Storage Stability And Application Of Starch-based Composite Films

Starch-based composite film solved the problem of low tensile strength,poor water resistance and poor gas resistance of single layer starch film.It could be widely used in many fields,but it was also important to consider the changes in the properties of starch-based composite film.Therefore,this paper studied the changes of the properties of starch-based composite film under normal temperature,including water vapor permeability,gas permeability,Light transmission,tensile strength,XRD and other indicators,provided theoretical basis for packaging application.The application effect of starch-based composite film in fresh wheat germ and storage cherries was studied.The main results were as follows:1.The results showed that the storage time was prolonged,the tensile strength and elongation of single layer starch film decreased gradually,and the water vapor permeability and gas permeability increased sharply.The scanning electron microscopy(SEM)showed fracture at 180 days.The X-ray diffraction(XRD)showed that crystal structures of starch molecules and PVA molecular were destroyed and have been degraded.In the process of storage,three kinds of starch-based composite film were significantly more stable than that of single layer.In storage for 180 days,the tensile strength increased gradually,and the elongation decreased slightly,the change of water vapor permeability and gas permeability were not obvious,there was a slight downward trend,the degree of declining was smaller than the single layer of starch film.There was no significant change in the membrane surface from the scanning electron microscopy(SEM)and the crystallinity increased slightly in the X-ray diffraction.2.In the process of accelerated oxidation storage,the wheat germ of PE packaging appeared color deepening and clumping phenomenon,and the acid value,peroxide value,malondialdehyde and moisture content of wheat germ oil in PE packaging were significantly higher than that of three kinds of starch-based composite film(P<0.05).The starch-based composite film could effectively block oxygen into the inside of the package,effectively inhibit the rise of acid price,peroxide value and malondialdehyde,and delay the oxidation and deterioration of wheat germ.It was found that HP1 composite membrane was the best to store wheat germ.3.There was no significant difference in the quality of cherries between the non-perforated and micro-perforated packaging during 20 days(P>0.05).It was confirmed that the good fruit rate,total soluble solide content,V_C content and firmness changed slowly when cherries were preserved with micro-perforated packaging for 10 holes after storage for40 days.Therefore,micro-perforated packaging with starch-based composite films,particularly in the 10 holes or 15 holes,and further resulted in increasing shelf life for 60 days and achieving good fruit rate for 85.9%under the conditions of 0±0.5°C and relative humidity of 99-100%.