| As a common edible fungus,button mushrooms?Agaricus bisporus?is prone to senescence,browning and microbial invasion during storage after harvest due to its high water content and no obvious tissue protection.As an important way to preserve fresh fruits and vegetables,packaging is widely used in the storage of the edible fungus.Packaging,as an important way to preserve fruits and vegetables,has a unique advantage in preserving button mushrooms.Button mushrooms can be adjusted to form a spontaneous atmosphere through the respiration and the different sizes of micropores in the packaging process.In addition,films with different pore sizes and materials can also inhibit the evaporation of moisture,leaving the lost water in the bag,creating a high-humidity micro-environment,reducing its weight loss rate,maintaining freshness and improving the quality of mushrooms.In this study,rotting button mushrooms during storage at 4? was used as the experimental material.First,the main pathogenic bacteria of button mushrooms during storage were screened.Plant essential oil with good antifungal effect was studied and its main components were added to alginate biological composite films.In the end,the effects on the properties of the composite films and the antifungal and fresh-keeping application of button mushrooms were studied in order to provide a theoretical basis for the preservation of button mushrooms during storage.The main findings are as follows:?1?Through the isolation and identification of pathogen in the storage period of button mushrooms 4?,nine pathogens were obtained from the total screening,which were divided into three kinds of molds and two kinds of bacteria.Repeated verification of the pathogenic bacteria in the experiment revealed that the pathogen was the main pathogen.The 18SrDNA technique and phylogenetic tree comparison analysis confirmed that the pathogen No.3 was Trichoderma sp.?2?The thirteen kinds of plant essential oils such as turmeric,forsythia,and eucalyptus were used to carry out in vitro antifungal test against Trichoderma sp..The results showed that holly essential oil and oregano essential oil had a better inhibitory effect on Trichoderma sp.,followed by eucalyptus essential oil,arenaceous essential oil,forsythia essential oil and spearmint essential oil.Further study on the main components of these six essential oils showed that carvacrol,the main component of oregano essential oil,had the strongest inhibitory effect on Trichoderma sp..And the minimum inhibitory concentration of carvacrol on Trichoderma sp.is 0.2?L/m L,and the minimum fungal concentration is 0.4?L/m L.?3?The carvacrol?CAR?is added to the sodium alginate film,and its addition amount plays an important role in the physical properties and mechanical properties of the sodium alginate composite film.The resultant composite film containing 0.8%CAR?volume fraction?exhibited the optimal comprehensive performance with a water solubility of 90.48%,a transparency of 0.23 mm-1,a water vapor transmission rate of 0.17 g d-1cm-2,a tensile strength of 72.24 MPa,an elongation at break of 83.41%and the inhibition efficiency against Trichoderma sp.of 65.79%.?4?The CAR was microencapsulated by?-cyclodextrin??CD?.In addition,the embedding rate and antifungal activity of the?CD-carvacrol microcapsule core wall ratio of 1:10 is the highest.The ?CD-CARM/SA films with ?CD-CARM of different concentrations?0,15,30,and 60 g/L?were prepared by solution casting.And the addition of 30 g/L of the?CD-CARM microcapsule can be more.It is uniformly dispersed in the sodium alginate film to form a strong intermolecular interaction.Under this condition,the composite film has better comprehensive performance and the strongest antibacterial activity.The transmittance at 600nm is 0.49 mm-1,the water solubility is 92.34%,and the water vapor transmission rate is 0.17 g is 55.43 MPa,and the elongation at break is 93.08%.?5?Button mushrooms were put in the trays?7.00×15.00×9.50 cm?and then sealed up the trays with pure SA films,CAR/SA films and ?CD-CARM/SA films respectively.The control was not packaged.The overall preservation effect of the ?CD-CARM/SA composite film on the postharvest button mushrooms mushroom was better than that of other treatment groups.The weight loss rate,hardness and browning of button mushrooms were observed when stored for 12 days.The situation,openness and overall acceptability and total number of microorganisms were 4.14%,0.35 MPa,31.92%,6.3 and 7.77 lg CFU/g,respectively.It can effectively inhibit the increase of weight loss rate,browning and total number of microorganisms of button mushrooms,and delay the decline of hardness,umbrella opening and overall acceptability.The ?CD-CARM/SA composite film increased the superoxide dismutase?SOD?,catalase?CAT?and ascorbate peroxidase?APX?activities of button mushrooms to reduce oxidative damage and prolong its post-harvest storage period. |
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