The active components of turmeric oil (TO) were analyzed using gas chromatography-mass spectrometry (GC-MS), gas chromatography-ion mobility spectrometry (GC-IMS), and electronic nose. The major components of TO were found to be ar-curcumone (23.09%), curcumone (21.36%), and β-curcumone (14.93%). In order to maximize the stability of TO and to mask its irritating substances, a microemulsion encapsulating it (TO-ME) was constructed by the water titration method. Based on the pseudo ternary phase diagram constructed, the optimal process parameters were determined as follows: TO as the oil phase, Tween-80 as the surfactant, propylene glycol as the co-surfactant, deionized water as the aqueous phase, a mass ratio of surfactant to co-surfactant of 4:1, a mass ratio of mixed surfactant to oil phase of 8:2, and a water content of 70% in the microemulsion. The largest area of the microemulsion region was formed under these conditions. The resultant microemulsion had a pH of 6.81 ± 0.02, a density of (1.053 ± 0.001) g/mL, a polydispersity index (PDI) of 0.27 ± 0.11, and an average particle size of (32.81 ± 14.54) nm. The microemulsion was characterized as an oil-in-water (O/W) type microemulsion, with spherical or ellipsoidal droplets. The prepared TO-ME exhibited good centrifugal stability, storage stability, and resistance to oral and gastric digestion, and could be released and utilized in the intestine. The microemulsion system significantly improved the scavenging capacity of TO against 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) cation radical. In conclusion, microemulsion encapsulation significantly improved the stability and antioxidant activity of TO while effectively facilitating its release and digestion in the intestine. Our research results provide a theoretical basis for the high-value development and utilization of TO.

Preliminary research identified three polysaccharide fractions, namely— VL8-EPS30, VL8-EPS50, and VL8-EPS70,— isolated from Lactobacillus. paracasei EPS using graded ethanol precipitation. These fractions varied in yield, composition (Total sugar, protein, and uronic acid), monosaccharide profile, molecular weight, stability, and morphology. Despite these differences, all promoted RAW 264.7 cell proliferation. Among them, VL8-EPS50 exhibited the highest total sugar and uronic acid content, along with branched and folded structures, enhancing its macrophage activation, phagocytic activity, and nitric oxide (NO) secretion. However, its immunomodulatory mechanisms and effects on gut microbiota remain unclear. To investigate these mechanisms, we administered VL8-EPS50 at different doses to cyclophosphamide (CTX)-induced immunosuppressed mice. VL8-EPS50 significantly enhanced splenic lymphocyte proliferation and increased immunoglobulin and serum cytokine secretion. Additionally, it alleviated CTX-induced gut microbiota dysbiosis by increasing microbial diversity and richness, promoting beneficial bacteria (Lactobacillus), reducing pathogenic genera (Alistipes), and enhancing short-chain fatty acid production. These findings establish VL8-EPS50 as a promising immunomodulator that influences immune function through gut microbiota regulation. This research supports its potential application in developing functional dairy products with immunological benefits.