Where Each Comes From
PHGG is guar gum, from the guar bean, broken down by enzymes to reduce its thickening power. Psyllium is the husk of the Plantago ovata seed, used with minimal processing. Resistant dextrin is manufactured from starch, restructured with heat, acid and enzymes until it resists digestion. Only resistant dextrin has no equivalent naturally occurring form; PHGG and psyllium are both modified or used versions of a naturally fibrous plant material.
Texture in Water
| In water | |
|---|---|
| PHGG | Dissolves, low viscosity |
| Psyllium | Forms a gel, doesn't dissolve clear |
| Resistant dextrin | Dissolves clear, low viscosity |
PHGG is, in a sense, the middle ground structurally: it started as a thickening gum (native guar gum) and was deliberately processed to behave more like resistant dextrin in water, while psyllium's gelling is left largely intact by its minimal processing.
Fermentability
All three are at least partly fermented by gut bacteria in the large intestine, which is part of why all three qualify as dietary fibre under the Code. The specific rate and extent isn't something that can be reduced to a single comparable figure across all three; it depends on the specific ingredient, dose and individual gut microbiota.
How Each Is Regulated as Dietary Fibre in Australia
PHGG and psyllium are both naturally derived plant materials that meet the Food Standards Code's general dietary fibre definition without a dedicated FSANZ application, as far as we could confirm. Resistant dextrin needed a specific application (A491) to establish a method for measuring it, because as a manufactured ingredient it didn't have the same naturally-occurring precedent to rely on.
Side by Side
| PHGG | Psyllium | Resistant dextrin | |
|---|---|---|---|
| Source | Guar bean, enzyme-treated | Plantago ovata husk | Manufactured from starch |
| In water | Dissolves, low viscosity | Forms a gel | Dissolves clear |
| Naturally occurring? | Modified from a natural gum | Minimally processed | No natural equivalent |
Sources
- Mudgil D, et al., "Guar gum: processing, properties and food applications: A Review," Journal of Food Science and Technology, PMC
- Effect of extraction temperature on the rheological properties of psyllium husk mucilage, PMC
- FSANZ, Final Assessment Report, Application A491, Resistant Maltodextrin as Dietary Fibre