牛肉酶解物对牛肉特征香味形成的影响研究

以五种不同水解度牛肉酶解物分别制备得到5种热反应牛肉香精。利用定量感官分析和GCMS-O分析考察了5种热反应牛肉香精香气成分的变化。结果显示,添加DH29.13%酶解液的牛肉香精样品其牛肉味、肉香味和仿真度相比于其它样品是最强的。GC-O分析也发现DH29.13%的牛肉酶解液赋予形成了种类较多的香气活性化合物,而没有添加牛肉酶解物的肉味香精缺失了这些特征化合物。利用PLSR进行了香气活性化合物、感官评价和牛肉酶解液的肽分子量分布之间的相关性分析,进一步解释了DH为29.13%的牛肉酶解液是赋予热加工牛肉风味的最合适风味前体。     

Factors influencing sensory quality in red wines of the variety Aghiorghitiko (Vitis vinifera L.) from Nemea

Sensory quality in wines from the indigenous Greek cultivar Aghiorghitiko of Nemea, in 2 years, was studied with multivariate modelling. The appearance, aroma and oral attributes were assessed separately using rank-rating in 13 red Nemea wines, dominated (10 of 13) by Aghiorghitiko, and headspace congeners (51) quantified by solid phase microextraction with gas chromatography. Partial least squares regression (PLS) and discriminant PLS studied relationships between sensory data and congeners, viticultural and oenological data, producers and influence of wood maturations, respectively. Principal component analysis (PCA) spaces for aroma (11 attributes; 64% variance, 3 PCs), congeners (51; 72%, 7 PCs) and oral characters (13 attributes; 77%, 3 PCs) showed similarities in product clustering. Modelling showed clear relationships between sensory character and plant density, wood maturation and producer, respectively. Sensory characters in Aghiorghitiko wines were primarily differentiated by oak maturation and producer influences. A part of the results of this work was presented at the Second International Symposium on the Evaluation and Exploitation of Grapes of Corresponding Terroir through Winemaking and Commercialisation of Wines, 1–3 June 2006, Santorini.     

Sensory profiling of aroma in Greek dry red wines using rank-rating and monadic scoring related to headspace composition

Rank-rating and monadic scoring were compared in profiling sensory aroma character of 27 Greek dry red wines with 16 attributes. In parallel wine headspace volatiles were quantified using solid-phase micro-extraction gas chromatography but not identified. In rank-rating, 14 aroma attributes showed discriminations with P<0.05 and 11 P<0.001. In scoring, 6 of 16 attributes showed P<0.05. Principal component analysis (PCA) explained 88% variance in rank-rating data, with six significant components (PCs), in scoring 40% in two PCs. PCA analysis of 83 common flavour volatiles explained 48% variance in six PCs. Partial least-squares regression (PLS1) modelling achieved more and better models for attributes using rank-rating, 8 of 14, than for scoring, 3 of 16; PLS2 explained greater variance in rank-rating. For wine sensory/instrumental correlation studies, rank-rating has distinct advantages over monadic scoring in deciding volatiles contributing to sensory character prior to identification strategies such as HRGC–mass spectrometry.     

赤霞珠干红葡萄酒SO2与O2消耗动力学研究

该试验以新疆吐鲁番鄯善县新葡王酒庄赤霞珠干红葡萄酒为材料,研究在饱和氧消耗循环过程中,SO2含量、O2含量、葡萄酒酚类物质的变化,建立了葡萄酒中氧消耗动力学偏最小二乘（PLS）法回归模型。结果表明,该模型能很好的描述葡萄酒中O2变化规律,相关系数＞0.92,说明能用来描述葡萄酒中O2的消耗过程。这些模型主要解释了在葡萄酒氧化过程中葡萄酒成分的变化关系,消耗的总O2以及非SO2消耗的O2模型表明,O2主要投入氧化SO2和生产乙醛和乙酸。除了氧化乙醇之外,还可以降解黄酮醇和产生羟基肉桂酸。初始耗氧率（OCR）与总乙醛含量、没食子酸初始含量以及单宁中儿茶素的含量呈负相关。     

Fortification of Wheat Bread with Agroindustry By‐Products: Statistical Methods for Sensory Preference Evaluation and Correlation with Color and Crumb Structure

The use of agroindustry by‐products (BP) for fortification of wheat bread can be an alternative to waste disposal because BP are appealing sources of dietary fiber. Moreover, it may also contribute to indirect income generation. In this study, sensory, color, and crumb structure properties of breads fortified with fiber rich fraction recovered from four types of agroindustry BP were tested, namely orange (OE), pomegranate (PE), elderberry (EE), and spent yeast (YE). Statistical models for sensory preference evaluation and correlation with color and crumb structure were developed. External preference mapping indicated consumer preferences and enabled selection of the concentrations of BP fibre‐rich fraction with best acceptance, namely 7.0% EE, 2.5% OE, 5.0% PE, and 2.5% YE. Data collected from image analysis complemented sensory profile information, whereas multivariate PLS regression provided information on the relationship between “crust color” and “crumb color” and instrumental data. Regression models developed for both sensory attributes presented good fitting (R²Y > 0.700) and predictive ability (Q² > 0.500), with low RMSE. Crust and crumb a* parameters had a positive influence on “crust color” and “crumb color” models, while crust L* and b* had a negative influence.     

A comparison of methods for linear prediction of apple flavour from gas chromatographic measurements

A comparative study of linear methods for prediction of sensory profiles from gas chromatography (GC) measurements was performed. The data used came from an experiment on the effect of storing apples at various oxygen concentrations. Partial least-squares regression and continuum regression showed the best performance, measured by a two-step cross-validation principle. The traditional prediction error sum of squares (PRESS) overestimated the predictive ability of a multiple linear regression approach. The quality of the predictions of sensory properties from GC analyses was measured in terms of a ‘panel size equivalent’. Thus, the predictions obtained in the present study were as accurate as predictions from an assessor panel consisting of 4–9 assessors, depending on the sensory property in question.     

气相色谱-质谱联机结合感官分析共建樱桃香气关联网络

为探究食品香气的仪器分析结果与感官分析结果相结合的策略,挖掘仪器分析在一定程度上替代感官品评的潜力,以9?个不同品种的樱桃样品为试材,分别对其香气进行感官品评及气相色谱-质谱（gas chromatography-mass spectrometry,GC-MS）联用分析,对香气感官品评结果和GC-MS结果计算Pearson相关系数,用以建立二者间的关联网络。根据香气感官品评与GC-MS结果间Pearson相关性得分结果进行偏最小二乘回归（partial least squares regression,PLSR）分析,进一步验证由Pearson相关系数建立关联网络的可靠性。Pearson相关性分析结果及关联网络图均表明樱桃香气感官属性与GC-MS分析结果中多种香气物质显著相关,PLSR分析结果同样表明樱桃香气感官属性中的甜橙味、柠檬味、杏仁味、玫瑰味和酒味均可被GC-MS分析结果解释,证实了根据Pearson相关性分析建立关联网络将香气感官结果与GC-MS结果相结合的可行性。研究认为GC-MS分析作为一种客观、易于标准化的香气评价手段,在水果香气研究中具有一定替代感官分析的潜力。     

Identification of Drivers of Liking for Bar‐Type Snacks Based on Individual Consumer Preference

Understanding consumer hedonic responses on food products are of greatest interests in global food industry. A global partial least square regression (GPLSR) had been well accepted method for understanding consumer preferences. Recently, individual partial least square regression (IPLSR) was accepted as an alternative method of predicting consumer preferences on given food product, because it utilizes the individual differences on product acceptability. To improve the understanding of what constitutes bar‐type snack preference, the relationship between sensory attributes and consumer overall liking for 12 bar‐type snacks was determined. Sensory attributes that drive consumer product likings were analyzed using averaged‐consumer data by GPLSR. To facilitate the interpretation of individual consumer liking, a dummy matrix for the significant weighted regression coefficients of each consumer derived from IPLSR was created. From the application of GPLSR and IPLSR, current study revealed that chocolate and cereal‐flavored bars were preferred over fruit‐flavored bars. Attributes connected to chocolate flavor positively influenced consumer overall likings on the global and individual consumer levels. Textural attributes affected liking only on the individual level. To fully capture the importance of sensory attributes on consumer preference, the use of GPLSR in conjunction with IPLSR is recommended.     

广东花香型红茶与单丛茶挥发性成分比较分析

以不同茶树品种加工的红茶和单丛茶为试验材料,采用HS-SPME-GC-MS方法,比较分析同一茶树品种在不同年份、不同季节加工的红茶和单丛茶中挥发性成分差异,探明不同茶树品种红茶和单丛茶的特征性成分,为深入了解茶树品种特性和加工工艺对香气轮廓的影响提供借鉴。结果表明:萜醇是鸿雁12号(HY12)、大叶奇兰10号(QL10)、岭头单丛(LT)和乌叶单丛(WY)中最丰富的挥发性成分。萜醇和芳香醛是HY12和QL10的主体挥发性成分。萜烯、烃类、萜酮和脂肪酮是构成LT和WY的主体挥发性成分,吲哚可区分LT和WY香型。PLS-DA进一步证实,遗传背景相似且加工工艺相同的WY和LT香气轮廓略有差异;遗传背景不同但加工工艺相同的QL10和HY12香气轮廓不同。因此,相同的加工工艺其主体挥发性成分相同,但茶树品种的遗传背景决定茶叶香气轮廓。     

基于多元素分析的冬枣产地鉴别方法

为了探讨利用产地间差异性元素进行产地判别的可行性,测定了不同产地冬枣样本中10种元素的含量,并对数据进行了差异性分析、聚类分析、Fisher判别分析和偏最小二乘判别分析（partial least squares discrimination analysis,PLS-DA）。结果表明,不同产地冬枣中Mg、B、Mn、Fe、Zn元素存在显著差异,是具有产地特征的指纹元素。R型系统聚类分析也证实B、Mn、Fe和Zn元素具有共同特征。基于产地特征元素和Q型聚类、Fisher判别和PLS-DA建立的冬枣产地鉴别模型正确率均高于基于全部元素的分析结果,其中利用特征元素建立的PLS-DA模型鉴别正确率最高,回代检验和交叉检验正确率均为94.0%,Q型聚类模型的判别能力最差,最高的判别正确率为84.06%。本研究证实了产地间差异性元素是有效的产地判别因子,具有监督模式的Fisher判别和PLS-DA算法准确率远高于无监督模式的系统聚类法,更适于产地鉴别分析。      

基于电子舌技术区分酸奶的滋味

为探索应用电子舌区分酸奶滋味的可行性,以原味酸奶和风味酸奶为研究对象,应用电子舌交叉选择型传感器进行检测,获得酸奶响应信号值,采用主成分分析(PCA)、判别因子分析(DFA)对酸奶响应信号值进行分类辨别,并通过PCA、偏最小二乘法(PLSR)将感官评定值与响应值做相关性分析。结果表明:基于PCA、DFA方法分析响应信号值,电子舌技术能很好地辨别不同的酸奶。PLSR模型可以较好的预测酸奶的滋味品质,HA传感器与甜和鲜味具有相关性,以PC1为轴,它们呈显著负相关(p<0.05),苦味与BB和JB两根传感器以PC1轴呈显著正相关(p<0.05)。      

Flavour Instability of Pale Lager Beers: Determination of Analytical Markers in Relation to Sensory Ageing

Flavour changes of six Belgian pale lager beers were studied in order to estimate the importance of different parameters and reactions in relation to the ageing process. An attempt was made to link analytical data with sensory evaluation using multivariate statistical analysis. Partial least squares regression techniques (PLSR) were employed on the analytical and sensory data. As apparent from the PLSR model, significant indicators of lager beer ageing are aldehyde markers (especially total aldehydes, furfural, hexanal, 2‐methylpropanal, 2‐methylbutanal, and 3‐methylbutanal), cold and permanent haze, and beer colour. Conversely, compounds or parameters that load negatively in the PLSR model for beer ageing are trans‐isohumulones, cis‐isohumulones, total bitterness, the T/C‐ratio, polyphenolic markers (especially proanthocyanidins), the flavanoid content, and, to a lesser extent, the TB‐index and reducing power (TRAP). The integrated analytical‐sensorial methodology is proposed as a useful tool for evaluation of the flavour instability of pale lager beers.     

基于质谱与化学计量学的浓香型白酒等级鉴别

不同等级白酒的鉴别对控制白酒质量和保护消费者权益有重要意义,运用顶空固相微萃取质谱(HS-SPME-MS)技术获取3个不同等级的120个洋河大曲酒样质荷比m/z 55～191范围内的离子丰度值数据,结合偏最小二乘-判别分析和逐步线性判别分析法筛选出14个重要特征离子,且交叉验证的预测准确率达100%;然后将筛选出的14个特征离子作网络输入层,酒样的不同等级做网络输出层,构建神经网络等级鉴别模型,其在±0.3的误差范围内,预测准确率达100%,实现了白酒等级的数字化鉴别。