High Performance Thin Layer Chromatography (HPTLC): A new green approach to soluble fiber determination in plant matrices

It is common practice in the food industry to provide technical data sheets wherein information on soluble fiber are given as a difference of mass from other components (fat, protein, etc.) and its presence in high levels is often used to claim prebiotic activity for the product. However, considering that the expression “soluble fiber” is used to refer to specific structures e.g. inulins, fructooligosaccharides, it is clear that the characterization by mass difference is not sufficient to support such a claim and a more precise analytical method is required. The aim of this study was to develop a precise, reliable and green method for the qualitative characterization of oligosaccharides in plant matrices. To develop our novel high performance thin layer chromatography (HPTLC) based method, we decided to use a sample of Adansonia digitata fruit pulp due to its reported prebiotic activity. We used high performance liquid chromatography (HPLC) to validate the results before and after hydrolytic treatment. Samples were prepared following, and adapting, widely accepted solvent and solvent/ultrasound-assisted based extraction procedures. Our research demonstrated the use of HPTLC as a simple, green and reliable analytical technique for oligosaccharide analysis. Furthermore, despite previous reports on the Adansonia digitata dried fruit pulp, our analysis detected only sucrose, glucose and fructose. This emphasizes the need for more precise methods of composition assessment of fiber rich foodstuffs.