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Crystallization behavior of milk fat obtained from linseed-fed cows

Karen Smet UGent, Kathleen Coudijzer, Eveline Fredrick UGent, Sam De Campeneere, Jan De Block, Johan Wouters, Katleen Raes and Koen Dewettinck UGent (2010) JOURNAL OF DAIRY SCIENCE. 93(2). p.495-505
abstract
Milk with an increased content of unsaturated fatty acids was obtained by incorporating 60% of extruded linseed into the concentrate of cows. Two groups of Holstein cows (3 animals/group) were fed a concentrate(control or linseed enriched) together with the same roughage diet (ad libitum). After an adaptation period of 3 wk, evening and morning milk samples were collected every 7 d for 3 wk. Milk was decreamed and anhydrous milk fat (AMF) was isolated from the fat fraction by using the Bureau of Dairy Industries method. The objective of this study was to investigate if the crystallization mechanism of milk fat changed when the content of unsaturated fatty acids was increased. Therefore, the crystallization behavior of a milk fat enriched with unsaturated fatty acids was compared with that of a control milk fat. Nonisothermal crystallization was investigated with differential scanning calorimetry, and 1-step and 2-step isothermal crystallization behaviors were investigated using pulsed nuclear magnetic resonance, differential scanning calorimetry, and x-ray diffraction. A higher content of unsaturated fatty acids in AMF resulted in an increased proportion of low melting triglycerides. These triglycerides lowered the solid fat content profile, particularly at refrigerator temperatures. Furthermore, they induced some changes in the crystallization and melting behaviors of milk fat compared with a control AMF, although no fundamental changes in the crystallization mechanism could be revealed. Even though a lower melting point could be observed for milk fat with a higher content of unsaturated fatty acids, a similar degree of supercooling was needed to initiate crystallization, resulting in a shift in onset temperature of crystallization toward lower temperatures. In addition, slower crystallization kinetics were measured, such as a lower nucleation rate and longer induction times, although crystallization occurred in a similar polymorphic crystal lattice. During melting, a shift in offset temperature toward lower temperatures could be observed for the 3 melting fractions of AMF in addition to a higher proportion of low melting triglycerides. These results demonstrate that a higher content of unsaturated fatty acids has some effect on the crystallization behavior of milk fat. This knowledge could be used to produce dairy products of similar or superior quality compared with conventional products by intervening in the production process of dairy products.
Please use this url to cite or link to this publication:
author
organization
year
type
journalArticle (original)
publication status
published
subject
keyword
pulsed nuclear magnetic resonance, differential scanning calorimetry, X-ray diffraction, PROFILE, TEXTURE, OXIDATION, POLYMORPHISM, FRACTIONS, BUTTER, SENSORY PROPERTIES, ACID-COMPOSITION, DAIRY-PRODUCTS, PHYSICAL-PROPERTIES, milk fat
journal title
JOURNAL OF DAIRY SCIENCE
J. Dairy Sci.
volume
93
issue
2
pages
495 - 505
Web of Science type
Article
Web of Science id
000274102500007
JCR category
AGRICULTURE, DAIRY & ANIMAL SCIENCE
JCR impact factor
2.497 (2010)
JCR rank
2/54 (2010)
JCR quartile
1 (2010)
ISSN
0022-0302
DOI
10.3168/jds.2009-2588
language
English
UGent publication?
yes
classification
A1
copyright statement
I have transferred the copyright for this publication to the publisher
id
979644
handle
http://hdl.handle.net/1854/LU-979644
date created
2010-06-17 09:12:13
date last changed
2015-06-17 11:26:44
@article{979644,
  abstract     = {Milk with an increased content of unsaturated fatty acids was obtained by incorporating 60\% of extruded linseed into the concentrate of cows. Two groups of Holstein cows (3 animals/group) were fed a concentrate(control or linseed enriched) together with the same roughage diet (ad libitum). After an adaptation period of 3 wk, evening and morning milk samples were collected every 7 d for 3 wk. Milk was decreamed and anhydrous milk fat (AMF) was isolated from the fat fraction by using the Bureau of Dairy Industries method. The objective of this study was to investigate if the crystallization mechanism of milk fat changed when the content of unsaturated fatty acids was increased. Therefore, the crystallization behavior of a milk fat enriched with unsaturated fatty acids was compared with that of a control milk fat. Nonisothermal crystallization was investigated with differential scanning calorimetry, and 1-step and 2-step isothermal crystallization behaviors were investigated using pulsed nuclear magnetic resonance, differential scanning calorimetry, and x-ray diffraction. A higher content of unsaturated fatty acids in AMF resulted in an increased proportion of low melting triglycerides. These triglycerides lowered the solid fat content profile, particularly at refrigerator temperatures. Furthermore, they induced some changes in the crystallization and melting behaviors of milk fat compared with a control AMF, although no fundamental changes in the crystallization mechanism could be revealed. Even though a lower melting point could be observed for milk fat with a higher content of unsaturated fatty acids, a similar degree of supercooling was needed to initiate crystallization, resulting in a shift in onset temperature of crystallization toward lower temperatures. In addition, slower crystallization kinetics were measured, such as a lower nucleation rate and longer induction times, although crystallization occurred in a similar polymorphic crystal lattice. During melting, a shift in offset temperature toward lower temperatures could be observed for the 3 melting fractions of AMF in addition to a higher proportion of low melting triglycerides. These results demonstrate that a higher content of unsaturated fatty acids has some effect on the crystallization behavior of milk fat. This knowledge could be used to produce dairy products of similar or superior quality compared with conventional products by intervening in the production process of dairy products.},
  author       = {Smet, Karen and Coudijzer, Kathleen  and Fredrick, Eveline and De Campeneere, Sam and De Block, Jan and Wouters, Johan and Raes, Katleen and Dewettinck, Koen},
  issn         = {0022-0302},
  journal      = {JOURNAL OF DAIRY SCIENCE},
  keyword      = {pulsed nuclear magnetic resonance,differential scanning calorimetry,X-ray diffraction,PROFILE,TEXTURE,OXIDATION,POLYMORPHISM,FRACTIONS,BUTTER,SENSORY PROPERTIES,ACID-COMPOSITION,DAIRY-PRODUCTS,PHYSICAL-PROPERTIES,milk fat},
  language     = {eng},
  number       = {2},
  pages        = {495--505},
  title        = {Crystallization behavior of milk fat obtained from linseed-fed cows},
  url          = {http://dx.doi.org/10.3168/jds.2009-2588},
  volume       = {93},
  year         = {2010},
}

Chicago
Smet, Karen, Kathleen Coudijzer, Eveline Fredrick, Sam De Campeneere, Jan De Block, Johan Wouters, Katleen Raes, and Koen Dewettinck. 2010. “Crystallization Behavior of Milk Fat Obtained from Linseed-fed Cows.” Journal of Dairy Science 93 (2): 495–505.
APA
Smet, Karen, Coudijzer, K., Fredrick, E., De Campeneere, S., De Block, J., Wouters, J., Raes, K., et al. (2010). Crystallization behavior of milk fat obtained from linseed-fed cows. JOURNAL OF DAIRY SCIENCE, 93(2), 495–505.
Vancouver
1.
Smet K, Coudijzer K, Fredrick E, De Campeneere S, De Block J, Wouters J, et al. Crystallization behavior of milk fat obtained from linseed-fed cows. JOURNAL OF DAIRY SCIENCE. 2010;93(2):495–505.
MLA
Smet, Karen, Kathleen Coudijzer, Eveline Fredrick, et al. “Crystallization Behavior of Milk Fat Obtained from Linseed-fed Cows.” JOURNAL OF DAIRY SCIENCE 93.2 (2010): 495–505. Print.