| Chinese mitten crab（Eriocheir sinensis）is an important freshwater aquaculture species in my country.From October to December every year,people like to eat Chinese mitten crab.The composition of its gonad,hepatopancreas and muscle tissue is quite different.The characteristic distribution of macro and trace elements in edible tissues,the characteristic distribution of water-soluble arsenic species and fat-soluble arsenic,the bioavailability of elements and the risk assessment of dietary intake of heavy metals are lack of systematic and comprehensive studies.This paper takes adult Chinese mitten crabs cultured in Anhui,Hubei,Jiangsu,Jiangxi,Shandong,Shanghai,Zhejiang and Hunan from October to November 2017 to 2020 as the research object.The contents of elements and harmful elements in different edible tissues were compared,and the differences and specificities of different tissues,different specifications,and different regions were compared;The content,distribution characteristics and thermal stability of water-soluble arsenic species in edible tissues were studied,and the content,characteristics and thermal stability of fat-soluble arsenic in gonads（female crabs）and hepatopancreas were analyzed.The effects of steaming treatment on micronutrients and harmful elements bioavailability in different edible tissues of Chinese mitten crab were studied by digestion experiments.Risk assessment of simulated（Monte Carlo）dietary intake.The above studies provide data support for the dietary intake of Chinese mitten crab nutrition and harmful elements,and provide a scientific basis for eating Chinese mitten crab.The main findings are as follows:The differences and specificity of macro elements,micronutrients and harmful elements in different edible tissues,sizes and regions of female and male crabs were analyzed,and the contents of nutrient elements in different edible tissues were compared with the daily dietary reference intake and the daily acceptable intake.（1）Na,Mg,K and Ca are dominant in different edible tissues of female and male crabs,while Fe,Zn and Cu are also present in significant concentrations,which is due to the important role of these elements in maintaining normal physiological functions in vivo through various enzymatic activities.The mean contents of Na,Mg,K and Ca in the gonads of female crab were 731.96±105.37,954.77±98.47,2069.39±266.39 and 380.36±117.60 mg/kg,respectively.The mean contents of Na,Mg,K and Ca in the gonads of male crab were:The mean contents of Mg and K in male gonads of 4178.53±1220.22,298.68±84.65,1453.10±478.52,1038.04±328.36 mg/kg were significantly higher than those in male gonads（P<0.05）,and the mean contents of Na and Ca in male gonads were significantly higher than those in female gonads（P<0.05）.The mean contents of Mg and K in muscle tissue of female crab and male crab were significantly higher than those in hepatopancreas tissue（P<0.05）.The mean contents of Zn and Se in the gonads of female crab were 48.84±9.81 and 1.09±0.26mg/kg,respectively,and those in the gonads of male crab were 11.27±2.96 and 0.31±0.087 mg/kg,respectively.The mean contents of Zn and Se in gonad of female crab were significantly higher than those of male crab（P<0.05）.The mean content of Zn in muscle tissue of female crab and male crab was significantly higher than that in hepatopancreas tissue（P<0.05）.The mean contents of harmful elements Pb and Cd in different edible tissues of female crab and male crab showed a trend of hepatopancreas>gonad,body meat,leg meat and claw meat,and there were significant differences（P<0.05）,but there were no significant differences in Al,Hg and Cr contents in different edible tissues（P>0.05）.（2）The mean contents of Fe and Cd in hepatopancreas of female and male crabs with different specifications were significantly higher than those of other edible tissues（P<0.05）,but there was no significant difference in the mean contents of Fe and Cd in hepatopancreas of female and male crabs with different specifications（P>0.05）.There were no significant differences in the mean contents of Pb and Cr in 4 different edible tissues with different specifications（P>0.05）.The mean contents of Mn,Cu and Se in gonad and hepatopancreas of different specifications of female crab were higher than those in muscle tissue（P<0.05）,and the mean contents of Cu and Se in hepatopancreas of different specifications of male crab were higher than those in other edible tissues（P<0.05）.The mean content of Zn in muscle tissue of female and male crabs of different specifications was higher than that in hepatopancreas tissue（P<0.05）.（3）In to crab samples in eight different areas,the average content of zinc,Se in the crab roe all showed a trend of higher than that of crab roe,crab paste the average content of Fe,Pb,Cd in all showed a trend of higher than that of crab roe,the laws of the region of other elements with different,crab roe and crab paste with areas of different content of different elements in existence difference,Overall at a relatively stable level.（4）The ratios of average Fe,Cu,Zn and Se contents to daily recommended intake per 100g of hepatopancreas were 76.07%-290.13%,61.46%-120.01%,16.34%-26.55%and 101.43%-185.2%,respectively.The contents of Al,Pb and Cd were less than 12.5%of the acceptable daily intake,and the average contents of Heavy metals Pb and Cd did not exceed the limit value of 0.5mg/kg set by national standard for crustaceans.The detection method of 6 water-soluble arsenic species was improved,and the rapid separation of 6 water-soluble arsenic species was realized within 8 minutes.The total arsenic,water-soluble arsenic forms,fat-soluble total arsenic content and thermal stability of different edible tissues were analyzed.（1）The mean content of total arsenic in female crab showed a trend of gonad>hepatopancreas>body meat and leg meat>fornicate meat,and the difference was significant（P<0.05）.The mean content of total arsenic in male crab showed a trend of hepatopancreas>body meat,leg meat>pincer meat and gonad,and there were significant differences（P<0.05）,the female crab gonad average total arsenic content is 5.5 times that of the average male crab gonad total arsenic content,there were significant differences（P<0.05）,the female crab hepatopancreas and male crab hepatopancreas total average arsenic content had no significant difference.The total arsenic content in different edible tissues of female crab and male crab increased gradually with the increase of body weight.（2）The percentages of six water-soluble arsenic in muscle tissue were 83.3%-99.6%,and the percentages of six water-soluble Arsenic in gonad（female crab）and hepatopancreas tissue were18.8%-51.8%.The percentages of water-soluble Arsenic in muscle tissue,gonad（female crab）and hepatopancreas tissue were significantly different（P<0.05）.As B is the main component of water-soluble arsenic.As（Ⅲ）and As（Ⅴ）were only detected in a few samples of hepatopancreas,and the content was 0-0.21 mg/kg,which did not exceed the national standard limit value.（3）The average fat content of gonad（female）,hepatopancreas（female）and hepatopancreas（male）was9.76±1.57%,38.85±4.58%,39.97±7.33%,respectively,and there were significant differences between gonad and hepatopancreas tissues（P<0.05）.The percentages of fat-soluble total arsenic in gonad（female）and hepatopancreas（female and male）tissues ranged from 14.34%to 72.59%.There was no significant difference in the mean percentages of fat-soluble total arsenic in the three tissues（P>0.05）.The total arsenic content in fat of the three tissues was positively correlated with the total arsenic content in the corresponding tissues,but not with the percentage of fat in the corresponding tissues.The contents of non-polar arsenic in gonad,hepatopancreas and hepatopancreas of female crab were 15.5%,50.7%and 47.7%,respectively.There were significant differences between gonadal tissue and hepatopancreas tissue（P<0.05）,and the unstable percentage of hexane phase in the three tissues were 46.7%,47.1%and 60%,respectively.（4）The contents of As B,As C,MMA and i As（dry weight）in different edible tissues of Eriocheir sinensis did not change significantly after steaming for 0-60min,indicating that the four water-soluble arsenic forms had high thermal stability and no morphological transformation under steaming condition.After the hepatopancreas tissues of female crab and male crab were steamed at 105℃for 0-60min,the content of total fat-soluble arsenic did not change significantly,indicating that the thermal stability of fat-soluble arsenic was very high at 105℃.The effect of steaming on the bioavailability of essential and harmful elements in different edible tissues was studied,the molar ratio of Se to Hg in different tissues and the value of Se health benefits,and the relationship between element content and Chinese residents’dietary nutrients after considering element bioavailability were analyzed.Adequate intake or percentage of recommended intake per day.（1）The average range of water content in different edible tissues of female and male crabs was 43.76-80.07%and 45.35-80.36%,respectively.The water content showed a trend of body meat>gonad>hepatopancreas,and there were significant differences（P<0.05）..The moisture content of each tissue showed a decreasing trend after steaming,and there was a significant difference in the moisture content of the hepatopancreas before and after steaming（P<0.05）.（2）The bioavailability of all elements showed a downward trend after simulated digestion in vitro.Steaming can significantly affect the bioavailability of some elements.Zn,Se,As in female crab gonads and Mn,Al in body meat After steaming,the bioavailability of in vitro simulated digestion showed a decreasing trend（P<0.05）.After steaming,the bioavailability of Zn（female and male）was increased by simulated digestion in vitro（P<0.05）.The bioavailability of Fe,Se and As in muscle tissue was significantly higher than that in hepatopancreas tissue（P<0.05）.（3）Female crab gonads have the best Se health benefit value,and the molar ratio of Se to Hg in edible tissues is in the order of female crab gonads>female crab hepatopancreas>male crab hepatopancreas>male crab gonads>female crab body meat>male crabs The trend of crab meat was significantly different（P<0.05）.（4）After considering the biological givability of elements,The percentages of Fe,Mn,Cu,Zn,Se and Mg intake to recommended or suitable intake in female and male edible tissues were 1.84-69.18%,1.17-10.27%,11.13-50.55%,5.01-29.05%,0.03-0.1%and 3.18-20.43%,respectively,the percentage of element intake to recommended or appropriate intake in edible tissues decreased with the bioavailability of elements.The single-factor pollution index method and metal pollution index were used to evaluate the pollution of heavy metals in different edible tissues,and the Crystal Ball risk assessment software based on Monte Carlo simulation was used to evaluate the Pb,Cd,Hg,As and Cr 5 in Chinese mitten crab whole food tissues.Preliminary study on dietary exposure risk assessment of various heavy metals.（1）The single-factor pollution index showed that Pb and Cd were moderately polluted in the hepatopancreas of female and male crabs,and in the normal range in other tissues;Hg and Cr were in the normal range in all edible tissues of female and male crabs;As in the edible tissues of female crabs is in the heavy pollution range,in the male crab gonadal tissue is in the moderate pollution,other tissues are in the heavy pollution.Except for the contamination of As in the gonads,the contamination of heavy metals in different edible tissues of female and male crabs was the same.The heavy metal pollution index showed that the heavy metal pollution index of the hepatopancreas of female and male crabs were 0.1803 and 0.1444 respectively.The heavy metal pollution index of different edible tissues of female and male crabs showed the trend of hepatopancreas>gonad and muscle tissue.（2）The average daily exposures of 5 heavy metals including Pb,Cd,Hg,As and Cr ingested by dietary Chinese mitten crabs were 7.9×10-5,1.3×10-4,1.8×10-5,1.026×10-3,4.3×10-5mg/kg·d,the average exposure of Pb,Cd,Hg and Cr and their high percentile values were lower than the daily reference recommended by the Joint Expert Committee on Food Additives and the Chinese Nutrition Society Dosage,As content is below the reference dose specified by international organizations.When the exposure percentile was 99,the risk probability of As was more than 1,indicating that As in Chinese mitten crab had certain safety hazards to human health.（3）The Crystal Ball risk assessment based on Monte Carlo simulation showed that the risk of heavy metal intake of Chinese Eriocheir sinensis was inversely proportional to the age,and the older the age,the lower the risk of heavy metal intake;for groups of the same age,the risk of heavy metal intake was significantly higher than that of age.Exposure percentiles are proportional,and the higher the percentile,the greater the risk of ingesting heavy metals.In general,the intake risk values of Pb,Hg,and Cr in Eriocheir sinensis were low.At the high percentile,the intake risk value of Cd and As in children was above 1,indicating excessive intake of Chinese cashmere.Crabs are not conducive to the healthy development of children,and the risk probability of dietary intake of five heavy metals is As>Cd>Pb,Hg,Cr. |
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