# Optimization of Ultrasound-Assisted Extraction of Anthocyanins from Torch Ginger

## TL;DR

This study develops an efficient and eco-friendly method to extract anthocyanins from torch ginger flowers, which can be used as natural colorants and functional ingredients in food.

## Contribution

A novel ultrasound-assisted extraction method optimized for anthocyanin recovery from torch ginger under mild conditions.

## Key findings

- Solvent composition and solvent-to-sample ratio were the most influential factors for anthocyanin extraction.
- Optimized UAE conditions achieved high anthocyanin recovery with minimal degradation in 5 minutes.
- Flower color strongly correlates with anthocyanin concentration across torch ginger varieties.

## Abstract

The growing interest in using edible flowers as functional ingredients has increased the demand for reliable and sustainable strategies to recover and characterize their bioactive compounds. Torch ginger is a tropical species rich in anthocyanins. In this study, an ultrasound-assisted extraction (UAE) method was developed, optimized, and validated for the efficient recovery of anthocyanins from torch ginger flowers, with a clear focus on food-related applications. A Box–Behnken experimental design was applied to evaluate the influence of solvent composition, temperature, solvent-to-sample ratio, and pH on anthocyanin yield, using chromatographic responses. Solvent composition and solvent-to-sample ratio were identified as the most influential parameters, and effective extraction was achieved under mild temperature and pH conditions. The optimized conditions consisted of 84% methanol in water as the extraction solvent, a temperature of 30 °C, a solvent-to-sample ratio of 20:1 (mL g−1), and a pH of 5.6. Kinetic studies revealed that a 5 min extraction time maximized recovery while preventing compound degradation. The method was successfully applied to different torch ginger varieties, revealing a strong correlation between flower color and anthocyanin concentration. This research provides a fast, reliable, and environmentally friendly approach for assessing anthocyanin content in torch ginger flowers. The results support the valorization of this edible flower as a potential source of natural colorants and bioactive ingredients, contributing to ingredient selection, quality control, and the future development of functional foods and clean-label products.