高效液相色谱法测定马铃薯中绿原酸和原儿茶酸

目的:建立高效液相色谱法测定马铃薯块茎中绿原酸和原儿茶酸的含量,并测定了两种马铃薯贮藏期间绿原酸、原儿茶酸含量的变化。方法:采用高效液相色谱法梯度洗脱,使用反相C18色谱柱,以1%甲酸水溶液和100%甲醇为流动相,流速为0.8 m L/min,柱温:40℃,在326、280 nm波长处分别对绿原酸和原儿茶酸进行测定。结果:绿原酸、原儿茶酸分别在50~500、200~1000μg/m L范围内与峰面积线性良好,相关系数分别为0.9999、0.9992;精密度RSD均小于0.35%,稳定性RSD均小于1.68%,绿原酸、原儿茶酸重复性RSD分别为2.07%、3.58%,绿原酸、原儿茶酸平均加样回收率分别为98.29%、97.81%,RSD分别为1.46%、1.31%(n=5)。结论:该方法线性范围宽,分离效果好,快速、准确,可用于马铃薯块茎中绿原酸和原儿茶酸含量的测定。      

Temperature-sensitive polyurethane (TSPU) film incorporated with carvacrol and cinnamyl aldehyde: antimicrobial activity,sustained release kinetics and potential use as food packaging for Cantonese-style moon cake

Temperature-sensitive polyurethane (TSPU) films incorporated with carvacrol and cinnamyl aldehyde were prepared for the potential use of food packaging. The antimicrobial properties and sustained release kinetics of carvacrol and cinnamyl aldehyde in TSPU film were investigated. Results indicated that cinnamyl aldehyde and carvacrol had favourable antimicrobial properties at relatively low addition ratio. The diffusion and release of carvacrol were linearly related to temperature and its addition ratio. The release rates of carvacrol from TSPU film increased from 0.6% to 2.2% with the increase of addition ratio and temperature. The first-order kinetic equation could be used to describe its diffusion and sustained release process. TSPU films could significantly prolong the shelf life of Cantonese-style moon cakes by effectively inhibiting microbial growth and decreasing lipid oxidation comparing with commonly used polyethylene food packaging. Results obtained in the present work can provide technical guide of sustained release food packaging films with antimicrobial properties.     

Investigation of the Aroma Profile of Green Tea Leaves Using Organic Synthesis and Conventional Analytical Techniques

Although many aroma components have been identified in green tea leaves, the aroma compounds contributing to green tea＇s characteristic odor have not yet been reported. The authors recently reported that aroma components with a matcha-like odor are present in both green tea and black tea prepared from the Sayamakaori tea cuttivar. This matcha-like odor is similar to the odor of commercial available matcha （high-quality powdered green tea）, and is a specific odor feature of green tea leaves. At present, the green-tea odor is thought to arise from the combination of a large number of constituents. Recent reports indicate that a complex interaction between olfactory receptors and odorants is important for the evaluation of the odors. Taking into consideration these findings, the authors investigated the aroma profile of green tea, focusing on the characteristic molecular structures of the constituents that give matcha-like odor. Using a combination of organic synthesis and gas chromatography-mass spectrometry plus gas chromatography-olfactometry, the authors identified aroma components with matcha-like odors in five other tea cultivars. This investigation also revealed that several compounds with a formyl group were important constituents of the aroma of green tea leaves, although the odor of each constituent was not individually similar to the tea＇s overall aroma. The authors found for the first time a group of key components that have the matcha-like odor.     

窖泥中总酸、总酯和总醛测定方法的研究

窖泥是生产白酒的关键材料,窖泥的成分复杂,主要有醇类、酸类、醛类、酯类、酚类及芳香族化合物等。本研究建立了一种窖泥中总酸、总酯和总醛的快速连续测定方法,该方法所得3种物质的标准曲线线性关系良好,精密度试验相对标准偏差（RSD）值分别为1.81%、1.13%、0.887%,稳定性试验RSD值分别为1.35%、1.22%、0.96%,加标回收率平均值分别为98.10%、98.16%和98.69%。结果表明,该方法适合窖泥中总酸、总酯和总醛的测定,对白酒的窖泥发酵生产起到一定的指导意义。     

Contribution and importance of wine spirit to the port wine final quality—initial approach

The commercial wine spirit used for this study revealed that the aldehyde content mainly comprises acetaldehyde but other aldehydes such as propionaldehyde, 2‐methylbutyraldehyde, isovaleraldehyde, methylglyoxal, benzaldehyde and others are also present in significant amounts. A typical grape must was used to assess the influence of wine spirit in the analytical and sensorial characteristics of fortified wines. Decreasing levels of anthocyanins, as well the increase in the red colour and tanning capacity, were observed, and seem to be positively correlated with the increase of the aldehyde content present in the wine spirits used to fortify the must. Using the CIE L*a*b* system, this aldehyde content present in the spirit used seemed to be correlated with the decrease of the wines' lightness (darkening effect), the displacement of the hue angle to higher values (yellowing effect) and the increase of the chromaticity (colour saturation) of the wines. Copyright © 2005 Society of Chemical Industry     

表没食子儿茶素没食子酸酯与L-茶氨酸对乙醇脱氢酶和乙醛脱氢酶活性的体外协同作用

目的 探究表没食子儿茶素没食子酸酯(epigallocatechingallate,EGCG)与L-茶氨酸对乙醇脱氢酶(alcohol dehydrogenase, ADH)和乙醛脱氢酶(acetaldehyde dehydrogenase, ALDH)活性的体外协同作用。方法 设置不同浓度及组分,以0μg/mL实验组为对照,先后进行单因素实验和最优组合验证实验,通过对ADH、ALDH活性的检测,确认EGCG、L-茶氨酸不同剂量的解酒效果并探究其最佳配比。结果 单因素实验中,样品质量浓度为200、300μg/mL实验组相较于0μg/mL浓度组,随着EGCG和L-茶氨酸的添加, ADH和ALDH活性显著高于空白组(P<0.05);最优组合验证实验中,11组不同配比组合物对ADH和ALDH活性均具有促进作用,且协同组比单因素组激活效果要更好。其中,当配比组合物为7:3时, ADH、ALDH的活性最高。结论 EGCG、L-茶氨酸解酒组合物最佳配比为7:3时ADH与ALDH活性最高,研究结果为EGCG、L-茶氨酸组合物用于抗醉酒药物研发提供科学依据。     

间接电合成法制取双醛淀粉

提出了一种合成双醛淀粉（ＤＡＳ） 的新方法间接电合成法。在阳离子交换膜做隔膜的两室电解槽中,铅板做阳极,铁板做阴极,把淀粉和碘酸钠的酸性水溶液直接加入阳极室电解,即合成ＤＡＳ。优选电解条件：阳极电解液中ｃ（ＮａＩＯ３） ＝ ０－０５ ｍｏｌ／Ｌ,ｃ（Ｈ２ＳＯ４） ＝ ０－１ ｍｏｌ／Ｌ,ｗ（ 淀粉） ＝ ７ ％ ;阴极液为ｃ（Ｈ２ＳＯ４） ＝ ０－１ ｍｏｌ／Ｌ的稀硫酸;电流密度２ Ａ／ｄｍ２ 。在此条件下电流效率大于０－５ 。     

有机酸催化合成2,4,6,8,10,12-六苄基-2,4,6,8,10,12-六氮杂异伍兹烷

研究了十几种有机酸对合成２,４,６,８,１０,１２ 六苄基 ２,４,６,８,１０,１２ 六氮杂异伍兹烷（Ⅰ）的催化作用,每种催化剂均取得了较好催化效果。尤其是水杨酸和对甲苯磺酸,可分别使化合物Ⅰ的产率达到７５％ 和８２％ ～８４％ 。随对甲苯磺酸用量的增大,化合物Ⅰ的产率先增大后减小。     

食品中丙烯醛危害、形成及抑制

丙烯醛（acrolein, ACR）是结构最简单的α, β -不饱和醛,能够通过迈克尔加成或席夫碱反应与蛋白质、核酸、磷脂等亲核位点发生共价结合,导致细胞毒性和致畸性,从而引起多种慢性疾病如阿尔兹海默症、心脑血管疾病、癌症等。食品加工和贮藏过程中产生的ACR是人体内的主要来源。本文综述了ACR的危害性,对人体组织、器官损伤的机制,体内的来源及其代谢过程;同时,对食品加工贮藏过程的主要前体物质及形成途径进行了剖析与总结。并进一步综述了当前各类食源性ACR抑制剂,包括黄酮多酚类化合物、生物碱类化合物、氨基酸和肽含氮化合物、含硫化合物以及抗坏血酸,抑制ACR的作用机制和构-效关系。为控制食品加工中产生的有害ACR,保证食品安全,减少人们由膳食摄入的ACR提供理论基础,具有一定的现实意义。     

氯醇法环氧丙烷产品除醛方法的研究探讨

工业用环氧丙烷GB/T 14491-2015颁布实施后,下游聚醚客户对环氧丙烷质量要求更高.通过优化氯醇法环氧丙烷工艺降低环氧丙烷产品总醛质量分数,满足客户需求.