Study On Quality Of Corn Germ And Control Of Mycotoxins

Corn germ is a by-product of corn deep processing and raw material for producing edible maize oil and corn germ meal.Corn germ is rich in nutrients such as protein and dietary fiber.However,corn germ is extremely susceptible to contamination by Aflatoxins B₁?AFB₁?,Zearalenone?ZEN?and Deoxynivalenol?DON?and other mycotoxins,which affects the food safety of corn germ and corn germ-based products.In order to improve the safety for feed and edible and nutritional quality of corn germ and promote the development of corn germ industry towards high-value processing,it is necessary to study the influences of storage conditions and milling mathod on the quality and reduce its mycotoxins.?a?Comparative study on quality of corn germ extracted from different sources and milling processes.Collecting corn germ samples produced by different milling processes from different corn deep processing plants,and at the same time use different processes to extract corn embryos from high-quality corn in the laboratory.The differences in the quality of corn germ from different sources and different extraction methods were studied by analyzing the content of main components,mycotoxins,volatile flavor components and the quality of its maize oil from different sources of corn germ sample.The results show that:The pure germ rate of corn germ raw materials collected from the corn starch plant?60.29%-88.92%?is higher than that of corn germ collected from the corn alcohol plant?42.29%-57.25%?.After air separating and screening,the pure embryo rate of corn embryos can be increased to 84.11%-97.85%.The moisture content of semi-dry milling corn germ?9.09%-14.48%?is higher than that of wet-milled corn germ?3.51%-5.51%?;the oil content of semi-dry milling corn germ?23.63%-26.94%?is significantly lower than that of wet method corn corn germ?53.42%-54.77%?;the crude protein content?13.75%-18.46%?is higher than wet milling corn germs?10.10%-12.35%?,and the total amino acid content and essential amino acid content are higher than wet milling corn germ.The fatty acid composition and sterol content of the two crude oils is no significant difference,vitamin E content is higher than wet milling maize oil.The semi-dry milling corn germ has more volatile substances?38-46 species?than the wet milling corn germ?11-36 species?.The semi-dry milling corn germ had a grassy taste and a sweet fragrance,and the wet corn germ had the smell and stimulation of oil oxidation.The semi-dry milling corn germ has light color and luster,and the wet milling corn germ has yellowish and dull color,but the content of ZEN and DON in the wet corn embryo is lower.Corn embryos extracted from semi-dry milling methods using good quality corn as raw materials are suitable for the development of edible corn germ.?b?Study on the effect of different storage conditions on the comprehensive quality of corn germ.The corn germ extracted by the semi-dry milling method was used as the test material,and it was set to be stored under different storage temperature,humidity and vacuum conditions for 56 days.Analyze the effect of storage conditions on its main components:aflatoxin B₁?AFB₁?,zearalenone?ZEN?,Dvomitin?DON?and other mycotoxins.The results showed that under 25?and 75%relative humidity,the samples were severely moldy,the mycotoxin content,moisture content and acid value increased the most,and the crude fat content decreased the most.Under the conditions of 40?and 45%relative humidity,the sample had the highest VE loss and the highest increase in peroxide value.The sterol content did not change much under different storage conditions.The growth trends of the three mycotoxins during storage were out of sync,indicating that Aspergillus flavus and Fusarium may be antagonistic to each other.The content of main components and mycotoxins of corn germ stored at 25?,vacuum condition and 25?,45%relative humidity were relatively stable.?c?Comparison of different treatment methods on the degradation of mycotoxins in corn germ.In order to reduce the risk of mycotoxins in corn germ and improve the safety quality of corn germ,it is necessary to study the removal methods of mycotoxins in corn germ.By comparing the reduction effect of the extrusion and expansion,microwave,steamed germ,lightly steamed germ,ozone water conditioning and ozone fumigation on AFB₁,ZEN,and DON in corn germ,preliminary screening of effective control methods for mycotoxins in corn germ was conducted.The results showed that the highest reduction rates of ZEN by extrusion and microwave treatment were 36.01%and 36.86%,respectively.And the reduction effects on AFB₁and DON were limited.The moist steamed germ method had basically no effect on the elimination of the three mycotoxins?the highest reduction rate is only 2.63%?;while the light-alkali steamed germ treatment had a high reduction rate on the three mycotoxins,reaching 52.21%and 33.76%,61.12%.The highest reduction rates of AFB₁,ZEN,and DON in the samples by ozone water conditioning treatment were 29.28%,75.56%,and 91.91%,but the treatment time reached 12 h,and the flavor of the samples after treatment was poor.The ozone fumigation method for AFB₁in the samples The reduction rates of ZEN and DON can reached 69.49%,70.21%and 75.50%respectively.After comparison,the light alkali steaming method and ozone fumigation method can effectively reduce the AFB₁,ZEN and DON content in the corn germ,and the operation was simple,the processing time was short,and the sensory quality of the corn germ was less affected.?d?Study on degrading mycotoxins in corn germ by optimizing the conditions of steamming germ with light-alkali.The process conditions for reducing mycotoxins in corn germ by light-alkali steaming method were optimized.The Na OH solution with different concentrations was used to adjust the moisture content of the corn germ to reach 14%,and the germ steam was steamed for 30 min with superheated steam at 115?.The results showed that when the lye mass fraction was 6.55%,the light alkali steamed germ had the best reduction effect on AFB₁,and the AFB₁content decreased from 7.91?g/kg to 0.77?g/kg?the reduction rate was 90.30%?.When the lye mass fraction was 5.29%,the light alkali steamed germ had the best reduction effect on ZEN and DON.The ZEN content was reduced from 697.41?g/kg to 246.25?g/kg?the reduction rate is 64.69%?,and the DON content was from 2417.07?g/kg reduced to 802.83?g/kg?reduction rate 66.78%?.With the increase of the lye mass fraction,the color of corn germ and its crude oil obtained by light alkali steamed germ had darkened,and the acid value and peroxide value of the crude oil had decreased significantly.The use of light-alkali steamed germ can not only effectively reduce mycotoxins in corn germ and their crude oil,but also improve the quality of corn germ oil,which is the optimization and improvement direction of the wet steamed germ technology in the production of corn germ oil.?e?Study on optimizing the conditions of ozone treatment to degrade mycotoxins in corn germ.The ozone concentration was fixed at about 150 mg/L,and the effects of different sample moisture content and treatment time on the effect of ozone fumigation on reducing AFB₁,ZEN and DON in corn germ were investigated.The results showed that when the moisture content of the sample was 20%and the fumigation time was 80 min,AFB₁had the best reduction effect,and the reduction rate was 72.27%.When the moisture content of the sample is 10%and the fumigation time was 50 min,the reduction rate of ZEN was 68.88%.When the moisture content of the sample was 15%and fumigation was performed for 60min,the reduction rate of DON can reach 82.86%.The three mycotoxins had a better reduction when the sample moisture content was 15%and the treatment time was 60 min.As a result,the reduction rates can reach 66.61%,69.44%,and 90.96%,respectively.As the moisture content of the corn germ increases and the ozone treatment time increases,the color of the maize oil is lighter,and the acid value and peroxide value increase,but the increase is small.