Avaliação da aceitação de vinhos brancos varietais brasileiros através de testes sensoriais afetivos e técnica multivariada de mapa de preferência interno

The acceptability of nine commercial brazilian varietal white table wines (Riesling, Chardonnay and Gewürztraminer) was evaluated using sensory affective tests. The samples were assessed by 43 consumers of brazilian white wines using he nine-point structured hedonic scale. Judges were recruited based on their responses to a questionnary about consumer?s behavior towards white wines consumption. Subsequently, Analysis of Variance (ANOVA) with means comparision (Tukey test) and Internal Analysis of Preference Mapping (MDPREF) were performed on data. Analysis of Variance showed that two samples (a Riesling and a Gewürztraminer, both sweet table wines) had significantly (p < 0.05) higher acceptance means, around 7 in the hedonic scale. The least acceptance means (4,3) was obtained by a demi-sec Chardonnay wine and the other six samples achieved means around 5 in the hedonic scale, all of them either demi-sec or dry table wines. MDPREF confirmed the results showed by ANOVA showing that samples were segmented into two groups of preference. The first group was composed by 86% of consumers who prefered the sweet table wines (higher acceptance), converging to the region on the map where these samples were represented. Only 14% showed preference for the demi-sec and dry table wines, being represented on the region of the MDPREF where these samples were located. This study suggests that sweet table wines are prefered by Brazilian consumers, instead of dry or demi-sec table wines.

Perfil sensorial de vinhos brancos varietais brasileiros através de análise descritiva quantitativa

Descriptive terminology and sensory profile of three varieties of brazilian varietal white wines (cultivars Riesling, Gewürztraminer and Chardonnay) were developed by a methodology based on the Quantitative Descriptive Analysis (QDA). The sensory panel consensually defined the sensory descriptors, their respective reference materials and the descriptive evaluation ballot. Ten individuals were selected as judges based on their discrimination, reproducibility and individual consensus with the sensory panel. Twelve descriptors were generated showing similarities and differences among the wine samples. Each descriptor was evaluated using a nine-centimeters non-structured scale with the intensity terms anchored at its ends. The collected data were analysed by ANOVA, Tukey test and Principal Component Analysis (PCA). The results showed a great difference within the sensory profile of Riesling and Gewürztraminer wines, whereas Chardonnay wines showed a lesser variation. PCA separated samples into two groups: a first group formed by wines higher in sweetness and fruitty flavor and aroma; and a second group of wines higher in sourness, adstringency, bitterness, alcoholic and fermented flavors.

Evaluation of the performance of different plastics used to seal nylon cDNA arrays

cDNA arrays are a powerful tool for discovering gene expression patterns. Nylon arrays have the advantage that they can be re-used several times. A key issue in high throughput gene expression analysis is sensitivity. In the case of nylon arrays, signal detection can be affected by the plastic bags used to keep membranes humid. In this study, we evaluated the effect of five types of plastics on the radioactive transmittance, number of genes with a signal above the background, and data variability. A polyethylene plastic bag 69 μm thick had a strong shielding effect that blocked 68.7% of the radioactive signal. The shielding effect on transmittance decreased the number of detected genes and increased the data variability. Other plastics which were thinner gave better results. Although plastics made from polyvinylidene chloride, polyvinyl chloride (both 13 μm thick) and polyethylene (29 and 7 μm thick) showed different levels of transmittance, they all gave similarly good performances. Polyvinylidene chloride and polyethylene 29 mm thick were the plastics of choice because of their easy handling. For other types of plastics, it is advisable to run a simple check on their performance in order to obtain the maximum information from nylon cDNA arrays.