Milk powder analysis by near-infrared spectroscopy

Importance of the Topic

Ensuring accurate determination of moisture, fat, lactose, and protein in milk powder is vital for regulatory compliance, product consistency, and nutritional labeling. Rapid, reagent-free methods support real-time monitoring, reduce waste, and enhance quality assurance, particularly for sensitive applications such as infant formula.

Study Objectives and Overview

This application note demonstrates the development and validation of near-infrared spectroscopy (NIRS) models for quantifying key quality parameters in milk powder. Over 600 samples from diverse suppliers were analyzed to build robust calibration and external validation sets.

Methodology and Instrumentation

Diffuse-reflectance NIR spectra were recorded on an OMNIS NIR Analyzer Liquid/Solid with automatic sample rotation to capture heterogeneity. Reference values were obtained using official AOAC methods for moisture (AOAC 927.05), protein (AOAC 939.02), fat (AOAC 932.06), and a phenol-sulfuric acid assay for lactose. The averaged spectra were processed using multivariate regression to create prediction models.

Main Results and Discussion

Calibration and validation produced high correlation coefficients (R² > 0.98) and low prediction errors for all analytes. Moisture, protein, fat, and lactose predictions closely matched reference data across independent validation sets, confirming method reliability. The models successfully accommodated sample variability from different global origins.

Benefits and Practical Applications

• No sample preparation or reagents required
• Measurement time under 10 seconds per sample
• Seamless integration into laboratory and production-line workflows
• Real-time quality control to minimize batch deviations and waste

Future Trends and Possibilities

Advances in chemometric algorithms and hardware may further improve prediction accuracy and extend NIRS applications to other dairy and food matrices. Inline process control, cloud-based data management, and integration with automated sampling systems will drive broader adoption.

Conclusion

NIRS on the OMNIS platform provides a fast, accurate, and versatile tool for comprehensive milk powder analysis. Validated models deliver reliable quantification of moisture, protein, fat, and lactose, enabling manufacturers to enhance quality assurance and operational efficiency.

References

1. AOAC Official Method 927.05: Moisture in Milk Powder
2. AOAC Official Method 939.02: Protein in Milk Powder
3. AOAC Official Method 932.06: Fat in Milk Powder
4. Phenol-sulfuric acid method for lactose determination