Diets
thermal bran stabilization decreases total dietary fiber
In plain terms: Does heat-treating bran destroy its fibre?
Mostly no. Heating or processing bran tends to CONVERT its rough insoluble fibre into the soluble kind rather than destroy it — total fibre is usually preserved or only slightly reduced. Contested, and based on lab food-chemistry, not health outcomes.
Evidence ladder
How far up the ladder this claim has climbed. A high consensus on a low rung means "consistent so far," not "proven in people."
Top evidence so far: Cells in a dish (In-vitro)
How the studies fall
What the evidence shows
The claim that thermal stabilization lowers **total** dietary fibre (TDF) **leans against** on current evidence. Solmaz found TDF fell in all stabilized cookies (autoclave lowest), but independent higher-quality work disagrees: **Özkaya found autoclaving oat bran *increased* soluble, insoluble *and* total fibre**, and **Martín-Cabrejas found extrusion left TDF *unchanged*** — merely redistributing
The evidence (4)
| Source | Grade | Stance | Quality | Finding |
|---|---|---|---|---|
| Solmaz B, Levent H, Şahin N 2025 · Food Science & Nutrition | in-vitro | supports | moderate | TDF % fell in all stabilized samples vs raw bran: raw 15.68 → hot air 14.67 → microwave 14.52 → autoclave 12.78 (control 9.43). Authors attribute to glycosidic-bond cleavage / arabinoxylan loss. |
| Ozkaya et al. 2017 · J Agric Food Chem | in-vitro | contradicts | high | Autoclaving oat bran INCREASED soluble, insoluble AND total dietary fibre vs control - opposite of a TDF reduction. |
| Tian et al. 2024 · Food Res Int | in-vitro | tested-null | low | Steam explosion of rice bran degraded IDF cellulose/hemicellulose (glycosidic bonds broken) - structural degradation of extracted IDF; net TDF mass not reported; harsher than stabilization. |
| Martin-Cabrejas et al. 1999 · J Agric Food Chem | in-vitro | contradicts | low | Extrusion of beans redistributed insoluble->soluble fibre but TOTAL dietary fibre was unaffected (legume/extrusion, off-method). |
Disagree, or know a study we missed?
We grade by evidence, not opinions. The way to weigh in is to point us to a study we haven't cited (check the evidence table above first), or to flag a problem with one we have. Every submission is reviewed; if it holds up, the grade updates and shows in Science Changes Its Mind.
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Educational only, not medical advice. Grades and scores reflect published evidence weighted by study design and quality; see the methodology.