# Dehydrated Hibiscus sabdariffa Calyces as Anthocyanin-Rich Natural Colorants: Influence of Food-Grade Extraction and Syrup Formulation on Stability and Technological Performance

## TL;DR

This study explores using dried hibiscus calyces as natural colorants, showing that they can be effectively extracted and used in food products with good stability.

## Contribution

The study introduces a method for extracting stable anthocyanins from dehydrated hibiscus calyces and evaluates their performance in syrup formulations.

## Key findings

- Dehydration reduced moisture and improved storage stability of hibiscus calyces.
- The 5% sucrose syrup formulation showed the highest anthocyanin concentration and minimal loss over 30 days.
- Color stability in food matrices was pH-dependent, with strong correlations to hue and saturation.

## Abstract

The clean-label trend demands stable natural colorants. H. sabdariffa L. calyces is a sustainable anthocyanin source; however, the effects of dehydration and food-grade extraction on pigment recovery and performance remain unclear. Fresh and dehydrated calyces were physicochemically characterized, and dehydrated material with aqueous and hydroalcoholic food-grade solvents was used for extraction. Extraction efficiency was evaluated through total phenolic compound (TPC) content and anthocyanin characterization by HPLC-DAD-ESI-MS/MS. The aqueous extract with the highest anthocyanin concentration was selected for the syrup formulation containing 5–35% sucrose. The physicochemical stability of the formulations was monitored during refrigerated storage (4 °C/30 days) and subsequently tested in food matrices with different pH values. Dehydration calyces reduced moisture content (11.61%) and water activity (aw = 0.56), indicating improved storage stability. The anthocyanin concentration was highest in the 5% sucrose syrup (495.12 ± 40.66 mg mv-3,5-glc·100 g−1), with a 12.71% loss over 30 days. Application in food matrices demonstrated a pH-dependent color response, with correlations between hue angle (h°, r = 0.86) and color saturation (C*, r = −0.77).These results demonstrate that hibiscus calyx syrups are promising natural colorants and bioactive ingredients, particularly for acidic food systems, offering stability.