Abstract

Rapid and precise detection of volatile gases generated during pork spoilage is vital for visually assessing meat freshness. In this study, a nano-bionic colorimetric sensor was developed by embedding anthocyanins (ANS) in pectin-chitosan microcapsules (ANS@PCM) and incorporating them into a corn starch-cellulose nanocrystal (CS-CNC) matrix, enabling real-time monitoring of spoilage-related gases. Four natural ANS extracts with strong pH responsiveness were obtained from purple sweet potato (ANS 1 ), purple kale (ANS 2 ), moonflower (ANS 3 ), and butterfly pea flower (ANS 4 ) using a green solvent method. To enhance ANS stability, microencapsulation within a pectin-chitosan system was performed to obtain ANS@PCM, which were then uniformly dispersed into the CS-CNC matrix via solution casting, producing four types of ANS@PCM/CS-CNC sensors. After evaluating their physical characteristics, barrier performance, ammonia sensitivity, and pH responsiveness, the ANS 1 @PCM/CS-CNC and ANS 4 @PCM/CS-CNC sensors demonstrated superior performance. These were further tested as freshness indicators for pork spoilage. Notably, the ANS 1 @PCM/CS-CNC sensor displayed a distinct color transition from purple to pale yellow, with color difference (ΔE) values showed strong correlations with total volatile basic nitrogen (TVB-N, R 2  = 0.9688) and pH ( R 2  = 0.9209). Overall, the ANS 1 @PCM/CS-CNC sensor provides an effective, eco-friendly, and visually intuitive approach for real-time monitoring of pork freshness.