inventive method is by adding an amount of lime carbonate and cellulase in rice bran, make the rice bran crude oil that makes, acid number is low, and peroxide value is low, detect according to standard GB 19112-2003 prescriptive procedures, acid number (KOH)≤1.3mg/g, peroxide value 4.9≤mmol/kg, nutritive ingredient fully keeps, yield 〉=16%, and organic solvent-free is residual, and is with low cost, operational safety.

Embodiment

The invention will be further described below in conjunction with embodiment.

Embodiment 1

(1) raw materials pretreatment: different foreign material are removed in fresh rice bran screening, crossed 30 mesh sieves;

(2) lime carbonate thermal treatment: be equivalent to the dry powder of food grade lime carbonate that rice bran weighs 4% mistake 100 mesh sieves toward in the pretreated rice bran of step (1), adding, mix, put into jacketed kettle, 155 ℃ of high-temperature steams are fed in the interlayer of pot, be heated to 85 ℃, be incubated 25 minutes, and constantly stir;

(3) enzyme is handled: reduce the steam flux, the rice bran temperature is dropped to 72 ℃, add in the atomizers spray mode and be equivalent to rice bran and weigh 0.3% liquid cellulase, spray on the limit, and rice bran is stirred on the limit, after cellulase is added, continues to stir 25 minutes under 72 ℃ of temperature;

(4) squeezing: will put into existing oil equipment through the rice bran that step (3) enzyme was handled, and get oil by at present common oil expression method squeezing, going into to press temperature is 50 ℃, and control screw speed 30r/min filters, and removes different foreign material, promptly gets rice bran crude oil.

Detect gained rice bran crude oil acid number (KOH) 1.3mg/g, peroxide value 4.8mmol/kg according to standard GB 19112-2003 prescriptive procedures.Yield 16.3%.

Embodiment 2

(1) raw materials pretreatment: different foreign material are removed in fresh rice bran screening, crossed 30 mesh sieves;

(2) lime carbonate thermal treatment: be equivalent to the dry powder of food grade lime carbonate that rice bran weighs 4% mistake 100 mesh sieves toward in the pretreated rice bran of step (1), adding, mix, put into jacketed kettle, 150 ℃ of high-temperature steams are fed in the interlayer of pot, be heated to 80 ℃, be incubated 30 minutes, and constantly stir;

(3) enzyme is handled: reduce the steam flux, the rice bran temperature is dropped to 74 ℃, add in the atomizers spray mode and be equivalent to rice bran and weigh 0.2% liquid cellulase, spray on the limit, and rice bran is stirred on the limit, after cellulase is added, continues to stir 20 minutes under 74 ℃ of temperature;

(4) squeezing: will put into existing oil equipment through the rice bran that step (3) enzyme was handled, and get oil by at present common oil expression method squeezing, going into to press temperature is 60 ℃, and control screw speed 25r/min filters, and removes different foreign material, promptly gets rice bran crude oil.

Detect gained rice bran crude oil acid number (KOH) 1.2mg/g, peroxide value 4.1mmol/kg according to standard GB 19112-2003 prescriptive procedures.Yield 16.5%.

Reference examples

Be that with the difference of embodiment 1 save step (2), (3), all the other are with embodiment 1.Detect gained rice bran crude oil acid number (KOH) 3.7mg/g, peroxide value 7.3mmol/kg according to standard GB 19112-2003 prescriptive procedures.Yield 9.5%.

Claims (1)

1. the preparation method of a low-acid value rice bran crude oil is characterized in that, may further comprise the steps:

(1) raw materials pretreatment: foreign material are removed in fresh rice bran screening, crossed 30 mesh sieves;

(2) lime carbonate thermal treatment: toward the dry powder of the food grade lime carbonate that in the pretreated rice bran of step (1), adds mistake 100 mesh sieves that are equivalent to the heavy 2-5% of rice bran, mix, put into jacketed kettle, 〉=150 ℃ high-temperature steams are fed in the interlayer of pot, be heated to 80-90 ℃, be incubated 20-30 minute, and constantly stir;

(3) enzyme is handled: reduce the steam flux, the rice bran temperature is dropped to 70-75 ℃, add the liquid cellulase that is equivalent to the heavy 0.1-0.5% of rice bran in the atomizers spray mode, spray on the limit, rice bran is stirred on the limit, after cellulase is added, continues to stir 20-30 minute under 70-75 ℃ of temperature;

(4) squeezing: will put into existing oil equipment through the rice bran that step (3) enzyme was handled, and get oil by at present common oil expression method squeezing, going into to press temperature is 40 ℃～75 ℃, control screw speed 20-35r/min, refilter, remove foreign material, promptly get rice bran crude oil.