Enchanted stability of butterfly pea flower extract through colloidal gas aphrons (CGA) separation method using Tween-20 surfactant

Abstract

Butterfly pea flower (BPF) is known to contain secondary metabolites, including anthocyanins. However, anthocyanins are unstable and easily degraded due to processing during food production, hence making the applications limited. This study aimed to determine the stability of BPF ethanolic extract with colloidal gas aphrons (CGA) separation, which is a surfactant-based separation method. The result showed that anthocyanins recovered by CGA at a volumetric ratio of 20 (AV20) showed higher stability (half-life = 295 days [d]) than in ethanolic extract (EE) (half-life = 43 d) and their stability increased with the concentration Tween-20 in CGA samples (6.07-8.58 mM). Loss of anthocyanins in the CGA-processed sample (AV20) (18.75\%) was lower than in ethanolic extract (74.57\%). Loss of anthocyanins during storage fitted to a first-order reaction model and the rate constant ranged from 0.0024 d-1-0.0161 d-1. AV20 exhibited lower values of rate constant (0.0024 d-1) compared to EE (0.0161 d-1). Higher concentrations of Tween-20 in aphron phases lead to higher encapsulation efficiency and separation factors. Therefore, we conclude that V20 of CGA-processed sample was more stable than the ratios studied. Although the stabilization effect is not fully understood, these findings contribute to a better understanding of the proposed method. Further research is necessary to explore novel applications of surfactant-based extraction methods.