Exploring the relationship between protein secondary structures, temperature-dependent viscosities, and technological treatments in egg yolk and LDL by FTIR and rheology

Determination of heat-induced changes in the protein secondary structure of reconstituted livetins (water-soluble proteins from hen’s egg yolk) by FTIR

“…This can be explained by thermally-induced transitions in the secondary structure of the egg yolk proteins, providing information on the conversion from the native state to a heat-denatured one. Such thermal transitions in egg yolk proteins investigated with FTIR have also been described by Blume et al (2014). No such characteristic change was detectable for the rttfd livetins (Fig.…”

“…FTIR has been successfully applied in the investigation of antibodies other than IgY by Devi et al (2011), who analysed second-derivative plots of the absorbance values of intra-and intermolecular b-sheets and reported that thermal treatment of bovine IgG formulations caused protein secondary structure changes: absorbance values of intramolecular (native) b-sheets decreased in a sigmoidal manner, concomitant with an increase in intermolecular b-sheets, indicating thermal unfolding followed by aggregation of proteins. Furthermore, we recently showed by means of FTIR that there were only marginal changes in the protein secondary structure of egg yolk following pasteurization and optimized freeze-drying, whereas the egg yolk fraction LDL was remarkably sensitive to freeze-drying (Blume, Dietrich, Lilienthal, Ternes, & Drotleff, 2014). To the best of our knowledge, FTIR has thus far not been applied to investigate the protein secondary structures of the commercially relevant livetin fraction consisting of a-, b-and c-livetin.…”

Destabilization and removal of immobilized enzymes adsorbed onto polyethersulfone ultrafiltration membranes by salt solutions

“…2a). In addition, the shift of the infrared mode located around 1620 cm -1 towards higher frequency suggests a contribution of the band usually assigned to intermolecular β-sheets bonds, well known as "aggregation band" [38,39]. This shift is also observable for membranes coming in contact with 2 g/L pectinase solution (Fig.…”

“…Also, at 1168 cm -1 an IR mode associated to C-O-C stretching vibrations appears to be more intense confirming a different local chemical environment due to a varied rearrangement of the protein assembling. It is noteworthy that stretching located at 1620 towards higher frequency suggests intermolecular β-sheets bonds confirming a protein aggregation state [38,39].…”

Molecular structure characteristics, functional parameters and in vitro protein digestion of pressure‐cooked soya bean flours with different amounts of water

“…The effect of these parameters on the protein molecular structure is one of the characteristics that determine its digestive behaviour, nutritional quality and application in food products (Dyson & Wright, 1993;Tonge et al, 1996;Yu et al, 2004;Yu, 2005;Doiron et al, 2009). Therefore, the changes on the molecular structure of soya bean protein due to these parameters can be semi-quantitatively measured through its functional characteristics, in which secondary structures arrangement plays an important role (Hager, 1984;Prudencio-Ferreira & Areas, 1993;Blume et al, 2015). Other proposed approach to assess protein structure changes as affected by thermal treatments is attenuated total reflectance-fourier transform infrared spectroscopy (ATR-FTIR) (Samadi & Yu, 2011).…”