Effect of alkaline pH-shift processing on in vitro gastrointestinal digestion of herring (Clupea harengus) fillets
Journal article, 2013
The effect of alkaline pH-shift processing on herring (Clupea harengus) protein oxidation, salt solubility and digestibility, has been evaluated. For the latter, herring mince and pH-shift produced herring protein isolate, both raw and heat-treated, were digested using a static gastrointestinal in vitro model. The pH-shift process resulted in drastically lowered protein salt solubility and increased lipid oxidation while protein carbonyl formation was unaffected. Yet, no significant differences in the degree of hydrolysis (DH) were observed between mince and isolates after completed gastrointestinal digestion, something which was confirmed by a similar release of proteinaceous material <3 kDa and similar free amino acid profiles. The polypeptide profiles of digested samples however revealed that two peptides (33 and 36 kDa) were present in larger amounts in the digested protein isolate compared to the digested herring mince. The results indicate that alkaline pH-shift processing had limited quantitative influence on the gastrointestinal digestibility of herring proteins despite its negative effects on protein salt solubility and lipid oxidation.
functional proteins
digestibility
acid solubilization
gelation characteristics
Solubilisation
myofibrillar proteins
solubilization process
lipid oxidation
pH-Shift
proteins
cod muscle
muscle
by-products
Precipitation
Salt
Alkaline
Gastrointestinal
Oxidation
In vitro digestion
Author
Sofia Marmon
Chalmers, Chemical and Biological Engineering, Life Sciences
Ingrid Undeland
Chalmers, Chemical and Biological Engineering, Life Sciences
Food Chemistry
0308-8146 (ISSN) 1873-7072 (eISSN)
Vol. 138 1 214-219Subject Categories
Clinical Medicine
Health Sciences
DOI
10.1016/j.foodchem.2012.10.035