Cassava Starch, Natural Rubber Latex, and Grape Stalks Residues for the Development of Biodegradable Stoppers in Wine Bottles

ABSTRACT The development of biodegradable stoppers is a field of research that lacks information. The cork‐based materials dominate this industrial sector. However, due to problems associated with cork stripping time and stopper production processes, the search for environmentally eco‐friendly materials has increased. Therefore, stoppers based on residues from the cassava and grape processing and latex were developed, uncoated, and coated with mineral oil. The stoppers presented low porosity values by the gas pycnometer technique, corroborated by the dense polymeric network observed by SEM images. The storage conditions proved to greatly influence the dimensions of stoppers, and consequently, the bulk density, being observed in higher values (1.15 g/cm 3 ) for the samples stored under a relative humidity of 75% ± 5%. The main coating advantage was assisting the samples’ insertion into the bottlenecks. There was a gradual increase in the stoppers’ firmness over time, reaching 434 N, like the cork‐based stopper (491 N). Regardless of the grape stalks’ incorporation into the composite, coated samples presented low values of water (14.4%) and wine (7.2%) absorption capacities. These results along with the wine sealing test helped to prove the high potential of these biocomposites in the storage of beverages, especially white young‐consumption wines.