Biodegradable and non-retrogradable starch–glycerol based films were obtained using citric acid (CA)as crosslinking agent at 75◦C. This material allowed decreasing water vapor permeability (WVP) morethan 35%, remained amorphous for at least 45 days as a result of the network formed by the CA thatavoided starch retrogradation and maintained the degradability in compost, occurring only six daysafter the films without citric acid. A simulation of the gelatinization process of starch–glycerol with andwithout CA, using a differential thermal analysis device, showed that the system with CA completed thegelatinization 5◦C before than the other and, CA first reacted with glycerol and then starch–glycerol–CAreaction occurred. The temperature at which the gelatinization process was carried out was critical toobtain the best results. An increase of gelatinization process temperature at 85◦C in system with CA,led to a worsening on WVP and its integrity after a swelling process with dimethylsulphoxide (DMSO),compared to the films processed at 75◦C.