Yung-Hun Yang

Lactic acid bacteria-fermented food materials are promising sources of functional ingredients, but the active components underlying their bioactivity often remain unclear. We localized the macrophage-stimulatory activity of a red pepper-based fermentate prepared with Lactiplantibacillus plantarum CJLP243. Compared with the unfermented matrix and a non-fermented matrix supplemented with freeze-dried CJLP243, the fermentate induced greater IL-6 and TNF-α production in J774A.1 macrophages. Activity was reproducibly concentrated in the pellet-derived lysate-insoluble fraction (PDIF) and remained in residual debris after solvent extraction. LTA-directed fractionation and analytical screening did not support lipoteichoic acid as the principal determinant. Lysozyme markedly reduced activity, whereas proteinase K had a partial effect, a pattern consistent with a lysozyme-sensitive, cell wall-associated structure or cell wall–matrix complex, within which peptidoglycan-associated material remains a plausible candidate; contributions from co-associated components cannot be excluded. Targeted metabolomics revealed fermentation-associated changes in pellet-associated amino acid pools, consistent with broader adaptation of amino acid and nitrogen metabolism during fermentation; their biochemical linkage to cell-wall precursor pathways provides metabolic support rather than direct structural evidence. These findings identify a reproducible, process-linked insoluble fraction with macrophage-stimulatory activity and provide a framework for developing and standardizing fermentation-derived functional food ingredients.

Levan is a microbial fructan type exopolysaccharide that has attracted increasing attention due to its biocompatibility, biodegradability, low toxicity, and versatile functional properties. However, the direct application of native levan is often limited due to poor mechanical strength, moisture sensitivity, and instability under processing or storage conditions. To overcome these limitations, levan has been integrated with natural polymers, synthetic polymers, nanoclays, and metal or metal oxide nanoparticles to develop advanced hybrid composites with enhanced physicochemical and biological performance. These levan based composites exhibit improved tensile strength, thermal stability, barrier properties, controlled swelling, and tunable surface characteristics, making them promising materials for biomedical and healthcare applications. Recent studies have highlighted their potential in drug delivery, wound healing, antimicrobial and antibiofilm coatings, tissue engineering scaffolds, biosensors, and anticancer systems. This review critically discusses levan structure, biosynthesis, production strategies, and the key factors governing successful composite formation, including interfacial compatibility, filler dispersion, and molecular architecture. In addition, major challenges such as high production cost, batch‐to‐batch variability, scalability, long‐term stability, and regulatory concerns are addressed. Overall, levan inspired hybrid composites represent a promising platform for next‐generation sustainable biomaterials, although further process optimization and translational studies are required for commercial realization.