Production of oligosaccharides from Leuconostoc lactis CCK940 was optimized using a response surface methodology with a central composite design. Culture temperature and the concentrations of sucrose and maltose were used as the main factors. The predicted optimum conditions for the production of oligosaccharides were a culture temperature of 30 °C, a sucrose concentration of 9.6% (w/v), and a maltose concentration of 7.4% (w/v). Using these optimal conditions, Leuconostoc lactis CCK940 was cultured using a fermenter to produce oligosaccharides, and the resulting oligosaccharides with a degree of polymerization greater than 4 were purified by Bio-gel P2 gel permeation column chromatography and then lyophilized. When macrophages were treated with the purified oligosaccharides at concentrations of 0.1–10 mg/mL, no cytotoxicity towards the macrophages was observed. However, nitric oxide production levels were similar to those following treatment with 1 μg/mL lipopolysaccharide. The mRNA expression levels of tumor necrosis factor-α, interleukin-1β, interleukin-6, and inducible nitric oxide synthase were all also increased in a dose-dependent manner following treatment with the oligosaccharides. These data suggest that oligosaccharides produced by Leuconostoc lactis CCK940 could be used as an immune enhancer of macrophages.

Glycosyltransferase-producing Leuconostoc lactis CCK940 produces CCK- oligosaccharides, gluco-oligosaccharide molecules, using sucrose and maltose as donor and acceptor molecules, respectively. In this study, the immunostimulatory activities of CCK-oligosaccharides on RAW264.7 macrophages and BALB/c mice were evaluated. CCK-oligosaccharides induced the expression of phosphorylated-p38, extracellular-signal-regulated kinase (ERK), and c-Jun N-terminal kinase (JNK) and upregulation of phagocytic activity in RAW264.7 macrophages, suggesting their involvement in mitogen-activated protein kinase (MAPK) signaling pathway and phagocytosis. When CCK-oligosaccharides were administered to mice intraperitoneally injected with cyclophosphamide (CY), spleen indices and expressions of interleukin (IL)-6, IL–10, and tumor necrosis factor-α increased, compared with those in only CY-treated group. These findings suggest that CCK-oligosaccharides can be used as an effective immunostimulating agent.

Soybean-derived peptides exert several beneficial effects in various experimental models. However, only a few studies have focused on the radical scavenging and anti-wrinkle effects of soymilk-derived peptides produced via different processes, such as fermentation, enzymatic treatment, and ultrafiltration. Therefore, in this study, we investigated the radical scavenging and antiwrinkle effects of soymilk fractions produced using these processes. We found that 50SFMKUF5, a 5 kDa ultrafiltration fraction fermented with Lacticaseibacillus paracasei MK1 after flavourzyme treatment, exhibited the highest radical scavenging activity using the 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay as well as potent anti-wrinkle effects assessed by type 1 procollagen production and tumor necrosis factor-α production in ultraviolet B (UVB)-treated human dermal fibroblasts and HaCaT keratinocytes. To identify potential bioactive peptides, candidate peptides were synthesized, and their anti-wrinkle effects were assessed. APEFLKEAFGVN (APE), palmitoyl-APE, and QIVTVEGGLSVISPK peptides were synthesized and used to treat UVB-irradiated fibroblasts, HaCaT keratinocytes, and α-melanocyte-stimulating hormone-induced B16F1 melanoma cells. Among these peptides, Pal-APE exerted the strongest effect. Our results highlight the potential of soymilk peptides as anti-aging substances.