Modeling and experimental validation of mass transfer from carbonated beverages in polyethylene terephthalate bottles

Mass transfer and related shelf life assessment is an important issue in the beverage industry. Product change due to mass transfer is at stake and, with it, its consumer value and consideration. Carbonation loss takes place at the product/package interface, and to the environment through the package itself. In this paper a joint experimental/computational approach has been exploited: the CO2 loss through the polyethylene terephthalate barrier has been computed by means of a multidimensional finite element code, while actual measurements have been carried out to validate the computations. Residual carbonation histories are validated and presented for a variety of thermal regimes and for two different bottles carrying the same capacity. The paper highlights on the combination of bottle weight, initial carbonation and storage temperature, indicating the operational set for the longest shelf life within the explored cases. Lighter bottles can be used with no inference on shelf life, while the carbonic loss depends non-linearly on initial carbonation and temperature increment. The associated concentration maps help infer on the importance of polyethylene terephthalate thickness uniformity. It is then demonstrated that the model carries the flexibility of a general tool, applicable to any carbonated beverage at any storage condition.