Effects of slit dual-frequency ultrasound-assisted pulping on the structure, functional properties and antioxidant activity of Lycium barbarum proteins and in situ real-time monitoring process.

To improve the protein dissolution rate and the quality of fresh Lycium barbarum pulp (LBP), we optimized the slit dual-frequency ultrasound-assisted pulping process, explored the dissolution kinetics of Lycium barbarum protein (LBPr), and established a near-infrared spectroscopy in situ real-time monitoring model for LBPr dissolution through spectral information analysis and chemometric methods. The results showed that under optimal conditions (dual-frequency 28-33 kHz, 300 W, 31 min, 40 °C, interval ratio 5:2 s/s), ultrasonic treatment not only significantly increased LBPr dissolution rate (increased by 71.48 %, p < 0.05), improved other nutrient contents and color, but also reduced the protein particle size, changed the amino acid composition ratio and protein structure, and increased the surface hydrophobicity, zeta potential, and free sulfhydryl content of protein, as well as the antioxidant activity of LBPr. In addition, ultrasonication significantly improved the functional properties of the protein, including thermal stability, foaming, emulsification and oil absorption capacity. Furthermore, the real-time monitoring model of the dissolution process was able to quantitatively predict the dissolution rate of LBPr with good calibration and prediction performance (Rc = 0.9835, RMSECV = 2.174, Rp = 0.9841, RMSEP = 1.206). These findings indicated that dual-frequency ultrasound has great potential to improve the quality of LBP and may provide a theoretical basis for the establishment of an intelligent control system in the industrialized production of LBP and the functional development of LBPr.

Slit dual-frequency ultrasound-assisted pulping of Lycium barbarum fresh fruit to improve the dissolution of polysaccharides and in situ real-time monitoring.

In this study, the slit dual-frequency ultrasound-assisted pulping of fresh Lycium barbarum fruit was optimized to improve the dissolution of polysaccharides. The microscopic mechanism of polysaccharide dissolution was explored through establishing polysaccharides dissolution kinetics model and visualizing the multi-physical fields during ultrasonic process, and an in situ real-time monitoring model was established by the relationship between the chemical value and spectral information collected by near-infrared spectroscopy. The results showed that, under optimal conditions, treatment with ultrasound (28-33 kHz, 250 W, 30 min) not only significantly promoted the dissolution rate of polysaccharides in Lycium barbarum pulp (LBPPs, increased by 43.64 %, p < 0.01), reduced its molecular weight, but also improved the arabinose molar ratio, the uniformity of polysaccharide particles, and the antioxidant activity of LBPPs. Correlation analysis indicated that ultrasonic treatment is closely related to LBPPs content, particle size and scavenging capacity against superoxide anion radicals (ptotal sugar content < 0.01, pparticle size < 0.05 and psuperoxide anion scavenging < 0.05). Moreover, the in situ real-time monitoring model for the pulping process could quantitatively predict LBPPs dissolution rate and its superoxide anion radical scavenging capacity with good calibration and prediction performance (Rc = 0.9841, RMSECV = 0.0873, Rp = 0.9772, RMSEP = 0.0530; Rc = 0.9874, RMSECV = 0.1246, Rp = 0.9868, RMSEP = 0.0665). These results indicated that slit dual-frequency ultrasound has great potential in improving the quality of Lycium barbarum pulp, which may provide theoretical support for the industrial development of intelligent systems for polysaccharides preparation.

Characterization, antioxidant, antineoplastic and immune activities of selenium modified Sagittaria sagittifolia L. polysaccharides.

This study proposed an optimal way to supplement organic selenium, boost polysaccharides solubility, antioxidant, anticancer, immune responses. A purified polysaccharide fraction of Sagittaria sagittifolia L. (PSSP) was successfully modified with selenium (Se-PSSP), and its characteristics, antioxidant, antineoplastic and immune activities were studied. The structure and the monosaccharide composition were determined by means of UV-visible spectrometry, FT-IR spectra, NMR spectra, X-ray diffraction spectroscopy (XRD), scanning electron microscope (SEM) and atomic force microscope (AFM). The results showed that both PSSP and Se-PSSP contained a pyranoid polysaccharide linked by α-glycosidic bonds in the main chain. In addition, PSSP and Se-PSSP were amorphous morphology without three-helix conformation. PSSP (47.12 kDa) was mainly composed of glucose, mannose and xylose with molar percentages of 55.82%, 14.86% and 14.35%, respectively. Se-PSSP (16.82 kDa) is mainly composed of glucose, xylose and galactose with molar percentages of 26.49%, 18.76% and 18.14%, respectively. Compared with PSSP, Se-PSSP showed stronger water-solubility, antioxidant activity, cytotoxicity and immunomodulatory activity than that of PSSP. These results suggested that Se-PSSP is a promising novel Se-supplement and may be served as an excellent potential antioxidant, antineoplastic, and immunomodulatory agents in the field of functional foods and medicine industry.