The danger of mycotoxin contamination entering the food supply through post-harvest infection is of perennial concern to food safety experts. To explore the distribution of Penicillium expansum and diffusion of its my...The danger of mycotoxin contamination entering the food supply through post-harvest infection is of perennial concern to food safety experts. To explore the distribution of Penicillium expansum and diffusion of its mycotoxin, patulin, in blue mold-damaged pears, Pyrus bretschneideri Rehd. cv. Yali obtained from markets and orchards in China were artificially inoculated with P. expansum and assayed for patulin accumulation and degree of fungal colonization. The inoculated pears were incubated until the lesions were 5, 10, 20, or 30 mm in diameter. We sampled tissue at a range of distances from the lesion, measured the spread of Penicillium by plate colony-counting methods, and used UHPLC-MS/MS to detect and quantify the patulin concentration. More P. expansum colony-forming units were isolated from pears with a higher degree of decay. Farther from the lesion, the fewer P. expansum colonies were observed, and the lower the patulin content detected. We found a significant difference in the patulin content between samples due to lesion size, and also in tissue sampled 10 mm away from the lesion. In consideration of this finding, to ensure food safety, we recommend that when a blue mold rot lesion on pear is 5, 10, or 20 mm in diameter, 20, 30, and 40 mm beyond the lesion should be removed, respectively. If a lesion surpasses 30 mm in diameter, the whole pear should be thrown away.展开更多
Penicillium expansum 3.5425 was applied in solid-state fermentation(SSF)of agricultural wastes for polygalacturonase biosynthesis.Among various carbon additives,apple pomace was most suitable for the biosynthesis of p...Penicillium expansum 3.5425 was applied in solid-state fermentation(SSF)of agricultural wastes for polygalacturonase biosynthesis.Among various carbon additives,apple pomace was most suitable for the biosynthesis of polygalacturonase(1440.57 U/g).Optimization of medium parameters using rotational orthogonal design(ROD)experiment combined with optimal fermentation conditions resulted in a 2.72-fold increase in the polygalacturonase production.By using ammonium sulphate precipitation,ion-exchange and gel-permeation chromatography,the polygalacturonase produced by P.expansum 3.5425 was finally purified which had specific activity of 19269 U/mg and molecular weight of 30 kDa.The enzyme was remarkably active in the pH range of 3-5 and at 50℃,which makes it more acceptable in the industrial application.Besides,partially purified polygalacturonase(875.15 U/mL)was used for apple juice clarification and the clarity at 0.4 mL/kg was maximum,which reveals a great potential of polygalacturonase in food industry.展开更多
基金supported by the Quality and Safety Risk Assessment for Agro-products of China (GJFP 2015014)
文摘The danger of mycotoxin contamination entering the food supply through post-harvest infection is of perennial concern to food safety experts. To explore the distribution of Penicillium expansum and diffusion of its mycotoxin, patulin, in blue mold-damaged pears, Pyrus bretschneideri Rehd. cv. Yali obtained from markets and orchards in China were artificially inoculated with P. expansum and assayed for patulin accumulation and degree of fungal colonization. The inoculated pears were incubated until the lesions were 5, 10, 20, or 30 mm in diameter. We sampled tissue at a range of distances from the lesion, measured the spread of Penicillium by plate colony-counting methods, and used UHPLC-MS/MS to detect and quantify the patulin concentration. More P. expansum colony-forming units were isolated from pears with a higher degree of decay. Farther from the lesion, the fewer P. expansum colonies were observed, and the lower the patulin content detected. We found a significant difference in the patulin content between samples due to lesion size, and also in tissue sampled 10 mm away from the lesion. In consideration of this finding, to ensure food safety, we recommend that when a blue mold rot lesion on pear is 5, 10, or 20 mm in diameter, 20, 30, and 40 mm beyond the lesion should be removed, respectively. If a lesion surpasses 30 mm in diameter, the whole pear should be thrown away.
基金The authors would like to thank the High-Level Talent Scientific Research Staring Foundation(No.2015015)provided by Henan Institute of Science&TechnologyKey Scientific Research Project(17A550001)supported by Education Department of Henan Province+1 种基金Program for Innovative Research Talents(in Science and Technology)of Henan Provincial University(16HASTIT015)Excellent Youth Foundation of Henan Scientific Committee(174100510003).
文摘Penicillium expansum 3.5425 was applied in solid-state fermentation(SSF)of agricultural wastes for polygalacturonase biosynthesis.Among various carbon additives,apple pomace was most suitable for the biosynthesis of polygalacturonase(1440.57 U/g).Optimization of medium parameters using rotational orthogonal design(ROD)experiment combined with optimal fermentation conditions resulted in a 2.72-fold increase in the polygalacturonase production.By using ammonium sulphate precipitation,ion-exchange and gel-permeation chromatography,the polygalacturonase produced by P.expansum 3.5425 was finally purified which had specific activity of 19269 U/mg and molecular weight of 30 kDa.The enzyme was remarkably active in the pH range of 3-5 and at 50℃,which makes it more acceptable in the industrial application.Besides,partially purified polygalacturonase(875.15 U/mL)was used for apple juice clarification and the clarity at 0.4 mL/kg was maximum,which reveals a great potential of polygalacturonase in food industry.
