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Abstract: Applicability of solvent-free microwave extraction (SFME) for extraction of the fruits of Schisandra chinensis essential oil was examined; the composition and antioxidant activities and antibacterial activities of the essential oil were assessed in vitro. An orthogonal experiment (L9 (3)4) was applied to optimize the extraction process. The optimum conditions were: extraction time, 45 min; microwave power, 800 W; diameter of powder particles, 0.25 mm; and proportion of water pretreatment, 30%. Under these conditions, the extraction yield was 1.75%. Thirty-five compounds, representing 91.12% of the oil, were identified, of which the major ones, ylangene (50.11%), β-himachalene (10.76%)，α-bergamotene (9.52%) and β-Chamigrene (5.41%), accounted for of 75.80% the oil. Antioxidant activity, IC50 value of the essential oil was determined as 3.87 mg/mL by DPPH assay, and the inhibition values of the essential oil at 1.8 mg/mL was 41.88% by β-Carotene–linoleic acid bleaching assay. The essential oil was screened for antibacterial activity against both Gram positive (Staphylococcus epidermidis, Staphylococcus aureus, Bacillus subtilis) and Gram negative (Escherichia coli, Pseudomonas aeruginosa, Proteus vulgaris) bacteria. The essential oil showed antibacterial effect against all the gram (+) bacteria and gram (−) bacteria tested. These results show that S. chinensis essential oil could be considered as a natural alternative to food antioxidants and preservatives. [Copyright &y& Elsevier]

The oil-in-water (O/W) emulsions were prepared from Scutellaria baicalensis polysaccharide conjugates (SBPC) as an emulsifier and medium-chain triglyceride (MCT). Effects of pH, metal ions and heat treatment on the emulsion stability were investigated. Compared to that of 0.20 ̶ 1.00 wt% SBPC and 2.00 wt% GA, 2.00 wt% and 3.00 wt% SBPC stabilized emulsion droplets had a smaller particle size and were more stable during 10-day storage at 25 °C. The average particle sizes (d 32) of emulsions containing metal ions varied from 4.54 to 6.62 μm (0.100–0.500 mol/L Na+), from 2.63 to 3.86 μm (0.010–0.050 mol/L Ca2+), and from 2.66 to 7.89 μm (0.001–0.030 mol/L Al3+), as well as the zeta potential varying from −17.63 to −19.67 mV (Na+), from −16.50 to −18.13 mV (Ca2+) and from −15.02 to −18.56 mV (Al3+). SBPC emulsion possessed stability under pH 3.0–7.0 and thermal treatment at 70–100 °C during the 10-day storage period. Furthermore, SBPC emulsion inhibited oxidative polymerization of EGC. The average retention rate of EGC was 88.28% on the 10th day. This research provides a new way for development and application of SBPC as an emulsifier. • The emulsification of SBPC was discovered. • SBPC emulsion was stable under pH 3.0–7.0 and thermal treatment at 70–100 °C. • SBPC emulsion is stable under different concentrations of Na+, Ca2+ and Al3+. • SBPC emulsion inhibits epigallocatechin (EGC) oxidation. [ABSTRACT FROM AUTHOR]

Ice cover restructures the distribution of substances in ice and underlying water and poses non-negligible environmental effects. This study aimed to clarify the spatiotemporal variability and environmental effects of methane (CH 4), nitrous oxide (N 2 O), total nitrogen (TN), total phosphorus (TP), dissolved organic carbon (DOC), and dissolved inorganic carbon (DIC) in ice and water columns during different ice-covered periods. We surveyed the ice-growth, ice-stability, and ice-melt periods in an ice-covered reservoir located in Northeast China. The results showed that underlying water (CH 4 : 1218.9 ± 2678.9 nmol L−1 and N 2 O: 19.3 ± 7.3 nmol L−1) and ice (CH 4 : 535.2 ± 2373.1 nmol L−1 and N 2 O: 9.9 ± 1.5 nmol L−1) were sources of atmospheric greenhouse gases. N 2 O concentrations were the highest in the bottom water of the reservoir while CH 4 accumulated the most below the ice in the riverine zone. These can be attributed to differences in the solubilities and relative molecular masses of the two gases. Higher concentrations of N 2 O, TN, TP, DOC, and DIC were recorded in the underlying water than those in the ice due to the preferential redistribution of these substances in the aqueous phase during ice formation. Additionally, we distinguished between bubble and no-bubble areas in the riverine zone and found that the higher CH 4 concentrations in the underlying water than those in the ice were due to CH 4 bubbles. In addition, we reviewed various substances in ice-water systems and found that the substances in ice-water systems can be divided into solute exclusion and particle entrapment, which are attributed to differences between dissolved and particulate states. These findings are important for a comprehensive understanding of substances dynamics during ice-covered periods. • Ice-covered condition induced variations of CH 4 and N 2 O in water column. • Ice contained lower N 2 O, TN, TP, DOC and DIC than the underlying water. • CH 4 concentrations in and below ice were different between bubble and no bubble areas. • Substances in ice-water system were divided into solute exclusion and particle entrapment. • Seasonal ice-cover lead to environment effects in winter and subsequent spring. [ABSTRACT FROM AUTHOR]

This study focuses on the isolation of theabrownins (TBs) from Pu'er tea. This isolation process involves low temperature water extraction, membrane separation, and multi-stage extraction with organic solvents. Subsequently, purification was performed using column chromatography with macroporous adsorbent resin D-101 and ethanol aqueous solution with a concentration of 0–64.81 g/100g. Five purified fractions were obtained, namely TBs-D1, TBs-D2, TBs-D3, TBs-D4, and TBs-D5, collectively referred to as TBs-D(1–5). These fractions were found to contain TBs and polysaccharides but lacked catechins, caffeine, theaflavin, and free protein. The average molecular weights of these fraction components exceeded 104 Da. These results indicated that TBs-D(1–5) were not free, but combined with tea polysaccharide conjugates (TPC), that is, TBs-TPC complexes. Furthermore, ultraviolet–visible spectrophotometry and Flourier transformation infrared spectroscopy confirmed the nature of TBs-D(1–5) as TBs-TPC complexes. Fluorescence spectra revealed that polysaccharides exert a quenching effect on the intrinsic fluorescence of TBs. Atomic force microscopy indicated that the sample forms a spherical cluster due to the aggregation of theabrownin molecules. Additionally, measurements of interfacial tension and water contact angle demonstrated that TBs-D(1–5) exhibit some amphiphilic properties. This research provides a theoretical foundation for the industrial production and utilization of TBs. • Five purified fractions were obtained from theabrownin (TB) isolate by column chromatography. • These fractions are the complex of TBs and tea polysaccharide conjugates (TPCs). • Physicochemical properties of TBs-TPC complexes were investigated. • TBs-TPC complexes showed amphiphilic properties. [ABSTRACT FROM AUTHOR]

Plant genus Hippophae contains a variety of bioactive substances and has high nutritional and medicinal value. To help the classification of Hippophae plants and ensure its quality, a high-performance liquid chromatography-diode array detector (HPLC-DAD) fingerprinting method was established based on the distribution and relative contents of flavonoids. Chemometrics analysis were used to analyze and compare the differences of Hippophae samples. Differences were observed among Hippophae varieties, and different plants within the same variety showed good similarity. Chemometrics analysis showed that 16 samples of Hippophae fruit and 40 samples of Hippophae leaf were divided into three groups. Four flavonoids were identified in fruit (isorhamnetin-3- O -glucoside-7- O -rhamnoside, rutin, isorhamnetin-3 -O -rutinoside, and isorhamnetin) and five were identified in leaf (quercetin-7- O -glucoside, isorhamnetin-3- O -glucoside-7- O -rhamnoside, rutin, guaijaverin, and kaempferol-3- O -rutinoside). The highest flavonoid content in fruit was observed in Hippophae rhamnoides ssp. yunnanensis (average 3.651 mg/g). In leaf, Hippophae neurocarpa had the highest flavonoid content (average 13.303 mg/g) and a higher flavonoid content was observed in male plants (average 8.348 mg/g) than in female plants (average 7.273 mg/g). Correlation was observed between flavonoid content and climate factors. HPLC fingerprinting combined with chemometric analysis and quantitative analysis can provide a good foundation for subsequent production and processing. [Display omitted] • Tibetan Hippophae plant is a valuable source of functional ingredients. • HPLC fingerprint method was developed for fruit and leaf flavonoids. • HCA, PCA, and PLS-DA were successfully applied to cluster samples. • Flavonoids are highly related to mean temperature and vapor pressure. [ABSTRACT FROM AUTHOR]

Food grade titanium dioxide (TiO 2) usually contains a nanosized fraction, while only a few studies had investigated the effects of TiO 2 nanoparticles (NPs) on the other food components via oral exposure. This work investigated the impact of TiO 2 NPs on the content, bioaccessibility and antioxidant activity of polyphenols in the apple juice. Results indicated that adding 500 mg/100 g TiO 2 NPs significantly decreased the contents of total polyphenol and the main individual polyphenols in the apple juice, which was attributed to the formation of polyphenol-TiO 2 NPs charge transfer complexes aggregation. Additionally, the addition of TiO 2 NPs reduced the bioaccessibility and antioxidant activity of apple polyphenols in a dose dependent manner. This study indicated that TiO 2 NPs can bind polyphenols in the complex food matrix, and provided valuable insights into the influence of food grade TiO 2 NPs on the other food components after oral consumption. [Display omitted] • Effect of TiO 2 NPs on the bioaccessibility and antioxidant activity of apple polyphenol was studied. • TiO 2 NPs can bind with polyphenols in the complex food matrix. • TiO 2 NPs reduced the contents of total and individual apple polyphenols in a dose-dependent manner. • The formation of polyphenol-TiO 2 NPs complexes reduced the antioxidant activity of apple juice. [ABSTRACT FROM AUTHOR]

With increasing consumer demand for label-friendly products, there is a push towards the identification and utilization of effective natural emulsifiers from botanical sources. In this study, we investigated the effect of controlled thermal treatments on the physicochemical and functional properties of tea polysaccharide conjugates (TPCs). Thermal treatment of the TPCs at 110 °C for 3 days (TPC-3d) markedly improved their emulsifying activity without negatively impacting their antioxidant activity. In comparison with animal-based (sodium caseinate) and synthetic (Tween 80) emulsifiers, TPC-3d stabilized emulsions were more effective at inhibiting the chemical degradation of encapsulated ω-3 oils and curcumin during storage at elevated temperatures. The improvement in the chemical stability of the bioactive lipids was mainly ascribed to the antioxidant activity of the conjugated phenolic groups in the TPC. Our results show that thermally-treated TPC has the potential to be used as a novel plant-based antioxidant emulsifier to encapsulate and protect chemically labile hydrophobic compounds. [Display omitted] ● The impact of heating on tea polyphenol conjugate (TPC) functionality was studied ● Thermal treatment did not negatively influence TPC antioxidant activity ● Thermal treatment (110 °C, 3 days) improved TPC emulsifying activity ● In emulsions, TPC inhibited ω-3 oil oxidation and curcumin degradation [ABSTRACT FROM AUTHOR]