SELECTION AND SCREENING OF A DESCRIPTIVE PANEL FOR EWES MILK CHEESE SENSORY PROFILING

The aim of this work was to select a competent sensory panel considering its ability to describe ewes milk cheese sensory properties. The panelists evaluated the sensory characteristics of several ewes milk cheeses in terms of odor, flavor and texture. The performance of judges was assessed taking into account the following aspects: (1) individual discriminatory ability and reproducibility for each sensory attribute; (2) group discriminatory ability and reproducibility and agreement between judges for each attribute; (3) panel homogeneity; (4) panel consonance; and (5) overall panel discriminatory ability. The panel performance was checked with a set of statistical procedures. The results obtained by the selected group were better than the initial panel from the point of view of discriminant power, reproducibility and agreement. The suggested method can be easily applied in routine control of assessors performance and to discover deviant behavior or differences in individual perception of the samples.     

A COMPARISON OF TWO MULTIVARIATE METHODS FOR THE ANALYSIS OF SENSORY PROFILE DATA

Tables of means, over assessors, are often used to summarize the results of sensory profile experiments. These tables are sometimes further summarized by Principal Components Analysis (PCA) to give plots of the samples in the principal sensory dimensions. An alternative procedure is to use Generalized Procrutes Analysis (GPA) on the assessor data to allow for differences in usage of the vocabulary and in the proportion of the scale used. It is shown that these methods give different configurations in the principal sensory dimensions when applied to the data from a study of cheeses (Muir et al. 1995). Using a Jackknife method to calculate the variability of the samples in the principal sensory dimensions, the results from the GPA method are shown to have a higher dimensionality than from the PCA method. Jackknife estimates of variability are used to calculate confidence ellipses to attach to the sensory space maps.     

粘虫在不同温度下的生命表及其发育的热量需要

用人工饲料在不同温度下饲养的粘虫Mythimna separata(Walkcr),组建了种群生命表.未成熟期的存活率在24℃下最高(90％),28℃次之,32℃下最低(27.1％)o在20—28℃,成虫的繁殖力都比较强,24℃时产卵最多,32℃时产卵量急剧下降.根据试验结果估测,粘虫卵孵化、幼虫存活和成虫繁殖的最适温度分别为25.6℃、23.2℃和22.5℃.种群增长指数可用下述方程表示:y=-2530.2850+282.1893X-6.2407X²在最适温度(22.6℃),繁殖一代,种群数量约增加660倍.粘虫的发育起点温度以卵期最低(8.4℃),蛹期最高(10.1℃),完成世代发育需要7.8℃以上的有效积温约925日度.     

An Analysis of the Influence of Plant Density on the Growth of Vicia faba: II. THE SIGNIFICANCE OF COMPETITION FOR LIGHT IN RELATION TO PLANT DEVELOPMENT AT DIFFERENT DENSITIES

In a further analysis of the changing pattern of developmentinduced in Vicia faba by varying the density, it has been foundthat a reduction from a high to a low density has little influenceon the subsequent development unless such thinning is delayeduntil the flowering phase. By this time, save for widely spacedplants, the level of self shading within the population hasbecome marked. In fact, at high densities (55–65 plants/metre²)during the early-ripening phase the light intensity at groundlevel may fall to 0.03 daylight while a considerable proportionof the plant—up to 38 per cent.—may receive lessthan o-1 daylight. At low densities (11-I2 plants/metre²) theminimum intensity at ground level is 0.14 daylight and lessthan 3 per cent, of the shoot is subjected to o-1 daylight.In pot experiments, using a range of screens, it was establishedthat the compensation point is about o-I daylight. Thus, asthe density is increased the light gradient between the apexand the base becomes progressively steeper and the proportionof the leaves not actively assimilating correspondingly greater. To assess the ways in which such a light gradient operates,experiments were carried out in which either the apex or theinflorescences or leaves were removed over different sectionsof the stem or various parts of the shoot shaded and detailedrecords made of development, particularly of flower- and pod-production.Removal of the upper leaves or shading the apex primarily increasesthe rate of pod abscission after the flowers have set. Partialremoval of the inflorescences, especially at the lower nodes,has an opposite effect, while decapitation, though it augmentsthe percentage of flowers which produce immature pods, subsequentlycauses fewer pods to reach maturity. Shading of the lower nodesreduces at these nodes the number of mature pods but may resultin more pods maturing at the upper nodes. It is concluded that when the light gradient is such as to restrictthe internal supplies of substrates the growth of those organswith the least competitive ability, e.g. the newly formed pods,is arrested. It is at this phase that the factors controllingabscission come into play and that abscission is dependent upona balance between the levels of auxins and the production ofan abscission factor.     

四川王朗自然保护区大熊猫主食竹——缺苞箭竹(Fargesia denudat)不同发育时期酯酶和α-淀粉酶同工酶的研究

通过聚丙烯酰胺凝胶电泳,对生长在亚高山地带的大熊猫主食竹的实生苗、成竹和开花竹中不同发生年龄鞭系,以及同一鞭系内一系列生长年龄竹株作了酯酶、α-淀粉酶同工酶的比较研究。结果表明,同一竹种的不同发生年龄鞭系之间叶酯酶电泳类型存在明显差异,而同一鞭系内α-淀粉酶同工酶的变化表现与竹株生长年龄有关。由此认为,上述同工酶系统可以用作竹类无性系发育分析的生理指标。