Carotenoid nanoforms from clementine peel stabilized by xanthan and arabic gums with antioxidant anti inflammatory and antimicrobial activities

Abstract Antimicrobial resistance is a major global health threat, causing 1.27 million deaths and contributing to nearly 5 million more annually. Citrus fruits are widely cultivated for their nutritional and health benefits, and their pigments may offer additional bioactivity. This study aimed to extract carotenoids from clementine peels and quantify carotene, lycopene, astaxanthin, and anthocyanins using colorimetric methods. The carotenoids were then encapsulated using xanthan-Arabic gums matrices to stabilize the pigments. The native carotenoids and their nanoform were evaluated for antioxidants, anti-inflammatory, and antimicrobial activities. Clementine peels contained total carotenoids (30.8 mg/kg), anthocyanins (13.69 mg/kg), lycopene (3.12 mg/kg), and astaxanthin (1.60 mg/kg). The physical characterization of the carotenoid nanoparticles was performed using FTIR, confirming interactions between carotenoids and the polymer matrices. Zetasizer analysis revealed a particle size of 17.05 nm and a zeta potential of − 26.7 mV, indicating good stability, while TGA demonstrated thermal stability up to 300 °C. Antioxidant activity ranged from 18.67% to 69.10% (phosphor-molybdenum and DPPH assays). Anti-inflammatory activity showed maximum protein denaturation inhibition at 83.87% (carotenoids), 74.45% (nanoform), and 69.10% (polymers) (p < 0.05). Antimicrobial activity was highest against Listeria monocytogenes (21.3 mm) and Penicillium verrucosum (20 mm), moderate against Escherichia coli (13.0 mm) and Aspergillus flavus (17.0 mm), and lower against Bacillus cereus (10.3 mm) and Pseudomonas aeruginosa (9.3 mm). Overall, xanthan and Arabic gums effectively stabilized carotenoids and enhanced their biological activities.