Characterization of whey based edible coating enriched with heen bovitiya (Osbeckia octandra L.) for shelf-life extension of cooked meatballs

Introduction Cooked meatballs are highly susceptible to lipid oxidation and microbial spoilage, limiting their shelf life. This study developed a whey protein-based edible coating enriched with phytochemicals from Heen bovitiya ( Osbeckia octandra L.) leaf extract, incorporating mangosteen peel anthocyanin as a pH-responsive freshness indicator. Methods Seven formulations were prepared by varying Heen bovitiya extract concentrations (C - 0%, H1 - 0.1%, H2 - 0.2%, H3 - 0.5%, H4 - 1.0%, H5 - 1.5%, and H6 - 2.5% v/v) in a heat-denatured whey protein matrix (90 °C, 15 min) with glycerol (1% v/v) as a plasticizer. Antioxidant activity was assessed by TPC, TFC, and DPPH assays, and film physical, mechanical, and barrier properties were characterized. Storage quality of coated meatballs was monitored over 15 days of refrigeration via pH, TBARS, weight loss, total plate count, and visual anthocyanin color change. Results The Heen bovitiya leaf extract yielded a TPC of 888.37 ± 0.10 mg GAE/g, TFC of 2.27 mg QE/g, and an IC₅₀ of 37 μg/mL. Film formulation H1 (0.1% extract) demonstrated the most balanced physicochemical and mechanical performance: moisture 13.38±0.35%, tensile strength 3.46 ± 0.11 MPa, elongation at break 16.51% ± 0.10%, and solubility 59.27% ± 0.22%. Among all formulations, H6 (2.5% extract) demonstrated the greatest shelf-life extension in the storage study by reducing lipid oxidation, weight loss, and microbial growth. H1 was selected as the optimal film formulation for physical and mechanical performance, while H6 was independently selected for the storage study based on its superior antioxidant loading capacity. Discussion Incorporating natural plant antioxidants proved to be a safe and effective alternative to synthetic preservatives.