Controlled porosity intelligent aerogel based on chitosan nanofiber, anthocyanins and starch nanoparticles: Preparation, characterization and application in monitoring food spoilage

The aim of this study was to design a food freshness colorimetric aerogel with controlled porosity based on chitosan nanofibers (CHNF), Ixiolirion tataricum anthocyanins (ITA), and starch nanoparticles (SNPs). Two size-controlled SNPs were produced via nanoprecipitation (133.3 nm; SNP-A) and H2SO4 hydrolysis methods (86.2 nm; SNP-B) and were used for controlling the porosity and morphological characteristics of aerogel solid support. According to FE-SEM images, the porosity of smart aerogels improved after SNPs incorporation, and SNP-B was able to decrease the disrupting effect of ITA on 3D porous network of aerogels. The formation of hydrogen bonds between the CHNF and ITA molecules was confirmed by FT-IR analysis and the absence of obvious change in the FT-IR spectra approved the physical entrapment of SNPs. The improvement in the crystallinity and thermal stability of the aerogels after SNPs loading was confirmed by the XRD and TGA tests, respectively. The SNPs loaded aerogels showed color variation from red to green over the pH range of 2-12. In addition, the SNP-B-incorporated aerogel exhibited high sensitivity to ammonia vapor and good color response reversibility. The CHNF/SNP-B/ITA aerogel with the best porosity and sensitivity was used for monitoring food spoilage and could differentiate minced beef into three stages: fresh, medium fresh, and spoiled, facilitating simple observation of freshness-spoilage progression. This research opens a new insight to develop advanced and highly sensitive indicators capable of monitoring freshness/spoilage in protein-based food products.