The Effect of Haptic Feedback on Basic Social. Interaction within Shared Virtual Environments

This paper describes an experiment that studies the effect of basic haptic feedback in creating a sense of social interaction within a shared virtual environment (SVE). Although there have been a number of studies investigating the effect of haptic feedback on collaborative task performance, they do not address the effect it has in inducing social presence. The purpose of this experiment is to show that haptic feedback enhances the sense of social presence within a mediated environment. An experiment was carried out using a shared desktop based virtual environment where 20 remotely located couples who did not know one another had to solve a puzzle together. In 10 groups they had shared haptic communication through their hands, and in another group they did not. Hence the haptic feedback was not used for completing the task itself, but rather as a means of social interacting – communicating with the other participant. The results suggest that basic haptic feedback increases the sense of social presence within the shared VE

Multivariate analysis of sensory data of Vitis vinifera L. cv. Graciano during ripening. Correlation with the phenolic composition of the grape skins

The aim of this work was to evaluate sensory changes in grape skins during ripening and to obtain a correlation with their phenolic composition. Flavan-3-ols (monomers and dimers), prodelphinidins, hydroxybenzoic acids, hydroxycinnamic acids, anthocyanins and flavonols were determined by HPLC-DAD-MS. In addition, skin dilaceration, tannic intensity, astringency, acidity, aroma intensity (AI) and type of aroma were evaluated. Multivariate analysis showed the evolution of these samples during ripening and the relationship among sensory scores and phenolic composition of grapes skins. Skin dilaceration, type of aroma and to a lesser extent AI tend to increase during ripening. The contents in the phenolic compounds in grape skins present a similar pattern to the aforementioned sensory parameters. Nevertheless, tannic intensity, astringency, dryness and acidity present an opposite pattern which indicates a decrease of these sensory scores during ripening.Ministerio de Ciencia e Innovación AGL2008-05569-C02-01Consolider-Ingenio 2010 Programme CSD2007-0006

Inhibitory effect of quinoa and fenugreek extracts on pancreatic lipase and α-amylase under in vitro traditional conditions or intestinal simulated conditions

Ethanol extracts (EE) from fenugreek and quinoa seeds with different total content of inhibitory compounds (TIC, total saponin plus phenolic) were prepared with and without concentration of TIC (CEE –concentrated EE-, and EE, respectively). Their inhibitory activity on pancreatic lipase and α-amylase was assessed by traditional in vitro methods (with or without orbital shaking), and by simulating intestinal digestion. CEE contained higher contents of TIC than EE, being fenugreek superior to quinoa (p < 0.001). The extracts inhibited enzymes in a dose-dependent manner, CEE extracts being stronger (fenugreek for lipase -p = 0.009-, and quinoa for α-amylase -p < 0.001-). Shaking did not impact the activity. Intestinal conditions worsened the inhibition of lipase, but slightly catalyzed the α-amylase. Longer times of reaction worsened activities. The importance of assessing the inhibitory activity of extracts under simulated intestinal conditions is concluded, being fenugreek more interesting than quinoa, especially against pancreatic lipaseThis work was supported by the Ministerio de Economía y Competitividad, Spain (AGL2016-76736-C3-1-R) and the Community of Madrid, Spain (ALIBIRD-CM S2013/ABI-2728

Sensory evaluation of bitterness and astringency sub-qualities of wine phenolic compounds: synergistic effect and modulation by aromas

[EN] Mouthfeel characteristics of wine phenolic compounds (catechin, epicatechin, coumaric acid, caffeic acid, protocatechuic acid and gallic acid) were evaluated by sensory analysis using a Labeled Magnitude Scale for rating the intensity of the perceived sensations. Synergisms on bitterness and on astringent sub-qualities were detected when the phenolic compounds were tested as mixtures in comparison to individual compounds, maintaining the total amount of stimulus constant in all tasted samples. Principal component analysis was applied to observe trends in the data and to indicate relationships between phenolic substances and sensory attributes. It allowed us to easily visualize the synergistic effect discussed above. To our knowledge, this is the first time that astringency synergism between phenolic compounds has been described. This research also shows that wine aromas may modulate the perception of the astringency. In this study, the addition of volatile compounds increased the intensity of the astringent perception of the flavanol solutions and also its persistence

Evaluation of sensory parameters of grapes using near infrared spectroscopy

[EN] Grape seed and skin sensory parameters are important characteristics in making decisions concerning the optimal harvest time and producing high-quality red wines. The potential of near infrared spectroscopy to determine several sensory parameters of seeds and skins was evaluated. Taste (sourness), texture (astringency, tannic intensity, dryness and hardness), visual (colour) and olfactory (intensity and type of aroma) attributes were considered. Calibration models were performed by modified partial least squares regression. The differences between sensory analysis and NIRS analysis in external validation were lower in the case of seeds; they were between 4.5% for hardness and 8.7% for colour. For the skins, differences in external validation were between 9.8% for tannic intensity and 13.7% for astringency. The results obtained show that NIRS technology has considerable potential for predicting the above sensory attributes

Feasibility study on the use of near infrared spectroscopy to determine flavanols in grape seeds

[EN] The potential of near infrared spectroscopy to determine the content of flavanols directly recording the infrared spectra of grape seeds has been evaluated. Moreover, the study shows the potential of this technique to obtain qualitative information related to the samples. In this case, the feasibility to discriminate between possible vineyards of origin has also been evaluated. Modified Partial Least Squares (MPLS) regression was used to develop the quantitative models in order to predict the content of flavanols. These models have been validated showing differences between 3.5% and 14.3% in the external validation. Moreover, Discriminant Partial Least Squares algorithm was used in the qualitative analysis to distinguish between two possible vineyards of origin and showed a high degree of accuracy. Prediction rates of samples correctly classified with a mean of 95% in internal validation and 97% in external validation were obtained. The procedure reported here seems to have an excellent potential for a fast and reasonably inexpensive analysis of these flavanols in grape seeds and could also be a tool to distinguish between possible vineyards of origin

Influence of the physiological stage and the content of soluble solids on the anthocyanin extractability of Vitis vinifera L. cv. Tempranillo grapes

[EN] The influence and the extent of the anthocyanin extractability from grape skins at different physiological stages and different soluble solids contents within each stage were investigated. For this purpose three different physiological stages (pre-harvest, harvest and over-ripening) and three soluble solids contents (22, 24 and 26 °Brix) within each stage were taken into account using Vitis vinifera L. cv. Tempranillo. This study revealed the influence of physiological stages and soluble solids contents on the amounts of anthocyanins. The most important factor was the physiological stage although the soluble solid contents effect was also relevant, especially for anthocyanins monoglucosides. The highest contents in anthocyanins were found at pre-harvest, following by harvest and finally at over-ripening. Within each physiological stage, the relative abundance of acylated derivatives was influenced by the soluble solids contents. The percentages of acylated anthocyanins tend to decrease as the soluble solids contents. Differences in the anthocyanin extractabilities were highly influenced by the physiological stages and in a lesser extent by the soluble solids contents. The lowest extraction percentages were obtained in pre-harvest samples whatever soluble solids contents. Over-ripening samples present the lowest contents of anthocyanins but these compounds are easily released from tissues to the hydroalcoholic solution providing the highest extraction percentages. Generally, non-acylated anthocyanins were better extracted than the acylated anthocyanins

Determination of phenolic compounds of grape skins during ripening by NIR spectroscopy

[EN] The potential of near infrared spectroscopy (NIRS) to determine the content of phenolic compounds in red grapes has been evaluated. The near infrared spectra of intact grapes and grape skins throughout maturity were recorded using a fibre-optic probe and a transport quartz cup, respectively. Reference values of phenolic compounds were obtained by HPLC-DAD-MS. Modified Partial Least Squares (MPLS) regression was used to develop the quantitative models for flavanols, flavonols, phenolic acids, anthocyanins and total phenolic compounds. The procedure reported here seems to have an excellent potential for fast and reasonable cost analysis. The results of this work show that the models developed using NIRS technology together with chemometric tools allow the quantification of total phenolic compounds and the families of main phenolic compounds in grape skins throughout maturation. The validation of these models showed the best results for the determination of flavonols (differences between HPLC and NIRS of 7.8% using grapes and 10.7% using grape skins) in the external validation procedure. Good results in the external validation were also obtained for the determination of total phenolic compounds (differences of 11.7% using grapes and 14.7% using grape skins). The best results were generally obtained recording the spectra directly in intact grapes

Colour and pigment composition of red wines obtained from co-maceration of Tempranillo and Graciano varieties

[EN] The Vitis vinifera L. cv Graciano is often used as an integral component of Rioja wines because it is considered to contribute significantly to the quality of Tempranillo based wines. The aim of this work was to determine the effect of the incorporation of the Graciano variety on the colour and pigment composition of Tempranillo based wine and to evaluate the possible differences between blending Tempranillo with Graciano varietal wine (W wine) in contrast to a wine obtained by mixing these two grape varieties in the prefermentative maceration step (M wine). Results indicated that pigment extraction and retention in M wine was higher than in Tempranillo (T) wine. Colour differences (DeltaE(ab)(*)) between wines at the end of the study (after 12 months in bottles) were detectable by the human eye (DeltaE(ab)(*) > or = 3) in all cases except for T and W. These wines have indistinguishable colours even when using analytical methods (DeltaE(ab)(*) < or = 1). Regarding hue h(ab), T and W presented higher values (more orange-red) than Graciano (G) and M (more blue-red). PCA allowed the colour and composition analytical data to be reduced to a small number of principal components that could separate successfully between T and G wines and between the different steps of the winemaking process

Extractability of Low Molecular Mass Flavanols and Flavonols from Red Grape Skins. Relationship to Cell Wall Composition at Different Ripeness Stages

[EN] Flavonol and flavan-3-ol extractabilities from red grape skins were evaluated in Tempranillo grapes harvested at different ripeness stages and with different soluble solid contents within each stage. Flavan-3-ol extractability is related to ripeness stage and also to cell wall composition, mainly to arabinogalactans (AG), mannans, rhamnogalacturonans-I (RG-I), homogalacturonans (HG), xyloglucans (XG), and total polysaccharides content, which are negatively correlated to flavan-3-ol extractability, whereas soluble solid content did not exert any influence on their extraction. Moreover, procyanidin extraction is more strongly related to cell wall composition than prodelphinidin extraction. Flavonol extractability was not influenced by insoluble material contents; although some cell wall components presented a relationship with flavonol extractability, the presence of AG and mannans would decrease total flavonol extractability, whereas protein is positively related to total and major flavonol compounds (i.e., quercetin and myricetin derivatives). The different behaviors observed between those two groups of polyphenol compounds could be due to different tissue and cellular location