Stabilization of Anthocyanins Crude Extracted from Rambutan (Nephelium Lappaceum L.) Peel Through Copigmentation and Encapsulation for Natural Food Colorants

Plant-derived anthocyanins are widely used as natural food colorants, with rambutan peels representing a potential source. However, their application is limited because of their inherent instability and susceptibility to rapid color changes. Copigmentation and encapsulation present promising strategies to increase both the stability and color intensity of anthocyanins. This study aimed to improve the stability and color intensity of anthocyanins extracted from rambutan peels through copigmentation and encapsulation. Rambutan peels were blanched, dried, and ground into powder before being subjected to ultrasound-assisted extraction via 0.2 citric acid in 96 ethanol. Copigmentation was conducted by adding Tannic acid at molar ratios of 1:0, 1:100, 1:150, and 1:200, followed by encapsulation with 10 maltodextrin. This study evaluated the color stability and anthocyanins degradation of copigmented rambutan peel anthocyanins extract, along with its characteristics and stability in powder form during storage at low temperatures. The results showed that increasing Tannic acid from a molar ratio of 1:100 to 1:200 caused a 10 nm wavelength shift, and the absorbance increased from 3 to 15. The 1:150 molar ratio resulted in the most significant improvement, effectively preserving red color stability and reducing anthocyanins degradation in copigmented anthocyanins. FT-IR analysis confirmed that the improved stability of the anthocyanins following tannic acid addition resulted from intermolecular interactions. Moreover, the incorporation of tannic acid produced anthocyanins powder with smoother surfaces and greater uniformity. The highest half-life values and the lowest ΔE values were observed for the anthocyanins powder stored at -16 ± 5 °C. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2025.