This research aims to obtain the Xanthium strumarium sprouts extract with the most potent antioxidant activities. The single-factor experiments were used to extract. Factors of extraction, including temperatures (40, 50, 60, and 70°C), time (6, 8, 10, 20, and 30 minutes), and % ethanol in solvent (40, 50, 60, and 70 % EtOH), were applied in the ultrasonic assist extraction of 40°C oven-dried Xanthium strumarium sprouts 1 gram in 25 mL of solvent. Extraction yield (% yield) and % inhibition of active radical DPPH and ABTS were determined, and the correlation to varied factors was analyzed using a statistical program (SPSS). The results showed that, at low temperatures, it would give a low % yield but not affect antioxidant activities. The longer extraction time did not provide a different % yield than the shorter one. The extraction yield is a little better when 50% ethanol is used in water as a solvent and does not affect antioxidant activities. As they observe, we can conclude that the antioxidant activities of extracts do not depend on temperature, time, or % EtOH in solvents. The % inhibition of ABTS radicals is higher than that of DPPH radicals in all experiments, and it can be relied on that the active components in this extract are more polar and favorable to solute in water than EtOH.

In this study, an ultrasound-assisted extraction (UAE) method combined with ion chromatography (IC) was developed, optimized and validated for the determination of benzoate in Northern Thai green chili dip. Four extraction variables were optimized using response surface methodology (RSM) based on a Box–Behnken design (BBD). The optimal conditions were a sample mass of 5.0 g, water volume of 20.0 mL, extraction temperature of 70 °C, and extraction time of 20 min. The validated method showed good linearity in the range of 0.5 to 100 mg L⁻¹, limits of detection (LOD) and quantification (LOQ) of 0.305 and 1.070 mg L⁻¹, respectively, precision in the range of 0.31 to 6.37% (%RSD, n = 11), and spiked recovery in the range of 85.50 to 107.80%, all of which were within the acceptable criteria. The AGREE score of the developed method was 0.45, which was higher than that of the conventional LLE-HPLC-UV method (0.27) due to the use of only deionized water as the extracting solvent and no generation of organic waste. The developed method was sensitive, validated, and environmentally friendly, and was successfully applied to the determination of benzoate in traditional condiment products. The proposed method may serve as an alternative approach for routine food analysis and quality control.