| Recent years, more and more people began to focus on active food packaging. The antimicrobial packaging is a kind of packaging which add the antibacterial agent to the packaging material to prolong the shelf life of food. Polyvinyl alcohol(referred to as PVA) is a water-soluble polymer. The high barrier packaging films which was made by PVA, and it has features with non-toxic, environmentally friendly. The ?lms can be produced to have antimicrobial properties by adding antimicrobial agents such as the chitosan quaternary ammonium salt, polyphenols, calcium propionate, ethyl paraben,and PVA was served as the basement membrane.First different concentrations of calcium propionate were used to modified the polyvinyl alcohol film and the film’s packaging properties were researched.Second the packaging properties of chitosan quaternary ammonium salt, polyphenols, chitosan quaternary ammonium salt blend polyphenols, calcium propionate blend ethyl paraben modified-polyvinyl alcohol films were researched.Then the modified antibacterial polyvinyl alcohol packaging flims were used to packaged the Bream during cold storage and Fresh cut yam in room temperature. And the preservation effect of the groups with the antimicrobial modified polyvinyl alcohol films and the control group were observed. The following conclusions:(1)Different concentrations(0-2.5g/100 m L) calcium propionate were added in polyvinyl alcohol(PVA) to prepare for the calcium propionate modified polyvinyl alcohol packaging films.The results showed that calcium propionate had a good compatibility with the polyvinyl alcohol films,and the films had a good heat resistance. Calcium propionate increased the tensile strength, water vapor permeation coefficient,Swelling ratio and dissolution rate of the films;reduced the breaking elongation of the films and affected the optical properties, the sealing temperature of the films.Concentration of 2.5g/100 m Lcalcium propionate modified film produced a certain inhibitory effect on Bacillus cereus, E. coli, Aspergillus oryzae.Calcium propionate modified polyvinyl alcohol films had a good packaging performance and some antibacterial properties, which can be used as a new type of packaging film for food.(2)Several antimicrobial agents(quaternary ammonium salt of chitosan, tea polyphenols,calcium propionate / Ethylparaben)were added in polyvinyl alcohol(PVA) to prepare for the antibacterial modified PVA film.The results showed that added the quaternary ammonium salt of chitosan, tea polyphenols, calcium propionate combined with Ethylparaben would reduce the elongation at break of PVA film in varying degrees. Added tea polyphenols reduced the tensile strength of the film.Whereas other antimicrobial agents increased its tensile strength;All antimicrobial agents increased coefficient of friction, haze of the film, and improved film’s water vapor permeability, swelling ratio and the dissolution rate, however reduced the transmittance, and changed the color of the PVA film; All antibacterial modified PVA packaging films had good antimicrobial effect against E.coli,S.aureus.and Bacillus cereus. 0.5g/100 m L tea polyphenols, 0.5g/100 m L tea polyphenols combined with 2g/100 m L quaternary ammonium salt of chitosan had showed the antioxidant capacity. The research indicated modified PVA film has good properties of packing and antimicrobial capacity, which can be used as a new type of packaging film for food.(3) The polyvinyl alcohol was selected as membrane material and the 2g/100 m L quaternary ammonium salt of chitosan、0.5g/100 m L tea polyphenols、2.5g/100 m L calcium propionate、0.5g/100 m L Ethylparaben+1.5g/100 m L calcium propionate were selected as antibacterial ingredients to fabricate the antibacterial polyvinyl alcohol packaging films.The effect of the films on bream during cold storage was investigated by analyzed the change of bream’s WHC, p H,Whiteness,TBA,TVB-N,aerobic plate count,texture properties and Sensory Scores.The results indicated the antibacterial polyvinyl alcohol packaging film with 0.5g/100 m L Ethylparaben+1.5g/100 m L calcium propionate could keep the bream fresh effectively under 4±1℃ storage.(4) Packing fresh cut yam with above-mentioned antibacterial modified PVA films Respectively, then store them at room temperature for 10 days.The effect of the films on yam during storage was investigated by analyzing the changes of yam’s quality, weight loss rate, the relative electric conductivity, MDA, aerobic plate count, TA, TSS, Sensory Scores, color and lustre, and PPO.The results indicated the antibacterial polyvinyl alcohol packaging film with 0.5g/100 m L Ethylparaben combined with 1.5g/100 m L calcium propionate and 0.5g/100 m L tea polyphenols could keep the yam stored under room temperature fresh more effectively compared to others antimicrobial agents in this research. |
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