Research On Forming And Application Of Whey Protein Film

A film was made from whey protein concentrate(WPC) by solution cast method with different protein concentrations, glycerol concentrations and heat temperatures. The forming method, mechanical performance and barrier performance of WPC film was studied.First, the effect of film-forming factors to the performance of WPC film was discussed through single factor experiment with the mechanical performance, barrier performance, solubility and uncovery as the goal. The result indicated that barrier performance and solubility of WPC film decreased with the increase of protein concentration, but mechanical performance increased. Barrier performance and tensile strength(TS) decreased with increase in glycerol concentrations, but elongation(E) increased significantly. Water vapor permeability (WVP) and oxygen permeability (OP) reached the lowest when the heating temperature was80℃. Combined grade of WVP, OP, TS and E, packaging performance was investigated using Response Surface Methods. Mixture proportions of protein concentration102g/L, glycerol concentration27g/L, heating temperature82℃,would yield an edible film with WVP0.427g·mm/m2·h·kPa,OP0.153cm3·mm/m2·d·kPa, TS4.46Ma and E8.21%.WPC film was used in preserve of peanut and almond, and peroxide value(PV) and acid value(AV) was measured regularly. The results showed that fat oxidation in storing can be delayed by coating and wrapping. Furthermore, coating is better than wrapping in store effectiveness, and sensory performance of peanut and almond was improved by coating. Ratio between protein and glycerol60:40has better store effect than70:30. Coating peanut storing in middle relative humidity(RH53%) showed better storability than storing in low relative humidity(RH21%). Compared with other groups,40℃, RH53%, W60/G40x5treatment group peanut stored42days, PV and AV has the minimum increase.