Rapid screening for anthocyanins in cane sugars using ESR spectroscopy.
Kheamrutai Thamaphat1, Bernard A Goodman2, Pichet Limsuwan1
1Green Synthesis and Application Laboratory, Department of Physics, Faculty of Science, King Mongkut's University of Technology Thonburi, Bangkok 10140, Thailand.
Food Chemistry
|October 14, 2014
Summary
Anthocyanin content in various sugars was measured using electron spin resonance (ESR) spectroscopy. ESR revealed differences in anthocyanin and mineral content across sugar types, correlating with sugar color.
Area of Science:
- Food Chemistry
- Spectroscopy
- Analytical Chemistry
Background:
- Anthocyanins are water-soluble pigments found in plants.
- These pigments can be released into sugar steam during extraction.
- Understanding their presence in different sugar types is important for quality assessment.
Purpose of the Study:
- To determine anthocyanin content in refined, plantation white, soft brown, and raw sugars.
- To compare anthocyanin spectra with standard anthocyanin using ESR spectroscopy.
- To investigate the presence of naturally occurring minerals (Fe(III) and Mn(II)) in different sugar types.
Main Methods:
- Electron spin resonance (ESR) spectroscopy at room temperature.
- Comparison of sugar spectra with standard anthocyanin spectra.
- Correlation of ESR results with apparent sugar color (ICUMSA method) and ICP-OES.
Main Results:
- ESR spectra of red and violet anthocyanins showed a predominant signal at g ≈ 2.0055.
- Fe(III) and Mn(II) signals were detected in raw sugar, soft brown sugar, and standard anthocyanin.
- These mineral signals were absent in refined and plantation white sugars due to processing.
- ESR findings correlated with the apparent color of the sugars.
Conclusions:
- ESR spectroscopy is effective for analyzing anthocyanin and mineral content in sugars.
- The refining process removes naturally occurring minerals and affects anthocyanin presence.
- Sugar type significantly influences its spectral characteristics and color.
