# Effects of High Pressure Processing and Ultrasound-Assisted Extraction on Physicochemical Properties, Antioxidant Activity and Flavor Compounds of Cold Brew Citri Reticulatae Pericarpium Beverage

## TL;DR

This study shows that combining high pressure processing and ultrasound-assisted extraction improves the flavor and antioxidant activity of cold brew citrus peel beverages.

## Contribution

The combined HPP+UAE method was found to synergistically enhance flavor and antioxidant activity in cold brew CRP beverages.

## Key findings

- The combined HPP+UAE method increased the number of VOCs in 10-year CRP from 45 to 81.
- The total VOC content increased from 2.44 to 5.98 μg/mL with the HPP+UAE method.
- The flavor profile shifted from fresh to a richer woody type using HPP+UAE.

## Abstract

HPP and UAE-assisted extraction enhanced the extraction efficiency of cold brew CRP water.

The combined HPP+UAE approach maximized the diversity and total content of VOCs of CRP water.

Aging years induced a clear shift in the aroma profile of CRP water from a fresh type to a woody type.

The flavor quality and antioxidant activity of CRP water were synergistically improved by the combined HPP+UAE approach.

High pressure processing (HPP) and ultrasound-assisted extraction (UAE) can effectively shorten extraction time and increase extraction efficiency of the cold brew (CB) process. However, their application in CB citri reticulatae pericarpium (CRP) and the underlying mechanisms of flavor modulation remain poorly understood. In this study, CB-CRP beverage was prepared with HPP-assisted, UAE-assisted, and HPP+UAE-assisted extraction from 1, 3, 5, and 10 years CRP. Results revealed that the total soluble solids (TSS), total sugars, flavonoids, polyphenols, and volatile organic compounds (VOCs) and antioxidant activity of CB-CRP increased after assisted extraction. The combined application of HPP and HPP+UAE-assisted extraction exhibited the most pronounced effects. The kinds and total content of VOCs of CB beverages prepared from 10-year-aged CRP increased from 45 to 81, and from 2.44 to 5.98 μg/mL, respectively. Moreover, the combined HPP+UAE extraction promoted the enrichment of fatty and woody aroma-related compounds, which drove a shift in the flavor profile from fresh to a richer woody type. And this endowed the CB-CRP water with a more complex and multidimensional aroma profile.