Valorization of black carrot pomace for the development of anthocyanin rich bio functional edible films: implications on structural, morphological and thermal properties for a sustainable approach

Black carrot pomace (BCP), a byproduct of juice processing, offers a cost-effective and sustainable source of polyphenols and anthocyanins for edible packaging. In this study, we incorporated BCP extract at varying concentrations of 0, 15, 25, 35, and 45% (v/v) into corn starch films blended with hydroxymethyl cellulose (HMC) and glycerol. Results indicated a consistent increase in film thickness, moisture content, and solubility with increase in BCP extract levels. Films with increase in extract concentrations from 15 to 45%, displayed reduced tensile strength (0.45to 0.31 MPa), decreased elongation at break (28.0 to 19.03%) and increased water vapor transmission rates (0.142to 0.173 g/h cm²).Incorporating BCP extract, 15 to 45% substantially enriched films with anthocyanins (8.03 to 11.53 milligram Cyanidin-3-glucoside equivalent per gram), flavonoids (4.42 to 19.96 milligram of catechol per gram), and total phenol content (10.14 to 13.96 micro gram of gallic acid equivalent per gram) enhancing their antioxidant properties. Higher anthocyanin content intensified film redness (a*) and opacity while reducing lightness (L). Morphological analysis (Fourier Electron Scanning Emission Microscopy, FESEM) revealed that control films without BCP extract, displayed smoother, fracture-free surface. In contrast, films with BCP extract exhibited surface agglomerations. Fourier transform infrared spectroscopy (FTIR) confirmed presence ofcrosslinking between protein, polyphenols and hydrocolloidsinthe matrix. Films enriched with anthocyanins demonstrated superior thermal stability (DSC) and enthalpy changes (TGA) compared to control films.