Effects Of Drying Methods On Sulfur Dioxide Residues In Three Edible Fungi And Their Dietary Exposure Risk Assessment

The problem of excessive sulfur dioxide residues in edible fungi seriously affects the quality and safety of edible fungi,constitutes an industrial technical barrier,and hinders the healthy and rapid development of the edible fungi industry.Numerous studies have shown that sulfur dioxide residues in edible fungi mainly come from artificial additions during post-harvest production and processing.In addition,the accumulation of sulfur dioxide caused by soil,culture materials,water sources,and respiratory metabolism during the growth process and processing methods The endogenous transformation of sulfur-containing species is also an important aspect of the source of sulfur dioxide.Therefore,finding out the real source of sulfur dioxide residues in edible fungi can provide a theoretical basis for the processing and supervision of edible fungi.This paper takes three typical edible Tremella fuciformis,Lentinus edodes and Agaricus blazei as research objects,focuses on the effect of drying methods on the residual sulfur dioxide in edible fungi,and provides technical support for obtaining products with safe and good sensory quality,as follows:(1)Optimize the distillation-iodine titration method(GB5009.34-2016)to determine the residual sulfur dioxide in samples from different sources.The distillation time was shortened to 8 min by using the Kjeldahl distillation system instead of the all-glass distillation apparatus.The optimized method was used to detect the residual amount of sulfur dioxide in the fresh,dry and simulated sulfite-treated samples of commercially available edible fungi,and the values were in the range of 20-12250 mg/kg.Sulfur dioxide residues have a certain impact.Without considering the addition of external sources,the residues of sulfur dioxide before and after drying with different drying methods(hot air drying,natural air drying,and vacuum freeze drying)were tested for Tremella fuciformis,Lentinus edodes and Agaricus blazei.Three kinds of hot air drying treatment The change of sulfur dioxide residue in edible fungi(on a dry basis)was the largest,with Tremella fuciformis 35.7 mg/kg,Lentinus edodes 40.4 mg/kg,Agaricus blazei 34.0 mg/kg;followed by natural drying Tremella fuciformis 29.4 mg/kg,Lentinus edodes 35.9 mg/kg,Agaricus blazei 31.3 mg/kg,the least effect was vacuum freeze-dried Tremella fuciformis 21.1 mg/kg,Lentinus edodes 26.2 mg/kg,Agaricus blazei 23.2 mg/kg.The results showed that the drying method was one of the factors affecting the residual amount of sulfur dioxide in edible fungi.(2)Cause analysis of the effect of different drying methods on sulfur dioxide residues in three different edible fungi.The contents of glutamic acid-oxaloacetate aminotransferase,sulfur-containing amino acids and sulfur-containing volatile compounds in three edible fungi treated with different drying methods were determined by spectrophotometry,acid hydrolysis and HS-SPME-GC-MS.type changes.The results showed that for Tremella fuciformis,Lentinus edodes and Agaricus blazei,the enzyme content of hot air drying was the highest(12.61 U/g for Tremella fuciformis,15.21 U/g for Lentinus edodes,79.09 U/g for Agaricus blazei),followed by natural drying(12.29 U/g,8.31 U/g,70.17 U/g),and vacuum freeze-drying was the lowest(10.58 U/g,8.8 U/g,61.34 U/g);Two sulfur-containing amino acids were detected in three edible fungi:methionine,Cystine(cystine and methionine in Tremella fuciformis are 0.10 g/100 g,0.27 g/100 g;respectively,2.26 g/100 g,2.23 g/100 g in Lentinus edodes,0.19 g/100 g,2.01 g/100 g in Agaricus blazei).After hot air drying treatment,the content of sulfur amino acid in the three edible fungi was the highest,followed by vacuum freeze drying.26,50,and 58 volatile compounds were detected in Tremella fuciformis,Lentinus edodes and Agaricus blazei,and 3,22,and 6 sulfur-containing volatile compounds were detected.Among them,the edible fungi treated by hot air drying have the highest content of sulfur-containing volatile compounds,and the types of vacuum freeze drying are the most..The results confirmed that glutamate-oxaloacetate aminotransferase in edible fungi plays an important role in converting methionine to produce sulfur dioxide.At the same time,the sensory qualities such as appearance,texture and smell of the three edible fungi were evaluated after different drying methods.It was found that the three edible fungi after hot air drying had the highest scores and generally higher quality.Vacuum freeze-drying preserved the fresh products to the greatest extent shape,color and other quality characteristics.(3)Combined with the safety index method and the risk business method,the dietary exposure and risk quotient of sulfur dioxide in the fresh and dried edible fungi products were evaluated.Taste.The chronic dietary exposure risk assessment of sulfur dioxide residues in edible fungi found that the%ADI values of adults and minors were both less than 100%,ranging from 11.57%to 38.60%,indicating the chronic dietary risk of sulfur dioxide residues in three edible fungi.an acceptable risk.Moreover,the chronic dietary risk of sulfur dioxide residues in adults ingested by fresh or dried edible fungi was lower than that of minors,indicating that with the increase of age,the chronic dietary risk of sulfur dioxide residues in edible fungi gradually decreased.