Quality control of non-nutritive sweeteners with NIR spectroscopy

Importance of the topic

Non-nutritive sweeteners such as sucralose and Stevia are increasingly used in food and beverage products to replace sugar while reducing calorie content. Regulatory requirements demand reliable quality control methods that are fast, cost-effective, and compliant with modern production environments.

Objectives and Study Overview

This application note presents the development and validation of a near-infrared spectroscopy (NIR) method for the simultaneous quantification of sucralose and Stevia in sucrose matrices. The aim was to establish a rapid alternative to conventional chromatographic techniques.

Methodology and Instrumentation

Samples containing 0.5–4.5 % sucralose and 0.5–4.5 % Stevia in 95 % sucrose were prepared. Measurements were performed on a Metrohm NIRS DS2500 Solid Analyzer in reflection mode using a DS2500 Iris accessory, 15 mm disposable vials, and Vision Air Complete software for data acquisition and model generation.

Results and Discussion

Vis-NIR spectra of all samples were collected and used to build prediction models. Correlation diagrams comparing NIR predictions with HPLC reference values showed excellent linearity. Key figures of merit:

• Sucralose prediction: R² = 0.9854, SEC = 0.1898 %, SECV = 0.1997 %
• Stevia prediction: R² = 0.9885, SEC = 0.1500 %, SECV = 0.1997 %

The high correlation and low prediction errors demonstrate the method’s accuracy and robustness for routine analysis.

Practical Benefits and Applications

NIR spectroscopy delivers results in less than one minute without chemical reagents or extensive sample preparation. This approach reduces analysis costs and turnaround time compared to HPLC, which typically requires 5 minutes of sample preparation plus 40 minutes of run time per analysis.

Future Trends and Potential Applications

Integration of NIR spectroscopy into process analytical technology (PAT) frameworks can enable real-time monitoring of sweetener concentrations directly on production lines. Portable and inline NIR instruments will further extend applications to quality control in packaging, blending, and finished product inspection.

Conclusion

The Metrohm DS2500 Solid Analyzer with NIR spectroscopy offers a fast, accurate, and cost-efficient alternative to conventional chromatographic methods for determining non-nutritive sweeteners in sucrose blends. Its simplicity and robustness make it well suited for both laboratory and production environments.