Promotie

Natural variation in casein composition of milk

Promovendus E (Etske) Bijl PhD MSc
Promotor prof.dr.ir. ACM (Toon) van Hooijdonk
Copromotor ir. HJF (Hein) van Valenberg
Copromotor dr ir T Huppertz
Organisatie Wageningen University, Food Quality and Design
Datum

vr 23 mei 2014 11:00 tot 12:30

Locatie Auditorium, building number 362
Generaal Foulkesweg 1
362
6703 BG Wageningen
0317-483592

The research described in this thesis is focused on the natural variation in protein composition of milk between individual cows. Almost 80% of the milk protein fraction consists of caseins. Most of these caseins are assembled in casein micelles; protein clusters consisting of several thousands of individual casein molecules and salts. The unique structure of casein micelles allows the delivery of large amounts of calcium and phosphate to the neonate.

Considerable natural variation exists in casein composition between milk samples from individual cows. One of these variations is the presence of eight or nine phosphate groups on a casein. In this research we show that this variation can influence the structure of casein micelles and the break-down of caseins in milk gels, which are basic models for cheese.

The use of milk from individual cows is more suitable for research on casein micelle properties than the use of bulk milk.
The use of milk from individual cows is more suitable for research on casein micelle properties than the use of bulk milk.
Etske Bijl

Optimization of dairy products

Furthermore, variation in the amount of sugar groups on the caseins is associated with changes on the surface of casein micelles. Therefore, variation in phosphate and sugar groups of the caseins are an important aspect to consider for optimization of dairy products and the design of future breeding strategies.