Performance of edible films obtained from Citrus pectins and transglutaminase-modified phaseolin

The growing social and economic consequences of pollution derived from plastics are focusing attention on the need to produce novel and environmental friendly systems for enhancing food shelf-life. As a consequence, in recent years the use of edible films for food packaging is generating a huge scientific interest. An edible film is defined as a thin film made of natural substances, which gives the film the characteristic of being ingested. Hydrocolloid films are composed of proteins, cellulose derivatives, pectin and other polysaccharides. In particular in this work edible hydrocolloid films were made by using citrus pectins and the protein phaseolin modified by microbial transglutaminase, an enzyme able to catalyze isopeptide bonds between glutamines and lysines into proteins. Our results have demonstrated that such films show technological features (mechanical properties and barrier properties to gases such as CO2, O2 and H2O) comparable to those performed by the commercial plastics. It is worth noting that such characteristics are maintained even following a storage of the films at 4 °C or -20°C suggesting that our bioplastics can be tailored to protect also those foods that need to be frozen or kept in the fridge. Moreover digestibility studies conducted under physiological conditions have demonstrated that such films are easily digested by the human gut.