柠檬酸的合成研究进展

柠檬酸是一种广泛应用于食品和日用化学品工业的天然香料，随着柠檬酸用途的扩大，从植物油中提取的柠檬醛已无法满足工业发展的需要，因此人工合成柠檬酸的方法不断涌现，文章综述了近年来柠檬醛的合成研究进展。     

欢迎订阅1987年度《精细化工》双月刊

《精细化工》系国内创办最早的精细化工专业技术刊物,主要报导我国食品与饲料添加剂、油田化学品、纺织染整助剂、工业表面活性剂、合成香料、功能高分子材料、电子电器用化学品、粘接剂、橡胶助剂、工业清洗与水质处理剂、果蔬保鲜剂、卫生与日用化学品、建筑用化学品、汽车化学品等尚未形成独立行业的、精细化工新领域中的研究报告、文献综     

木质素类油田化学品的研究与应用

简要介绍了木质素资源的利用及提取方法，对木质素在油田化学中的应用进行了综述，木质素可用作稀释剂、降滤失剂、牺牲剂、稠油降粘剂及堵水调剖剂等。结果表明，木质素资源丰富，在油田化学品中用途广泛，应加强研究与应用开发力度。     

《精细石油化工》广告业务简则

<正>《精细石油化工》是经国家科委批准,由中国石化集团资产经营管理有限公司天津石化分公司主办的公开发行科技期刊,属全国中文核心期刊。主要报道油田化学品、日用化学产品、纺织染整助剂、催化剂、胶粘剂、表面活性剂、合成洗涤剂、合成材料助剂、炼油精细化学品及有关中间体等方面的市场动向、生产应用进展和科技成就。发行范围遍及全     

《精细石油化工》广告业务简则

<正> 《精细石油化工》是经国家科委批准,由中国石化天津石油化工公司主办的公开发行科技期刊,属全国中文核心期刊。主要报道油田化学品、日用化学产品、纺织染整助剂、催化剂、胶粘剂、表面活性剂、合成洗涤剂、合成材料助剂、炼油精细化学品及有关中间体等方面的市场动向、生产应用进展和科技成就。发行范围遍及全国30个省、市、自治区及海     

《精细石油化工》广告业务简则

<正>《精细石油化工》是经国家科委批准,由中国石化天津石油化工公司主办的公开发行科技期刊,属全国中文核心期刊。主要报道油田化学品、日用化学产品、纺织染整助剂、催化剂、胶粘剂、表面活性剂、合成洗涤剂、合成材料助剂、炼油精细化学品及有关中间体等方面的市场动向、生产应用进展和科技成就。发行范围遍及全国30个省、市、自治区及海     

《精细石油化工》广告业务简则

<正>《精细石油化工》是经国家科委批准,由中国石化天津石油化工公司主办的公开发行科技期刊,属全国中文核心期刊。主要报道油田化学品、日用化学产品、纺织染整助剂、催化剂、胶粘剂、表面活性剂、合成洗涤剂、合成材料助剂、炼油精细化学品及有关中间体等方面的市场动向、生产应用进展和科技成就。发行范围遍及全国30个省、市、自治区及海     

《精细石油化工》广告业务简则

<正>《精细石油化工》是经国家科委批准,由中国石化天津石油化工公司主办的公开发行科技期刊,属全国中文核心期刊。主要报道油田化学品、日用化学产品、纺织染整助剂、催化剂、胶粘剂、表面活性剂、合成洗涤剂、合成材料助剂、炼油精细化学品及有关中间体等     

《精细石油化工》广告业务简则

正《精细石油化工》是经国家科委批准,由中国石化集团资产经营管理有限公司天津石化分公司主办的公开发行科技期刊,属全国中文核心期刊。主要报道油田化学品、日用化学产品、纺织染整助剂、催化剂、胶粘剂、表面活性剂、合成洗涤剂、合成材料助剂、炼油精细化学品及有关中间体等方面的市场动向、生产应用进展和科技成就。发行范围遍及全国30个省、市、自治区及海外的数千家石油、化工、轻工、纺织、医药行业的生产企业,科     

《精细石油化工》广告业务简则

正《精细石油化工》是经国家科委批准,由中国石化集团资产经营管理有限公司天津石化分公司主办的公开发行科技期刊,属全国中文核心期刊。主要报道油田化学品、日用化学产品、纺织染整助剂、催化剂、胶粘剂、表面活性剂、合成洗涤剂、合成材料助剂、炼油精细化学品及有关中间体等方面的市场动向、生产应用进展和科技成就。发行范围遍及全国30个省、市、自治区及海外的数千家石油、化工、轻工、纺织、医药行业的生产企业,科     

scCO_2与日用化工

介绍了超临界流体的特性、萃取原理及超临界二氧化碳作为 SFE 溶剂、作为化学反应介质在日用化工中的应用。     

Method development for the analysis of phthalate esters in tea beverages by ionic liquid hollow fibre liquid-phase microextraction and liquid chromatographic detection

A novel method, termed ionic liquid-based hollow fibre liquid phase microextraction (IL-HF-PLME), coupled with high-performance liquid chromatography (HPLC) was developed for separation and preconcentration of three phthalate esters (PAEs) in tea beverage. In the present study, ionic liquid 1-butyl-3-methy-limidazolium hexafluorophosphate ([BMIm]PF₆) was placed in the porous-walled polypropylene hollow fibre as the acceptor phase, and nonanol was used as the supported liquid membrane phase that accomplished extraction. Several important parameters influencing the extraction efficiency were investigated in detail. Under the optimized conditions, good linearity occurred in the range of 5–1000 ng mL⁻¹ with the correlation coefficients values above 0.998. The limits of detection ranged from 0.67 to 1.73 ng mL⁻¹. Recoveries of three PAEs in two kinds of spiked tea beverage samples (PAEs, 10.0–100.0 ng mL) were between 94.2 and 103.4%, with relative standard deviations (RSDs) ranged from 1.77 to 3.02%. The enrichment factors were 200. The developed IL-HF-PLME method allowed the simple, rapid, and sensitive determination of phthalate esters in tea beverage samples with an extraction time of just 4 min.     

Development and application of an analytical procedure for specific migration of green tea compounds in IV gamma nectarine active packaging

The aim of study was to develop an easy and reliable method for the quantification of tea compounds migrated from an active packaging to the foodstuff, being IV gamma nectarine the product tested. The method was based on a solid phase extraction (SPE) followed by ultra performance liquid chromatography-mass spectrometry analysis. SPE conditions were first optimized by spiking the nectarine flesh 1% of tea extract in methanol. A previous dilution of the sample extract in water (1:10) was required to remove the major matrix interferences. Then, the washing was optimized for 10 mL water and the extraction was optimized for 0.8 mL methanol. SPE method provided recoveries ranging between 81 and 99%. Limits of detection (0.006–0.048 μg kg⁻¹), quantification (0.008–0.160 μg kg⁻¹) and reproducibility below to 4.2% were obtained. The method has been applied to IV gamma nectarine packaging containing green tea extract. Samples were analyzed by the methodology described and the specific migration values of tea compounds were for all the cases below to the limit of detection calculated ensuring food safety and quality of nectarine active packaging.     

Micromechanism of ultrahigh pressure extraction of active ingredients from green tea leaves

Ultrahigh pressure extraction (UPE), as a promising novel technique, has exhibited great potential for extracting bioactive ingredients from plant materials. The objective of this work was to investigate the micromechanism of UPE of active ingredients from green tea leaves. The microstructure and ultrastructure of the untreated green tea leaves samples and UPE samples will be examined by SEM and TEM, and the micromechanism of UPE of active ingredients from green tea leaves will be discussed. SEM micrographs and TEM micrographs revealed that ultrahigh pressure could result in the disruption of the leaves tissue, cellular wall, membrane and organelles, which enhanced the mass transfer of the solvents into the leaves materials and the soluble constituents into the solvents. This work could help better utilize plant materials to obtain biologically active compounds as a readily accessible source for pharmaceutical usage.     

Enhancement of the storage quality of frozen bonito fillets by glazing with tea extracts

The effect of glazes of various tea extracts upon the storage stability and the quality of bonito fillet and its associated storage deterioration are examined. Fresh bonito fillets were glazed using either water or tea extracts, which had been allowed to ferment to various extents. Ice glazing enhanced the storage quality of the bonito fillet as compared to an untreated sample. Some of the tea-glazing treatments did provide some degree of protection, although some did not. The antioxidant activity of a particular species of tea as impacted upon bonito flesh related substantially to the extent of natural fermentation of the tea species used for glazing. Green tea and Pouchong tea afforded better protection than black tea for both lipid oxidation and protein oxidation within bonito flesh, therefore they maintained a better quality of preserved bonito fillet. The combination of a glazing treatment and the application of green or Pouchong tea extract at a 5% concentration was able to greatly increase the storage quality of the frozen bonito fillets.     

SUPERCRITICAL AND CATALYTIC FLUID EXTRACTIONS OF TEA WASTES

Air dried and ground tea waste was subjected to supercritical and catalytic fluid extraction by using water or acetone as solvent at different temperatures. The most important reactions variables were temperature and ratio of catalyst to the solid sample. The yields of the catalytic fluid reaction have been increased from 70.3 % to 92.4 % as the temperature increased from 230 °C to 340 °C by using water as solvent. The yield of extract was obtained from non catalytic supercritical water extraction was about 50.0 % at380°C.     

SUPERCRITICAL AND CATALYTIC FLUID EXTRACTIONS OF TEA WASTES

Abstract

Air dried and ground tea waste was subjected to supercritical and catalytic fluid extraction by using water or acetone as solvent at different temperatures. The most important reactions variables were temperature and ratio of catalyst to the solid sample. The yields of the catalytic fluid reaction have been increased from 70.3 % to 92.4 % as the temperature increased from 230 °C to 340 °C by using water as solvent. The yield of extract was obtained from non catalytic supercritical water extraction was about 50.0 % at380°C.     

Radionuclides and heavy metals concentrations in Turkish market tea

Tea is one of the most popular beverages in the world. The Eastern Black Sea Region of Turkey is one of the main tea producers in Turkey and the fifth in the world. Thus, the chemical components in tea have received great interest because they are related to health. Since this region was contaminated by the Chernobyl accident in 1986, a comprehensive study was planned and carried out to determine the radioactivity level in the tea growing region. The activity concentrations of ²³²Th, ²³⁸U, ⁴⁰K and ¹³⁷Cs were measured in 29 black tea and one green tea samples from local Turkish markets using gamma spectrometry with an HpGe detector. The average activity concentration of ²³²Th, ²²⁶Ra, ⁴⁰K and ¹³⁷Cs were found 3.2 ± 0.6 Bq/kg, 6.4 ± 0.7 Bq/kg, 445.6 ± 17.8 Bq/kg and 42.0 ± 1.4 Bq/kg in tea samples, respectively.In addition, the concentration of five heavy metals including Fe, Mn, Zn, Cu and Pb were determined by inductively coupled plasma spectroscopy (ICP/OES) on tea samples. Among the investigated metals, Mn was the highest levels. The levels of manganese were in the range of 1850.75–292.65 μg/g (mean: 1286.35 ± 0.58 μg/g). Levels of Pb in the tea samples analyzed were below the detection limits. The concentrations of all elements for daily intake are below safety levels for human consumptions.     

Polyphenolic extract from Rosa rugosa tea inhibits bacterial quorum sensing and biofilm formation

Quorum sensing (QS) is an intercellular signaling and gene regulatory mechanism, which is implicated in bacterial pathogenicity and food spoilage. Therefore, blocking bacterial QS system may prevent QS-controlled phenotypes responsible for food spoilage. In the present study, we aimed to investigate the anti-biofilm and quorum sensing inhibitory potentials of Rosa rugosa tea polyphenol (RTP) extract, which is rich in polyphenols (87.52%) and flavonoids (61.03%). The RTP specifically inhibited QS-controlled violacein production in Chromobacterium violaceum 026 with 87.56% reduction without significantly affecting its growth. Moreover, RTP exhibited inhibition in swarming motility (84.90% and 78.03%) and biofilm formation (67.02% and 72.90%) of Escherichia coli K-12 and Pseudomonas aeruginosa PAO1 in a concentration-dependent manner, respectively. These findings strongly suggest that RTP potentially could be developed as a new QS inhibitor and/or anti-biofilm agent to enhance the shelf life and increase food safety.     

Effect of tea polyphenols on the physical and chemical characteristics of dried-seasoned squid (Dosidicus gigas) during storage

The effects of tea polyphenols (TP) dip treatment on the physical and chemical characteristics of dried-seasoned squid (Dosidicus gigas) during storage at 25 °C were assessed. After the storage, the b* value increased significantly, while the free amino acids (FAA) including Ser, Gly, Arg, Tyr and Lys, and the dominant reducing sugar (RS), lactose, decreased remarkably, which revealed the occurrence of browning reaction in dried-seasoned squid. The progressive conversion of trimethylamine oxide (TMAO) and production of thiobarbituric acid (TBA) and total volatile basic nitrogen (TVB-N) were found during the entire period of storage. Furthermore, the advantages of reducing moisture loss, inhibiting oxidation of lipids, depressing TMAO breakdown and TVB-N accumulation were observed, while the browning reaction exhibited no significant decrease for the TP samples. These results indicated that the addition of TP could maintain quality of dried-seasoned squid.