Kyungnam University, South Korea
Milk powder products consisting of lactose, fat and protein are labile to moisture sorption, caking, oxidation and nonenzymatic browning in the packaged storage. Modified atmosphere packaging (MAP) applying a combination of nitrogen and carbon dioxide is used to protect the products from physical and chemical stresses under outside environment. Several aspects can be considered in designing MAP ensuring the required shelf life. Packaging conditions of material and atmosphere needs to be selected considering the expected distributional environment. Typical product of infant formula powder was examined in the design of MAP of a milk powder product, infant formula. Carbon dioxide absorption by the product was characterized and used through a mathematical model to create negative or balance pressure of the rigid metal package under expected distribution condition of temperature and pressure. Moisture sorption isotherm was used to estimate critical moisture content for possible apparent caking, which was useful for water barrier design of the flexible package. Lipid oxidation was characterized as a function of initial oxygen concentration and could be used for gas barrier design of the flexible package. The oxidation kinetics formulated as a function of temperature and oxygen concentration could give shelf life estimation for different temperature and MAP conditions. While any oxygen-excluded atmospheric conditions were helpful for the prevention of oxidative deterioration, condition of high carbon dioxide concentration helped the survival of bifidobacteria. Further protection from oxidation under oxygen-exclusion was tried by antioxidant packaging films, which did not provide significant benefit in preservation.
Dr Dong-Sun Lee is Professor of Food Engineering and Packaging in the Department of Food Science and Biotechnology at Kyungnam University, South Korea. His major research areas are modified atmosphere and intelligent packaging of fresh produce, packaging of Korean indigenous foods, and active packaging. He has also been an active researcher in process modelling, quality optimisation of food processing, heat process determination, heat transfer analysis, energy accounting and analysis of thermal processes.
Dong-Sun is a former President of the Korean Society of Food Preservation, and the Korea Society of Packaging Science and Technology. He is Editor-in-Chief of the Korean Journal of Packaging Science and Technology and a member of the editorial board of several international journals.