Brookfield Engineering

Sweet Relish

Laboratory Viscometer Application Data Sheet

USE: Sweet Relish is a condiment or dressing. It is typically spread onto other foods, such as frankfurters (or “hot dogs”) or incorporated with other food products.

Test Equipment:

  • Spring Torque Range: Various, such as RV
  • Spindle: Various T-bars, such as T-D and T-F
  • Accessory: Helipath Stand
  • Speed, rpm: Various, such as 6 and 8 rpm

The test may be run at room temperature, or at refrigeration temperatures.

The choice of Spring Torque Range, spindle and speed may vary widely, depending upon the sweet relish. The Helipath Stand system may be used with various Brookfield Viscometers or Rheometers. In our example, we used a Brookfield RVDV-II+Pro instrument with Rheocalc v3.0 software, for automated instrument control and data acquisition. Representative data from the analyses are shown in Figure 1, below:

Figure 1: Store brand versus name brand sweet relish at room temperature.

The name brand product, shown in red, is far more viscous than the store brand sweet relish, shown in gold. The Helipath data traces progress from "zero" viscosity – before the spindle drills down into the material – to a "plateau" region where the spindle is in the bulk of the sample. The system then reverses direction, and the measured torque – and calculated viscosity – then drops to "zero" as the spindle rises up and out of the sample. The "plateau" for the name brand product data is between approximately 50 and 320 seconds, and the store brand "plateau" data lie between approximately 40 and 380 seconds. The store brand sweet relish data have a longer plateau region because the spindle drilled deeper into this particular sample. The “spikes” in the data are caused by the rotating T-bar spindle striking and releasing from pieces of the chopped vegetables in the relishes.

The Rheocalc data may be exported to a spreadsheet, and the plateau-region data averaged, to give a QC/QA number for viscosity. On the other hand, the Data Averaging feature available in the Rheocalc Wizard may also be used to output averaged data values. Another choice may be to simply have the system “drill” down into the sample for a specified amount of time, say 100 or 120 seconds, and then have the operator record the viscosity value at that time. This last procedure provides a one-point test.