Effect of different combinations of glycerol and/or trehalose on physical and structural properties of whey protein concentrate-based edible films

DELORENZI, N.J.; PICCIRILLI, G.N.; PICCIRILLI, G.N.; PÉREZ, L.M.; VERDINI, R.A.; PÉREZ, L.M.; VERDINI, R.A.; DELORENZI, N.J.

FOOD HYDROCOLLOIDS

ELSEVIER SCI LTD

Lugar: Amsterdam; Año: 2016 vol. 56 p. 352 - 359

0268-005X

In the present study, different combinations of glycerol (Gly) and/or trehalose (Tre) were added into whey protein concentrate (WPC)-based edible films in order to evaluate this sugar as a novel plasticizing agent. Moisture content, solubility, thickness, transparency, microstructure, colour parameters, and mechanical properties were assessed. The films incorporated with Tre were more insoluble in water than the control WPC/Gly films, being more suitable for food applications. WPC/Gly and WPC/Tre films were clear enough to be used as see-through packaging. However, when Tre was included into WPC/Gly film formulations, film opacity increased. Scanning electron microscope (SEM) images suggested that this phenomenon may be related to the growth of Tre crystals in the film matrix. Moreover, when Tre concentration increased in the WPC/Gly matrix, film surface was more heterogeneous. Interestingly, the presence of Tre in WPC-based films was effective in preventing Maillard reaction after heating. WPC/Tre films were the most rigid but the least stable for storage, resulting more susceptible to rupture and cracking. Only WPC/Gly and WPC/Gly-Tre 8% films were rather flexible, manageable, and stable up to 90 days of storage under ambient and freezing conditions. These findings can be used to better design applications of edible films containing plasticizers that may crystallize over time in order to optimize film formulation in a rational manner towards their eventual application as food packaging.