Study On Quality And Safety Factors Of Peanut Oil And Their Prevention And Control

Peanut was one of the three greatest oil crops in China and one of the five greatest oil crops in the world.It was also the oil crop with the highest total output at present.Peanut kernels are easily contaminated or improperly processed during storage,transportation and oil production to produce substances that are not conducive to human health.Irregular storage and transportation of peanuts can easily cause the contamination of peanuts by Aspergillus flavus and Aspergillus parasiticus to produce aflatoxin B1(AFB1).Irregular airing methods can easily cause the content of benzo(a)pyrene(BaP)in peanut kernels to exceeded the standard.BaP,3-chloro-1,2-propylene glycol ester(3-MCPDE)and trans-fatty acids(TFAs)in peanut oil were easily increased by high temperature roasting and deodorization.This subject mainly studies the AFB1 pollution removal research brought by peanut kernels and the comparison of four methods to remove AFB1 effect;the research on the production conditions of BaP,3-MCPDE and TFAs in the main section of peanut oil extraction process,the removal conditions,and the decolorization section.Adsorption studies of adsorbents and correlation studies of toxic substances in deodorization sections.(1)Determination of aflatoxin B1 content in peanut oil which was pressed from peanut soaking in alkaline solution,then the quality of peanut oil were measured.The results indicated that peanut soaking in alkaline solution had a certain effect on removing aflatoxin B1 from peanut oil.Comprehensive consideration should be given to reduce alkali consumption,water volume and avoid waste water,and the method in which the pH value 13.40,soak for 20 minutes and ratio of liquid to material 7.5 % was taken to be the best condition,then the removal rate of aflatoxin in grade four oil was 93.3%,and the removal rate of three grade oil was 98%.AFB1 content in peanut oil which was pressed from peanut soaking in alkaline solution decreased from 44.69 ?g/kg(four grade peanut oil)and 21.50 ?g/kg(three grade peanut oil)in the blank control group to national standard which standed less than or equal to 20 ?g/kg.At the best condition,aflatoxin content in peanut oil reached undetected level.Alkali treatment had no significant effect on the acid value,peroxide value,iodine value,flavor,fatty acid composition and percentage content of peanut oil.The inappropriate processing technology can easily make peanut kernels produce toxic substances in the process of oil production.(2)Four methods which were used to remove AFB1 from peanut oil taking effects on acid value,peroxide value,vitamin E content and phytosterol content of peanut oil were studied.Studing on the mechanism and safety of alkali removal ofaflatoxin from peanut oil and the effect of peanut oil flavor.After pressing,the content of AFB1 in peanut oil was 21.5 ug/kg,that was down to 2.00 ug/kg after alkali treatment,and the removal rate was 90.7%.The peanut oil AFB1 which was adsorbed once by bentonite down to 0.13 ug/kg,and the removal rate was 99.4%;After twice adsorbed,the residual amount of AFB1 in peanut oil down to 0.10 ug/kg with the removal rate of 99.4%.The residual amount of aflatoxin B1 in peanut oil was 0.10 ug/kg with the removal rate of 99.5%.Alkali refining and deacidification reduceing the residual amount of AFB1 in peanut oil to 0.10 ug/kg with the removal rate of 99.5%.The retention rate of vitamin E in peanut oil by alkali treatment was the highest by other methods.Compared with sensory evaluation,this method had the lowest loss of peanut oil flavor.(3)The high temperature roasting fragrance and high temperature deodorization are easy to produce toxic substances in the peanut oil preparation process.In this paper,the changes of the content about 3,4-Benzypyrene(BaP)and 3-chloro-1,2-propanediol(3-MCPD)ester(3-MCPDE)in peanut oil were studied in the high temperature section,in addition,the content and removal of BaP and 3-MCPDE in the main sections of the peanut oil preparation process were resarched.When the discharging temperature in roasting section exceeded 210 °C and the time exceeded 60 min,the BaP and 3-MCPDE content in peanut oil increased significantly;The BaP content in the peanut oil which was made by high steam flux deodorization was significantly lower than by low steam flux;When the deodorization temperature was raised from 240°C to 250 °C,the BaP and 3-MCPDE content in peanut oil increased significantly;Deodorization time had a continuous effect on BaP content,but the effect on 3-MCPDE content was limited when the time exceeded 120min;The content of chlorine in peanut oil before deodorization had a significant effect on the content of 3-MCPDE in the oil after deodorization;The amount of activated carbon,adsorption time and adsorption temperature had significant effects on the removal of BaP and 3-MCPDE in peanut oil.The removal rate of BaP in peanut oil when activated carbon at 0.5%,30 min and 110°C was the best,and the residual amount of BaP in peanut oil was 0.52 ?g/kg,and the removal rate was 77.5%;Comparative study on the adsorption of 3-MCPDE by three adsorbents,and the adsorption effect order was YS-900 activated carbon > activated clay > ordinary activated carbon,and the best removal rate of 23.5%;The adsorbent can not only significantly reduce the BaP and 3-MCPDE content in the peanut oil decolorization system,but also have a certain catalytic effect on the formation of the both.(4)The 3-MCPDE content in the deodorization section was related to the oleic acid,anti-linoleic acid and total TFAs content.High-temperature deodorization produces anti-oleic acid,and anti-linoleic acid also produces 3-MCPDE,which can also be reversed.