XPS analysis of food products: toward chemical functions and molecular compounds

Abstract

The concentrations of elements or functions ratioed to total carbon can be modeled on the basis of the known composition of model biochemical compounds, which leads to an evaluation of the surface composition expressed in wt% of these classes of compounds. Thereby, it was shown that surface accumulation, as compared to the bulk, increases in the order proteins < NL < PL. Moreover, the surface enrichment of PL compared to triglycerides was found to be increased after baking.

Effect of Motif‐Programmed Artificial Proteins on the Calcium Uptake in a Synthetic Hydrogel

“…This peak overlaps with the signal of the amide N 1 s , which – in proteins and polyamides – was reported to occur at energies between 399.8 and 401.1 eV 7, 42–49. A value close or equal to 400 eV is routinely considered as the signature of immobilized peptides or proteins 44–46, 49–51. In our analysis, the amide N 1 s signal appeared at 399.8, 399.9 or 399.9 eV in PHEMA modified with, respectively, the proteins PS382, PS458 or PS64.…”

“…The initiator V‐65 is an azo derivative, and XPS binding energies between 398.9 and 400.5 eV have been reported40, 41 for N 1 s in the azo linkage (NN). This peak overlaps with the signal of the amide N 1 s , which – in proteins and polyamides – was reported to occur at energies between 399.8 and 401.1 eV 7, 42–49. A value close or equal to 400 eV is routinely considered as the signature of immobilized peptides or proteins 44–46, 49–51.…”

“…In our analysis, the amide N 1 s signal appeared at 399.8, 399.9 or 399.9 eV in PHEMA modified with, respectively, the proteins PS382, PS458 or PS64. An additional N 1 s peak appeared only in the protein‐modified PHEMA samples at, respectively, 402.1 eV (PS382), 402.2 eV (PS458) and 402.2 eV (PS64), which is assignable to protonated nitrogen, a feature in the XPS spectra of proteins reported to occur between 401.5 and 402.5 eV 42, 43, 49…”

Physico-chemical mechanisms governing the adherence of starch granules on materials with different hydrophobicities

“…The C 1s peak showed contributions which can be unambiguously assigned on basis of literature data [25][26][27] and were quantified as detailed in Supporting Information (Section B) and illustrated in Fig. 12.…”

Conditioning materials with biomacromolecules: Composition of the adlayer and influence on cleanability

“…The C 1s peak was decomposed (Rouxhet et al, 2008;Rouxhet and Genet, 2011) with the S 2p 3/2 component near 163.7 eV, which was attributed to sulfur-containing residues of BSA (Caillou et al, 2007).…”