Pudding
Laboratory Viscometer Application Data Sheet
(Two Methods)
USE: Pudding is a common dessert, available in a variety of flavors and styles.
Method #1
Test Equipment:
- Spring Torque Range: RV
- Spindle: T-D
- Accessory: Helipath Stand
- Speed, rpm: 5
The test is run at room temperature.
The Helipath Stand with T-bar spindles is commonly used to test creamy or pasty materials in a wide variety of industries. In this example, two different puddings were tested directly in their containers (small cups). A Brookfield RVDV-II+ Pro Viscometer was used with Model D Helipath Stand and T-D spindle rotating at 5 rpm at 20°C. Typical data, from two samples of each material, are shown below:
Figure 1: Helipath data comparing two puddings.
The data from the "plateau" region of a given data set, indicated by the arrows shown above, are averaged to give a QC viscosity value. The two sets of data for each pudding overlay or superimpose well, indicating good repeatability of this technique for these materials. The viscosity of Pudding 1 is significantly higher than that of Pudding 2.
Method #2
TEST EQUIPMENT:
- Spring Torque Range: HB
- Spindle: V-72, immersed to the secondary mark
- Accessory: (none)
- Speed, rpm: 1
The test is run at room temperature.
Vane rheometry is relatively new in QC applications. The YR-1 Yield Rheometer is an easy-to-use instrument that comes with EZ-YieldTM software. The user selects the run parameters and then downloads them into the machine. The YR-1 may then be either:
- Detached from the PC and run in standalone mode - with the Yield Stress, Pa, Torque-at-Yield, percent, and temperature, °C, displayed on the instrument's LCD screen, or
- Run with EZ-YieldTM so that the data and graphs are displayed on the personal computer or PC screen.
In this example, three different puddings were directly tested in their containers at room temperature, approximately 20oC.
Figure 2: V-72 vane spindle inserted to its secondary immersion mark. The HBYR-1's temperature probe is inserted to the left.
The yield stress may be defined as the stress that is high enough to make a solid flow like a liquid. Typical data are shown below:
Figure 3: HBYR-1 data for three different puddings.
Both the slope of Pudding 1's curve, or modulus, and its peak value - corresponding to its yield stress - are significantly higher than those for the other two materials. This reflects the fact that Pudding 1 is significantly firmer than Puddings 2 and 3.
