Nano-armoured Vitamin C: A novel approach to micronutrient delivery and natural food preservation in integrated food systems

The present study highlights the development of nano-encapsulated ascorbic acid delivery systems to address challenges in food preservation and nutritional fortification. Ascorbic acid-producing Acetobacter strains isolated from natural sources were characterised and optimised for fermentation at pH 4–6 and 30°C, achieving 99% substrate conversion within 96 hours. Iron oxide nanoparticles synthesised via coprecipitation were functionalized with biosynthesised ascorbic acid through pH-controlled coating (pH 12.5, 80 ⁰ C, 1 hour). Scanning electron microscopy confirmed uniform coating architecture. Preservation efficacy was tested in fruit juices (apple, grape, orange, and banana) and dairy products (milk and curd), demonstrating that nano-encapsulated formulations achieved approximately 75% antimicrobial activity compared to commercial ascorbic acid. This reduction in microbial loads, from previously uncountable levels to 7–20 CFU at 10^ (-8) dilutions, was notable. The dual-functional vitamin C and iron fortification, and clean label compliance, are due to their biosynthetic origin. This integrated biotechnology-nanotechnology platform establishes proof of concept for next-generation multifunctional food additives that extend shelf life while enhancing nutritional value, providing viable solutions for food industries pursuing natural preservation strategies.