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Published on: August 18, 2017
Bovine milk fat globule membrane proteins are affected by centrifugal washing processes
Haotian Zheng1, Rafael Jiménez-Flores, David W Everett
1Riddet Institute and Department of Food Science, University of Otago , Dunedin 9054, New Zealand.
Abstract:
The impact of washing on the release of proteins from the milk fat globule membrane (MFGM) was examined by applying washing procedures with different degrees of stringency to milk fat globule (MFG) surfaces in simulated milk ultrafiltrate buffer solution. Three washing methods, M1 (3000g, 5 min, three washes), M2 (3750g, 15 min, one wash), and M3 (15000g, 20 min, three washes) were chosen. MFG ζ-potential increased after M3 washing (P < 0.05), suggesting surface damage. For M1, in which the native MFG surface was least damaged, cluster of differentiation 36 (CD 36) and periodic acid schiff 6/7 proteins were more strongly bound to the MFGM compared with other major membrane proteins. For M3, CD 36 together with fatty acid-binding protein was more strongly bound to the MFGM. Washing by centrifugation and redispersal of the fat globules damaged the MFGM, with release into the aqueous phase of some membrane-associated proteins. The current results show the impact of washing processes on retention of functional MFGM proteins.
Insights
Washing milk fat globule membrane (MFGM) proteins affects their release. More stringent washing damages the MFGM, altering protein binding and release into the aqueous phase.
Area of Science:
- Dairy Science
- Food Chemistry
- Biochemistry
Background:
- The milk fat globule membrane (MFGM) is a complex biological structure.
- MFGM proteins play crucial roles in various physiological functions.
- Understanding MFGM protein stability during processing is essential.
Purpose of the Study:
- To investigate the effect of different washing stringencies on protein release from MFGM.
- To identify specific proteins affected by washing procedures.
- To assess the impact of washing on MFGM integrity.
Main Methods:
- Washing milk fat globules (MFG) using three methods (M1, M2, M3) with varying centrifugation force, time, and washes.
- Analyzing MFG ζ-potential to assess surface damage.
- Identifying bound proteins using proteomic techniques.
Main Results:
- Washing, particularly M3 (15000g, 20 min, three washes), increased MFG ζ-potential, indicating surface damage.
- Less stringent washing (M1) showed stronger binding of cluster of differentiation 36 (CD 36) and periodic acid schiff 6/7 proteins.
- More stringent washing (M3) altered protein binding, with CD 36 and fatty acid-binding protein showing stronger association.
Conclusions:
- Washing processes, especially those involving high centrifugation, can damage the MFGM.
- Protein release into the aqueous phase occurs due to MFGM damage.
- Washing stringency significantly impacts the retention of functional MFGM proteins.
