PMID- 32078911 OWN - NLM STAT- MEDLINE DCOM- 20210107 LR - 20210316 IS - 1873-2828 (Electronic) IS - 1350-4177 (Linking) VI - 64 DP - 2020 Jun TI - High-power sonication of soy proteins: Hydroxyl radicals and their effects on protein structure. PG - 105019 LID - S1350-4177(19)32159-5 [pii] LID - 10.1016/j.ultsonch.2020.105019 [doi] AB - High-power sonication (HPS) is shown to alter protein structure, thus, its functionality, via intermolecular interactions. This study evaluated the effects of HPS on molecular structure of soy proteins in aqueous medium. Free radicals generated during HPS were quantitated using the 5,5-dimethyl-l-pyrrolin N-oxide (DMPO) spin trap method. Electron paramagnetic resonance (EPR) was used to identify them as mostly hydroxyl radicals. The minimum saturation concentration of spin trap solution was determined to be 500 mM of DMPO in water, when exposed to 5 W/cm(3) ultrasound power density (PD) for 10 min; subsequently, this concentration was used for quantitating radicals generated in protein samples. Five aqueous soy protein systems, namely, 5% soy protein isolate (SPI), 5% SPI without isoflavonoids (NO-ISO SPI), subunit solutions 1% glycinin (11S) and 1% beta conglycinin (7S), and 10% soy flakes (w/v), were sonicated at 2.5 and 5 W/cm(3) PDs. Only adducts of hydroxyl radicals (DMPO-OH) were detected in all of these aqueous systems. The highest concentration (3.68 microM) of DMPO-OH adduct was measured in 11S subunit solution at 5 W/cm(3), whereas, the lowest (0.67 microM) was in soy flakes solution at 2.5 W/cm(3). PD 5 W/cm(3) generated higher concentration of radicals in 7S subunit solution, NO-ISO SPI, and soy flakes protein, compared to sonication at PD 2.5 W/cm(3). No change in the protein electrophoretic patterns were observed due to HPS. However, some changes due to HPS were observed in the estimated secondary and tertiary structures, and the contents of free sulfhydryl groups and disulfide bonds in proteins. CI - Published by Elsevier B.V. FAU - Rahman, Md Mahfuzur AU - Rahman MM AD - Department of Food Science and Human Nutrition, Iowa State University, Ames, IA 50011, United States. FAU - Byanju, Bibek AU - Byanju B AD - Department of Food Science and Human Nutrition, Iowa State University, Ames, IA 50011, United States. FAU - Grewell, David AU - Grewell D AD - Department of Industrial and Manufacturing Engineering, North Dakota State University, Fargo, ND 58102, United States. FAU - Lamsal, Buddhi P AU - Lamsal BP AD - Department of Food Science and Human Nutrition, Iowa State University, Ames, IA 50011, United States. Electronic address: lamsal@iastate.edu. LA - eng PT - Journal Article DEP - 20200210 PL - Netherlands TA - Ultrason Sonochem JT - Ultrasonics sonochemistry JID - 9433356 RN - 0 (Cyclic N-Oxides) RN - 0 (Disulfides) RN - 0 (Soybean Proteins) RN - 3352-57-6 (Hydroxyl Radical) RN - 7170JZ1QF3 (5,5-dimethyl-1-pyrroline-1-oxide) SB - IM EIN - Ultrason Sonochem. 2021 May;73:105504. PMID: 33725646 MH - Cyclic N-Oxides/chemistry MH - Disulfides/chemistry MH - Hydroxyl Radical/*chemistry MH - Protein Structure, Secondary MH - *Sonication MH - Soybean Proteins/*chemistry OTO - NOTNLM OT - High power sonication OT - Hydroxyl radicals OT - Protein oxidation OT - Protein structure OT - Soy protein OT - Spin trapping COIS- Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. EDAT- 2020/02/23 06:00 MHDA- 2021/01/08 06:00 CRDT- 2020/02/21 06:00 PHST- 2019/12/31 00:00 [received] PHST- 2020/02/06 00:00 [revised] PHST- 2020/02/08 00:00 [accepted] PHST- 2020/02/23 06:00 [pubmed] PHST- 2021/01/08 06:00 [medline] PHST- 2020/02/21 06:00 [entrez] AID - S1350-4177(19)32159-5 [pii] AID - 10.1016/j.ultsonch.2020.105019 [doi] PST - ppublish SO - Ultrason Sonochem. 2020 Jun;64:105019. doi: 10.1016/j.ultsonch.2020.105019. Epub 2020 Feb 10.