Volume 11
Issue 3
Food Science and Technology
JOURNAL OF
POLISH
AGRICULTURAL
UNIVERSITIES
Available Online: http://www.ejpau.media.pl/volume11/issue3/abs-04.html
SENSORY EVALUATION AND RHEOLOGICAL PROPERTIES OF YOGHURTS PREPARED FROM GOAT, COW AND SHEEP MILK
Jacek Domagała
Department of Animal Products Technology,
University of Agriculture, Cracow, Poland
ABSTRACT
Set-yoghurts produced from goat, cow and
sheep milk in the middle of the lactation period were examined fresh and after
14 days cold storage for sensory quality, pH and rheological properties.
Rheological investigations consisted of the determination of apparent viscosity
and drawings of flow curves. They were descripted using three rheological
models: Ostwald de Waele, Herschel-Bulkley and Casson. The values of
rheological parameters of these models and the area of the hysteresis loop were
calculated. In comparison to cow and sheep milk yoghurts, goat milk yoghurt had
a looser consistency, higher acidity and was less acceptable sensoricaly. The
apparent viscosity of goat milk yoghurt was lower and its flow curve was
characterized by a smaller hysteresis loop area and slant than these of
yoghurts from cow and sheep milk. Smaller values of the consistency
coefficient, yield stress and deviation from the Newtonian flow for goat milk
yoghurt were also found in comparison to yoghurts from goat and sheep milk. To
obtain the proper rheological and sensory properties of yoghurt from goat milk,
the modification of the composition and properties of milk or modification of
processing conditions are necessary.
Key words: apparent viscosity, flow curves, rheological models, sensory evaluation, yoghurt.
Jacek Domagała
Department of Animal Products Technology,
University of Agriculture, Cracow, Poland
Balicka Str. 122, 30-149 Cracow, Poland
Phone: 012 6624803,
Fax: 012 6624810
email: rtdomag@cyf-kr.edu.pl
Responses to this article, comments are invited and should be submitted within three months of the publication of the article. If accepted for publication, they will be published in the chapter headed 'Discussions' and hyperlinked to the article.