固定化单宁对酒类营养成分的吸附性能研究

采用固定化单宁对酒中可能存在的营养成分蛋白质、氨基酸、糖类、有机酸、乙醇和铁离子等进行吸咐试验。结果表明：固定化单宁对不同营养成分的吸附率差别明显，它通过氢键和疏水作用对蛋白质有较大的吸附率，通过多个酚羟基与中心铁离子形成螯合物而对其有较大的吸附率，对氨基酸、糖、有机酸和乙醇等营养成分或风味物质吸附率不大，固定化单宁可以作为一种较为理想的酒类处理剂。     

基质辅助激光解吸附飞行时间质谱分析缩合单宁的阳离子化问题

以单价金属离子Cs 和Na 作为离子化试剂,对3种缩合单宁进行基质辅助激光解吸附飞行时间(MALD I-TOF)质谱分析。加入Na 作为阳离子化试剂,能得到较高质量的质谱图。但由于实验通道中几乎不可能完全去除的K 的干扰而会高估棓儿茶酚/表棓儿茶酚单元的组成比例,从而影响对棓儿茶酚/表棓儿茶酚单元存在与否的判断;选择Cs 作为阳离子化试剂可以避免此问题,但在复杂的缩合单宁分析中,同样因为杂质离子Na 和K 的干扰而使得质谱图变得更复杂;未去离子处理直接对缩合单宁进行MALD I-TOF质谱分析与去离子并加入Cs 的处理比去离子并加入Na 能检测到更高聚合度的高聚物,检测到离子峰强度最高的聚合物随离子不同而不同。     

Determination of moutan tannins by high‐performance liquid chromatography and capillary electrophoresis

Cortex Moutan (Radicis Cortex Moutan), the dried root bark of Paeonia moutan and P. spp., contains a series of water‐soluble tannins. With the eight components, 1 4,6‐di‐O‐GG (4,6‐di‐O‐galloyl‐D‐glucose), 2 1,2,3,6‐tetra‐O‐GG, 3 1,2,3,4,6‐penta‐O‐GG, 4 1,3,4,6‐tetra‐O‐GG, 5 3,4,6‐tri‐O‐GG, 6 1,3,6‐tri‐O‐GG, 7 3,6‐di‐O‐GG, and 8 1,2,6‐tri‐O‐GG, as marker substances, a rapid and efficient method of analysis based on HPLC and CE was developed. Using a phosphate eluent, a 5C18‐MS separating column, and a detection wavelength of 280 nm, HPLC was successfully used to analyze the eight constituents within 60 min. The analysis can be completed within 50 min, using the MEKC mode with a buffer composed of borate, SDS, and isopropanol, and a detection wavelength of 210 nm. The detection limit for the marker substances varied from 0.04 to 0.93 μg/mL for the HPLC method and 0.02 to 0.36 μg/mL for the CE method.     

Substitution pattern elucidation of hydroxypropyl Pinus pinaster (Ait.) bark polyflavonoid derivatives by ESI(−)‐MS/MS

The structure of condensed tannins (CTs) from Pinus pinaster bark extract and their hydroxypropylated derivatives with four degrees of substitution (DS 1, 2, 3 and 4) has been characterized for the first time using negative‐ion mode electrospray ionization tandem mass spectrometry (ESI(?)‐MS/MS). The results showed that P. pinaster bark CTs possess structural homogeneity in terms of monomeric units (C₁₅, catechin). The oligomer sizes were detected to be dimers to heptamers. The derivatives showed typical phenyl‐propyl ether mass fragmentation by substituent elimination (58 amu) and inherent C₁₅ flavonoid fissions. The relative abundance of the product ions revealed a preferential triple, tetra‐/penta‐ and octa‐ hydroxypropylation substitution pattern in the monomer, dimer and trimer derivatives, respectively. A defined order of –OH reactivity towards propylene oxide was established by means of multistage experiments (A‐ring ≥ B‐ring > C‐ring). A high structural heterogeneity of the modified oligomers was detected. Copyright © 2014 John Wiley & Sons, Ltd.     

Physico-Chemical and Phytochemical Characterization of Moroccan Wild Jujube “Zizyphus lotus (L.)” Fruit Crude Extract and Fractions

Wild jujube “Ziziphus lotus (L.) Desf.” belongs to the Rhamnaceae family and is a traditionally herbaceous medicinal plant. It is very common in arid and semi-arid regions and is currently used for its antidiabetic, sedative, analgesic, anti-inflammatory and hypoglycemic activities. The aim of the present work was to characterize the physico-chemical properties and the phytochemical profile of wild jujube sample collected from the Guercif region, in order to determine the polyphenolic compounds and the antioxidant ability Analyses were carried out directly after the harvest for the determination of pH, refractive index, total soluble solid (°Brix), dry matter, sugar/acidity, total sugars, reducing sugars, as well as lipid and protein content. Results showed that the investigated fruit is acidic (pH 4.9 ± 0.23) and rich in sugars (80.2 g/100 g ± 3.81). The GC-MS analysis of the fruit revealed a number of volatile compounds, as many as 97, belonging to different chemical classes. The HPLC-DAD-ESI/MS analysis showed the presence of a total of 20 polyphenolic compounds in both EtOAc and MeOH-water extracts. Among them, p-Hydroxybenzoic acid was the most abundant in the EtOAc extract (185.68 µg/100 mg ± 0.5) whereas Quercetin 3-O-rhamnoside-7-O-glucoside was found in higher amounts in the MeOH-water extract (25.40 µg/100 mg ± 0.5). These components have medical interest, notably for human nutrition, as well as health benefits and therapeutic effects. Therefore, Moroccan jujube “Zizyphus lotus (L.)” fruit may have potential industrial applications for food formulations.     

Terminalic Acid, a New Tannin from the Fruit of Terminalia chebula

AsatheraPeuticherbusedintraditionalChinesemedicine,TerminaliachebulaisconventionallygrowninGuangdong,Guangxi,andtheYunnanprovinceofChina.Itsripefruitisefficaciouslycurativewhenusedintreatingdiarrheaandhoarsenessofthethroatandcanalsobeusedasanastringenttobringabouthemostasisortoremovesomepathogenic"internalheat"ortoxicelementsfromwithinhumanphysique'.SeveralstudiesonhydroIysabletanninswithchebuloylgrouphavebeenreportedsofar2.AspartofaprogramforasystematicstudyofTchebula,wehavesuccessfullyis…     

The Tannins from Sanguisorba officinalis L. (Rosaceae): A Systematic Study on the Metabolites of Rats Based on HPLC–LTQ–Orbitrap MS2 Analysis

Sanguisorba tannins are the major active ingredients in Sanguisorba ofJicinalis L. (Rosaceae), one of the most popular herbal medicines in China, is widely prescribed for hemostasis. In this study, three kinds of tannins extract from Sanguisorba officinalis L. (Rosaceae), and the metabolites in vivo and in vitro were detected and identified by high-pressure liquid chromatography, coupled with linear ion trap orbitrap tandem mass spectrometry (HPLC–LTQ–Orbitrap). For in vivo assessment, the rats were administered at a single dose of 150 mg/kg, after which 12 metabolites were found in urine, 6 metabolites were found in feces, and 8 metabolites were found in bile, while metabolites were barely found in plasma and tissues. For in vitro assessment, 100 μM Sanguisorba tannins were incubated with rat liver microsomes, liver cytosol, and feces, after which nine metabolites were found in intestinal microbiota and five metabolites were found in liver microsomes and liver cytosol. Moreover, the metabolic pathways of Sanguisorba tannins were proposed, which shed light on their mechanism.     

Sensitive Electrochemical Quantification of Proanthocyanidins in Grapevine (Vitis vinifera) by Utilizing Disposable Screen-printed Carbon Electrodes

This work presents quantification of proanthocyanidins (PAs) isolated from grapevine using disposable screen-printed carbon electrodes (SPCE). Procyanidin B2 (B2) used as a model to investigate the electrochemical characteristics of complicated PAs structures in Britton Robinson buffer solution using cyclic voltammetry and square wave voltammetry. B2 exhibits a well-defined reversible redox wave at +0.49 V vs. Ag/AgCl. Significantly, the B2 was determined over a linear concentration range of 3.45–34.6 μM with a detection limit of 2.07 μM. The SPCE was used to analyze PAs in grapevine samples, and the results were consistent with those obtained using Folin-Ciocalteu standard method.     

A new sensitive and selective sensor for heavy metal ions based on tannin extracted from the skin of Punica granatum L

This article presents the development of a sensor made from a gold electrode and a receiving polymeric membrane based on tannin extracted from the skin of Punica granatum. L (pomegranate) for real-time detection of heavy metals in a hydrous environment. The basic principle of this device is the complexing (chelating) of metal ions through the adjacent hydroxyl groups contained in the chemical structures of the tannins. The electrochemical characterisation was performed by using electrochemical impedance spectroscopy and square wave voltammetry. Other morphological and structural analyses were performed by using Fourier transform infrared spectroscopy and atomic-force microscopy. The results obtained showed the high sensitivity of the developed device (detection limits of 6.35 × 10^?9 g L^?1 for Cu²⁺, 1.1 × 10^?8 g L^?1 for Cd²⁺ and 2 × 10^?7 g L^?1 for Pb²⁺) and the possibility of simultaneously detecting several heavy metals, each one in a highly selective manner with highly acceptable response time (48s).