FODMAPs in cereals, pseudo cereals and legumes: a systematic approach for the development of functional low FODMAP products

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Ispiryan, Lilit
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University College Cork
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FODMAPs (fermentable mono-, di, oligosaccharides and polyols) are dietary carbohydrates that have been identified as triggers of symptoms of irritable bowel syndrome (IBS); a diet with a reduced intake of FODMAPs is successfully alleviating symptoms in > 70 % of IBS patients. While whole grain cereals, pulses and products made from those are an essential part of a healthy plant-centered diet, they are also a major source of FODMAPs. Hence, with a lack of functional products with lowered FODMAP contents on the global market, the development of such is emerging in food science and industry. Firstly, an accurate and efficient analytical method for the quantification of FODMAPs, using one single analytical approach (high-performance anion-exchange chromatography coupled with pulsed amperometric detection; HPAEC-PAD), was developed, and served as analytical tool throughout further studies. The FODMAP-profiles of a broad range of cereal-product ingredients, including different cereals, pseudo cereals, gluten-free flours, pulses, pulse protein ingredients, commercial sprouts, and isolates were characterised. Two main classes of FODMAPs were found in the ingredients: fructans in gluten-containing cereals (wheat, spelt, barley, rye) and α-galactooligosaccharides (GOS) in pulses (peas, lentils, chickpeas, etc.). Isolates and fractions from different raw material (pulse protein ingredients, different starches, gluten) had varying GOS or fructan contents, depending on their production process. Gluten-free product ingredients (e.g., rice, millet, buckwheat) did not contain any of the FODMAPs commonly investigated. However, buckwheat accumulates other soluble indigestible carbohydrates (fagopyritols) that may act as FODMAPs. Six ingredients were selected to investigate the impact of malting on FODMAPs: wheat and barley (high in fructans), chickpeas and lentils (high in GOS), oat and buckwheat (‘low in FODMAPs’). In the pulses GOS levels diminished by 80 − 90 % upon the malting process; also, buckwheat fagopyritols were degraded. In contrast, fructan contents in barley and wheat malts were slightly elevated; 0.8 % fructans were even de novo synthesised in oat malt. Finally, aiming for the degradation of fructans and the production of a low FODMAP whole wheat bread, the application of yeast fermentation was investigated. The screening of the FODMAP degradation capability of various yeast isolates led to the selection of two promising strains: Lachancea fermentati FST 5.1 and Cyberlindnera fabianii NTCyb. While the latter revealed to be unsuitable for baking application (very low fermentation rate in wheat dough matrix), L. fermentati FST 5.1 outperformed conventional baker’s yeast (Saccharomyces cerevisiae), with a much more efficient fructan degradation and metabolism of the resulting excess fructose. Apart from low FODMAP contents, the resulting bread had optimal quality characteristics (technological as well as sensory attributes) comparable to the baker’s yeast fermented bread. Overall, the fundamental and systematic work of this thesis provides comprehensive and applicable knowledge essential for developing of low FODMAP products.
IBS (irritable bowel syndrome) , HPAEC-PAD carbohydrate anaylsis , Functional food , Gastrointestinal health , Yeast fermentation , Malting , Low FODMAP foods
Ispiryan, L. 2021. FODMAPs in cereals, pseudo cereals and legumes: a systematic approach for the development of functional low FODMAP products. PhD Thesis, University College Cork.