Study On Selection Of Compound Decoloring Materials For Different Vegetable Oils

Oil decolorization,often called adsorption decolorization,is a very important process in the refining process of edible oil.For different decolorization purposes,the raw oil should choose appropriate adsorption materials and decolorization process conditions.Due to the lack of comprehensive evaluation of nutritional value and safety in the decolorization process of edible oil in China,which mainly takes the decolorization rate and color as the indexes,a great deal of nutrient components are lost in the process of decolorization of edible oil,seriously affected the quality of edible oil.Therefore,based on the nutritional value of rice bran oil and the safety of peanut oil,this paper selects the suitable adsorption materials for different vegetable oils,uses the composite decolorization materials to decolorize,and optimizes the innovative decolorization process of vegetable oils,in order to reduce the amount of adsorbents,reduce energy consumption and improve the quality of oils and fats,and make the oil decolorization process more green and environmental protection,a refining decolorization process based on the quality of oils and fats was suggested,it provides a new direction for the decolorization process of edible oil.The main contents are as follows:(1)The specific surface area,pore diameter,total pore volume,decolorization rate,oil absorption rate and filtration rate of activated clay,Attapulgite,activated carbon,Bentonite and diatomite were measured,and effects on acid value,peroxide value,iodine value,toxic substance,nutrient substance and trans fatty acid in vegetable oil.Among them,the specific surface area and total pore volume of activated carbon are the largest,reaching 966.037m²/g and 0.794cm³/g,respectively,with the best decolorization effect;the decolorization effect of activated clay and attapulgite is the second,and the oil absorption rate of attapulgite and activated clay are smaller;while the pore diameter of diatomite and bentonite are larger,8.112nm and 8.028nm,respectively,with the best filtering effect of diatomite;The decolorization effect of activated clay and attapulgite is the second,and the oil absorption rate of both is small;The pore size of diatomite and bentonite is larger,among them,the pore size of diatomite is the largest,reaching 8.112nm,with the best filter aid effect,followed by bentonite;Under the addition of 1g adsorption material/100g rice bran oil,the effect of activated clay was the most obvious to reduce the acid value and peroxide value of rice bran oil,followed by activated carbon,and activated carbon had the greatest influence on the iodine value of rice bran oil;Compared with bentonite and diatomite,activated carbon,attapulgite and activated clay adsorbed more toxic substances and nutrients of rice bran oil.Therefore,activated clay,attapulgite and activated carbon were selected as the"main decolorizer"and bentonite and diatomite as the"auxiliary decolorizer";For the rice bran oil with high nutritional value,high acid value,deep color and peanut oil with high safety and poor stability,the"main and auxiliary decolorizer"should be selected as the decolorizing material of composite decolorizer according to its specific quality index.(2)For the rice bran oil with deep color,many kinds and high content of nutrients,the effects of different adsorbents on the retention rate,decolorization performance and cost of nutrients were compared.On the premise of ensuring better decolorization effect of rice bran oil,activated carbon with higher phytosterol retention rate and activated clay with higher retention rate of oryzanol and vitamin E were selected as the composite materials under the same amount;On the basis of single factor,Box-Behnken response surface method was used to analyze the decolorization process.The amount of decolorizer,decolorization time and decolorization temperature were taken as independent variables,the decolorization rate was taken as the target value,and the regression model was obtained by variance analysis of regression model to determine the best decolorization process conditions of rice bran oil.The results showed that 4.17g of activated clay and 0.83g of activated carbon were added to every 100g of degummed rice bran oil to decolorize.At this time,the mass ratio of the composite decolorizer(activated clay/g:activated carbon/g)was 5:1,the amount of decolorizer accounted for 5%of the oil weight;the decolorization time was 33min,the decolorization temperature was 116?;at this time,the decolorization rate of rice bran oil was 97.11%.Under this condition,the color of rice bran oil is Y20 R0.8,the retention rate of oryzanol is 89.62%,the sterol is90.16%,and the vitamin E is 79.91%.Compared with the existing decolorization process of rice bran oil,oryzanol,vitamin E and phytosterol are effectively preserved after decolorization with composite decolorizer;the color of decolorized rice bran oil is shallow,and its acid value is relatively low,and the basic indexes such as peroxide value,water content and volatile matter all reach the level of national first-class rice bran oil.The combination of activated clay and activated carbon is a kind of composite decolorizing material for rice bran oil with high nutritional value.Optimization of decolorizing process can significantly improve the nutrient retention rate of rice bran oil.(3)For peanut oil with high toxic substance content and high production cost,active carbon with good decolorization performance and high removal efficiency of toxic substances such as Ba P and AFB₁in peanut oil and bentonite with the lowest cost are selected as composite materials;Single factor experiments were carried out with the compound ratio,the amount of decolorizing agent,decolorizing time and decolorizing temperature,respectively.With the filtration speed,oil absorption rate,Ba P residue,AFB₁residue and decolorizing cost as the index of orthogonal optimization comprehensive score,the best process conditions for decolorization of peanut oil were determined by orthogonal optimization.The results showed that 0.33g of activated carbon and 1.67g of bentonite were added to every 100g of deacidified peanut oil for decolorization.At this time,the ratio of decolorizer(activated carbon/g:Bentonite/g)was 1:5,the amount of decolorizer was 2%,the decolorization time was20min,and the decolorization temperature was 90?.At this time,the comprehensive score was the highest.Under this condition,the oil absorption rate is 39.47%,filtration speed is 2.08m L/min,Ba P content is 0.15?g/kg,AFB₁content is 0.12?g/kg,and addition cost is 4.41 yuan/ton.After decolorization with composite decolorizers(activated carbon and bentonite),peanut oil has higher yield,lower acid value and peroxide value,higher iodine value,better stability,lower decolorization cost,and the content of toxic substances in peanut oil is lower than the national standard.The combination of activated carbon and bentonite is a kind of composite decolorizing material suitable for high safety peanut oil.Optimization of decolorizing process can significantly improve the quality of peanut oil and reduce the process cost.To sum up,this paper compares the adsorption decolorization and detoxification performance,adsorption stability,oil absorption rate,filter aid effect,decolorization cost of five adsorption materials:activated clay,attapulgite,activated carbon,bentonite and diatomite;The basic indexes of rice bran oil and peanut oil to be decolorized were determined.Through single factor test,response surface and orthogonal test optimization,suitable composite decolorizer materials and process optimization were proposed for rice bran oil and peanut oil,which provided theoretical guidance for the realization of refining decolorization process guided by oil quality.