Effect of ultrasound on the extraction of bioactive aglycone isoflavones for the green valorization of black soybean residue (okara)

Abstract

The effect of ultrasound on the extraction of bioactive aglycone isoflavones for the valorization of black soybean okara was investigated. A high extraction efficiency for total isoflavones was achieved with the total isoflavones extracted using water being 77.8% of that using 80% methanol as the solvent. The fraction of bioactive aglycones (daidzein and genistein) in total isoflavones using ultrasound (40 kHz/300 W) for 10 min was 81.7%, and further enhanced to 86.7% for 30 min. The profile of isoflavones was significantly influenced by temperature with the amounts of 351.00 μg/g‐okara of aglycones and 91.43 μg/g‐okara of glycosides using ultrasound at 60°C for 3 hr, and the fractions of aglycones in isoflavones were 96.4, 89.6, and 79.3% for 35, 50, and 60°C, respectively. An extraction model was proposed to successfully correlate the extraction rate coefficients and the limit concentrations of the four isoflavones in water. Practical applications The bioactive aglycone isoflavones are beneficial for human health. The okara produced from food industries contains high‐quality isoflavones, which have to be recovered for the potential use in functional foods. The process developed in this study allows the recovery of high‐content aglycone isoflavones from black soybean okara without further biotransformation of glycoside isoflavones, and provides the effective valorization of okara and process sustainability in food applications.

Effect of different extraction techniques and drying conditions for the assay of isoflavone fromHaritsoya seeds

“…A similar effect was noticed by Jankowiak, Kantzas, et al. (2014) and Yu and Yang (2019). In addition, ultrasonic treatment increases the affinity of aglycone form of isoflavone which leads to the high fraction of extracted aglycone.…”

“…Rostagno et al. (2007) achieved maximum extraction of isoflavone at 45°C for 20 min while Yu and Yang (2019) at 60°C from soybean. The overall interaction exhibited a significant effect of solvent concentration, temperature and time with the mean maximum (18.80 mg/g) value at 50% solvent concentration extracted at 50°C for 30 min.…”

“…The studies on the effect of water for the extraction of isoflavone by indicated the highest isoflavone concentration (911.l0 μg/g) at 50°C, 10 pH, and 1:50 as okara to water ratio. Yu and Yang (2019) studied the extraction of aglycones (daidzein and genistein) form of isoflavone from okara. Their investigation recorded the recovery of 81.70% with ultrasonic treatment at 40 kHz/300 W for 10 min.…”

Evaluation of Semi-Solid-State Fermentation of Elaeocarpus serratus L. Leaves and Black Soymilk by Lactobacillus plantarum on Bioactive Compounds and Antioxidant Capacity

“…The HPLC system was equipped with diode Array-detector (JASCO, MD-2010, Tokyo, Japan) and Mightysil RP-18 GP column (5 μm, 250 mm × 4.6 mm, Kanto Chemical Co., Tokyo, Japan). The HPLC conditions followed the method of Chen and Yang (2020) for myricitrin analysis [ 5 ] and the method of Yu and Yang (2019) for isoflavones analysis [ 30 ]. With the solvent A (acetonitrile) and solvent B (0.1% trifluoroacetic acid) as the mobile phase, the gradients were set as: (1) for myricitrin analysis, solvent A: 10 to 20% at 0 to 10 min, 20 to 40% at 10 to 35 min, 40 to 100% at 35 to 40 min, 100% at 40 to 45 min, and 100 to 10% at 45 to 46 min, (2) for isoflavones analysis, solvent A: 10% at 0 to 10 min, 10 to 55% at 10 to 35 min, 55 to 10% at 35 to 45 min, and 10% at 45 to 60 min.…”

Ultrasound-Assisted Aqueous Extraction of Chlorogenic Acid and Cynarin with the Impact of Inulin from Burdock (Arctium lappa L.) Roots

“…Ultrasound with frequency waves above 20 kHz can promote chemical reactions by generating cavities and local hotspots in the liquid medium, and has been employed in food processing efficiently [ 21 , 22 , 23 ]. Ultrasound can be used to extract the bioactive compounds from plant materials by destroying the plant cell walls to facilitate the transport of ingredients and increase the extraction efficiency [ 24 , 25 , 26 ].…”