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Apples are rich in nutrients, flavor, in people's daily lives occupy an increasingly important position, loved by the people. But Apple will be planted geographical and time constraints, and a shorter shelf life at room temperature. Among them, the mold is one of the important reasons rotten apples, such as Penicillium expansum. Chemical fungicides can effectively reduce the incidence of mold, but because of public resistance to pesticide residues and bacteria concerns, many countries have begun to restrict or even prohibit the use of chemical fungicides used, so look for safe and easy apple preservation methods become the focus of attention . The experiment will be filming preservation and biological preservation technology, the use of natural non-toxic substances, prepared to contain marine antagonistic yeast alginate - gellan gum blend films (abbreviated active edible films) for fresh apples, preservation order for Apple to provide basis for the development of new technologies. The main results are as follows: First, there is purpose and targeted screening in a wide temperature range and oligotrophic environment inhibited the growth of Penicillium expansum marine yeast, and thus a certain depth of water from the water samples were screened suitable strains as soon as possible Adaptation apple surface micro-environment, and select the anaerobic conditions strains hardly produce ethanol. Adopted after BIOLOG system and 26S molecular methods was identified as Candida orthopsilosis. Finally, the basic properties of the yeast strains and growth conditions related experiments and found that the yeast cells are spherical, filamentous cells can form a false string, growth and reproduction ability, to grow to 16 h to reach 108 CFU / mL biomass, and can grow on poor medium, the optimum medium composition: 3% glucose, 3% maltose, 1.5% yeast extract, 0.15% KH 2 PO 4 , 0.03? Cl 2 , 0.2% MgSO 4 , 0.35% NaCl. Meanwhile at Apple vivo inhibition of the growth of Penicillium expansum related experiments, found mostly from the inhibitory effect of bacterial and yeast cells, and yeast fermentation broth can not afford basic antimicrobial effect. In addition, the antimicrobial activity and inoculated with yeast concentration intervals are related to yeast fungal inoculation before, yeast concentration is larger, stronger antibacterial ability. Second, antagonistic yeast with antibacterial mechanism was discussed, to reflect its ability to inhibit the growth of Penicillium expansum, it with Cryptococcus laurentii comparison, which is recognized as Cryptococcus laurentii ability antagonistic fungi yeast. It was found that the ocean can be a long antagonistic yeast inhibit the growth of mold, even in the flat on the 7th day experiment still about 8 mm zone of inhibition, and Cryptococcus laurentii no longer play in the three days that the role of inhibiting the growth of mold, 7th day throughout the flat are covered with mold spores. Meanwhile, marine antagonistic yeast in the inhibition of spore germination and fungal germ tube elongation and competition for space and nutrition capacity is more than Cryptococcus laurentii. Meanwhile, the holes from Apple vivo experiments point of view, the ocean and the antagonistic yeast Cryptococcus laurentii can significantly inhibit the growth of Penicillium expansum, reduce corruption rate and extent of corruption, corruption levels can be apples, respectively, from the control group 31.3 mm drop to 12.9 mm and 14.4 mm, you can see the ocean stronger antagonistic yeast antibacterial properties. In addition, two yeast mold (Penicillium expansum, Aspergillus niger, Aspergillus flavus, etc.) have a certain inhibitory effect, but the bacteria (Escherichia coli, Staphylococcus aureus, Clostridium perfringens, Bacillus subtilis, fluorescent Pseudomonas, etc.) is not inhibited. Visible, marine antagonistic yeast Cryptococcus laurentii and antimicrobial spectrum similar, but the minimum inhibitory concentration (MIC) experimental point of view, ocean antagonistic yeast MIC of 106 CFU / mL, while the MIC of Cryptococcus laurentii than it is much higher, as 108 CFU / mL, see antagonistic yeast with antibacterial ability. On the other hand, compared with Cryptococcus laurentii, at low temperature and under adverse conditions such as poor nutrition ocean antagonistic yeast multiply rapidly and can quickly adapt to more biomass. Third, a variety of edible films (gellan gum, gelatin, carrageenan, xanthan gum, locust bean gum, carboxymethyl cellulose, konjac gum, high methoxyl pectin, etc.) and of sodium alginate Mixed results were studied by orthogonal optimization experiments the final selection of alginate - gellan gum (1: 9) blend films as edible films in this experiment. Meanwhile, in order to enhance the stability of edible films, so it will not be dissolved due to condensate thus affecting apple sensory effects, using CaCl2 crosslinking way to make edible blend films adhere better to the surface at the apple. Finally, the edible blend films by IR, DSC and microscopic detection of electron microscopy and found edible blend films good compatibility, was multi-grid-like structure. Also found that the edible blend film thickness is small, and the oxygen transmission rate of water vapor at a low level, good mechanical properties, it can be well applied to fresh apples. Fourth, the marine antagonistic yeast added to sodium alginate - gellan gum blend films, prepared surface active edible coating applied to apples, then by CaCl 2 Edible crosslinking process activity film is firmly attached to the surface of apples for apples fresh experiments. The results showed that the activity of edible films edible films and also play the role of antagonist, with the control group, compared yeast group and membrane, the membrane yeast group can significantly reduce the rate of weight loss and corruption, and to fruit firmness and pressure intensity remained at a high level, and contains a higher soluble solids, better physical properties. In addition, the activity of edible films can be slowed down significantly Vc content, polysaccharide content and titratable acid content decreased rate and inhibition of malondialdehyde (MDA) levels to rise. Apple marine antagonistic yeast can induce the body to produce enzymes related to protection of the body, such as enzymes SOD, CAT enzymes. Thus, the active edible films can effectively control the occurrence of corruption and apple microbial contamination and better maintain the quality of apples.
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