MP37:Gezgin:Food Nanotechnology on the Shelf: Fabricating Nano-thin Ice Nucleating Layers on Polyethylene Films

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 Zafer Gezgin, PepsiCo Global R&D, Tung-Ching Lee and Qingrong Huang, Rutgers University

Food Nanotechnology on the Shelf: Fabricating Nano-thin Ice Nucleating Layers on Polyethylene Films

Food nanotechnology is allowing us to carry the functionalities of biological molecules observed in nature to foods. Nanofoods are becoming more common with the implementation of nanotechnological methods to the production, processing & packaging of foods. Layer-by-layer (LbL) deposition is one of these methods, which is a simple yet powerful way of engineering nano-thin polymer layers. Here, function to be transferred from nature is the ability of extracellular ice nucleators (ECINs) to trigger ice formation at higher sub-zero temperatures and shorter times, which can deliver energy savings and improve the quality of frozen foods. It is hypothesized that this effect can be retained with the nano-thin layers of ECIN. Our objective is to investigate the biopolymer systems suitable for building food grade multilayers, use these multilayers to immobilize ECINs, and evaluate the ice nucleation activity. Surface morphology of nano-thin films was investigated by atomic force microscopy (AFM), and the surface hydrophobicity was studied by the water contact angle measurements. Layer thicknesses were determined using the quartz crystal microbalance with dissipation monitoring (QCM-D) technique. A refrigerated water/ethylene glycol bath was used to study ice nucleation activity. Following nanoscale experimentation, we built those layers on UV-Ozone modified Low Density Polyethylene (LDPE) film surfaces. Biopolymers were as effective as synthetic polyelectrolytes in multilayer formation. Molecular weight, molecular conformation, charge density and degree of esterification of these polymers affected the nanoscale properties of multilayer systems. Increased ice nucleation temperatures and decreased freezing times were observed when freezing ultra-pure water in ECIN coated LDPE films. Films retained their activity for up to 50 freeze-thaw cycles. This study verified that the LbL deposition technique can be used to engineer functional food grade nano-thin films. Implementation of this technology in frozen food packaging applications can actualize the energy-saving and quality-improvement potentials of ECIN nano-thin films.

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