Extraction of Pb(II) from wheat samples via dual-frequency ultrasound-assisted enzymatic digestion and the mechanisms of its interactions with wheat proteins. (30th November 2021)

• Record Type: Journal Article
• Authors: Cao, Hui; Meng, Denghui; Liu, Xutao; Ye, Tai; Yuan, Min; Yu, Jinsong; Wu, Xiuxiu; Li, Yan; Yin, Fengqin; Xu, Fei
• Is Part Of: Food chemistry. Volume 363(2021)
• Publication Date: 2021-11-30
• Subjects: Dual-frequency ultrasound-assisted enzymatic digestion -- Lead ions -- Extraction -- Wheat proteins -- Binding mechanism; Food -- Analysis -- Periodicals; Food -- Composition -- Periodicals; 664
• DOI: 10.1016/j.foodchem.2021.130247
• Languages: English
• ISSNs: 0308-8146

Abstract

Graphical abstract: Highlights: A novel dual-frequency ultrasound-assisted enzymatic digestion method was used to extract Pb(II). Up to 97.9% of Pb(II) in the wheat flour was recovered in 6 min using the dual-frequency ultrasound. The extraction of Pb(II) was mainly attributed to the exopeptidase activity of flavourzyme. Oxygen, nitrogen and sulfur-containing groups of wheat proteins offered binding sites for Pb(II). The binding of Pb(II) to wheat proteins can occur spontaneously at any temperature. Abstract: A novel dual-frequency ultrasound-assisted enzymatic digestion (DUED) technique was used to extract Pb(II) from certified reference materials (CRMs) of wheat flour. Following this, the interactions of Pb(II) with wheat proteins were investigated to provide evidence for the selection of enzyme species. The results showed that the simultaneous use of α-amylase and flavourzyme resulted in the recovery of 97.9% of Pb(II) in 6 min under a 40 kHz ultrasonic bath combined with a 20 kHz ultrasonic probe. The exopeptidase activity of the flavourzyme was found to be the main contributor to the extraction of Pb(II) from the CRMs. Additionally, the proposed method exhibited a low detection limit (8.2 ng/g) and high recoveries of real samples (93.4%-112.2%) with RSD less than 7.33%. Furthermore, the oxygen-containing groups of wheat proteins, the nitrogen-containing groups of albumins and globulins, and the sulfur-containing groups of gliadins and glutenins were found to offer coordination sites for Pb(II).