Acorn flours are valued for nutrition and health benefits. This study investigated heat-moisture treatment (HMT) at 100 °C for 4 h on acorn flour properties using varying moisture contents (15–35 g/100 g). HMT minimally altered microstructure but changed particle size distribution, increasing aggregation, bulk/tapped densities, and flowability with rising moisture content. It shifted acorn starch from C- to A + V -type, reducing crystallinity (34.42% to 21.88%), short-range order ( R 1047/1022 from 1.26 to 0.83), and mass fractal dimension (2.52 to 1.84). HMT increased β -sheet content and starch–lipid complexing index, while decreasing swelling power and solubility. Pasting viscosities of acorn flour increased or retained after HMT at moisture content of 15–20 g/100 g, but declined at higher moisture levels. HMT-treated flours yielded softer, more elastic gels with reduced hardness (82.63 g to 19.45 g) and increased springiness (0.47 to 0.90) versus untreated flour. Overall, HMT enhanced acorn flour's structural and physicochemical properties, improving gel texture and viscoelasticity. • Native acorn flour (NAF) was rich in amylose (44.23% of starch) and fat (8.59%). • Heat-moisture treatment (HMT) effects on NAF properties were moisture dependent. • HMT disrupted starch order in NAF and shifted C-type crystals to A + V-type. • Moisture promoted starch-lipid complexation during HMT, with CI rising to 49.36%. • HMT induced heterogeneous gels with higher G ′ but lower hardness than the NAF gel.
Ren et al. (2026) studied this question.