An integrative salivary approach regarding palate cleansers in wine tasting

Authentication of selected white wines by geographical origin using ICP spectrometric and chemometric analysis

An important aspect of assessing the authenticity of wines is its geographical origin. The aim of the work is to authenticate by geographical origin according to the data of the ICP-spectrometric and chemometric analysis of elemental "images" of wines produced from white grape varieties Chardonnay, Riesling and Muscat grown in four regions of the Krasnodar Territory, Russia. The difference in the contents of Al, Ba, Ca and Rb in wines was found depending on the variety, and Al, Ba, Rb, Fe, Li, Sr - depending on the region of grape growth. Different models of the experimental data processing were used for attribution of the produced varieties of wine to the area of the grape's growth. The criterion for the quality of the constructed models was the accuracy of the attribution of a wine variety to the area of the grape's growth (%). Analysis of the elemental analysis data of 153 wine samples showed that in terms of attribution accuracy, automated neural networks (100 %) are preferred among machine learning methods, followed by support vector machines (98.69 %) and general discriminant analysis (94.77 %). The applied mathematical models enabled the revealing of the cluster structure of the analyzed wine varieties and their attribution to the area of a grape growth with high accuracy. Sr, Li and Fe concentrations in wines were found as the dominating predictors in the constructed models for definition of the geographical origin of wines. The combination of ICP-spectrometric analysis data with the capabilities of statistical modeling of machine learning methods focused on large-dimensional data made it possible to successfully solve small-dimensional problems of the definition of the geographical origin of wines by their elemental composition and variety.

Multidimensional analysis of the interaction of volatile compounds and amino acids in the formation of sensory properties of natural wine

The content of free amino acids and aroma compounds present in wine and dependent on the grape variety, conditions of its growing and technology of production form its consumer properties. In this paper, the structure of interactions of amino acids and volatile organic compounds in 150 samples of natural dry red and white wines produced in the Krasnodar region, Russia, (2010-2013) was studied. The aim of this work was to comparatively evaluate the contribution of volatile compounds and amino acids to the sensory properties of wines by using regression, canonical, covariance, factor analyses, as well as principal component analysis. The list of volatile compounds, i.e., acetaldehyde, ethyl acetate, methanol, the total content of higher alcohols, acetic acid, and furfural, and such amino acids as arginine, proline, threonine was selected based on their influence on sensory properties of wines. The concentrations of volatile compounds and amino acids in wines were determined by gas chromatography and capillary electrophoresis, respectively. Sensory evaluation was conducted by experts with professional experience in wine tasting. Application of statistical methods allowed to establish intra- and inter-group correlations among amino acids and volatile compounds as well as between the groups of these compounds, which determined sensory properties of wines. More than 80% of the variability of the sensory assessment of wines is determined by the degree of relationship between the selected amino acids and volatile compounds; the contribution of amino acids to this indicator is 4.5-fold higher. The results obtained can be used to predict the sensory assessment of red and white wines based on the levels of volatile compounds and amino acids.

Current Perspectives on Food Oral Processing

Food oral processing (FOP) is a fast-emerging research area in the food science discipline. Since its first introduction about a decade ago, a large amount of literature has been published in this area, forming new frontiers and leading to new research opportunities. This review aims to summarize FOP research progress from current perspectives. Food texture, food flavor (aroma and taste), bolus swallowing, and eating behavior are covered in this review. The discussion of each topic is organized into three parts: a short background introduction, reflections on current research findings and achievements, and future directions and implications on food design. Physical, physiological, and psychological principles are the main concerns of discussion for each topic. The last part of the review shares views on the research challenges and outlooks of future FOP research. It is hoped that the review not only helps readers comprehend what has been achieved in the past decade but also, more importantly, identify where the knowledge gaps are and in which direction the FOP research will go.

Astringency Sensitivity to Tannic Acid: Effect of Ageing and Saliva

Astringency is an important sensory characteristic of food and beverages containing polyphenols. However, astringency perception in elderly people has not been previously documented. The aim of the present work was to evaluate sensitivity to astringency as a function of age, salivary flow and protein amount. Fifty-four panellists, including 30 elderly people (age = 75 ± 4.2 years) and 24 young people (age = 29.4 ± 3.8 years), participated in this study. Astringency sensitivity was evaluated by the 2-alternative forced choice (2-AFC) procedure using tannic acid solutions. Whole saliva was collected for 5 min before and after the sensory tests. The results showed that the astringency threshold was significantly higher in the elderly group than the young group. No correlation was observed between the salivary protein amount and threshold value. However, a negative correlation between salivary flow and threshold was observed in the young group only. These results showed a difference in oral astringency perception as a function of age. This difference can be linked to salivary properties that differ as a function of age.

Data on the sensory evaluation of the dry red and white wines quality obtained by traditional technologies from European and hybrid grape varieties in the Krasnodar Territory, Russia

The analysis of data on the sensory evaluation of the quality of wines obtained using traditional technologies in the Krasnodar Territory, Russia, was carried out using the statistical ranking criteria - the Spearman and Kendall correlation coefficients, as well as the positional analysis - Cronbach's alpha. Data on the sensory evaluation of 60 samples of natural dry red and white wines are presented, among which 20 are white wines, 40 are red wines produced in 2010-2015. Eleven specialists aged between 32 and 66 years (the average age was 50 years; 4 females and 7 males) participated in the sensory evaluation procedure. All participants are considered experts in the field of wine, work in the wine industry and have professional experience in the field of sensory analysis. The results of the consistency study of expert evaluations, the reliability of the general score scale, as well as the analysis of the loyalty of experts in the wine quality assessment are presented in the article. The reliability of the proposed loyalty scale is shown, i.e., the scale of the sum of scores given by each expert in the evaluation of the quality of wines. The database on the sensory evaluation of the quality of wines, obtained for all wine samples using positional analysis, makes it possible to assess the contribution of each of the 60 wine samples to their ranking by mean scores. The data may be of interest to scientists and oenologists for the wine quality assessment.

Rescuing Flavor Identity and Dynamic Perception in Puréed Dishes; A Restructuring Solution for the Purée Diet

With age, difficulties with masticating and swallowing means food consistency and structure must be modified, such as puréeing food. However, elderly consumers have reported that puréed food’s taste lacks appeal. This study shows how puréeing food changes the recognition and dynamics of flavors and new strategies to improve them. Further, to measure the identification and dynamics of flavor, a new sensory method was investigated that combined Free Choice and Temporal Order of Sensation (Free-TOS). Three dishes (macaroni, pizza, and potato salad), their purées, and three pasta purées with added flavors (cheese and dry-cured ham; added directly or as an oil in water emulsion or using two types of emulsions (oil in water and water in oil) were assessed by three groups of 60 consumers using Free-TOS. Results showed that in the purée the frequency of mentioned sensations decreased compared with the dish, as it was more difficult to identify flavors. Adding flavors in powder form only allowed a cheese/ham flavor identification, but in the purées with emulsions, it was possible to identify the dry-cured ham flavor. Therefore, this study showed that the Free-TOS method does not need a predetermined attribute list and registers the actual identified flavors and their order of appearance.

Study of consistency of expert evaluations of wine sensory characteristics by positional analysis

Individual characteristics inherent in the expert, as well as their physical and psycho-emotional state subject to the influence of random, uncontrollable factors, contribute to subjectivity in the sensory evaluation of wines. With great variability of opinions, the final results of sensory evaluation may become doubtful. The presence of a random component in the sensory evaluation justifies the use of statistical methods for analyzing the consistency of expert evaluations. Along with Spearman's correlation coefficients and Kendall matching, Cronbach alpha criterion was used to assess the consistency of expert opinions. The advantages of positional analysis have been discussed – Cronbach's alpha criterion is calculated not by the rank of expert points, but by the initial point scale considering its variability; it allows to evaluate the contribution of each expert to the consistency of expert evaluations, as well as the reliability of the total scale of points set for each wine sample. Based on the data analysis from sensory evaluation of the quality of dry red and white wines of Russian production, the results of the consistency study of expert evaluations as well as the reliability of the total score scale have been presented. What is more, analysis of the “loyalty” of experts in evaluating the quality of wines has been performed.

Oral Wine Texture Perception and Its Correlation with Instrumental Texture Features of Wine-Saliva Mixtures

Unlike solid food, texture descriptors in liquid food are scarce, and they are frequently reduced to the term viscosity. However, in wines, apart from viscosity, terms, such as astringency, body, unctuosity and density, help describe their texture, relating the complexity and balance among their chemical components. Yet there is uncertainty about which wine components (and their combinations) cause each texture sensation and if their instrumental assessment is possible. Therefore, the aim of the present work was to study the effect of wine texture on its main components, when interacting with saliva. This was completed by using instrumental measurements of density and viscosity, and by using two types of panels (trained and expert). For that, six different model-wine formulations were prepared by adding one or multiple wine components: ethanol, mannoproteins, glycerol, and tannins to a de-alcoholised wine. All formulations were mixed with fresh human saliva (1:1), and their density and rheological properties were measured. Although there were no statistical differences, body perception was higher for samples with glycerol and/or mannoproteins, this was also correlated with density instrumental measurements (R = 0.971, p = 0.029). The viscosity of samples with tannins was the highest due to the formation of complexes between the model-wine and salivary proteins. This also provided astringency, therefore correlating viscosity and astringency feelings (R = 0.855, p = 0.030). No correlation was found between viscosity and body perception because of the overlapping of the phenolic components. Overall, the present results reveal saliva as a key factor when studying the wine texture through instrumental measurements (density and viscosity).