Effect of high moisture extrusion on the structure and physicochemical properties of Tartary buckwheat protein and its in vitro digestion.
Level 5 - mechanism / opinion, no new human data
In vitro food science bench study without human subjects
PubMed 38395582 · doi:10.1016/j.foodres.2024.114065
What was done
Researchers evaluated the impact of high moisture extrusion (HME, 60% moisture content) at 70 °C and 100 °C on the structural characteristics, physicochemical properties, and in vitro digestibility of Tartary buckwheat protein (TBP) relative to native TBP (NTBP). Outcomes measured included microstructural changes, molecular weight distribution, disulfide bond (SS) content, solubility at pH 7, foaming ability, surface hydrophobicity, and emulsifying activity.
What was found
HME induced unfolded, amorphous microstructures and lowered protein molecular weight, with greater degradation at 70 °C than 100 °C (including near-complete disappearance of bands near 35 kDa). Disulfide bond content was 44.53 µmol/g protein in NTBP, dropping to 42.67 µmol/g protein after 70 °C HME, but increasing to 45.70 µmol/g protein after 100 °C HME. Across treatments, solubility at pH 7 ranged from 55.96% to 83.31%, foaming ability from 20.00% to 28.57%, and surface hydrophobicity from 8.34 to 23.07. TBP extruded at 70 °C demonstrated higher emulsifying activity and in vitro digestibility than NTBP, whereas TBP extruded at 100 °C showed the opposite trend.
Why it matters
Tartary buckwheat protein has limited baseline digestibility due to its native structural conformation. These findings show that low-temperature high moisture extrusion (70 °C) can enhance functional properties and simulated digestion while avoiding the structural cross-linking seen at higher extrusion temperatures.
Limits
This was entirely an in vitro laboratory study without human or animal trials, meaning actual physiological bioavailability remains unmeasured. The abstract does not provide exact numeric values for emulsifying activity, digestibility rates, or sample replicate sizes.
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