【摘要】：香菇(Lentinula edodes)是我國廣泛栽培的食用菌之一,年產量長期居各種食用菌之首。近些年來,隨著香菇出口量的不斷增加,重金屬含量超標問題也逐漸被人們所關注。砷元素是一種有毒的重金屬元素,在香菇產品中砷含量超標問題也時有發(fā)生。本課題對香菇主產區(qū)的栽培原料和子實體進行了抽樣調查,了解了香菇栽培原料及子實體中重金屬砷污染現狀,并研究了外源添加物(砷鹽、磷酸鹽、硅鹽)和培養(yǎng)溫度對菌絲體和子實體吸收砷的影響,分析了砷在子實體不同部位的分布特點,探討了香菇對重金屬砷的污染規(guī)律和防控技術。對湖北和河南的部分香菇產區(qū)栽培原料和子實體的砷污染情況調查表明,重金屬砷污染情況極少發(fā)生。依據《GB 2762-2012食品安全國家標準食品中污染物限量》中的相關標準,僅河南省沙河店的1個樣品砷含量超標,其含量達到了約0.667mg/kg。研究了外源添加物對菌絲體吸收砷的影響,結果表明,培養(yǎng)基中砷濃度越高,對菌絲生長的抑制作用越強,到2 mg/L時菌絲幾乎無法生長,而其菌絲體中的砷含量是隨著培養(yǎng)基中砷濃度的增大而增大;添加一定濃度的磷酸鹽后,在含有五價砷[As(V)]的培養(yǎng)基中的菌絲長速明顯高于未添加磷酸鹽的對照組,但對于含有三價砷[As(Ⅲ)]的培養(yǎng)基,添加磷酸鹽則沒有明顯作用,說明磷酸根離子(PO43-)可以有效緩解As(V)對菌絲生長的抑制作用。其次研究了溫度對菌絲體砷含量的影響,結果表明,菌絲在較低溫(16℃-22℃)時吸收的砷比較高溫(25℃-28℃)時的稍多。在香菇栽培料中外源添加不同濃度的砷,其栽培試驗結果顯示,當培養(yǎng)料中添加的砷越多,子實體中富集的砷就越多,富集系數為0.071~0.302;通過線性回歸分析發(fā)現,兩者之間呈顯著正相關,符合方程y=0.5458x+0.1254,R2=0.9935。當培養(yǎng)料中添加一定量砷時,香菇不同品種子實體中砷含量也有差異,在供試的5個品種中,矮花1號子實體砷含量最高,矮花2號最低,兩者差異顯著。對于香菇不同潮次的子實體,其砷含量是不同的,第一潮菇子實體的砷含量明顯高于第二潮菇。香菇子實體中不同部位的砷含量亦不相同,其中菌褶的含量最高,其次是菌蓋,菌柄含量最低。綜上所述,香菇子實體砷污染僅零星發(fā)生,子實體中砷含量隨著培養(yǎng)基質中砷含量的增加而上升,溫度可稍微影響菌絲體對砷的吸收量。在培養(yǎng)基中添加一定濃度的磷酸鹽后,可以顯著地緩解五價砷[As(V)]對菌絲的抑制作用,但對三價砷[As(Ⅲ)]則沒有明顯作用。選擇合適的香菇品種,有利于控制子實體中砷含量。
[Abstract]:Lentinus edodes (Lentinula edodes) is one of the widely cultivated edible fungi in China. In recent years, with the increasing export of lentinus edodes, the problem of heavy metal content exceeding the standard has been paid more and more attention. Arsenic is a toxic heavy metal element. In this paper, the cultivation raw materials and fruiting bodies of Lentinus edodes in the main producing areas were investigated, and the present situation of arsenic pollution in the raw materials and fruit bodies of Lentinus edodes was investigated, and the exogenous additives (arsenic salt, phosphate, phosphate) were studied. The effects of silicon salt and culture temperature on the absorption of arsenic in mycelium and fruiting body were studied. The distribution characteristics of arsenic in different parts of fruit body were analyzed, and the pollution law and control technology of heavy metal arsenic in Lentinus edodes were discussed. The investigation on arsenic pollution of cultivated raw materials and fruit bodies in parts of Lentinus edodes production areas in Hubei and Henan shows that arsenic pollution of heavy metals is rare. According to the relevant standard of "GB 2762-2012 national food safety national standard food pollutant limit", only one sample in Shahedian, Henan Province, contains more arsenic than the standard, and its content reaches about 0.667mg / kg. The effects of exogenous additives on the uptake of arsenic by mycelium were studied. The results showed that the higher the arsenic concentration in the culture medium, the stronger the inhibitory effect on the growth of hyphae. The hyphae could hardly grow at 2 mg/L. The content of arsenic in the mycelium increased with the increase of arsenic concentration in the medium, and the hyphal length in the medium containing pentavalent arsenic [As (V)] was significantly higher than that in the control group without phosphate after adding a certain concentration of phosphate. But for the medium containing trivalent arsenic [As (鈪，

本文編號：2216844