Ascorbic acid‐induced degradation of liposome‐encapsulated acylated and non‐acylated anthocyanins of black carrot extract

BACKGROUND: In the presence of ascorbic acid, the degradation of acylated (sinapic, ferulic and p‐coumaric acid derivatives of cyanidin‐3‐xylosylglucosylgalactoside) and non‐acylated anthocyanins of black carrot extract (BCE) encapsulated in liposomes was studied. BCEs (0.2% and 0.4% w/w) were encapsulated in liposomes using different lecithin concentrations (1%, 2% and 4% w/w). RESULTS: The liposomes were prepared with particle diameters of less than 50 nm and zeta potentials of about −21.3 mV for extract‐containing liposomes and −27.7 mV for control liposomes. The encapsulation efficiency determined using high‐performance liquid chromatography (HPLC) showed that increasing lecithin levels increased the efficiency to 59% at the same extract concentration. The concentrations of total anthocyanins and individual anthocyanins were determined for ascorbic acid (0.1% w/w)‐degraded extract and liposomes (containing 0.2% w/w extract). Anthocyanin quantification of both liposomal and extract samples was performed by HPLC using cyanidin‐3‐O‐glucoside chloride as standard. Five anthocyanins in the extract and encapsulated liposomes were quantified during 24 h (0–24 h): cyanidin‐3‐xylosylglucosylgalactoside 1.0–0.51 and 0.82–0.58 mg g⁻¹, cyanidin‐3‐xylosylgalactoside 2.5–1.1 and 2.2–1.7 mg g⁻¹, cyanidin‐3‐xylosyl(sinapoylglucosyl)galactoside 0.51–0.14 and 0.35–0.28 mg g⁻¹, cyanidin‐3‐xylosyl(feruloylglucosyl)galactoside 1.37–0.41 and 1.06–0.98 mg g⁻¹, and cyanidin‐3‐xylosyl(coumaroylglucosyl)galactoside 0.28–0.08 mg g⁻¹ for extract and 0.27–0.26 mg g⁻¹ for liposomes, respectively. CONCLUSIONS: This study demonstrates the potential beneficial effect of liposomal encapsulation on individual, particularly acylated, anthocyanins after addition of ascorbic acid during a storage time of 24 h.