Advances in Biomass Radiative Cooling Materials for Food Freshness Preservation

The global food system is confronted with the dual challenge of substantial postharvest losses and the high energy demands from the conventional cold chain. Passive radiative cooling (RC) presents a zero-energy alternative by reflecting sunlight and dissipating heat directly into deep space through the atmospheric transparency window. Biomass-derived materials have emerged as a sustainable pathway, leveraging their inherent biocompatibility, biodegradability, and structurally tunable optical properties for next-generation food preservation. This review provides a systematic and timely analysis of recent progress in biomass-based RC materials. We begin by elucidating the fundamental principles and thermal balance mechanisms of RC, and systematically summarizing the classification, structural characteristics, and cooling mechanisms of typical biomass RC materials. Subsequently, we discuss advanced design strategies essential for food preservation, including antibacterial integration, scalable processing, and temperature-adaptive regulation. Furthermore, Practical applications in preserving fruits, vegetables, and temperature-sensitive foods are highlighted, demonstrating their efficacy in extending shelf life and reducing energy reliance. Finally, we outline current challenges related to complex environmental stability, cost, and safety assessment, and propose forward-looking research directions. This work provides a comprehensive roadmap for the development of biomass RC materials to the transformation of food preservation toward zero-energy, sustainable, and high-efficiency paradigms.