Wheat milling across history altered sugar bioaccessibility assessed using TIM-1 in vitro digestion model

The differences in wheat flour characteristics caused by ancient (pestle and mortar), old (stone hand mill), and modern (roller and cyclone) milling techniques and their effect on in vitro starch digestibility of wheat porridge using the simulated TIM Gastrointestinal Model (TIM-1) were investigated. Ancient flour (AF) was the coarsest flour (similar to 70 % is >1000 mu m), followed by old wholemeal flour (OWF) and old refined flour (ORF) with similar particle size distribution showing one prominent peak (at similar to 1000 mu m for OWF and similar to 800 mu m for ORF). Modern refined flour (MRF) had a monomodal distribution centered at a particle size of similar to 100 mu m, while modern wholemeal flour (MWF) particle size was distributed between 40 and 600 mu m. MRF and MWF porridges had higher cumulative sugar bioaccessibility than OWF and AF porridges, with ORF porridge having an intermediate cumulative sugar bioaccessibility. Characterizing the cumulative sugar bioaccessibility profile with a shifted logistic model allows identifying that the maximum sugar bioaccessibility and rate of sugar release were significantly higher (p < 0.05) for MRF and MWF compared to OWF and AF porridges, while the induction times were shorter, demonstrating the importance of processing on modulating starch digestibility.