title: Surface topography, nano-mechanics and secondary structure of wheat gluten pretreated by alternate dual-frequency ultrasound and the correlation to enzymolysis.
abstract: The effects of alternate dual-frequency ultrasound (ADFU) pretreatment on the degree of hydrolysis (DH) of wheat gluten (WG) and angiotensin I-converting enzyme (ACE) inhibitory activity were investigated in this research. The surface topography, nano-mechanics and secondary structure of WG were also determined using atomic force microscope (AFM) and circular dichroism (CD). The correlations of ACE inhibitory activity and DH with surface topography, nano-mechanics and secondary structure of WG were determined using Pearson's correlation analysis. The results showed that with an increase in either pretreatment duration or power, the ACE inhibitory activity of the hydrolysate also increases, reaching maximum at 10 min and 150 W/L, respectively, and then decreases thereafter. Similarly, AFM analysis showed that as the pretreatment duration or power increases, the surface roughness also increase and again a decrease occurs thereafter. As the pretreatment duration or power increased, the Young's modulus and adhesion of WG also increased and then declined. Young's modulus and adhesions average values were compared with ACE inhibitory activity reversely. The result of the CD spectra analysis exhibited losses in the relative percentage of α-helix of WG. Pearson's correlation analysis showed that the average values of Young's modulus and the relative percentage of α-helix correlated with ACE inhibitory activity of the hydrolysates linearly and significantly (P<0.05); the relative percentage of β-sheet correlated linearly with DH of WG significantly (P<0.05). In conclusion, ADFU pretreatment is an efficient method in proteolysis due to its physical and chemical effect on the Young's modulus, α-helix and β-sheet of WG.
authors.affiliation: School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, China.
authors.forename: Yanyan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, China.
authors.forename: Bei
authors.initials: B
authors.lastname: Wang
authors.affiliation: School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, China.
authors.forename: Cunshan
authors.initials: C
authors.lastname: Zhou
authors.affiliation: Department of Food Science, University of Arkansas Division of Agriculture, 2650 N Young Avenue, Fayetteville, AR 72704, USA.
authors.forename: Griffiths G
authors.initials: GG
authors.lastname: Atungulu
authors.affiliation: School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, China.
authors.forename: Kangkang
authors.initials: K
authors.lastname: Xu
authors.affiliation: School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, China. Electronic address: mhl@ujs.edu.com.
authors.forename: Haile
authors.initials: H
authors.lastname: Ma
authors.affiliation: School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, China.
authors.forename: Xiaofei
authors.initials: X
authors.lastname: Ye
authors.affiliation: School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, China.
authors.forename: Mohammed A Y
authors.initials: MA
authors.lastname: Abdualrahman
mesh_terms: D000110:Acetylcholinesterase / Q000737:chemistry*; D002942:Circular Dichroism; D005983:Glutens / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D017433:Protein Structure, Secondary; D059748:Proteolysis; D013499:Surface Properties; D014908:Triticum / Q000737:chemistry*; D014465:Ultrasonics
chemical_list: D005983:Glutens; D000110:Acetylcholinesterase
keywords: Enzymatic hydrolysis; Nano-mechanics; Surface topography; Ultrasound pretreatment; Wheat gluten