Application of red carrot pomace carotenoids for the development of biofunctional edible film: a sustainable approach

Red carrot pomace (RCP), a juice processing by-product, is an encouraging and affordable source of polyphenols and carotenoids. In the present study, lyophilized RCP was subjected to carotenoid extraction at different concentrations (15, 25, 35, and 45% (w/v)) in 100 ml ethyl acetate followed by delivering the RCP carotenoids in lemongrass oil emulsions. The RCP carotenoids emulsion was further used in the development of a ternary blended edible film. Results revealed that addition of RCP carotenoid emulsion significantly (p < 0.05) improved the thickness and water barrier properties of the films, with decreased moisture, water solubility, and water vapor permeability. Incorporation of RCP carotenoid emulsion enhanced the carotenoids (18.22–41.46 mg/100 g), β-carotene (2.16–6.61 mg/100 g), lycopene (5.54–7.93 mg/100 g), and phenolic content (6.39–8.78 mg gallic acid equivalent/gram), along with antioxidant properties. Increased carotenoid levels enhanced the redness value (a*) and opacity while decreasing lightness. Fourier transform infrared analysis (FTIR) confirms the crosslinking between RCP carotenoids emulsion with film-forming hydrocolloids. Field emission scanning electron microscopy (FESEM) revealed that control films had a smoother and more compact surface without fractures, whereas RCP carotenoid emulsion resulted in agglomerations on the film’s surface, as a result of which films showed lower tensile strength and elongation at break. However, films enriched with carotenoids demonstrated lower thermal stability (40.04–138.15 °C and 36.04–125.35 °C for control and RCP extract film) and enthalpy changes (TGA) (up to 230 °C) compared to control films. Overall, the results indicated that RCP could be used in the development of bioactive compound-rich functional edible film for sustainable and greener approach.