Bioactive Edible Gel Films Based on Wheat Flour and Glucose for Food Packaging Applications

In order to prepare bioactive edible gel films with enhanced properties, the feasibility of using wheat flour as a raw material with glucose added at several concentrations was studied in this investigation. Films were prepared with glucose concentrations of 0.5, 0.7 and 1 g/g of flour and characterized for their physicochemical properties, including water content, solubility, degree of swelling, chemical structure by FT-IR (ATR) spectroscopy, morphology by SEM microscopy, thermal properties by DSC, gas and water vapor permeability and antioxidant activity. Biodegradation studies were also carried out in soil for 27 days and evaluated by weight loss measurements. It was found that the gel film with the higher glucose concentration exhibits a homogeneous and continuous structure with no cracks and no fragility, accompanied by an increased thickness and solubility and a decreased degree of swelling compared to those with lower concentrations. The chemical structure of all films was verified. Moreover, the increase in glucose content leads to better gas barrier properties with lower oxygen, CO2 and water vapor transmission rates and increased water vapor permeability. A slightly elevated melting temperature was observed in the films with higher glucose content. Higher antioxidant activity was also associated with higher percentage of glucose. Finally, the biodegradation of the films ranged from 13 to nearly 70%. Therefore, it can be concluded that the addition of glucose to wheat flour in concentration up to 1 g/g could result in edible gel films with excellent properties to be used in food packaging applications.