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Studies on Influence Factor and Existing Fome of Formaldehyde in Lentinula Edodes

Author: ZhangZuo
Tutor: DingXiaoZuo
School: Southwestern University
Course: Of Food Science
Keywords: Mushrooms Formaldehyde Influencing factors State of existence
CLC: TS207
Type: Master's thesis
Year: 2007
Downloads: 206
Quote: 1
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Abstract


The mushroom is a kind of delicacies, but due to the presence of formaldehyde and experienced international \The mushrooms as the main raw material, the enzyme activity of the formaldehyde generated mushrooms influencing factors: different extraction methods, the presence of formaldehyde in mushrooms status; establishment of formaldehyde with polysaccharide and protein binding model system to explore mushrooms combined with formaldehyde substances; formaldehyde solution and the genetic effects of the mushroom extract compared to food safety evaluation provides some data on the mushrooms. Results are as follows: (1) Compare mushrooms and other edible fungi gamma-Valley aminoacyl GGT and cysteinyl sulfoxide lyase activity, to further define the mechanism of the formation of formaldehyde in mushrooms: mushrooms metabolism can produce formaldehyde , there are two different types of enzymes involved in the reaction, namely the gamma-glutamyl endopeptidase and the cysteinyl sulfoxide lyase. pH 7.0, 37 ° C under the conditions of gamma-glutamyl GGT activity of 3.62; pH 9.0,37 ° C under the conditions of cysteinyl sulfoxide cleavage activity of 2.38. (2) gamma-glutamyl GGT optimum pH was 7.0, the optimum temperature is 37 ° C, the Ca 2 - GGT activity of Cu 2 - , Pb 2 , Zn 2 can inhibit enzyme activity. Except leucine and glycine, L-cysteine, L-proline, L-tryptophan, valine vitality of the enzyme was activated. (3) cysteinyl sulfoxide lyase is an alkaline enzymes, the optimum temperature is 37 ° C, the Ca 2 , the Pb 2 Cu 2 < / sup>, Mg 2 can contribute to the enhancement of enzyme activity, and Zn 2 lyase activity inhibition. L-cysteine, proline, glycine lyase activity can be suppressed. (4) acetylacetonate spectrophotometric determination of formaldehyde in the mushrooms, mushrooms and various parts of the formaldehyde content and gamma-glutamyl GGT and cysteinyl sulfoxide lyase activity corresponding to. (5) mushrooms formaldehyde free and bound states exist without acidic water distillation extraction of free formaldehyde, plus acidic water distillation the total formaldehyde mushrooms, acetylacetone spectrophotometric determination. This method recovery was 103.68% to 117.51%, with good repeatability. Mushroom samples, combined with the state total formaldehyde formaldehyde content of 71.7 to 74.6%, 34.1% to 39.5% of free formaldehyde and formaldehyde ratio of bound. (6) mushrooms proteins and polysaccharides can be combined with formaldehyde, combined were 71.6 and 229.9 mg / kg, formaldehyde polysaccharide conjugate. The combination of proteins with formaldehyde is almost free from the influence of pH, temperature, time, the binding amount is slowly increased with the increase of the concentration of formaldehyde; the optimum polysaccharide conjugate formaldehyde pn 7.0, the binding capacity is reduced with time, with the increase in the concentration of formaldehyde large increase, independent of temperature. (7) various concentrations of mushroom extract treated Vicia faba root tip cells micronucleus and water negative control group, there is a highly significant difference (P <0.01), that the mushroom water extract on Root Tip Cells the generation of micronuclei showed a significant inhibition. Formaldehyde solution processing micronucleus rate increases with the concentration, indicating that the formaldehyde solution may have genotoxic effects. (8) mushroom extract and formaldehyde solution induced by the test strains TA97, TA98 number of revertant colonies did not exceed more than 2 times the spontaneous back to the variables in the experimental concentration, and back to change the dose - response relationship between the number of colonies detected result is negative, suggesting that the shiitake extract and formaldehyde solution had no direct role induce gene mutations shift pattern. (9) fresh mushrooms soaked for 30 min formaldehyde content from 7.70mg/kg to 4.13 mg / kg, simmer for 25 min after the formaldehyde content from 3.71mg/kg to 1.70mg/kg, fried 4min when formaldehyde content by 11.82 mg / kg reduced to 5.25mg/kg. Through the above processing method to reduce formaldehyde in mushrooms.

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CLC: > Industrial Technology > Light industry,handicrafts > Food Industry > General issues > Food standards and testing
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