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The Separation Identification and Regulation of Idiosyncratic Microorganisms in Preserved Fruit

Author: XuFang
Tutor: XiaoGengSheng
School: Jiangxi Agricultural University,
Course: Microbiology
Keywords: Preserved fruit Debaryomyces hansenii Aerococcus viridans salinity
CLC: TS255.3
Type: Master's thesis
Year: 2011
Downloads: 36
Quote: 0
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Abstract

Succades are the typical local characteristics fruit and vegetable food.The traditional process is aoume, almond, plums and some south fruits are salted and expored to the sun and stored, and then desalted, candied,dried. The succades have low sugar, distinct flavor, soft feeling and deeply loved by consumer. The production process is unique, but equipment conditions is so simple, the whole way by hand, so its not whole accorded with modern food manufacturing. So this thesis uesd several salted fruits as materials, study the relativity analysis among the number of colony with salinity, acidity and other indexes in salted fruits for succades material, the separation and identification of microorganisms from traditional preserved fruit, the research of three traditional way to kill aerococcus viridans and beneficial microorganisms effect the product quality.(1) The number of colony, salinity, acidity and moisture content in salted fruits had some relativities. Results showed that the number of colony was significantly negatively related with salinity, negatively related with moisture content, weak significantly related to acidity. It also showed that increasing the salinity was an effective method to ensure the quality of the initial microorganism for succades material.(2) Pour plate method was used to isolate the varieties of microorganisms from eight kinds of preserved fruits. Micro-examination, physiological and biochemical tests, and 16SrDNA gene sequencing analysis were used to identify microorganisms, and built the phylogenetic trees of them. The results showed that 32 strains of bacteria and 7 strains of fungi were isolated, in Which has a sweet smell of Debaryomyces hansenii and a conditional pathogenic bacteria:Aerococcus viridans.(3) Results showed that under the condition of 50℃water bath heating for 23min or micromave power 700W for lmin or microwave power 600W for 70s, the fatality of aerococcus viridans can be 100%; adding 200mg/mL sodium benzoate or 100mg/mL potassium sorbate or 10mg/mL ethyl p-hydroxybenzoate the fatality also can be 100%. It follows that microwave and heat treatment are effective ways to kill aerococcus viridans; the added antiseptic amount is higher than the amount of national standards, so adding antiseptic is not an effective way to kill aerococcus viridans in the food industry.(4) When Debaryomyces hansenii added into the Preserved plum, the content of total sugar and reducing sugar reduced effectively, and the reducing level of total acid became slowly. The more added Debaryomyces hansenii, the total sugar and reducing sugar reduced more, the total acid reduced slowly, but when the additive amount was 2%, no apparent change in volume. When salt was lower in the preserved plum, the reduce speed of total sugar and reducing sugar became fast, the reduce speed of total acid became slowly.

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