CONFIDENCE ELLIPSES APPLIED TO THE COMPARISON OF SENSORY PROFILES

Our experiment involved seven panels and six chocolates – five dark chocolates and one milk chocolate. The aim of the study was to compare the sensory profiles of the chocolates. A natural question to ask is “Did the panelists detect any differences among the five dark chocolates or did they systematically contrast them with the milk chocolate?” The scatter plot of the chocolates obtained by principal component analysis was useless to answer that question, because of the proximity of the points. To overcome that, we used confidence ellipses calculated using bootstrap. The originality of the study lies in the fact that we applied those ellipses to hierarchical multiple factor analysis (HMFA): among the seven panels, six were composed of trained professionals and the last one was composed of untrained students, and through that method, we managed to compare the two types of panels and balance the role of each trained panel. HMFA provides in a single scatter plot a representation of the six chocolates for each panel, the trained panels and all the panels. Confidence ellipses around each chocolate show that the combined panels – the six trained panels and also the untrained panel – differentiate the five dark chocolates. They also show how much larger the untrained panel's variability is than that of the trained panels, and how comparable are the trained panels' variability to each other.     

Genetic structure in cultivated and wild carrots (Daucus carota L.) revealed by AFLP analysis

Genetic variation within and among five Danish populations of wild carrot and five cultivated varieties was investigated using amplified fragment length polymorphism (AFLP). Ten AFLP primer combinations produced 116 polymorphic bands. Based on the marker data an UPGMA-cluster analysis and principal component analysis (PCA) separated the Daucus collections into three groups, consisting of the wild populations, the old varieties, and the recently bred varieties. The genetic distance between the wild populations reflected the physical distance between collection sites. Analysis of genetic diversity showed that the old varieties released between 1974 and 1976 were more heterogeneous than the newly developed F₁ hybrid varieties. The analysis of molecular variation (AMOVA) showed that the major part of the genetic variation in the plant material was found within populations/varieties. The presence of markers specific to the cultivated carrot makes it possible to detect introgression from cultivated to wild types. Received: 6 October 1999 / Accepted: 4 November 1999     

SENSORY PROPERTIES OF EXTRUDED CORN MEAL RELATED TO THE SPATIAL DISTRIBUTION OF PROCESS CONDITIONS

The quality determining factors of extruded products are affected by the temperature, shear and pressure generated by any input to the extruder during the short residence time (< 120s). Although the relationship of process history to measurable product qualities has been established, sensory qualities have not been well correlated to these process responses. Sensory attributes of extruded corn meal products were investigated and correlated to measured physical properties in this study. Corn meal was extruded in a twin screw extruder (Baker Perkins MPF 50/25; LD ratio 15:1) with step increases in screw speed from 200-400 rpm, and moisture from 16-22%. Principal component analysis (PCA) of main factors from sensory color, crispness, and adhesiveness was correlated to process torque, pressure and temperature. Spatial distribution of process response and product attributes showed crispness to be dependent on extrusion temperature. Porosity and adhesiveness were not correlated to any measured process response. PCA analysis identified significant differences in the effects of moisture and screw speed input to the extruder on product properties.     

Numerical taxonomy of some taxa of the genus Fucus in the Iberian Peninsula

A study of morphological variation patterns in three Iberian Fucus species has been carried out. Data on 36 features from 113 specimens have been studied by numerical methods (PCA, discriminant analysis and ANOVA).The PCA ordination displayed a continuous trend of variation in the following Fucus species: F. ceranoides, F. vesiculosus and F. spiralis. However, no obvious morphological discontinuities have been observed. In addition, three varieties of F. spiralis and five of F. vesiculosus have been identified.At the varietal level discriminant functions could be used for identifying 93–100% of the individuals within F. vesiculosus and 72–91% of F. spiralis.The most discriminating diagnostic character appeared to be the midrib size, as detected by ANOVA procedures.Some qualitative characters, such as presence of vesicles, dioecious-monoecious character and receptacle edge shape, frond and receptacle shape, have been also important for discriminating specific and infraspecific taxa.A nomenclatural discussion of varietal taxa is also included.     

ICP-MS法测定广西金樱根及炮制品中22种金属元素

为建立广西金樱根药材中22种金属元素的电感耦合等离子体质谱(ICP-MS)分析方法,该文对不同产地药材及其炮制品中金属元素含量进行比较分析,评价其药材的质量和优选适当的炮制方法。同时,采用 ICP-MS 法测定22种金属元素含量,绘制其特征金属元素柱状图谱,并采用系统聚类分析和主成分分析对金樱根药材不同产地、不同炮制品的45个样品进行判别研究。结果表明:广西金樱根不同产地药材及其炮制品的45个样品中金属元素含量存在一定差异,其中Al元素含量偏高,经聚类分析和主成分分析将产地分为三类,主成分分析特征元素为Al、Pb、Ba、Zn、As、Sr。该研究通过金属元素在不同产地金樱根及炮制品中的变化规律,发现金樱根醋炙的炮制方法最优,为金樱根的临床安全应用及质量控制提供了理论依据和方法学参考。     

麦类品种对麦双尾蚜自然感虫性的初步观察

在新疆伊犁地区1993年和1994年分别观察了195个和36个麦类品种对麦双尾蚜Diuraphis noxia(Mordvilko)的自然感虫性。36个品种两年的结果进行比较表明,感虫率级别相同的品种有18个,占50%;其中“一粒小麦”稳定地表现为不感虫性;感虫率稳定地表现在20%以下的品种有13个,即“86-2-4-2-3-3”、“京772”、“M85 189”、“T579”、“永良13”、“T494”、“浮纳尔”、 “Mg4521”、 “广引74”、“Mg5824”、“Mg8586”、“T1008”和“短芒黑边红”; 感虫率稳定在20%～40%的品种2个,即“额敏黑芒”和“白长穗”; 感虫率稳定在40%～60%的品种2个,即“黑芒红”和“勾毛白”。其余品种,有14个两年的感虫率相差一个级别（20%）;“黑芒长穗”、“高原602”、“伊宁黄库尔班”和“82-10-42-1-1”等4个品种感虫率相差二个或三个级别。另外,1996年塔城引种试验的2个品种“春麦雄性不育系 901”和“啤酒大麦(石引1号)”均遭受麦双尾蚜的严重为害。     

THE EVOLUTION OF RESISTANCE TO HERBIVORY IN IPOMOEA PURPUREA. I. ATTEMPTS TO DETECT SELECTION

In this study, we looked for evidence of directional or stabilizing/disruptive selection on plant size and on the level of damage (resistance) caused by four types of herbivores in the annual morning glory Ipomoea purpurea. Selection was estimated by standard phenotypic regression analysis and by regression on breeding values. The phenotypic regression analysis revealed directional selection for all five characters (i.e., plant size and resistance to four types of herbivores) and indicated that plant size and resistance to corn-earworm damage were subject to stabilizing selection. By contrast, the analysis using breeding values revealed directional selection only for plant size and resistance to corn earworms, while none of the characters examined indicated stabilizing or disruptive selection. These results suggest that intermediate levels of damage in I. purpurea are, in general, not maintained by stabilizing selection. Rather, they may reflect either 1) a transient state that exists while directional selection pushes the population toward complete resistance (or, in one case, total absence of resistance) or 2) the evolution of susceptibility to damage by genetic drift.     

DISSIMILARITIES IN COGNITION OF FLAVOUR TERMS RELATED TO VARIOUS SENSORY LABORATORIES IN A MULTIVARIATE STUDY

A study of dissimilarities in cognitive perception of 20 common flavor terms was carried out by the Sensory Group of Norway. An average cognitive pattern of the flavor terms was revealed from multidimensional scaling (MDS) and cluster analysis (CLU). In general, small but interesting deviations between different sensory laboratories working with various food products were found by a multivariate pattern recognition technique based on principal component analysis (PCA). Suggestions for finding general reference standards for flavor terms are discussed.     

FORAGING BEHAVIOR OF BOMBUS (HYMENOPTERA: APIDAE) IN RELATION TO AQUILEGIA POLLINATION

Observations on native and cultivated plants indicated that the ruby-throated hummingbird (Archilochus colubris L.) and at least four species of Bombus are probably effective pollinators of Aquilegia canadensis L. in southeastern Wisconsin. Bombus affinis Cresson perforated more than 90% of 2173 nectar spurs of flowers at full anthesis on wild plants. Cinematographic and stereo-photographic records of insects revealed a general behavioral pattern of mandibular perforation following exploration by antennae, maxillae, and tongue. Pollen-foraging behavior on 19 cultivated Aquilegia species and varieties was uniform, but nectar-foraging behavior varied with flower form and position and not with color variation within one flower form. Observations on marked insects showed that workers tended to forage in one manner on one plant variety, while queens foraging in one or more ways visited up to five different flower forms on one flight. Initial observations on neonate workers from a cultivated B. affinis colony suggested that a probably innate mandibular perforation behavior is not instinctively directed toward nectar-bearing floral parts, and that foraging behavior is capable of rapid establishment and considerable versatility.     

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.     

EFFECT OF VARIETAL DIFFERENCES AND POLISHING OF RICE ON QUALITY PARAMETERS OF IDLI

The effect of varietal differences and polishing of rice on quality parameters of “idli,” an Indian fermented product, were studied. In addition, the functional properties of decorticated (whole and split) black gram (Phaseolus mungo Roxb.), were also determined. Two varieties of raw rice, “Jaya” and “Minilong,” and one variety of parboiled rice “Ponni” with two degrees of polishing (high and low) were selected. Idlis were prepared following standard procedures. Variations were observed in water and fat absorption capacities of two black gram samples. Emulsification capacity ranged from 102 to 110 mL/100 g. Foam capacities at different pH range were similar, but foam stability differed as a function of time. The pH of the fermented batter was between 4.1 and 4.8. Rice with a lesser degree of polishing fermented better with higher batter volume and microbial count, lesser shear value and gave softer idlis. However, sensory analysis revealed that idlis prepared with low‐polish rice scored significantly lower for appearance and color quality compared with products prepared with high‐polish rice. Significant differences were observed in the quality of flavor of all products. It can be concluded that the quality characteristics of Idli were influenced by the variety of rice and the degree of polishing, but the two types of black gram used, whole and split, had no effect.     

Phenetics in Tree Peony Species from China by Flower Pigment Cluster Analysis

Paeonia   section Moutan DC. (fifteen accessions) from China. As the pigment markers, five anthocyanins together with three flavone and three flavonol aglycones were used. Principal component analysis (PCA) provided five eigenvectors from nineteen pigment patterns, in which peonidin and cyanidin as well as the types of glycosides greatly influenced the first factor, Z ₁. The Euclidean distances of standardized values obtained by eigenvector matrices with five factors (Z ₁ to Z ₅) produced a dendrogram in Ward's minimum variance cluster analysis, which showed good agreement with a classification based on the morphological characteristics of two subsections Vaginatae F.C. Stern and Delavayanae F.C. Stern. The results obtained by PCA and clustering qualify a chemical classification of section Moutan using secondary metabolites, specifically flower pigments, as taxonomic markers. Received 15 January 2001/ Accepted in revised form 6 April 2001     

Identification of NRRL strain B-18602 (PR3) as Pseudomonas aeruginosa and effect of phenazine 1-carboxylic acid formation on 7,10-dihydroxy-8(E)-octadecenoic acid accumulation

A new compound, 7,10-dihydroxy-8(E)-octadecenoic acid (DOD), produced from oleic acid by a new bacterial isolate PR3, was discovered in 1991. We have now identified isolate PR3 as a strain of Pseudomonas aeruginosa by DNA reassociation studies. Strain PR3 also produced a crystalline yellowish compound the structure of which, as determined by GC/MS and NMR, is phenazine 1-carboxylic acid (PCA). In cultures of PR3, high PCA production was associated with low DOD accumulation.The mention of firm names or trade products does not imply that they are endorsed or recommended by the US Department of Agriculture over other firms or similar products not mentioned.     

Taxonomic discrimination of flowering plants by multivariate analysis of Fourier transform infrared spectroscopy data

Fourier transform infrared spectroscopy (FTIR) provides biochemical profiles containing overlapping signals from a majority of the compounds that are present when whole cells are analyzed. Leaf samples of seven higher plant species and varieties were subjected to FTIR to determine whether plants can be discriminated phylogenetically on the basis of biochemical profiles. A hierarchical dendrogram based on principal component analysis (PCA) of FTIR data showed relationships between plants that were in agreement with known plant taxonomy. Genetic programming (GP) analysis determined the top three to five biomarkers from FTIR data that discriminated plants at each hierarchical level of the dendrogram. Most biomarkers determined by GP analysis at each hierarchical level were specific to the carbohydrate fingerprint region (1,200–800 cm^–1) of the FTIR spectrum. Our results indicate that differences in cell-wall composition and structure can provide the basis for chemotaxonomy of flowering plants.Abbreviations FTIR Fourier transform infrared spectroscopy - GP Genetic programming - PCA Principal component analysis - PyMS Pyrolysis mass spectrometry     

A NUMERICAL–TAXONOMIC STUDY OF THE GENUS BULNESIA (ZYGOPHYLLACEAE): CLUSTER ANALYSIS,ORDINATION AND SIMULATION OF EVOLUTIONARY TREES

Cluster analysis by four methods, ordination by principal component analysis (PCA) and simulation of evolutionary trees (Wagner Trees) were performed on morphological data from 43 characters of eight species of the South American genus Bulnesia (Zygophyllaceae). The results of cluster analysis and principal component analysis in general agree and show that there are three pairs of taxa that appear, or obviously are, closely related. These are the pairs B. arborea–B. carrapo, B. foliosa–B. schickendantzii and B. retama–B. chilensis. These methods also indicate that the southern species B. bonariensis occupies an intermediate position between the pair of northern tropical species (B. arborea, B. carrapo) and the remaining southern species. From the beginning it was assumed that these three multifoliolate species with large flowers may be rather primitive. The Prim network indicates that these three species are closely related among themselves. Also in two of the three Wagner Trees they are placed in a group. In all cases B. sarmientoi is shown as the more remote and isolated of all species. It is regarded as a unique, specialized arboreal species showing extreme reduction in number of leaflets and carpels, leaf and flower size, etc. All graphic representations (Fig. 1–3) show the phenetic similarity or the close phylogenetic relationships of the pairs B. foliosa–B. schickendantzii and B. retama–B. chilensis to each other. These four species would represent a rather advanced group. The most xerophytic species B. retama and B. chilensis are regarded as the most advanced taxa and the most specialized histophysiologically. These occupy extreme and distant positions in PCA diagrams and Prim network, and top positions in the Wagner Trees.     

Application of ultra-performance LC-TOF MS metabolite profiling techniques to the analysis of medicinal <Emphasis Type="Italic">Panax</Emphasis> herbs

The morphological appearance and some ingredients of Panax ginseng, Panax notoginseng and Panax japonicus of the Panax genus are similar. However, their pharmacological activities are obviously different due to the significant differences in the types and quantity of saponins in each herb. In the present study, ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOFMS) was used to profile the abundances of metabolites in the three medicinal Panax herbs. Multivariate statistical analysis technique, that is, principle component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) were used to discriminate between the Panax samples. PCA of the analytical data showed a clear separation of compositions among the three medicinal herbs. The critical markers such as chikusetsusaponin IVa, ginsenoside R0, ginsenoside Rc, ginsenoside Rb1, ginsenoside Rb2 and ginsenoside Rg2 accountable for such variations were identified through the corresponding loading weights, and the tentative identification of biomarkers is completed by the accurate mass of TOFMS and high resolution and high retention time reproducibility performed by UPLC. The proposed analytical method coupled with multivariate statistical analysis is reliable to analyze a group of metabolites present in the herbal extracts and other natural products. This method can be further utilized to evaluate chemical components obtained from different plants and/or the plants of different geographical locations, thereby classifying the medicinal plant resources and potentially elucidating the mechanism of inherent phytochemical diversity.     

Weighted regression analysis for comparing varietal adaptation

Summary The normally used joint linear regression analysis (OLS) is not appropriate for comparing estimates of stability parameters of varieties when the error variances of site means are heterogeneous. Weighted regression analysis (WLS), in these situations, yields more precise estimates of stability parameters. A comparison of the two analytical methods using the grain yield (kg ha^–1) data of 12 varieties and one hybrid of pearl millet [Pennisetum typhoides (Burm.) S. & H.], tested at 26 sites in India, revealed that the weighted regression analysis yields more efficient estimates of regression coefficients (b _i ) than the ordinary regression analysis, and that the standard errors of b _i values were reduced by up to 43%. The estimated b _i differed with the two procedures. The number of varieties with b _i ssignificantly deviating from unity was not only more (five varieties) with weighted regression analysis than the ordinary regression analysis (one variety), but the classification of varieties as possessing general or specific adaptation differed with the two procedures.     

ISOLATION OF HIGH-QUALITY RNA FROM GRAINS OF DIFFERENT MAIZE VARIETIES

The study of gene expression in maize varieties represents a powerful tool aiming to increase vitamin A precursors. However, the isolation of RNA from different maize varieties is challenging because these varieties show different levels of polysaccharides, and most methods available for RNA isolation are inappropriate for grain samples. The polysaccharides co-purify and co-precipitate with RNA during isolation, resulting in low-quality RNA, compromising the use of RNA in subsequent applications. Thus, a cetyltrimethylammonium bromide (CTAB)-based method was adapted in this study and compared with six methods for RNA isolation, including commercial reagents and RNA and DNA isolation kits, in order to identify the most appropriate for maize grains from different varieties. Most of the methods evaluated were considered inadequate due to limitations in terms of purity and/or quantity of the isolated RNA, which affected the efficiency of subsequent RT-qPCR analysis, resulting in nonamplification of β-carotene hydroxylase gene (HYD3) or high deviation among replicates. However, the CTAB modified method allowed the study to obtain intact RNA, with high quality and quantity, from 25 maize varieties. Furthermore, this RNA was successfully used to evaluate the expression of HYD3 gene by real-time qualitative polymerase chain reaction (RT-qPCR), and thus represents a simple, efficient, and low-cost strategy.     

Liquid seaweed extracts identified using <Superscript>1</Superscript>H NMR profiles

Aqueous extracts of Ascophyllum nodosum and several other brown seaweeds are manufactured commercially and widely distributed for use on agricultural crops. The increasingly regulated international trade in such products requires that they be standardized and defined to a degree not previously required. We examined commercially available extracts using quantitative ¹H NMR and principal components analysis (PCA) techniques. Extracts manufactured over a 4-year period using the same process exhibited characteristic profiles that, on PCA, clustered as a discrete group distinct from the other commercial products examined. In addition to recognizing extracts made from different seaweeds, analysis of the ¹H spectra in the 0.35–4.70 ppm region allowed us to distinguish amongst extracts produced from the same algal species by different manufacturers. This result established that the process used to make an extract is an important variable in defining its composition. A comparison of the ¹H NMR integrals for the regions 1.0–3.0 ppm and 3.0–4.38 ppm revealed small but significant changes in the A. nodosum spectra that we attribute to seasonal variation in gross composition of the harvested seaweed. Such changes are reflected in the PCA scores plots and contribute to the scatter observed within the data point cluster observed for Acadian soluble extracts when all data are pooled. Quantitative analysis using ¹H NMR (qNMR) with a certified external standard (caffeine) showed a linear relationship with extract concentration over at least an order of magnitude (2.5–33 mg/mL; R ² > 0.97) for both spectral regions integrated. We conclude that qNMR can be used to profile (or “fingerprint”) commercial seaweed extracts and to quantify the amount of extract present relative to a suitably chosen standard. Issued as NRCC no. 42,652.