Structure-engineered colorimetric sensors for volatile amine detection: Advances in freshness monitoring of meat and aquatic products

Timely and accurate monitoring of meat and aquatic product freshness is crucial for public health and food industry. Volatile amine (VA) colorimetric sensors show great potential, but require structural innovation to improve accuracy in complex environments. In this review, we focused on novel structures (porous film, multi-layer film, hydrogel, and aerogel structure) in VA colorimetric sensors. The formation processes and the mechanism for the enhancement in VA sensing performance by these structures were summarized. The macromolecular interactions were the crucial factors that influence sensor structure. By enhancing VA capturing efficiency, optimizing mass transport pathways, and extending diffusion paths of dyes, the sensing performances were improved. Then, recent advances in VA colorimetric sensors for meat and aquatic products’ freshness monitoring were summarized. We also suggested future prospects in this field, including establishing structure-performance relationship, engineering selectivity of the sensor, and using artificial intelligence for sensor design and freshness monitoring in practice.