Rice flour storage and growing region effects on starch digestibility
What it found
Storing rice flour for six months lowered its estimated glycemic index in lab tests.
The region where the rice was grown also changed how quickly its starch broke down.
What they found
Storage raised moisture and starch
After six months at 30 °C, all samples held more moisture and had higher total starch levels. Protein stayed mostly the same, with only small rises.
Estimated glycemic index fell
The estimated glycemic index dropped in every sample after storage. The biggest fall was in one region, going from 136.0 to 125.0.
Fast-digesting starch declined
In lab tests, the amount of starch that breaks down quickly fell a lot across all samples. Slowly digested starch barely changed.
Growing region mattered
Where the rice was grown changed the flour's freshness markers and how its starch behaved. One region showed the least change over time and another showed the most.
What the authors conclude
- They say the region where rice flour comes from strongly shapes its starch breakdown and physical traits.
- They suggest that storing this rice flour may lead to a slower blood sugar rise after eating, possibly because starch binds with fats or proteins during aging.
- They note that natural differences in the environment create real variation in rice flour.
How it was done
How fast the starch in rice flour breaks down depends on what is in it and how it is stored. The authors wanted to see how growing region and storage time changed these properties.
They tested rice flour made from the same rice variety grown in four regions of Japan. They measured moisture, protein, fat, starch and estimated glycemic index before and after six months of storage at 30 °C.
What it can’t tell you
- We summarised it from the abstract only.
- These were lab measurements on flour, not feeding trials in people.
- Lab estimates of glycemic index cannot show exactly what happens to blood sugar when someone eats the flour.
Who paid
- Funding
- Funded by 57th Leave a Nest Research Grant Suzumo Machinery Award (from the PubMed record).
- Authors work at
- Tokyo University of Agriculture and Technology, Japan; Federal Institute of Industrial Research, Nigeria; Utsunomiya University, Japan
The paper
- Title
- Influence of production area and storage on starch digestibility and glycemic properties of rice flour
- Type
- Study
- Summarised from
- Abstract only
- Cite
- Nwaeche CF, Saito T, Kitamura R, Tamura M (2026). Influence of production area and storage on starch digestibility and glycemic properties of rice flour. Journal of the science of food and agriculture. doi:10.1002/jsfa.70538PubMed 41794551DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error