Challenges in relating concentrations of aromas and tastes with flavor features of foods

Flavor sensations in food are highly influenced by the aroma and taste compounds. Reviewing the extensive literature of recent years in this field has shown that the reconstitution of flavor based on aroma and taste compounds poses numerous problems. These are of different nature and include among others (a) chemical transformations among these compounds, (b) changes in the concentrations of the compounds responsible for the perceived flavor, (c) interactions among the chemical compounds that enhance or reduce a specific flavor sensation, and finally, (d) the complexity of the different food matrices and its influence in the flavor perception. Another difficulty that flavor scientists must face is how to properly model and visualize the complex relationships existing between the chemical composition of foods and the flavor perception. These problems have repercussions on the reconstitution of the flavor signature of food based on the natural concentrations of its key aroma and taste compounds. Therefore, the main aim of this review is to deal with all these issues to propose potential solutions for a robust transformation in a science-based quality approach.     

Determination of industrial pollution effects on citrus honeys with chemometric approach

The aim of this study was to determine the levels of essential, trace and toxic elements, such as K, Ca, Fe, Cu, Al, Ni, Sn, Pb and Cd in citrus honeys from different regions (industrialized and nonindustrialized) of Hatay, Turkey. K, Ca, Na and Mg were the most abundant elements, with mean contents of 363.5, 256.6, 88.1 and 37.7 mg/kg, respectively. The trace element mean contents ranged between 0.032 and 15.58 mg/kg. Significant differences in Fe, Cu, Al, Ni, Sn, Pb, Cd, Co and Sr levels were observed between two different regions. The findings that Fe, Cu, Al, Ni, Sn, Pb, Cd, Co and Sr contents in citrus honeys from industrialized regions were higher than citrus honeys from non-industrialized regions indicate that the honeys were affected by industrial pollution. Chemometric methods were applied to classify honey according to mineral content. Cluster analysis showed three clusters corresponding to the three different regions.     

酸解-酶膜联用法检测谷氨酰胺

研究了谷氨酰胺在酸性条件下的水解特性后 ,建立了酸解 酶膜联用的谷氨酰胺定量分析方法。此方法的线性范围为 10～ 40mmol/L ,相关系数R =0 .999,分析误差为 0 .1mmol/L ,测量所需时间约为 30min。     

豆腐产量、品质与籽粒营养成分及加工性状的关系

以南方、黄淮、东北地区261个品种为材料,运用通径分析方法研究干豆腐产量、品质与籽粒营养成分及加工性状的关系。结果表明提高总糖利用率、脂肪利用率、蛋白利用率对提高干豆腐产量具有较大促进作用;增加籽粒脂肪含量及其利用率,能较大地促进干豆腐脂肪含量的提高,蛋白利用率的提高能较大地促进干豆腐蛋白含量的提高;总糖利用率的提高能较大地促进干豆腐总糖含量的提高;营养成分利用率与其抽提率、絮凝率的典型相关分析表明蛋白絮凝率和脂肪絮凝率的提高有利于蛋白利用率的提高;总糖抽提率和絮凝率的提高有利于总糖利用率的提高。     

RP-HPLC法分离和定量测定未变性的乳清蛋白成分

建立了一种基于反相高效液相色谱(RP-HPLC)来分离并定量测定脱脂乳、加热脱脂乳及脱脂乳粉中未变性的乳清蛋白的分析方法。采用Venusil ASB-C8色谱柱;流速0.8 mL/min;检测波长215 nm;柱温30℃;流动相A为体积分数0.1%的三氟乙酸水溶液;流动相B为体积分数0.1%的三氟乙酸乙腈溶液;洗脱方式:流动相B开始在38%下等度洗脱2 min,然后在5 min内上升到43%,最后在43%下等度洗脱13 min。此方法在20 min内将4种乳清蛋白组分分离且各蛋白线性关系良好,适合定性和定量检测未变性的乳清蛋白组分。     

不同品牌食醋味感特征的电子舌分析

为了研究不同区域、不同品牌食醋的味感差别,文章采用TS-5000Z型味觉分析系统,将食醋样品按陈醋∶水为1 ∶ 5(V/V)进行稀释后检测.经过丰富的图形展示,对其传感器响应信号进行了主成分分析(PCA).结果显示:电子舌能够很好地辨别不同地域、不同品牌的食醋,能够直观地反映各品牌之间的味感差异,这为消费者根据自己的喜好与需求购买商品提供参考.     

电子舌对鸡精的味觉分析

为了验证电子舌对不同品牌鸡精的区分能力,考察不同品牌鸡精的味觉差别,文章采用TS-5000Z型味觉分析系统,将7种品牌的鸡精进行稀释后检测.经过丰富的图形展示,对其传感器响应信号进行了主成分分析(PCA)及评价分析,结果表明:样品鲜味指标在14.9～15.8之间,丰富性指标在5.2～6.1之间,差距均在一个单位以内.结论:该电子舌检测7种品牌鸡精的鲜味几乎相同,不能进行有效区分.这与不同品牌鸡精的鲜味物质主要是谷氨酸钠的实际情况相符.     

烤烟表面颜色的量化及其与胡萝卜素类物质的关系

为揭示我国不同产区烤烟颜色特征差异的成因,采用L*a*b*均匀颜色空间的颜色表征方法对我国11个省60个产烟县的C3F烟叶进行了测量分析,并研究了烤烟颜色的色空间分布指标与类胡萝卜素含量的关系。结果表明:①我国不同产区烤烟颜色的色空间指标明度L*、红度a*、黄度b*、色饱和度c*及类胡萝卜素类物质差异明显,东南烟区烟叶的明度、黄度和色饱和度较低,红度较高,类胡萝卜素含量较低,叶黄素比例较高;长江中上游和西南烟区烟叶的明度、黄度和色饱和度较高,红度相对较低,类胡萝卜素含量较高;北方烟区烟叶的明度相对较高,色饱和度相对较低,类胡萝卜素含量较低。②烤烟类胡萝卜素类物质与颜色色空间分布指标关系密切,随类胡萝卜素含量的提高,红度、黄度、色饱和度等指标均呈现出显著上升趋势,明黄度比值呈显著下降趋势。     

基于ANSYS Workbench的带夹套卧式储罐分析

以带夹套的卧式储罐为研究对象,应用ANSYS Workbench有限元分析软件,通过静力分析方法,得出在充满物料、雪载荷下,加强筋对储罐的作用非常显著,其变形及应力分布相似;通过响应谱分析方法,得到在地震载荷下,储罐在鞍座处出现应力最大值,低于材料的许用应力。验证储罐的可靠性,并提出优化方法。     

容器与裙座连接处强度的有限元分析

按《钢制压力容器—分析设计标准》（ＪＢ４７３２—９５），采用ＡＮＳＹＳ通用有限元程序，在考虑包括热载荷、内压载荷和自重的条件下，对压力容器与裙座连接处的局部进行了传热分析和结构分析，校核了该处的安全性．     

川昧发酵香肠的电子舌识别研究

该文采用α-ASTREE电子舌对不同发酵时间的川味香肠样品进行识别研究.通过对获得的电子舌传感器数据进行主成分分析和判别因子分析,结果表明电子舌可以有效区别不同发酵时间的川味香肠样品,尤其在判别因子分析中,仅第1、第2个判别因子的累计贡献率就达到99.992％,识别效果十分显著.     

蜂蜜用葡萄糖溶液掺假的近红外光谱检测

为实现蜂蜜用葡萄糖溶液掺假的快速检测,利用近红外光谱技术(NIRS)对真假蜂蜜样本进行了研究。121个真蜂蜜样本中取8个分别按5%、10%、15%、20%、25%、30%、35%、45%、55%和65%的质量比掺假,共得80个掺假样本。不同光谱预处理方法的模型结果表明最佳预处理方法为自归一化加一阶微分(真假判别)和中心化加一阶微分(掺假量分析)。利用CARS(Competitive adaptive reweighted sampling)法筛选变量,PLS-LDA模型对真假蜂蜜的判别准确率为100%,PLS模型对掺假量定量分析的交互验证均方差为3.137 7,预测均方差为2.980 0。结果表明NIRS能实现蜂蜜用葡萄糖掺假的检测。     

基于主成分分析的面筋聚集仪预测小麦品质

旨在验证面筋聚集仪测定快速评价小麦品质的可行性,建立基于聚集仪测试的小麦品质性状综合评价方法。采用常规品质测定法和面筋聚集仪法测定81 份不同小麦品种中33 个品质特性指标,利用主成分分析法对其进行综合品质评价。运用正交偏最小二乘法验证综合品质评价模型及其与面筋聚集仪测定指标的关系,分析其变量投影重要性及相关性。结果表明,33 个品质性状在品种间都存在广泛的遗传变异,其中启动能量、稳定能量、稳定时间、拉伸面积、最大拉伸阻力的变异系数均在60%以上。主成分分析结果表明,提取的6 个主成分累计贡献率高达84.221%,可综合反映小麦品质信息,构建小麦综合品质评价函数：Y=0.283F1＋0.214F2＋0.183F3＋0.130F4＋0.122F5＋0.066 3F6,其中峰前值和峰后值与综合品质评价得分的R2分别为0.706 1和0.739 2。18 个显著影响小麦综合品质的指标间的相关性分析表明,面筋聚集仪测定指标与籽粒品质、面团的流变学特性之间呈显著或极显著相关性。该研究验证了使用面筋聚集仪快速评价小麦品质的可行性,为准确、快速了解小麦品质、品质评价标准建立及品质调控提供参考和依据。     

Implementation of quality control methods (physico-chemical, microbiological and sensory) in conjunction with multivariate analysis towards fish authenticity

Nowadays authenticity of foods and fish in particular has become of crucial importance because of high number of adulteration cases. Authenticity control has gained ground thanks to the development of several rapid physico‐chemical and microbiological methods aiming at distinguishing one species from another based on solid scientific evidence. It has been proven that despite the precision and accuracy of robust analytical and protein and DNA‐based techniques, detection of authenticity could not be claimed without resorting to multivariate analysis. This review summarizes both the most advanced and state of the art used techniques for detecting fish and seafood authenticity (both in terms of species and geographical origin). Another issue reported in this review is the preservation of fish and seafood through the implementation of old and novel techniques (ice, modified atmosphere packaging). Several informative tables were included in this paper referring to the employed quality control and sensory analysis methods and multivariate analysis for fish and seafood.     

中红外光谱与模式识别相结合鉴别茶叶种类

采用漫反射傅立叶变换红外（FTIR）光谱法结合主成分分析对苏州“碧螺春”、浙江“龙并”、安徽祁门红茶、福建“铁观音”4种茶叶进行了聚类分析。结果表明，主成分分析结合马氏距离判据的方法对上述4种茶叶可进行鉴别，该法快速、准确，为客观评价茶叶品种提供了一种新的方法。