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.

This study aimed to evaluate the effect of steam explosion (SE) pretreatment on the physicochemical (particle size, zeta potential, functional groups and thermal stability) and functional (water-holding capacity (WHC); oil-holding capacity (OHC); glucose adsorption capacity (GAC); and cholesterol adsorption capacity (CAC) properties of microcrystalline cellulose (MCC), acid-extracted cellulose nanocrystal (ACNC) and enzymatically extracted cellulose nanocrystal (ECNC) from pear pomace. Results showed that the particle size of cellulose nanocrystal (CNC) prepared with SE at steam pressure levels of 0.6–0.9 MPa was the smallest (140.12 nm on average). The surface of SE treated pear pomace cellulose was negatively charged and SE reduced the absolute potential value. MCC had higher absolute potential value than CNC. Fourier transform infrared (FTIR) spectroscopy showed that all pear pomace cellulose samples had the molecular structural characteristics of cellulose and the structure of CNC was not damaged. The best thermal stability of MCC and the best OHC of ACNC were obtained by SE treatment at 0.9 MPa and 0.3–0.6 MPa, respectively. SE at 0.6 and 0.3 MPa resulted in the best GAC and CAC of ACNC, respectively. Overall, the optimum conditions for the preparation of CNC from pear pomace with good properties were obtained as SE pretreatment at steam pressure of 0.3–0.6 MPa followed by sulfuric acid (64%) treatment for 50 min. The findings of this study lay a theoretical foundation for the high-value utilization of pear pomace.

In order to enhance the flavor and texture of sourdough steamed bread, this study analyzed the growth, fermentation and aroma production characteristics of Saccharomyces cerevisiae XTC-y11 and XTC-m13, Cyberlindnera jadinii HSO-y3, which had been isolated from sourdough, and S. cerevisiae CICC 31616 and evaluated the sensory quality and volatile flavor compounds of steamed bread made with each of these strains. The results revealed that XTC-y11 grew at the fastest rate. XTC-y11 and XTC-m13 had better sugar metabolism than the other strains. Compared with S. cerevisiae CICC 31616, XTC-y11 produced more gas, and XTC-m13 resulted in a larger expansion volume of dough, showing higher fermentation capacity. The total ester concentration of the fermentation broth of HSO-y3 at 24 h was highest (1.672 g/100 mL). The whiteness, hardness, chewability and elasticity of steamed bread with XTC-y11 or XTC-m13 were moderate. The results of sensory evaluation showed that steamed bread with XTC-y11 or XTC-m13 scored highest. Altogether, 37 volatile components were identified in the four steamed breads by gas chromatography-ion mobility spectrometry (GC-IMS), with the predominance of alcohols and esters. 4-Pentenoic acid, 2-methylbutyraldehyde, (E)-2-hexenoic acid, ethyl lactate, ethyl acetate and 2-amylfuran were predominant in steamed bread with XTC-y11, while esters were predominant in steamed bread with HSO-y3. Using partial least square-discriminant analysis (PLS-DA), we found significant differences in volatile components among the four steamed breads, and identified 18 differential compounds. In summary, XTC-y11 had a positive effect on the flavor and quality of steamed breads. This study provides a favorable reference for improving the quality and flavor of steamed bread.