Among natural sources of anthocyanins, Clitoria ternatea (butterfly pea flower, BPF) is an edible flower traditionally recognized for its agricultural and medicinal relevance. In recent years, growing scientific interest has focused on its intense and stable blue pigmentation and unique anthocyanin composition. This characteristic hue arises from complex anthocyanins known as ternatins, delphinidin-based compounds derived from delphinidin-3,3′,5′-triglucoside. These anthocyanins are highly polyacylated and polyglycosylated, a rare structural feature that confers exceptional properties compared with simple glycosylated anthocyanins [1,2]. This positions BPF as an interesting model to study structure-driven anthocyanin stability and gastrointestinal behavior. This work provides an integrative characterization of BPF anthocyanins, exploring how their structural features influence stability, bioaccessibility, and bioavailability. Full and purified BPF extracts were characterized by UHPLC-DAD-MS, confirming polyacylated ternatins as the dominant anthocyanins, with ternatin B2/B3 as the major compound. Chemical stability of BPF anthocyanins was assessed under varying pH, temperature, and time conditions. pH exerted the strongest influence on ternatin stability, while temperature and time had negligible effects, highlighting the intrinsic stability of these highly acylated anthocyanins. Chromatic stability analysis by UV-visible spectroscopy demonstrated sustained blue coloration over 14 days across a wide pH range, with minimal degradation. Simulated digestions following the INFOGEST guidelines revealed an increase in anthocyanin content after the intestinal phase, relevant for their behavior as dietary compounds. In vitro cytotoxicity assays showed no substantial cytotoxicity across the tested concentrations in gastric and intestinal cell models (NCI-N87 and Caco-2/HT29-MTX, respectively). Transepithelial transport studies revealed that both gastric and intestinal absorption followed a time-dependent pattern. Altogether, these findings indicate that the highly polyacylated structure of ternatins underlies their exceptional stability and modulates anthocyanin release during simulated digestion, emphasizing the role of structure in anthocyanin stability and bioaccessibility, supporting their use in stable, naturally colored food systems.

1. Oguis, G.K., et al. (2019), Front. Plant Sci., 10.
2. Escher, G.B., et al. (2020), Food Chem., 331: p. 127341.