Tailoring anthocyanin stability with pea–rice proteins and fructooligosaccharides: A microencapsulation study using double emulsion

This study investigated the impact of plant protein matrix composition and fructooligosaccharide (FOS) concentration on the microencapsulation performance of black carrot anthocyanins. Nine formulations were developed using pea, rice, and their blends with varying FOS levels (0–1 %). The combination of pea–rice protein with 1 % FOS (T9) demonstrated optimal performance, exhibiting the highest color retention (L* = 76.06, a = 21.23, b* = −4.92), enhanced solubility in simulated gastric and intestinal fluids (76.19 % and 80.79 %, respectively), and extended anthocyanin half-life (t₁/₂ = 364.8 days). Fourier transform infrared (FT-IR) spectroscopy revealed that FOS altered the secondary structure of proteins, promoting the formation of β-turns and β-sheets, which contributed to improved matrix density and pigment stability. Particle size analysis showed that FOS-containing samples generally produced smaller, more uniform microcapsules, supporting enhanced bioavailability. Controlled gastrointestinal release profiles further confirmed the functional role of FOS, with T9 achieving 50.34 % anthocyanin release in the intestinal phase while minimizing premature release. These findings highlight the synergistic potential of plant protein–FOS systems for protecting anthocyanins during processing and digestion. The results support their application in functional foods and nutraceutical formulations, offering improved stability, controlled release, and targeted delivery. In conclusion, incorporating FOS into plant protein-based microcapsules (especially a pea–rice protein blend) markedly enhanced anthocyanin stability and targeted intestinal release, demonstrating the effectiveness of this encapsulation strategy for functional food applications. Future research should explore real-food integration, in vivo validation, and process scalability to unlock their full potential. • FOS enhanced color retention and storage stability of anthocyanin-loaded microcapsules. • Pea–rice protein with 1 % FOS showed highest solubility and controlled release. • FT-IR revealed FOS-induced β-sheet and β-turn structure in protein matrices. • FOS improved microcapsule uniformity and anthocyanin bioaccessibility. • Synergistic protein–FOS systems optimized anthocyanins delivery and protection.