| Take carrageenan /konjac glucomannan composite film as the material, the films are modified by adding nano-SiO2, glycero and ultrasonic dispersion, and their properties such as water vapor permeability, water solubility, swelling degree, oxygen permeabiliby, light trabsmittance were determined. The Fourier transform infrared spectroscopy(FTIR), X-ray diffraction(XRD), Ultraviolet visible spectroscopy(UV), scanning electron microscopy(SEM), were used to characterize the change of structure and properties of blend films. Effects of modified nano-composite film on postharvest physiology and qualities of Agaricus bisporus during storage at 2℃ were studied. The main results are as follows:The nano-sized SiO2 composite film was better in storage. After the storage of 12 d, compared with the control, the values of whiteness, flesh firmness, TSS of Agaricus bisporus treated by nano-packing material were 87.75 and 82.48, 9.0×105Pa, 6.9%, respectively, which were significantly lower than that of control(84.22 and 78.48, 7.6×105Pa, 5.3%). Modified nano-composite film on Agaricus bisporus can delay the increase of cell membrane relative permeability and weight loss. In a word, modified carrageenan/konjac glucomannan/nano-SiO2 composite film had a potential on improving the preservation quality.Carrageenan and konjac glucomannan were modified by adding nano-SiO2, a dopting three factors quadratic orthogonal and rotational combination design, the effects of nano-SiO2, glycerel monostearte on the water permeability rate of the fresh-keeping film were studied. Relevant quadratic regression models were developed. The films with homogeneous structure were prepared via the casting method, which were then characterized by means of IR, UV and SEM. The optimal condition for the film with comprehensive function as follows: nano-SiO2 content 0.03%, carrageenan content 0.60%, konjac glucomannan content 0.48%.The addition of nano-Si O2, the gum ratio carrageenan and konjac, amount of glycerol added L9(3)4 orthogonal experimental design to study the effect of three factors on the nanocomposite film performance. The results showed that the high performance composite film can be obtained when 0.03% of nano-SiO2, 3:1 of the mass ratio of carrageenan(0.60%)and konjac glucomannan and 0.70% of glycerin are used during preparation,which the light trabsmittance of modified composite film is 88.26%, the oxygen permeabiliby is 0.41meq/g,the water solubility is 51.78%,the swelling degree is 76.90%,the water permeability rate is 62.31%.Applying appropriate intensity of ultrasonic on film liquid, and to power ultrasonic treatment, time, temperature as the main study factors(independent variables) respectively X1, X2, X3, using orthogonal rotation experiment design. The effect of properties of carrageenan /konjac glucomannan/ nano-SiO2 blend films was studied. It could also expose out more polar groups, break hydrogen bonds and hydrophobic combining poles inside liquid, and make macromolecule to recombine into non-polar bonds. Under the appropriate treatment power and time, the film could get better properties the surface homogeneity has been improved.Postharvest physiology and qualities of Agaricus bisporus under the different ways of keep-freshing during storage at 2℃ were studied. The results showed that carrageenan / konjac glucomannan /nano-SiO2 composite film packaging and coating could be better to delay increases agaricus bisporus of weight loss and reduce the whiteness and hardness, thereby maintaining a good texture characteristic fruiting to appropriate storage and preservation of agaricus bisporus. carrageenan / konjac glucomannan /nano-SiO2 composite film made agaricus bisporus effectively maintain good organoleptic quality, extend its storage time, according to the various needs of its different preservation methods to improve its commodity value, stored in a mushroom preservation has broad application prospects. |
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