FODMAP Content Like-by-like Comparison in Spanish Gluten-free and Gluten-containing Cereal-based Products.

Gluten-free foods (GF) availability on supermarket shelves is growing and it is expected to continue expanding in the years ahead. These foods have been linked to a lower content of fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAPs), molecules that trigger gastrointestinal symptoms in sensitive persons. In this study, the FODMAP content of 25 cereal-based GF foods in Spain (breakfast cereals, pasta, bread, biscuits, bakery products, and dough and puff pastry) and 25 gluten-containing equivalents (GC) available in the same supermarket were analysed and compared. Lactose, fructose, glucose, sorbitol, mannitol, raffinose, stachyose and fructans were quantified. In a like-by-like analysis, GF foods were found to generally contain fewer FODMAPs than their GC counterparts. The ingredients used in the manufacture of GF cereal-based foods may contribute to this fact. When the individually wrapped size was considered, the proportion of samples classified as high-FODMAPs in GC and GF foods showed a trend towards fewer samples in the GF. However, not all the GF samples were low-FODMAP. Altogether, our findings provide essential information for FODMAP content databases of GF products in Spain.

Laser desorption/ionization mediated by bionanostructures from microalgae.

RATIONALE: Organic matrices are the state-of-the-art ionization mediators in Laser Desorption/Ionization Mass Spectrometry (LDI-MS). Despite improvements in understanding matrix chemistry, interfering matrix-related signals complicate the analysis. Surface-assisted LDI techniques like desorption/ionization on silicon (DIOS) or nanostructure initiator mass spectrometry (NIMS) provide promising alternatives but rely often on elaborate materials. METHODS: We introduce nanopatterned biomineralized cell walls of microalgae as easily accessible biological surfaces that support the ionization of embedded molecules in LDI-MS. Microalgae cell walls were cleaned through oxidation and washing before pipetting on a stainless-steel matrix-assisted laser desorption/ionization (MALDI) target. Added molecules were efficiently ionized in positive and negative ionization mode in common MALDI sources. The method was rigorously validated by comparison with established MALDI experiments. RESULTS: Ionization of PEG600, D-sphingosine and raffinose was successfully mediated by nanostructured cell wall preparations from two different microalgae. Without any change in protocol, steric acid could be detected in the negative ionization mode. Ionization is also supported by commercially available celite, a material containing mineralized diatom cell walls. Characteristic ingredients of fresh coffee were detected in LDI-MS after pipetting it on celite without further sample preparation. Caffeine and saccharose were detected in positive and characteristic fatty acids in negative ionization mode. Detection limits were comparable to established MALDI experiments. CONCLUSIONS: Bionanostructure-enhanced ionization allows the analysis of a diverse selection of analytes including polymers, sugars, amino alcohols, and organic acids without interfering matrix signals. We also show that celite, a commercially available porous material containing mineralized algal bionanostructures, supports LDI-MS.