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Interactions between mucin and okra gum during pH cycling
- Yuan, Bo, Ritzoulis, Christos, Wang, Xinmiao, Pan, Weichun, Chen, Jianshe
- Food hydrocolloids 2019 v.95 pp. 1-9
- electrostatic interactions, fluorometry, hydrocolloids, hysteresis, intestines, models, mucins, okra gum, pH, rheology, stomach, viscosity
- Solutions of okra gum and mucin were studied during pH cycling (7–3–7), as to model the interactions between these components in the oral-gastrointestinal tract. Okra gum aggregates with mucin at pH close to 3, while they redissolve back at pH 7 due to electrostatic interactions. Fluorimetry shows that complexes form at low pH, and break-up upon return to pH 7. At pH 3 both static and transient complexes are detected. Shear viscosities reduce upon pH lowering from 7 to 3 pH 3 and then are partially restored back at pH 7, suggesting a hysteresis in the macromolecular rearrangement after pH cycling. Hysteresis is more pronounced in the extensional rheology, leading to Trouton ratios with a strong dependence on the pH. Thus flow can be regulated in different ways in compartments with different pH (mouth, stomach, intestine).