Moisture Stability and Sensory Quality of Metallized-Packaged Biscuits During Storage: A Comparison with Non-Metallized Packaging in a Single Product

 Biscuits are dry food products that are highly susceptible to moisture uptake during storage due  to their porous structure and low initial moisture content, making the control of water vapor transfer a  critical factor in maintaining product stability. This study aimed to evaluate the effectiveness of  metallized biaxially oriented polypropylene (Metallized BOPP) packaging in reducing moisture uptake  through a direct comparison with non-metallized biaxially oriented polypropylene (BOPP) packaging  in a single biscuit product, while also monitoring the response of three biscuit products stored under  metallized packaging. A longitudinal field study was conducted over a twelve-month period at three  storage locations in Yemen. Monthly measurements of moisture content, water activity, and sensory  properties were collected, and the data were analyzed using linear mixed models. The results showed  that metallized packaging was associated with significantly lower moisture content and water activity  compared with BOPP packaging in the product used for the direct packaging comparison, accompanied  by a clear improvement in crispness. The analysis also indicated that storage time was the factor most  strongly associated with changes in both physical and sensory properties. Among the products stored  under metallized packaging only, no significant differences were observed in moisture content,  whereas differences were detected in water activity and sensory properties. These findings support the  effectiveness of metallized packaging within the limits of a direct comparison conducted on a single  product, while highlighting differences in product responses under the same packaging system.