Properties Of Whey Protein-based Composite Film

In this study,the feasibility of whey protein based composite film was studied.whey protein?WPC?,hydroxypropyl methyl cellulose?HPMC?and carboxymethyl chitosan?CMC?were used as the main materials for films formation and glycerol as the plasticizer.The effects of HPMC and pH on the properties of whey protein-based composite film were investigated,and the influence of CMC on the properties of whey protein-based composite film were investigated,which including the light transmittance,mechanical properties,WVP,and digestive degradation capability,therefore,the feasibility of whey protein-based composite film was determined.At the same time,transglutaminase?TGase?was used to modify the edible film,and its effect on the properties of composite film was investigated.The preparation condition for whey protein-based composite film was established as following:The whey protein concentration of 10%?w/v?,the mass weight ratio of glycerol addition to protein was1.0:2.2,pH 6.8,and the amount of TGase was 6 U/g _WPC.When the amount of HPMC is 20%at the mass weight of whey protein,the overall properities of the WPC-HPMC composite film was superior.When the amount of CMC is 20%at the mass weight of WPC,the overall properities of WPC-HPMC-CMC film was superior.Furthermore,the mechanisms for TGase,HPMC and CMC effect the composite film were investigated by applying the contact angle analysis,rheological analysis and differential scanning calorimetry,fluorescence analysis,scanning electron microscopy,fourier transform infrared spectroscopy,aiming to study the physical properties and microstructure characterization of whey protein based composite film.In the fluorescence spectrum analysis,the fluorescence intensity of the film-forming solution was attenuated after the addition of HPMC and CMC.The fluorescence intensity decreased upon TGase treatment.In the FT-IR analysis,the infrared absorption intensity in the range of 1150-763cm^-1 in the composite film was enhanced,which caused by the presence of amino and carboxyl groups of HPMC or CMC.Its absorption peak of the amide I band was increased,and its absorption peak in 1150-763 cm^-1 was weakened.In the thermal stability analysis,the denaturation temperature increased after the incorporation of hydroxypropyl methyl cellulose and carboxymethyl chitosan to whey protein based film.When the content of CMC is 20%at the mass weight of whey protein,the denaturation temperature increased significantly,but it increased slightly after TG treatment.The whey protein-based composite films developed were applied to package milk tea powder,milk candy,and instant noodle oil sauce,respectively.Results showed that the composite film has the feasibility as inner package for small food,and the potentiality to be applied to solid food packaging.