| Antimicrobial packing paper has an effect of inhibiting and sterilizing microorganism.It can not only protect the contamination through producing,transportation,storage,selling from microorganism and others,but also can ensure the food quality and shelf life.Lettuce is rich in nutrition,which includes antioxidant,β-carotene,vitamin B,vitamin C,vitamin D and also full of dietary fiber and micronutrients,such as magnesium,phosphorus,calcium and a little of iron,copper,zinc.People who intakes lettuce frequently can strengthen the digestion and absorption of protein and fat,as well as improve the circulation of intestines and stomach.However,the research in regard to the antimicrobial packing materials of lettuce is lacking in China.1.In this research,according to the single factor experiment,cinnamon essential oil were identified as an antimicrobial agent,and the technology of producing antimicrobial packing paper came from evaluation of orthogonal experiment.Using 10%(mass fraction,the same below)cinnamon essential oil,3.0%hydrophilic nano-silica dioxide,2.0%pullulan,1.5%konjac glucomannan and 0.2%Twain 20 to make coating liquid.Drying for 120sat30℃.2.According to the physical test of paper,the surface of antimicrobial packing paper is formed with a steady coating layer.The average grammage of antimicrobial packing paper is 105 g/m2 while the average coating grammage is 27.0 g/m2.Some physical indicators are as follows.Oxygen permeance is 112.5 cm3/(m2·24 h·0.1 MPa),water vapor transmission rate is 760 g/(m2·24h),cobb value is 15.0 g/m2,strain is 247%,folding endurance is 2.28,fold number is 188,bursting strength is 435 kPa and tearfng resistance is 189 mN.The decrease of oxygen permeance,water vapor transmission rate,cobb value and the increase of strain,folding endurance,fold number,bursting strength,tearfng resistance can be seen from the experiment.It could be concluded that the combination between coating layer and paper is stable,and the coating layer increases physical strength packing performance of the paper.From the antimicrobial experiment,the paper has a prominent effect of antibacterial ability.E.coli,S.enterica,S.aureus and L.mnocytogenes were sensitive to this paper.The antibacterial circle diameter of each bacteria is 20.18 mm,32.25 mm,34.96 mm and 27.02 mm Moreover,the antibacterial ability of this paper was superior to penicillin tablets in the CK.The times higher than penicillin tablets in the CK were 2.16,1.55,1.41 and 1.06.3.From the experiment of lettuce storage,we compared the test result from three ways of store,which included antimicrobial packing paper,PE film bag and unpacked.It can be seen from the result that antimicrobial packing paper could protect the nutrition during the lettuce storage and the weight lass rate is 5.34%.It prevented the loss of chlorophyll(chlorophyll decreases 17.96%).Besides,it also relieved the degree of yellowing tendency(value b is 25.4)and protect green state(value a is-4.8).In addition,the antimicrobial packing paper has obvious antibacterial effect and restrained the total numbers of colony and MDA from growing,and decreased the speed of freshness decline. |
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