Vibration-induced particle formation during yogurt fermentation—Effect of frequency and amplitude

Journal article
(Original article)

Publication Details

Author(s): Körzendörfer A, Temme P, Schlücker E, Hinrichs J, Nöbel S
Journal: Journal of Dairy Science
Publication year: 2018
Volume: 101
Journal issue: 5
Pages range: 2866-3877
ISSN: 0022-0302
Language: English


Machinery such as pumps used for the commercial production of fermented
milk products cause vibrations that can spread to the fermentation
tanks. During fermentation, such vibrations can disturb the gelation of
milk proteins by causing texture defects including lumpiness and
syneresis. To study the effect of vibrations on yogurt structure
systematically, an experimental setup was developed consisting of a
vibration exciter to generate defined vibrational states and
accelerometers for monitoring. During the fermentation of skim milk,
vibrations (frequency sweep: 25 to 1,005 Hz) were introduced at
different pH (5.7 to 5.1, step width 0.1 units) for 200 s. Physical
properties of set gels (syneresis, firmness) and resultant stirred
yogurts (visible particles, rheology, laser diffraction) were analyzed.
Vibrational treatments at pH 5.5 to 5.2 increased syneresis, gel
firmness, and the number of large particles (d > 0.9 mm); hence, this
period was considered critical. The particle number increased from 34 ±
5 to 242 ± 16 particles per 100 g of yogurt due to vibrations at pH
5.4. In further experiments, yogurts were excited with fixed frequencies
(30, 300, and 1,000 Hz). All treatments increased syneresis, firmness,
and particle formation. As the strongest effect was observed by applying
30 Hz, the amplitude was set to vibration accelerations of a = 5, 10,
15, 20, and 25 m/s2 in the final experiments. The number of
large particles was increased due to each treatment and a positive
correlation with the amplitude was found. We concluded that vibrations
during gelation increase the collision probability of aggregating milk
proteins, resulting in a compressed set gel with syneresis. Resultant
stirred yogurts exhibit large particles with a compact structure leading
to a reduced water-holding capacity and product viscosity.

FAU Authors / FAU Editors

Schlücker, Eberhard Prof. Dr.-Ing.
Lehrstuhl für Prozessmaschinen und Anlagentechnik
Temme, Philipp
Lehrstuhl für Prozessmaschinen und Anlagentechnik

How to cite

Körzendörfer, A., Temme, P., Schlücker, E., Hinrichs, J., & Nöbel, S. (2018). Vibration-induced particle formation during yogurt fermentation—Effect of frequency and amplitude. Journal of Dairy Science, 101(5), 2866-3877.

Körzendörfer, Adrian, et al. "Vibration-induced particle formation during yogurt fermentation—Effect of frequency and amplitude." Journal of Dairy Science 101.5 (2018): 2866-3877.


Last updated on 2019-04-01 at 19:10