Moisture and Ash Determination in Flour

Significance of the Topic

This application note addresses the simultaneous determination of moisture and ash content in flour, critical parameters for assessing product quality, shelf-life, and compliance with food standards. Reliable and rapid measurement of these values supports quality control and regulatory requirements in the cereal processing and baking industries.

Aim and Overview of the Study

The objective of the study is to establish a standardized method for moisture and ash analysis in various flour types using the TGA701 thermogravimetric analyzer. Key goals include defining instrument parameters, optimizing heating profiles, and demonstrating method precision and reproducibility across wheat, corn, and soy flours.

Instrumentation Used

• Thermogravimetric Analyzer: TGA701
• Accessories: Large ceramic crucibles (Part No. 621-331)
• Balance Specifications: Readability 0.0001 g to support sample masses of 1.4–1.7 g

Methodology and Experimental Procedure

General analysis conditions were set as follows:

• Sample mass: ~1.4 to 1.7 g of flour
• Crucible type and cover: Ceramic, half-open during analysis
• Atmosphere: Air with high flow rate
• Temperature control and stability ensured by automatic crucible placement and digital balancing with 0.0005 g comparator sensitivity

The thermal program consisted of two sequential steps:

• Moisture determination: Ramp from 25 °C to 130 °C at 10 °C/min, hold 30 min
• Ash determination: Ramp from 130 °C to 600 °C at 20 °C/min, hold 30 min

Analysis steps were configured via the TGA701 software, and sample loading and run initiation followed the instrument manual instructions.

Main Results and Discussion

Typical results for three flour types are summarized below:

• Wheat flour: Moisture 9.16 % (s = 0.010), Ash 1.85 % (s = 0.015)
• Corn flour: Moisture 10.43 % (s = 0.006), Ash 0.33 % (s = 0.015)
• Soy flour: Moisture 4.30 % (s = 0.018), Ash 5.42 % (s = 0.015)

Results demonstrate high precision and repeatability of the TGA701 method. Moisture and ash values fall within expected ranges for each flour type, confirming method accuracy.

Benefits and Practical Applications

The described method offers:

• Simultaneous moisture and ash determination, reducing total analysis time (~1 h)
• Minimal sample preparation and operator intervention
• High throughput suitable for routine QC in milling and baking facilities
• Compliance with food safety and labeling regulations

Future Trends and Applications

Potential advancements include integration of evolved gas analysis for compositional insights, automated sample handling to increase throughput, and adaptation of the protocol to a broader range of cereal-based products and ingredients.

Conclusion

The TGA701 method provides a robust, precise, and time-efficient approach for simultaneous moisture and ash determination in flour. Its reproducibility and ease of use make it ideal for quality control laboratories and industrial process monitoring.

References

• LECO Corporation. Moisture and Ash Determination in Flour. Form No. 203-821-359, 1/09-REV0, 2009.