Study On Fresh Maize Preservation Packaging Technology And Packaging Material

With the development of economy and the improvement of people's living standards,consumers'demand for food is not only satisfied with fruit and vegetables in the current season.In this general trend,people's demand for fresh corn is also growing.Fresh corn is rich in nutritional value,rich in dietary fiber,vitamins and so on.It is called"green vegetables"and"longevity food".According to relevant statistics,the consumption of fresh maize in China is 57 billion ears,and has a trend of continuous expansion,which has broad market prospects.However,fresh corn has strong seasonality and short storage period at room temperature.Therefore,how to prolong the storage period of fresh corn at room temperature and increase its commodity value has been the pursuit of fresh corn industry.Fresh-eating maize is still a living organism after harvest because of its high water content.During storage,it will undergo a series of physiological and biochemical reactions,resulting in rapid decline in nutritional value.At the same time,because of its high nutritional value,it is easier to be infected by microorganisms and fungi,which reduces the sensory quality and storage life,and seriously affects the market value of fresh corn.In view of the quality change of Fresh-eating maize during storage,the fresh-keeping effect of Fresh-eating Maize at room temperature was studied by the combination of pretreatment solution and bacteriostatic film.Firstly,using household condiments:sugar,salt and vinegar as pretreatment solution,single factor experiments were carried out to prepare a fresh-keeping solution for Fresh-eating corn.Orthogonal experiments were carried out to prepare a compound fresh-keeping solution for Fresh-eating corn.The fresh-keeping properties of Fresh-eating corn were determined at room temperature?temperature 22°C,relative humidity 75%?for 20 days.To include:sensory quality,weight loss rate,elasticity,odor and so on,data analysis,the best combination group.Then,calcium propionate modified CA-CP bacteriostatic film was prepared by blending,extrusion-blow moulding with low density polyethylene?LDPE?as substrate,calcium propionate?CP?and modified bacteriostatic resin?CA?as additives.Finally,fresh corn was treated with the best compound fresh-keeping solution and packaged with CA-CP bacteriostatic film bags modified with calcium propionate,in order to study the fresh-keeping effect of pretreatment solution and bacteriostatic film on fresh corn at room temperature.The main results are as follows:?1?By changing the solubility of white sugar,salt and vinegar aqueous solution,the fresh-keeping effect of various factors on fresh corn was studied.The results showed that the preservation effect of fresh corn treated with different concentration of pretreatment liquid was better than that of blank group;The experimental analysis showed that the optimal ratio of fresh-keeping liquid was the best when the concentration was 3g/L white sugar aqueous solution,10g/L salt solution and 5g/L vinegar aqueous solution as mixed pretreatment liquid for 20min,the preservation effect was the best.?2?Through the process of granulation,blown film,etc.,low density polyethylene?LDPE?was used as the substrate,and calcium propionate with a concentration of 0%,0.8%,1.8%,2.8%and 3.8%and a concentration of 0.2%were added respectively.A modifier,a calcium propionate modified CA-CP bacteriostatic film was prepared.The results show that the tensile strength of the film decreases first and then increases with the increase of CP content.When the CP content is 3.8%,the film shows the best mechanical properties,and the tensile strength reaches the maximum;with CP When the content is increased,the barrier property of the film is also enhanced.When the CP content is 2.8%,the water vapor transmission coefficient and the oxygen permeability of the film are the lowest,respectively 0.2203×10^-13g/?m·s·Pa?,1479.6955cm³·?m²·24h·0.1MPa?^-1,the barrier performance is best at this time;the bacteriostasis of the film is also enhanced with the increase of CP content,and the inhibition of CP is 3.8%.The effect is the strongest;the microstructure shows that the surface of the film is smooth,there are no large particles,and no obvious holes appear.?3?Pretreatment solution,calcium propionate modified CA-CP bacteriostatic film bag packaged fresh-eating Maize at room temperature during storage,determine the quality indicators of Fresh-eating maize,mainly including sensory quality,weight loss rate,microorganism,starch content,soluble protein content,soluble sugar content,hardness and so on.The experimental results show that the best preservation method is the combination of pretreatment solution and bacteriostatic film,followed by only using bacteriostatic film packaging,and finally the blank LDPE film packaging.The quality indexes of Fresh-eating Maize in the experimental group were better than those in the blank group,indicating that the pretreatment solution and CA-CP bacteriostatic film modified by calcium propionate had better fresh-keeping function for Fresh-eating maize,and the combination of the two made the best fresh-keeping effect.