Study On Influence Factors Of Formaldehyde Forming In Lentinus Edodes & Control Measures In Processing

This article studied the influence factors of Formaldehyde forming and control measures during preserving and drying of Lentinus edodes. Freshly harvested and dryed fruit bodies of shiitake mushroom were obtained from the local wholesale market. Results of experiment are as follows:1. Acetylacetone spectrophotometer was used to measure formaldehyde contents in edible mushroom. Formaldehyde contents of Chongqing is 4~25mg/kg in freshly shiitake mushroom and 100~200mg/kg in dryed ones, there were formaldehyde in all shiitake mushroom, while the contents of formaldehyde in other edible mushroom, such as Flammulina velutipes, Pleurotus ostreatus and Pleurotus sajor-caju(Fr.)Sing were just a few. Formaldehyde contents in dryed shiitake mushroom are much higher than freshly ones.2. Formaldehyde contents is increasing step by step in growing. Formaldehyde was not detected in growth stuff. It was detectd from mycelial phase to mature phase. Formaldehyde contents in mature phase were most, which is twice higher than the contents in beginning phase—mycelial phase. Formaldehyde is forming in the growth of shiitake mushroom and is a naturally metabolizable substance.3. Formaldehyde contents in manpower plant shiitake mushroom is range from 4mg/kg to 30mg/kg while 10mg/kg to 50mg/kg in wild ones; Generally, Formaldehyde contents is from 4mg/kg to 50mg/kg in freshly shiitake mushroom, and from 100mg/kg to 200mg/kg after dryed.4. II -Yigufen played an important role in control the content of Formaldehyde in mushroom. Formaldehyde contents is 5.8mg/kg in freshly shiitake mushroom that were growed in II -Yigufen culture medium and 30mg/kg after dryness, which is only one fifth of compasion.5. Lentinic enzyme can accelerate formaldehyde forming and increase its contents. Its optimum temperature is 37℃ and optimum pH value is 8.0. Contents of Formaldehyde, which is added Lentinic enzyme, are nine times higher than compasion after 3 hours. The ablity of Lentinic enzyme to defend heat is better. It lose activity in 60°C20min, 80°C5min and 90℃ 1min.