Scope
- Assess gluten quality in wheat flour
- Quality control
Rapid Visco Analyzer
The Rapid Visco Analyser (RVA) is a cooking stirring viscometer with elevated temperature and variable shear profiles augmented for testing viscous properties.
The instrument contains international standard methods as well as being dynamic enough for tailor-made customer profiles. Through a combination of precision, flexibility, speed and automation, the RVA is a novel tool for product development, quality assurance and quality and process control.
Image Credit: PerkinElmer Food Safety and Quality
Description
Between samples, wheat flour quality can greatly vary. Its suitability largely determines the quality of the gluten protein in wheat flour for use in several products, including pan breads, cakes, pastries, flat breads and alkaline noodles; each application of wheat flour necessitates a different quality.
For instance, for commercially produced pan breads, strong wheat flour is preferred due to its good mixing tolerance and excellent baking qualities.
Figure 1. Differences between soft and hard wheat flours. The soft flour produces the highest viscosity and a second peak later during cooling. Image Credit: PerkinElmer Food Safety and Quality
Method
Thirty-minute pasting profile.
Sample Preparation
3.00 g flour (12% mb) and 3.5 g ethanol (98%). Stir until all lumps are eliminated. Add 20.0g of distilled water (total amount of water, ethanol, + flour is 26.5 g). Insert rubber stopper and vigorously shake to disperse the mixture.
Profile
Table 1. Source: PerkinElmer Food Safety and Quality
| Time |
Type |
Value |
| 00:00:00 |
Temp |
50°C |
| 00:00:00 |
Speed |
960 rpm |
| 00:00:30 |
Speed |
160 rpm |
| 00:02:00 |
Temp |
50°C |
| 00:06:30 |
Temp |
85°C |
| 00:08:30 |
Temp |
85°C |
| 00:24:00 |
Temp |
20°C |
| 00:30:00 |
End |
Idle Temperature: 50 ± 1°C
Time Between Readings: 4 s |
Measure
Table 2. Source: PerkinElmer Food Safety and Quality
| . |
. |
| P1V: Peak 1 viscosity (cP) |
P2V: Peak 2 viscosity (cP) |
| P1T: Peak 1 temperature (°C) |
P2T: Peak 2 temperature (°C) |
| T1V: Trough 1 viscosity (cP) |
T2V: Trough 2 viscosity (cP) |
| T1T: Trough 1 temperature (°C) |
T2T: Trough 2 temperature (°C) |
| FV: Final viscosity (cP) |
|
The RVA Wheat Flour Ethanol Index is signified by the viscosity of the second peak.
This information has been sourced, reviewed and adapted from materials provided by PerkinElmer Food Safety and Quality.
For more information on this source, please visit PerkinElmer Food Safety and Quality.