Fabrication of antimicrobial colorimetric pad for meat packaging based on polyvinyl alcohol aerogel with the incorporation of anthocyanins and silver nanoparticles

Abstract A novel colorimetric pad with porous structure, good antimicrobial activity, and pH‐sensitivity has been developed based on polyvinyl alcohol (PVA), paper fibre, silver nanoparticles (AgNPs) and purple sweet potato anthocyanins (PSPA), aiming for the preservation and freshness indication of fresh meat. The effects of AgNPs content on the structure, physical properties and colour‐changing behaviour in response to pH of the pad were investigated. The results showed that AgNPs physically interacted with polymer matrix and improved the uniformity of the internal pore structure of the pad. The antibacterial capability, DPPH radical scavenging activity and surface hydrophobicity of the pad increased significantly with increasing AgNPs content. However, the pH sensitivity of the pad was maintained with the addition of AgNPs, and the colour change of pad A‐9 with pH was the most distinguishable when AgNPs content was the highest. When pad A‐6 was used in the packaging of minced pork, compared to pad A‐0 without the addition of AgNPs, it showed more significant effects in inhibiting microbial growth, reducing the production of volatile nitrogen compounds, improving the sensory quality of meat ( p < 0.05), thereby extending the shelf life from 72 h to 120 h at 4°C. Moreover, A‐6 displayed a visible colour change in response to the spoilage of minced pork in real time. Therefore, the developed pad with dual functions had great potential to be applied as a novel active and intelligent packaging for fresh meat, which would contribute towards reducing food waste and ensuring food safety.