In this study, a high internal phase emulsion (HIPE) stabilized by proso millet bran protein (PMBP) was developed to enhance the delivery of β-carotene. Specifically, the effects of PMBP concentration (2%, 4% and 6%) and aqueous phase pH (5, 7 and 9) on the structure and stability of HIPE were systematically evaluated. As the PMBP concentration or pH increased, the droplet size decreased and the absolute value of the zeta potential increased, indicating improved stability under refrigeration, freezing, and heating conditions. Furthermore, PMBP-stabilized HIPE significantly inhibited the release of free fatty acids and increased the in vitro bio-accessibility of β-carotene to 67.47%. This enhancement was mainly attributed to the dense interfacial adsorption layer formed by PMBP at the oil-water interface, which in turn strengthened both electrostatic repulsion and steric hindrance, thus slowing down lipid hydrolysis and protecting the encapsulated compounds. Overall, PMBP-stabilized HIPE shows strong potential for application in the delivery of lipophilic nutrients, providing a theoretical basis for its application in nutrient delivery systems and lipid alternatives.

In this study, 13 different varieties of non-waxy, intermediate-type and waxy proso millets were compared for differences in their basic components, structural, pasting, textural properties, cooking and aroma properties, and the relationship between structural and processing properties was investigated. The results showed that significant differences in basic components among the varieties, with the greatest variation observed in the amylose content. The relative crystallinity and short-range ordered degree of waxy proso millet flour were higher than those of intermediate-type and non-waxy proso millet flour, whereas the pasting properties of non-waxy proso millet flour were higher than those of intermediate-type and waxy proso millet flour. Non-waxy proso millet flour gels had higher hardness, gumminess and chewiness, waxy proso millet flour gels had higher springiness, cohesiveness and resilience, and intermediate-type proso millet flour was intermediate. During cooking, non-waxy proso millet showed higher water absorption and swelling capacity, while waxy proso millet displayed higher dissolution rate with its soup having higher pH. By solid-phase microextraction coupled with gas chromatography-mass spectrometry (SPME-GC-MS), 43, 44, and 51 volatile compounds were identified in non-waxy, intermediate-type and waxy proso millet, respectively. Correlation analysis indicated that the difference in amylose content among the different proso millet varieties was a key factor affecting their structural and processing properties, and there was a correlation between structural and processing properties. This study provides a theoretical basis and guidance for the processing and utilization of different types of proso millet as whole grain food ingredients.

Proso millet starch from two waxy proso millet cultivars (‘Shaanmi 3’ and ‘Shaanmi 5’) and two non-waxy proso millet cultivars (‘Shaanmi 4’ and ‘Shaanmi 6’) was extracted using the wet-milling method and analyzed for structural and physicochemical properties. The results showed that all four kinds of proso millet starch exhibited polygonal or spherical granules; their crystal structure was type A and their Fourier transform infrared (FTIR) spectra were similar to one another. The crystallinity, short-range ordered degree, peak viscosity, breakdown, gelatinization temperature, and enthalpy of waxy proso millet starch were significantly higher than those of non-waxy proso millet starch (P < 0.05), whereas the pasting temperature, final viscosity, setback, and retrogradation rate of waxy proso millet starch were substantially lower than those of non-waxy proso millet starch (P < 0.05). Proso millet starch paste exhibited pseudoplastic non-Newtonian fluid characteristics and thixotropy. Non-waxy proso millet starch pastes showed higher shear-thinning degree and gel strength, while waxy proso millet starch pastes displayed higher pseudoplasticity and thixotropy. Compared with waxy proso millet starch, non-waxy proso millet starch possessed lower rapidly digestible starch content and higher resistant starch content, indicating higher resistance to digestion. The physicochemical properties of proso millet starch were significantly affected by its amylose content and structure.