Innovations in Biodegradable Packaging and Edible Coating of Shelled Temperate Nuts

Temperate nuts are globally recognized for their nutritional value, being rich in unsaturated fatty acids, proteins, carbohydrates, antioxidants, and vitamins. They are widely consumed as healthy snacks and are integral to various health food formulations. Heat treatments such as roasting, blanching, pasteurization, and drying are vital processes in producing value-added temperate nuts. However, their high unsaturated fatty acid content renders them susceptible to rancidity during processing and storage, posing a challenge to maintaining their quality and shelf-life. The current methods for preserving temperate nuts, which include synthetic plastic packaging and synthetic antioxidants have been condemned due to their negative health and environmental impact. In response to the increasing demand for safe, environmentally friendly and sustainable food preservation methods, the use of biodegradable packaging (BP) and edible coatings (ECs) has emerged as a promising solution. ECs and BP promote environmental sustainability while significantly reducing reliance on traditional synthetic packaging. This review article discusses recent advancements in the application of ECs and BP on temperate nuts. It focuses on their role as treatment methods for enhancing the quality of raw and stored nuts and as post-roasting treatments to preserve the physicochemical, phytochemical, and antioxidant properties of the nuts, highlighting the mechanisms of action, which involves minimizing the loss of moisture, oxygen transfer, mechanical damage and facilitating the incorporation of antioxidants and antimicrobials. Additionally, the review explores the effectiveness of ECs and BP on raw nuts and discusses the integration of modified atmosphere packaging, nanotechnology, and cold plasma treatment with ECs and BP to enhance the preservation effect on temperate nuts through a hurdle technology. The goal is to provide a comprehensive overview of current research trends, both at industrial and laboratory scale, and potential future directions in this relatively new field. Future work should focus on addressing issues of scalability, sensory acceptance, toxicity levels, allergenicity and regulating the use of ECs and BP.