FTIR-ATR Characterization of Commercial Honey Samples and Their Adulteration with Sugar Syrups Using Chemometric Analysis

Importance of the Topic

Honey is a widely consumed natural sweetener valued for its nutritional and medicinal properties. Ensuring its purity is essential to protect consumer trust, support market growth, and prevent economic fraud. Adulteration with cheaper sugar syrups undermines product integrity and influences quality control in food industries.

Objectives and Study Overview

This study employed Fourier Transform Infrared Spectroscopy with Attenuated Total Reflectance (FTIR-ATR) and chemometric analysis to detect sugar syrup adulteration in commercial honey. The goals were to quantify major sugars in honey samples and identify deviations suggestive of adulteration.

Methodology and Instrumentation

The analytical procedure involved:

• Sample Preparation: Nine commercial honey samples diluted at 10% w/w in deionized water.
• Spectral Acquisition: FTIR-ATR spectra recorded using a Shimadzu IRTracer-100 spectrometer equipped with a ZnSe Quest ATR accessory.
• Chemometric Analysis: Partial Least Squares (PLS) regression built on a calibration set of aqueous sugar mixtures (fructose, glucose, sucrose) spanning a multidimensional concentration range.

Main Results and Discussion

PLS calibration enabled quantification of fructose, glucose, and sucrose in each honey sample. Key findings included:

• Samples labeled as 100% pure honey exhibited higher glucose levels than expected, indicating possible corn syrup addition.
• One sample claiming 7% honey showed significant sucrose content, suggesting sugar water adulteration.
• Fructose-to-glucose ratios below the typical range (1.2:1) flagged samples for potential adulteration.

Benefits and Practical Applications

FTIR-ATR combined with chemometrics offers a rapid, non-destructive screening tool for honey authenticity. It enables quality control laboratories and regulatory bodies to:

• Quickly assess sugar profiles without extensive sample preparation.
• Ensure compliance with food labeling standards.
• Detect economically motivated adulteration to maintain consumer confidence.

Future Trends and Possibilities

Advancements may include:

• Integration with portable FTIR devices for on-site testing.
• Expansion of spectral libraries to cover diverse honey floral sources.
• Development of machine learning algorithms for enhanced pattern recognition.

Conclusion

The combination of FTIR-ATR spectroscopy and PLS chemometric analysis is a robust approach for detecting sugar adulteration in honey. Results demonstrated its effectiveness in identifying deviations from expected sugar compositions, supporting its role in routine authenticity testing.

Reference

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