Micro-nano particle formation and transformation mechanisms of broth in meat braised processing.

• Morphology changes of MNPs were characterized in a quantitative braising process. • Compositions of MNPs were intrinsically rich in glycoconjugates and triglycerides. • MNPs initially formed were inclined to self-assemble into larger particles. • Mechanisms of MNP evolution were revealed from microcosmic-spatial perspectives. • A hypothesis that MNP might be a key factor of broth flavor regulation was proposed. The formation and transformation mechanisms of micro-nano particles (MNPs) in broth during meat braising were systematically investigated through a sophisticated controlled process. Dynamic changes in the morphology, composition and spatial distribution of MNPs were comprehensively characterized, and subsequently the mechanisms were visually uncovered from microcosmic-spatial perspectives. MNPs formed as circular-shape colloidal systems with an aggrandizing tendency for particle number and size and gradually stabilize eventually. Specifically, the major MNPs gradually increased the size from <400 nm to ~1500 nm and accumulated triglycerides and glycoconjugates resulting from lipid oxidation, Maillard reaction, etc. Continuous formation of MNPs in broth progressively facilitated the spatial coalescence and self-assembly of free substances driven by intermolecular interactions, and consequently principal nutrients and flavor compounds further accumulated in the MNPs by the braising process. Hence, this work not only revealed the MNP formation and transformation mechanisms but offered a foundation for investigating MNP-dependent effect on broth flavor. [ABSTRACT FROM AUTHOR]