Smart packaging materials based nanoencapsulated bromothymol as monitoring sensors for spoilage of chilled fillet

Abstract Food preservatives have long been used to prevent spoilage due to microbial activity. Detecting spoilage without opening packaging is increasingly important. Smart packaging, a third-generation innovation, was developed to improve spoilage detection. A smart label was created using encapsulated polymer/bromothymol blue and analyzed using Attenuated Fourier Transform Infrared (ATR-FTIR) spectroscopy. In acidic and basic media, significant shifts in the -OH group on the benzene ring were observed (840 to 813 cm − 1 ). Ultraviolet-visible (UV-Vis) spectroscopy showed shifts in maximum absorption at 610 and 411 nm, depending on pH. The label’s topography was studied with a polarized optical microscope (POM), and dynamic light scattering (DLS) revealed nano-encapsulation particle sizes of 63–84 nm with a unimodal distribution. Additionally, a strong positive correlation ( P < 0.5) was found between aerobic plate count and pH (0.82), demonstrating a connection between microbial activity and food quality. Bromothymol blue capsules (BC) effectively visualized pH changes, confirming their potential as indicators for food spoilage. Sensory evaluation of BC indicates its suitability as a safe and effective intelligent label for monitoring chilled chicken fillets.