The rates of water vapour and oxygen transmission through barrier packaging of perishable foods are often used as a predictor of product shelf life. For said barrier packaging, there currently exists ubiquitous use of petrochemical-rich laminations. It is desirable to move towards use of extruded starch-based biopolymer barrier packaging as it is renewable, biodegradable and biologically-derived. Unfortunately, the rates at which water vapour and oxygen transmit through biopolymer barrier packaging of perishable foods, and resultant deterioration and product shelf, are thus far widely unchartered. With a dependence on many variables, empirical evaluation of oxygen and water vapour transmission rates in the laboratory often proves time-consuming and financially costly. It is for this reason that this project¡¦s statement of purpose is contribution to the development of a practical, fast,
easy-to-perform, repeatable and empirically validated methodology for determining oxygen and water vapour transmission rates through multi-layer extruded starch-based biopolymer barriers. Project scope was limited to two primary aims:
• Development of a general process methodology for determining water vapour and oxygen
transmission rates through barrier packaging of perishable foods.
• Development of a detailed computational model of water vapour transmission rate and
Through the application of extensive existing research and literature on biopolymers, the project proceeds to define a general process methodology for determining water vapour and oxygen transmission rates through barrier packaging of perishable foods, identifying nine required primary operations. The first and second operations feature the aforementioned computational modelling of water vapour transmission rate and permeability coefficient as a function of time.
A discussion of the model¡¦s limitations highlighted a lack of first-principles modelling of intrinsic phenomena, reliance on simple Fickian diffusion in defining water vapour transmission rate, simplistic modelling of the influence of temperature on permeability coefficients of a permeant by the Arrhenius equation, reliance on the two layer model, assumption of constant water concentration across water sensitive multilayer films, and a lack of account for 3-dimensional package barrier shapes. It was expected that the above computational model iterations could be validated via comparison with empirical data, however logistical problems experienced by the AIBN have necessitated a delay in said validation. As such, recommendations included ensuring availability of extensive and variable empirical data to assist with validation of computational modelling. Such validation will elucidate which, if any, of the aforementioned intrinsic phenomena need to be modelled from first principles, ensure computational modelling accuracy, enable primary methodological operations 3 to 9 to be completed, and thereby promote sustainability and ethical practise in the packaging industry.