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Studies on the Phisio-chemical Characteristics and Fresh Keeping Technologies of Post-harvest in Pleurotus Nebrodensis

Author: XiongQiaoLing
Tutor: BianYinBing；XingZengTao
School: Huazhong Agricultural University
Course: Microbiology
Keywords: P. nebrodensis fresh keeping irradiation chitosan MAP phisio-chemical characteristics
CLC: S646
Type: Master's thesis
Year: 2007
Downloads: 98
Quote: 2
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Abstract

Pleurotus nebrodensis （Inzengae）Quél（P. nebrodensis） is an edible mushroom whichthe fruit body has highly nutritious and good taste, it is also has very good market valueand development future. This article used ⁶⁰COγray irradiation、chitosan solution coatingand MAP（modified atmosphere package） treatment with lower temperature storage,research the phisio-chemical characteristics of P. nebrodensis and found the rational freshkeeping method in the storage of post-harvest.1. Used different dosage of 0.8、1.2、1.6 and 2.0kGy ⁶⁰COγray irradiationirradiated the fruit body of P. nebrodensis and stored them in 4℃. The results showed thatthe 1.2kGy dosage irradiation treatment could retained higher superoxidase dismutases（SOD） and catalase （CAT） activity, and exhibited less polyphenol oxidase （PPO） andprotease activity. At the same time the max value of PPO and protease activity appearedlatest. 1.2kGy dosage irradiation treatment could exhibited least post-harvest rooting andretained longest shelf-life. The later of the PPO and protease activity max value appeared,the longer of the storage time of the fruit body. ⁶⁰Coγray irradiation on P. nebrodensiscould decreased the enzymes activity, reduced the protein degrading and browning of thefruit body of P. nebrodensis. The soluble protein and total sugar content of P. nebrodensiswere keeping decreased during the storage time of P. nebrodensis.The fruit body of P. nebrodensis treated with 2.0kGy dosage irradiation retained lessantioxidant enzymes activity, soluble protein and total sugar content, at the same time themalonaldehyde（MDA） content and cell wall electronic relative conductivity were high.The storage time of 2.0kGy dosage irradiation treatment was shortest. Those indicated toohigher dosage level （≥2.0kGy） of irradiation could accelerate the nutrition degradationand rotting. ⁶⁰COγray irradiation irradiated on P. nebrodensis could increased the MDAcontent and cell wall electronic relative conductivity, and damage the cell wall. ⁶⁰Coγrayirradiation on P. nebrodensis could decreased the enzymes activity, reduced the proteindegrading and browning of the fruit body, and we think this is the main reason whyirradiation treatment could prolong the storage time.2. Research the effect of 0.5% chitosan、1.0% chitosan、1.5% chitosan、1.0%chitosan+0.5%CaCl₂ and 0.5%CaCl₂ solution treatment on the fresh keeping of P.nebrodensis. The results showed that the fruit body treated with 1.0% chitosan retainedless weight lost and MDA content. 1.0% chitosan treatment retained higher antioxidant enzymes activity and less PPO and protease activity, and the protein degrading andbrowning of the fruit body were least. The nutritious contents and the sense quality wereall better than the other trestments and CK. So we think that 1.0% is the rational chitosancoating solution concentration.The shelf-life of the fruit body of 0.5% chitosan and 1.5% chitosan treatment werevery short, and retained higher PPO activity, protease activity and MDA content, lessantioxidant enzymes activity during the storage time. Incongruity concentration of thechitosan coating solution could accelerate rotting. 0.5%CaCl₂ solution treatment on P.nebrodensis could retained the structure of the cell wall and retandant senescence. But thestorage time of used 0.5% CaCl₂ and 1.0% chitosan solution treatment was not longer thanthat used 1.0% chitosan solution only.3. Used different modified atmosphere package （MAP） film packaged the fruit bodyof P. nebrodensis. The storage quality of different MAP from good to bad wererespectively single direction ventilated film、PO（polyolefin） film、ventilated film、PE（polyethylene） film、PVC（polyvinyl chloride） film,single direction ventilated film werethe best MAP film. The fruit body packaged by single direction ventilated film retainedhigher SOD activity、CAT activity、soluble protein content and amylose content, exhibitedless MDA content. At the same time the sense quality were goog and the storage timewere long.This article used Texture analyzer on the texture analyzed of P. nebrodensis fruitbodies for the first time. The results showed that fruit body packaged by single directionventilated film retained highest hardness during the storage time. The results of usedTexture analyzer were the same to that of sense quality assessing.

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