Application of ATR-FTIR spectroscopy for profiling of non-structural carbohydrates in onion (Allium cepa L.) bulbs.
Qualitative and quantitative composition of non-structural carbohydrates comprising glucose, fructose, sucrose and fructooligosaccharides (FOS) is one of the key determinants of market suitability, storability and technological processability of onions. To develop a cost-effective and rapid tool for carbohydrate profiling, applicability of attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy of onion juice was investigated with special regard to FOS patterns. As reference, detailed carbohydrate profiles of onion juices were generated by high-performance liquid chromatography coupled with evaporative light scattering detection (HPLC-ELSD). Hierarchical cluster analysis (HCA) of ATR-FTIR spectra was successfully applied for classifying onions into fresh market, storage and dehydrator type according to HPLC-ELSD profiles. A bootstrapping method for automatized test-set validation by projection to latent structures (PLS) algorithms using HPLC and ATR-FTIR spectroscopy data was developed. Model statistics showed promising perspectives for reliable quantification of individual saccharides and sum parameters. The presented methodology allows estimating the nutritional and pre-biotic value directly during cultivation and processing.
['Krähmer|Andrea|A|', 'Böttcher|Christoph|C|', 'Gudi|Gennadi|G|', 'Stürtz|Melanie|M|', 'Schulz|Hartwig|H|']
D002241:Carbohydrates D005504:Food Analysis D019697:Onions D018517:Plant Roots D018547:Plant Stems D017550:Spectroscopy, Fourier Transform Infrared
Non-structural carbohydrates Fructooligosaccharides Carbohydrate profiling Onion juice HPLC-ELSD Bootstrapping Quantification Infrared spectroscopy