Wheat particle size and starch digestion in lab tests
What it found
In lab tests, finely milled wheat released more starch, glucose and protein than coarser wheat pieces.
The smallest flour gave the biggest release.
What they found
Animal and lab studies
Starch breakdown
The finest flour (0.11 mm) broke down much more than the largest pieces (1.95 mm), 52% versus 25%. The semolina and medium sizes gave 32% and 28%.
Glucose release
Glucose release fell as particle size rose, from 92.16% for the finest flour to 47.39% for the largest pieces.
Protein digestion
The finest flour also gave the most digestible protein, following the same pattern as starch.
Particle size and blood sugar
The authors say the results support the idea that how tightly starch is trapped in the wheat particle changes the blood glucose response.
What the authors conclude
“This data provide further evidence that, by decreasing the size of wheat endosperm, starch release and glycaemic response are enhanced.”
Also in their conclusions
- They say the data give further evidence that making wheat endosperm particles smaller increases starch release and the glycaemic response.
- They also showed that protein bioaccessibility followed a similar trend to starch digestion.
- Their results support the hypothesis that different degrees of starch encapsulation elicit different blood glucose responses.
How it was done
The authors wanted to measure how much starch and protein is released from wheat during digestion, and how that release changes with the size of the wheat particles.
They made five porridge meals from durum wheat endosperm with different average particle sizes, from 0.11 mm flour to 1.95 mm large pieces. Each meal was put through simulated mouth, stomach and small intestine digestion in the lab.
What it can’t tell you
- We summarised it from the abstract only.
- These are lab tests that mimic digestion. They can't show what happens to blood sugar in people eating these meals.
- The study did not measure blood glucose responses in people, only glucose released in the lab.
Who paid
- Funding
- Funded by Biotechnology and Biological Sciences Research Council (from the PubMed record).
- Authors work at
- Institute of Food Research, UK; University of Messina, Italy
The paper
- Title
- Durum wheat particle size affects starch and protein digestion in vitro
- Type
- Study
- Evidence
- Animals and lab studies
- Summarised from
- Abstract only
- Cite
- Mandalari G, Merali Z, Ryden P, et al (2018). Durum wheat particle size affects starch and protein digestion in vitro. European journal of nutrition. doi:10.1007/s00394-016-1321-yPubMed 27785565DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error