Low-viscosity soluble fibres for individuals with gastroparesis

Abstract

The combined research aim of this thesis was to investigate whether beneficial dietary modification using soluble dietary fibre was viable in patients with gastroparesis. To find an answer to this question, three different investigative approaches were required, namely, rheological analysis, mass spectrometric monomer characterisation, and clinical investigation in a pilot cohort of gastroparesis patients. A multidisciplinary approach was required since there are current knowledge gaps regarding the potential viability of soluble fibres in patients with gastroparesis. This thesis tries to identify suitable "low-viscosity" type soluble dietary fibres in Chapter 2 using rheology. Among the ten different soluble fibres tested, partially hydrolysed guar gum (PHGG) and gum Arabic displayed the most promising "low-viscosity" characteristics under simulated digestion. Therefore, they were selected for a pilot clinical study analysing their short-term effects in mild-to- moderate symptom gastroparesis patients (no enteral tube feeding). The pilot study (n = 10) in Chapter 3 was designed as a crossover study with PHGG and gum Arabic as test fibres, with "high-viscosity" psyllium husk as the positive control and water as the negative control against a glucose challenge. The pilot study demonstrated that PHGG and gum Arabic were very tolerable, cause very few increases in symptoms (similar to water), while displaying glycaemic index lowering (low-GI) properties similar to the positive control psyllium husk. Therefore, both PHGG and gum Arabic were determined to be viable supplements for a future long-term study in gastroparesis patients. The monomer components of major polysaccharides in the PHGG, gum Arabic and psyllium husk supplements were characterised in Chapter 4 using a rapid (21.0 min) HPLC-ESI-Q-ToF-MS method that was specifically developed and validated. In total, separation of nine monomer sugar analytes was achieved using sample derivatization, with five monomers being identified and quantified in PHGG, gum Arabic and psyllium husk. The method displayed very good linearity R2 = 0.999 and recoveries (96.22 - 109.49%). The developed method will be very useful for standardisation and labelling of commercial prebiotic soluble dietary fibre supplements. In summary, a multi-disciplinary approach investigated the rheological behaviour, clinical effects, chemical composition and the potential viability of "low-viscosity" soluble fibre in gastroparesis patients.

Date of Award	2022
Original language	English