RESUMO
Chlorogenic acid (CA), especially that found in soybeans, is a rich bioactive compound but has received very little attention in research settings in past decades. Ultrasonic-assisted extraction (UAE) could be an efficient method to increase CA release from soybeans. Hence, this study aimed to optimize UAE parameters for CA extraction from heilong48 soybean (HS) variety and evaluate the physicochemical and bioactive properties of the soybean. Optimization of ultrasound parameters with a Box-Behnken design found a frequency of 20.0 kHz, a power density of 30.0 W/L), a temperature of 37.9°C, and a time of 28.0 min to be the best conditions, which gave a CA yield of 5.007 ± 0.033 mg/g and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity of 93.197 ± 0.213 µmol of AA eq/g dry sample; these were higher than those of a non-ultrasound-treated (raw) HS sample (CA yield of 1.627 ± 0.528 mg/g and DPPH radical scavenging activity of 10.760 ± 0.207 µmol of AA eq/g dry sample). A satisfactory model was obtained. Scanning electron microscopy results confirmed the structural changes of the HS variety caused by the optimized UAE parameters. High total polyphenol contents (TPCs; 4.726 ± 0.002 mg GAE/g) and total phenolic acids (1.883 ± 0.005 mg GAE/g) and low total flavonoid contents (0.040 ± 0.008 mg RE/g) were obtained. A positive linear correlation between antioxidant activity and TPC was established. A protein-phenolic interaction in the HS variety was observed. The results established that polyphenols should be considered a significant component of the HS variety. Likewise, the HS variety could be used for CA extraction.
RESUMO
Chlorogenic acid (CA), especially that found in soybean, is a rich bioactive compound but has received very little attention in research settings in past decades. Ultrasonic-assisted extraction (UAE) could be an efficient method to increase CA release from soybean. Hence, this study aimed to optimize UAE parameters for CA extraction from heilong48 soybean (HS) variety with comprehensive physicochemical and bioactive properties evaluation. Optimization of ultrasound parameters with Box-Behnken design (BBD) found frequency (20.0 kHz), power density (30.0 W/L), temperature (37.9â), and time (28.0 min) as the significant optimized parameters, which gave CA yield of 5.007 ± 0.033 mg/g and DPPH of 93.197 ± 0.213 µmol AA eq/g dry sample and were higher than that of nonultrasound-treated (raw) HS sample (CA yield, 1.627 ± 0.528 mg/g, and DPPH, 10.760 ± 0.207 µmol AA eq/g dry sample). A satisfactory model was obtained. SEM results confirmed the structural alterations of HS variety caused by the optimized UAE parameters. High TPC (4.726 ± 0.002 mg GAE/g), TPA (1.883 ± 0.005 mg GAE/g), and low TFC (0.040 ± 0.008 mg RE/g) were obtained. A positive linear correlation between antioxidant activity and TPC was established. Protein-phenolic interaction in HS variety was observed. The results proposed that polyphenols should be considered as a significant component of HS variety. Likewise, HS variety could be utilized for CA extraction.
