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Effect of free cysteine on the denaturation and aggregation of holo α-lactalbumin
- Source :
- International Dairy Journal. 79:52-61
- Publication Year :
- 2018
- Publisher :
- Elsevier BV, 2018.
-
Abstract
- α-Lactalbumin (α-LA) is a key commercial whey protein for nutritional purposes. The holo protein (calcium saturated) is considered the most heat stable whey protein, capable of refolding from unfolded states under many conditions. This is due to the absence of free thiols (cysteine residues) that are typically involved in thermal aggregation and thiol–disulphide exchange reactions of other whey proteins. Heating (0–120 min at 90 °C, pH 7.0) holo α-LA generates free thiols through thermal cleavage of disulphide bonds, resulting in aggregates comprising unfolded α-LA species. The addition of free cysteine promotes the formation of soluble aggregates, effectively decreasing the holding time required to reach a particular aggregate size in a dose-dependent manner (0.35–1.4 m m cysteine). Excess cysteine (≥14 m m ) causes a destabilisation of α-LA, shown by decreased denaturation temperature and gel formation. These data indicate that low doses of cysteine can be used to control α-LA aggregation.
- Subjects :
- 0301 basic medicine
Lactalbumin
Whey protein
Chemistry
chemistry.chemical_element
04 agricultural and veterinary sciences
Calcium
Cleavage (embryo)
040401 food science
Applied Microbiology and Biotechnology
03 medical and health sciences
030104 developmental biology
0404 agricultural biotechnology
Biophysics
Denaturation (biochemistry)
Destabilisation
Food Science
Cysteine
Holding time
Subjects
Details
- ISSN :
- 09586946
- Volume :
- 79
- Database :
- OpenAIRE
- Journal :
- International Dairy Journal
- Accession number :
- edsair.doi...........d6251def47f2e4261c95631f91949d08