Effects Of Cooking On The Distribution Of Elements In Eriocheir Sinensis And The Risk Assessment Of Arsenic Consumption

The Chinese mitten crab(Eriocheir sciences)is a unique freshwater crab breed in China.It is larger in scale and has a high economic effect.Rapid urbanization and industrialization make heavy metals in freshwater systems too high,and as a benthic organism.The Chinese mitten crab can easily absorb heavy metals in mud and water environment,so that heavy metals can add value in the tissues of crabs.Because Chinese mitten crab needs to be cooked before it can be eaten,the contents of various elements in the crab tissue will change during the cooking process.At present,the risk assessment of heavy metals in food is usually based on the content of heavy metals in raw materials,and the content of heavy metals in raw materials cannot accurately reflect the bioavailability of organisms.So it is not enough to assess the health risks caused by eating food.Although the content of heavy metals is low,they will accumulate in the human body for a long time,which will cause harm to the human body.Therefore,it is necessary to evaluate the exposure of heavy metals through bioavailability.In this study,we selected Chinese mitten crab of the same origin,period and sexual maturity as the research object,and used cooking methods such as steamed,boiled,fried and microwaved to treat Chinese mitten crab.The distribution of elements in three edible parts(belly meat,leg meat and crab roe)of the crab was observed by inductively coupled plasma mass spectrometry(ICP-MS)(The mixed samples of hepatopancreas and gonads of male and female crabs is collectively called crab roe).To explore the influence of different cooking methods on the distribution of element content in each part.The effects of different cooking methods on the arsenic content in different tissues were examined by Chromatography-Inductively Coupled Plasma Mass Spectrometry(HPLC-ICP-MS).To investigate the effects of different cooking methods on arsenic content in various tissues.The bioavailability of arsenic and the effects of cooking methods on the bioavailability of different forms of arsenic in the Chinese mitten crab was investigated by in vitro gastrointestinal simulation digestion method.This study aims to make up for the deficiency in the assessment of heavy metal risk hazards in Chinese mitten crab based on food raw materials,and to provide theoretical and data support for the accurate dietary risk of Chinese mitten crab.The research contents and main results of each chapter of this study are as follows:1)Firstly,the collected fresh Chinese mitten crab was cultured and the distribution of elements in the three edible parts of the crab was detected by ICP-MS.Six trace elements(sodium(Na),calcium(Ca),magnesium(Mg),iron(Fe),copper(Cu),manganese(Mn)and four heavy metal elements(chromium(Cr),cadmium(Cd),mercury(Hg),arsenic(As))were detected.The results showed that the distribution of elements in edible parts of Chinese mitten crab before cooking was as follows:Na>Ca>Mg>Fe>Cu>Mn>As>Hg>Cr>Cd;After cooking,the content of Na and Mg increased overall,while the content of other elements decreased and the distribution pattern remained the same.The contents of Cr,Cd and Hg were all within the range of national standards before and after cooking,and As were above national standards before and after cooking.Four cooking methods,microwaved and fried,reduced the elemental content of three edible parts of Chinese mitten crab and steamed and boiled increased the content of elements.In the three edible parts,the decrease of elemental content the followed:belly meat>leg meat>crab roe.Male crab were more apt to have fewer elements after cooking than female crab.Sealed cooking samples tend to have higher elemental content than normal cooking.These results show that the main reason for the decrease of elemental content is that the elemental solubility is different in cooking water,and the changes of elemental content after cooking are different,as well as the cooking temperature,cooking medium,individual differences and composition of food matrix are all factors that influence the change of elemental content.2)Different arsenic patterns were further tested because the total arsenic levels before and after cooking were found to be above the national standard.Six arsenic forms(arsenic betaine(As B),arsenic lipids(As C),mono-arsenic acid(MMA),dimethylarsenic acid(DMA),trivalent arsenic(As~Ⅲ),and pentavalent arsenic(As~V))were analyzed by HPLC-ICP-MS.The results showed that As B was the main arsenic form in the three edible parts of the Chinese mitten crab before and after cooking.After cooking,arsenic content decreased in male crab belly meat,increased in female crab belly meat,and decreased in leg meat and crab roe.As~Ⅲand DMA were not detected in muscle samples;in crab roe,As~Ⅲand DMA levels decreased after cooking.Increased arsenic levels in cooking water indicate that arsenic decreases as water is lost during cooking.It is also possible that arsenic is transferred to the crab’s edible parts with water,resulting in an increase in arsenic content.Different forms of arsenic have different solubility,so different forms of arsenic change in cooking process.3)To further evaluate the human health risks of arsenic in food,raw,steamed,microwaved Chinese mitten crab were subjected to total arsenic and different arsenic morphology assays using in vitro gastrointestinal simulation digestion,analyzed for bioavailability of total arsenic and different forms of arsenic.And assessed the food safety and health risks of inorganic arsenic before and after digestion using Target Hazard Quotient(THQ)and Target Cancer Risk(TR).The results showed that the total arsenic bioavailability was higher during gastrointestinal digestion than during gastrointestinal digestion.No significant effect(P>0.05)Biological availability varies with arsenic form.The bioavailability of As B is greater in gastric digestion stage than in gastrointestinal digestion stage.The bioavailability of MMA is comparable to that of gastrointestinal digestion.The bioavailability of As~V is smaller in the gastrointestinal digestion stage and greater than 100%in the gastrointestinal digestion stage.Has a significant effect(P<0.05).The bioavailability rule of total arsenic in male crabs were:steamed>raw>microwaved.The bioavailability rule of total arsenic in female crabs were:raw>steamed>microwaved.Cooking increased the bioavailability of arsenic form and the bioavailability of arsenic form after microwaved treatment.The content of As~Ⅲand As C increased from zero to positive before and after digestion.DMA was not detected before and after digestion.No DMA was detected before or after digestion.In combination with the metabolic pathway of arsenic in humans,the process of demethylation of organic arsenic into inorganic arsenic during gastrointestinal digestion is suggested.Based on the results of this study,inorganic arsenic THQ<1 in digested crab does not yet pose a significant health risk,but there is a significant risk of arsenic carcinogenesis when consumed in the long term.