Dynamic oscillation tests were conducted to determine the flow
behavior and characterize the viscoelastic properties of yogurt, using a
rheometer (TA Instruments, SR-2000, DE, US) fitted with a 40-mm
diameter cone and 2° cone angle and plate geometry with a 4 mm gap.
To ascertain the applicable stress and frequency in which storage
modulus (G′) and loss modulus (G″) parameters of yogurt would
demonstrate a linear constant rate, dynamic frequency ramp tests and
dynamic stress ramp tests were conducted at 25 °C (range of
frequency from 1 to 10 Hz and stress set as 3 Pa and range of stress
from 1 to 10 Pa and frequency set as 2.5 Hz, respectively). Dynamic
temperature ramp tests were done at stress and frequency of 1.0 Pa
and 2.0 Hz, respectively, in a temperature range of 4 to 50 °C (heating)
and 50 to 4 °C (cooling), at a rate of 7 °C/min. Aliquots of the samples
were carefully removed from the undisturbed yogurt cup and placed
on the center of the rheometer plate; the top plate was slowly
lowered on the top of the sample prior to analysis
Dynamic oscillation tests were conducted to determine the flowbehavior and characterize the viscoelastic properties of yogurt, using arheometer (TA Instruments, SR-2000, DE, US) fitted with a 40-mmdiameter cone and 2° cone angle and plate geometry with a 4 mm gap.To ascertain the applicable stress and frequency in which storagemodulus (G′) and loss modulus (G″) parameters of yogurt woulddemonstrate a linear constant rate, dynamic frequency ramp tests anddynamic stress ramp tests were conducted at 25 °C (range offrequency from 1 to 10 Hz and stress set as 3 Pa and range of stressfrom 1 to 10 Pa and frequency set as 2.5 Hz, respectively). Dynamictemperature ramp tests were done at stress and frequency of 1.0 Paand 2.0 Hz, respectively, in a temperature range of 4 to 50 °C (heating)and 50 to 4 °C (cooling), at a rate of 7 °C/min. Aliquots of the sampleswere carefully removed from the undisturbed yogurt cup and placedon the center of the rheometer plate; the top plate was slowlylowered on the top of the sample prior to analysis
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