Marmon, Sofia
- Chalmers University of Technology
Abstract
Salt solubility of pH-shift isolated herring (Clupea harengus) muscle proteins was studied in relation to pH exposure and microstructure using transmission electron microscopy (TEM). Using protein solubilization at pH 11.2 with subsequent precipitation at pH 5.5, salt solubility of the proteins decreased from 78 to 17%. By precipitating the alkali-solubilized proteins at the pH of native herring muscle, 6.5, salt solubility only decreased to 59%, proving that pH values between 6.5 and 5.5 affected protein salt solubility more than the pH cycle 6.5 -> 11.2 -> 6.5. Precipitation at pH 5.5 resulted in hydrogen bonds, hydrophobic interactions, and S-S bridges, whereas precipitation at pH 6.5 resulted only in the formation of hydrophobic interactions. The alkaline pH-shift isolation process severely rearranged the protein microstructure, with precipitation at pH 6.5 forming a finer, more homogeneous network than precipitation at pH 5.5. The former protein isolate also contained less lipid oxidation products and formed more deformable gels, without affecting protein yield.
Keywords
pH-shift; alkaline solubilization; precipitation; salt solubility; protein; herring; transmission electron microscopy
Published in
Journal of Agricultural and Food Chemistry
2012, volume: 60, number: 32, pages: 7965-7972
Publisher: AMER CHEMICAL SOC
SLU Authors
Langton, Maud
- Swedish Institute for Food and Biotechnology - SIK
UKÄ Subject classification
Food Science
Publication identifier
- DOI: https://doi.org/10.1021/jf301352s
Permanent link to this page (URI)
https://res.slu.se/id/publ/85474