Recovery of Phenolic Compounds From Elsholtzia ciliata Leaves by Ultrasound-Assisted Extraction and Their Antioxidant Application in Food.

Elsholtzia ciliata is a potential source of potent antioxidant phenolic compounds. This study investigated the ultrasound-assisted extraction (UAE) of phenolic compounds (TPC) and chlorogenic acid (CGA) from E. ciliata (ELC) leaf extract. The study also evaluated the antioxidant efficacy of the extract during the preservation of 8F fat-containing gummy candies. Using the response surface method (RSM), the optimal extraction temperature, time, and sonication time were predicted to be 77°C, 67 min, and 3.6 min, respectively. At the same time, ethanol concentration (60%), pH (5.5), and material-to-solvent ratio (1:18) were fixed based on preliminary selection. Under these conditions, TPC, CGA, and antioxidant activity reached 28.45 ± 0.5 mg gallic acid equivalents (GAE)/g dry weight (DW), 6.07 ± 0.18 mg/g DW, and 304.72 ± 0.83 μmol Trolox equivalents (TE)/g DW, respectively. Scanning electron microscopy (SEM) images showed that UAE conditions were favorable for the release of phenolic compounds. When incorporated into gummy candies, lipid oxidation was monitored over 49 days by measuring peroxide (PV) and thiobarbituric acid reactive substances (TBARS) values and compared to butylhydroxytoluene (BHT) and vitamin E. These results support the use of the ELC extract as a natural antioxidant to stabilize fatty foods.