Enhancing the Stability of Butterfly Pea Flower (Clitoria Ternatea) Extract by Water-In-Oil In Water Encapsulation With Changes In pH and During Storage

Butterfly pea flowers (Clitoria ternatea) produce blue anthocyanin pigments, and it has the potential as natural colourants. However, they are highly sensitive to pH and storage conditions. This study aimed to evaluate the stability of anthocyanins extracted from butterfly pea flowers by employing a double water-in-oil-in-water (W/O/W) emulsion system stabilised with Tween 80 as a hydrophilic emulsifier and polyglycerol polyricinoleate (PGPR) as a lipophilic emulsifier. Emulsions containing different butterfly pea flower extract (BPE) concentrations (10%–40%) were analysed for encapsulation efficiency, colour characteristics at varying pH levels, and storage stability over four weeks in terms of creaming index, droplet size, pH, colour changes, total anthocyanin content, and antioxidant activity. All formulations exhibited high encapsulation efficiency (>95%), indicating effective anthocyanin retention. Encapsulated samples showed higher lightness (L*) compared to free extracts, likely due to increased light scattering and reduced anthocyanin exposure to light. During storage, encapsulated samples maintained significantly higher anthocyanin content and antioxidant activity, following first-order degradation kinetics with lower rate constants and longer half-lives than free extracts. Among all formulations, the 30% BPE-loaded emulsion demonstrated optimal performance, exhibiting the highest encapsulation efficiency (97.9%), minimal droplet growth (22.89 µm), creaming index (13.43%), stable pH, and strong colour intensity (chroma = 11.36). These findings indicate that the PGPR/Tween 80-stabilised double emulsion system effectively enhances the physicochemical and functional stability of butterfly pea anthocyanins, supporting their potential application as a stable natural blue colourant in food formulations.