Comparison of microbial communities and volatile profiles of wines made from mulberry and grape.

In this study, three kinds of wines separately made from mulberry (MW), grape (GW), or mulberry/grape (MGW) were developed and their enological parameters, sensory scores, volatile components, and microbiota were investigated and compared. Contrary to the order of residual sugar and acidity of the three kinds of wines, the order of alcohol content from high to low is GW, MW, and MGW. A total of 60 volatile components (VCs), including esters (17), alcohols (12), acids (6), aldehydes (7), ketones (3), alkenes (3), amines (3), alkanes (4), pyrazines (2), benzene (1), sulfide (1), and thiazole (1), were identified by gas chromatography-ion mobility spectrometer (GC-IMS). The fingerprint of VCs and principal component analysis revealed that the volatile profiles of MGW and GW were more similar in comparison to that of MW and were significantly correlated with the mass ratio of mulberry to grape. Lactobacillus, Weissella, Pantoea, Leuconostoc, Lactococcus, Paenibacillus, Pediococcus, and Saccharomyces were identified as the main microflora at the genus level shared by the MW, MGW, and GW, suggesting that the heterolactic bacteria may contribute more to the high content of volatile acids in MW and MGW. The heatmap of core microbiota and main VCs of MW, MGW, and GW suggested the complicated and significant correlation between them. The above data implied that the volatile profiles were more closely related to the raw materials of winemaking and markedly affected by the fermentation microorganisms. This study provides references for evaluation and characterization of MGW and MW and improvement of MGW and MW winemaking process. KEY POINTS: • Fruit wine enological parameters, volatile profile, and microbiota were compared. • Sixty volatile compounds were identified by GC-IMS in three types of fruit wines. • Winemaking materials and microbiota affect volatile profiles of the fruit wines.

Molecular Docking Revealed the Potential Anti-Oxidative Stress Mechanism of the Walnut Polypeptide on HT22 Cells.

The preparation of novel antioxidant peptides from food raw materials is one of the research focuses, but there are fewer studies on the preparation of antioxidant peptides from walnut meal, a by-product of processing walnuts. This study analyzed the antioxidant properties and protective effects of walnut protein hydrolyzed by alkaline protease and trypsin on the oxidative stress of HT22 cells. The peptides were identified by UPLC-MS/MS, and the anti-oxidative peptides were screened based on virtual computer tools. The potential anti-oxidative stress mechanism of the walnut polypeptide on HT22 cells was explored by molecular docking. The results revealed that walnut protein hydrolysates (WPH) with molecular weights of less than 1 kDa had good antioxidant properties and inhibited oxidative damage of HT22 cells by regulating the levels of reactive oxygen species (ROS) and antioxidant enzyme catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px). Six of the ninety identified new peptides showed good solubility, non-toxicity, and bioactivity. The molecular docking results showed that the six peptides could dock with Keap1 successfully, and EYWNR and FQLPR (single-letter forms of peptide writing) could interact with the binding site of Nrf2 in the Keap1-Kelch structural domain through hydrogen bonds with strong binding forces. The results of this study provided important information on the antioxidant molecular mechanism of the walnut polypeptide and provided a basis for further development of walnut antioxidant polypeptide products.

Study on effects of preparation method on the structure and antioxidant activity of protein-Tremella fuciformis polysaccharide complexes by asymmetrical flow field-flow fractionation.

Oxidation is an essential biological process for human life. In this study, low density lipoprotein-Tremella fuciformis polysaccharide (LDL-TFP) complexes were prepared by electrostatic and covalent methods. The effects of preparation method on the structure and antioxidant activity of LDL-TFP complexes were investigated by asymmetrical flow field-flow fractionation (AF4) coupled with ultraviolet-visible (UV/Vis), multiangle light scattering (MALS), and differential refractive index (dRI) detectors. The results showed that the electrostatic LDL-TFP complexes had a spherical structure, while the covalent LDL-TFP complexes had a rod-like structure as indicated by the ratio of Rg (radius of gyration) to Rh (hydrodynamic radius). Moreover, the results revealed that the antioxidant activity of the LDL-TFP complexes on the HepG2 could be related to the structure of LDL-TFP complexes. The antioxidant activity of LDL-TFP complexes formed by LDL modified with phospholipase A2 was further enhanced. This study would help expand the application of TFP.

Short- and medium-chain chlorinated paraffins in aquatic foods from 18 Chinese provinces: Occurrence, spatial distributions, and risk assessment.

Short-chain chlorinated paraffins (SCCPs) are classed as persistent organic pollutants and were included in the Stockholm Convention in May 2017. Large amounts of chlorinated paraffins (CPs) are produced in China than in any other countries. CPs can be released into the environment while being produced and used, and can bioaccumulate in aquatic biota and be ingested by humans. Dietary intake is the main route through which humans are exposed to CPs. It has previously been found that persistent organic pollutant concentrations are usually higher in aquatic foods than in other foods. The risk of human exposure to SCCPs in aquatic foods should therefore be of concerns. However, SCCP concentrations in aquatic foods have not been systematically studied. A total of 1620 aquatic food samples were collected, and 18 pooled samples were analyzed by two-dimensional gas chromatography coupled with electron-capture negative-ionization time-of-flight mass spectrometry. The mean SCCP and MCCP concentrations were 1472 and 80.5ng/gwet weight, respectively. The dominant SCCP and MCCP congener groups were C10Cl6-7 and C14Cl7-8, respectively. The concentrations were much higher than those have been found in aquatic foods in other countries. The CP concentrations in the samples consumed by local people from eastern and southern China were higher than the concentrations in samples from central and western China. Risk assessment results indicated that SCCPs and MCCPs in aquatic foods do not pose significant risks to residents of China.

Insoluble Dietary Fiber from Pear Pomace Can Prevent High-Fat Diet-Induced Obesity in Rats Mainly by Improving the Structure of the Gut Microbiota.

Supplement of dietary fibers (DF) is regarded as one of the most effective way to prevent and relieve chronic diseases caused by long-term intake of a high-fat diet in the current society. The health benefits of soluble dietary fibers (SDF) have been widely researched and applied, whereas the insoluble dietary fibers (IDF), which represent a higher proportion in plant food, were mistakenly thought to have effects only in fecal bulking. In this article, we proved the anti-obesity and glucose homeostasis improvement effects of IDF from pear pomace at first, and then the mechanisms responsible for these effects were analyzed. The preliminary study by real-time PCR and ELISA showed that this kind of IDF caused more changes in the gut microbiota compared with in satiety hormone or in hepatic metabolism. Further analysis of the gut microbiota by high-throughput amplicon sequencing showed IDF from pear pomace obviously improved the structure of the gut microbiota. Specifically, it promoted the growth of Bacteroidetes and inhibited the growth of Firmicutes. These results are coincident with previous hypothesis that the ratio of Bacteroidetes/Firmicutes is negatively related with obesity. In conclusion, our results demonstrated IDF from pear pomace could prevent high-fat diet-induced obesity in rats mainly by improving the structure of the gut microbiota.

[Levels distribution and risk assessment of the indicator and dioxin-like polychlorinated biphenyls in ten different species of marine fish of Bohai Bay, China].

Polychlorinated biphenyls (PCBs) are highly lipohilic compounds with high metabolic persistence and toxicity. PCBs tend to accumulate in the aquatic food chain and make fish a source of various environmental toxicants to humans. Industries in the Bohai Bay include iron and steel smelting, cement manufacturing and waste incineration, which are potential emission sources of PCBs. In this study, risks and potential effects of PCBs in the Bohai Bay were assessed. Twelve dioxin-like polychlorinated biphenyls (dl-PCBs) and seven indicator PCBs in marine fish samples were analyzed by High Resolution Gas Chromatography/High Resolution Mass Spectrometry (HRGC/HRMS). The concentrations of dl-PCBs in marine fishes ranged from 28.9 pg x g(-1) to 1067.6 pg x g(-1) wet weight. The concentrations of indicator PCBs were between 185.5 pg x g(-1) and 8 371.7 pg x g(-1) wet weight. PCB-118 and PCB-105 were the major congeners of the dl-PCBs congeners, which contributed 41% - 56% and 15% - 21%, respectively. The predominant indicator PCBs were PCB-153 and PCB-138, which contributed 27% and 22%, respectively. The concentrations of dl-PCBs and indicator PCBs were relatively low as compared with those in other studies.

Polyphenolic content and physiological activities of Chinese hawthorn extracts.

Hawthorn polyphenol (HP) was prepared by ethyl acetate treatment of the ethanol extract (HE) of Chinese hawthorn fruit. The concentrations of 15 polyphenols in the HP, HE, extraction residue (HJ), and a hawthorn leaf extract (HF) were determined by HPLC. For HP, the total content of the 15 polyphenols was 21.4%, comprised of 19.7% of procyanidins, 1.21% of chlorogenic acid, and 0.48% of flavonoids, compared to 2.55% for the HE. The yields of procyanidin monomer, dimer, trimer, tetramer, and pentamer were 50.5%, 30.3%, 23.0%, 14.6%, and 12.5% respectively, and the mean degree of polymerization was reduced to 1.39 (HP) from 1.65 (HE). Seven different physiological actions of the four extracts were investigated. The HP showed strong O(2)(-) and (.-)OH scavenging capacities (IC(50) values of 6.3 microg/ml and 1.1 microg/ml respectively), as well as selective prolyl endopeptidase inhibition (IC(50) of 60 microg/ml). The active constituents appeared to be procyanidins.

The use of CE-electrochemiluminescence with ionic liquid for the determination of bioactive constituents in Chinese traditional medicine.

CE / tris(2,2-bipyridyl) ruthenium(II) (Ru(bpy)(3) (2+)) electrochemiluminescence (ECL), CE-ECL, with an ionic liquid (IL) detection system was established for the determination of bioactive constituents in Chinese traditional medicine opium poppy which contain large amounts of coexistent substances. A minimal sample pretreatment which involves a one-step extraction approach avoids both sample loss and environmental pollution. As the nearby hydroxyl groups in some alkaloid such as morphine may react with borate to form complexes and IL, as a high-conductivity additive in running buffer, could cause an enhanced field-amplified effect of electrokinetic injection. Running buffer containing 25 mM borax-8 mM 1-ethyl-3-methylimidazolium tetrafluoroborate (EMImBF(4))IL (pH 9.18) was used which resulted in significant changes in separation selectivity and obvious enhancement in ECL intensities for those alkaloids with similar structures. Sensitive detection could be achieved when the distance between the Pt working electrode and the outlet of separation capillary was set at 150 microm and the stainless steel cannula was fixed approximately 1 cm away from the outlet of the capillary. Quantitative analysis of four alkaloids was achieved at a detection voltage of 1.2 V and a separation voltage of 15 kV in less than 7 min. Detection limits of thebaine, codeine, morphine, and narcotine were 2.5 x 10(-7), 2.5 x 10(-7), 1 x 10(-9) and 1 x 10(-6) M(S/N = 3), respectively. The method was successfully applied to determine the amounts of opium alkaloids in real poppy samples.

Determination of ranitidine in urine by capillary electrophoresis-electrochemiluminescent detection.

The fast analysis of ranitidine is of clinical importance in understanding its efficiency and a patient's treatment history. In this paper, a novel determination method for ranitidine based on capillary electrophoresis-electrochemiluminescence detection is described. The conditions affecting separation and detection were investigated in detail. End-column detection of ranitidine in 5 mM Ru(bpy)(3)(2+) solution at applied voltage of 1.20 V was performed. Favorable ECL intensity with higher column efficiency was achieved by electrokinetic injection for 10s at 10 kV. The R.S.D. values of ECL intensity and migration time were 6.38 and 1.84% for 10(-4) M and 6.01 and 0.60% for 10(-5) M, respectively. A detection limit of 7 x 10(-8) M (S/N=3) was achieved. The proposed method was applied satisfactorily to the determination of ranitidine in urine in 6 min.

[Determination of Chinese traditional medicine activity eliminating superoxide anion radical by kinetics spectrophotometry].

A new method to determine Chinese traditional medicine activity eliminating superoxide anion radical by kinetic spectrophotometry was developed. It is shown that the optimum determination condition may be obtained when wavelength is 520 nm, the concentration of enzyme is 4 x 10(-3) microg x mL(-1), the reaction time is between 2-7 min. Vitamin C activity eliminating superoxide anion radical was determined under the condition, and the results were identical with literature. The method is used to determine IC50 of Cortex Magnoliae Officinalis and Cortex Eucommia, and they are 7.580 and 323.800 mg x L(-1) respectively.

[Determination of eliminating ratio of Chinese traditional medicine for hydroxyl radical by fluorescent spectrophotometry].

Benzoic acid with weak fluorescence may react on .OH, and products with intense fluorescence are made. Extractives of Chinese traditional medicine may eliminate .OH in solution, and make amounts of the products to reduce. Then, increase level of fluorescence of products in solution will be lowered. Based on this principle, a new method is developed to determine eliminating ratio of Chinese traditional medicine for .OH. It is shown that productivity of .OH tends to saturation when H2O2 is shown more than 20 min by 280 nm UV light; .OH may react on benzoic acid completely when molar ratio of H2O2 and benzoic acid is 30:1; linear response range of products fluorescence is 2.2-80 mmol.L-1 with concentration of H2O2. IC50 of elimination .OH with magnoliae and eucommia are 1.025 and 515.3 mg.L-1 respectively. There are no remarkable difference between these results and that of spectrophotometry.