Development of an Oxygen Sensitive Model Gel System to Detect Defects in Metal Oxide Coated Multilayer Polymeric Films

Preserving Ready-to-Eat Meals Using Microwave Technologies for Future Space Programs

The crewed suborbital and space flights launched by private companies over the past three years have rejuvenated public interest in space travel, including space tourism. Ready-to-eat meals (MREs) are the main source of nutrients and energy for space travelers. It is critical that those meals are free of bacterial and viral pathogens and have adequate shelf life. The participation of private companies in space programs will create new opportunities and demand for high-quality and microbiologically safe MREs for future space travels. In this article, we provide a brief review of nutrition and energy requirements for human activities in space. We discuss the general thermal processing requirements for control of bacterial and viral pathogens in MREs and introduce advanced thermal preservation technologies based on microwaves for production of MREs with different shelf-lives under various storage conditions. We also present the latest advancements in the development of polymer packaging materials for quality preservation of thermally stabilized MREs over extended storage. Finally, we recommend future research on issues related to the sensory quality of specially formulated MREs, microbial safety of dried foods that complement high moisture MREs, and food package waste management in future space missions.

Stability of vitamin C, color, and garlic aroma of garlic mashed potatoes in polymer packages processed with microwave-assisted thermal sterilization technology

The U.S. Army and NASA need ready-to-eat meals with extended shelf-life for military operations and future manned space missions. For traditional heat sterilization methods, aluminum foil laminated pouches are used to achieve a shelf-life of 3 to 5 years at room temperature. However, those packages are not suited for advanced thermal processing technologies based on microwave energy. This research investigated the effect of polymeric packaging materials on storage stability of garlic flavor, vitamin C, and color of garlic mashed potatoes processed with microwave-assisted thermal sterilization (MATS) technology. Three types of high-barrier metal oxide-coated polymer pouches were used for MATS process, designed to achieve lethality approximately F₀ = 6 min. Aluminum foil-based pouches were used for retort process as control. Results demonstrated that both oxygen and water vapor barrier properties (oxygen transmission rate [OTR] and water vapor transmission rate [WVTR]) of the polymer pouches were affected by MATS processing. OTR increased by three to nine times, while WVTR increased by 5 to 20 times after processing. The MATS process resulted in 13% to 16% vitamin C loss, while retort process resulted in 18% loss in garlic mashed potato. The kinetics of vitamin C indicated that metal oxide-coated high-barrier packages (after processing OTR <0.1 cc/m² .day; WVTR <1.0 g/m² .day) could replace aluminum foil-based pouches for MATS processed shelf-stable ready-to-eat garlic mashed potatoes. PRACTICAL APPLICATION: Garlic mashed potatoes in polymer packages processed in a microwave-assisted thermal sterilization (MATS) system had better retention of vitamin C compared to samples packaged in aluminum laminated pouches and processed in retort. Polymer packages combined with MATS processing could potentially provide safe, better quality, and nutritious shelf-stable food products for military and space missions.

Multilayer packaging: Advances in preparation techniques and emerging food applications

In recent years, with advantages of versatility, functionality, and convenience, multilayer food packaging has gained significant interest. As a single entity, multilayer packaging combines the benefits of each monolayer in terms of enhanced barrier properties, mechanical integrity, and functional properties. Of late, apart from conventional approaches such as coextrusion and lamination, concepts of nanotechnology have been used in the preparation of composite multilayer films with improved physical, chemical, and functional characteristics. Further, emerging techniques such as ultraviolet and cold plasma treatments have been used in manufacturing films with enhanced performance through surface modifications. This work provides an up-to-date review on advancements in the preparation of multilayer films for food packaging applications. This includes critical considerations in design, risk of interaction between the package and the food, mathematical modeling and simulation, potential for scale-up, and costs involved. The impact of in-package processing is also explained considering cases of nonthermal processing and advanced thermal processing. Importantly, challenges associated with degradability and recycling multilayer packages and associated implications on sustainability have been discussed.