Active wheat gluten films obtained by thermoplastic processing

MARÍA R. ANSORENA; FRANCISCO ZUBELDÍA; NORMA E. MARCOVICH

LEBENSMITTEL-WISSENSCHAFT UND-TECHNOLOGIE-FOOD SCIENCE AND TECHNOLOGY

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2016 vol. 69 p. 47 - 54

0023-6438

Active films based on glycerol-plasticized wheat gluten protein containing different thyme oil concentrations(0e15 wt.%) were prepared by a thermoplastic process involving relatively high temperature andpressure. A complete thermal, structural, mechanical, antimicrobial and antioxidant characterization ofall formulations was carried out. Antimicrobial activity tests showed that neat thyme oil presented ameaningful antimicrobial activity. The addition of thyme essential oil to formulations based on glutenprotein allowed to prepare biodegradable and edible films with increased in vitro antioxidant andantimicrobial properties for the most concentrated samples. However, increasing essential oil concentrationled to a continuous decrease in the tensile and storage modulus but to an increase in thedeformability of the films. Only films containing 10 and 15 wt.% thyme oil showed reduced moisturesorption with respect to the control film (0% thyme oil), while the water vapor permeability and totalsoluble matter were not markedly affected by its addition. These changes were attributed to the interferenceof the oil in the formation of the protein molecular network, and were corroborated by theanalysis of the films microstructures by SEM.