Evaluation of Aglianico grape skin and seed polyphenols astringency by SDS-PAGE electrophoresis of salivary proteins after the binding reaction

SDS–PAGE electrophoresis and densitometry analysis were carried out to evaluate the reactivity of Aglianico red grape skin and seed polyphenols with human salivary proteins in order to find a method able to assess their astringency. Analysis of the supernatant obtained after a tannin/human salivary protein binding assay and sensorial analysis showed that four proteins, lactoferrin, PRPbg1, PRPbg2 and a-amylase, were the proteins best able to distinguish tannin solutions characterised by different levels of astringency. A correlation between densitometric data and tannin concentration was plotted in order to give an indirect measure of astringency. The two sources of Aglianico grape polyphenols differed from each other in astringency power; the seed extract solution was about two-fold more tannic than the skin one. The difference in astringency was also perceived by sensorial analysis. The results from this study show that SDS–PAGE electrophoresis of human salivary proteins after the binding reaction with grape polyphenol extracts, coupled with densitometric analysis and the use of a calibration curve, looks extremely promising as a new approach to evaluate polyphenol astringency

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

Evidence on the effect of the cocoa pulp flavour environment during fermentation on the flavour profile of chocolates

Empirical observations carried out by the first author during his many visits to cocoa producing countries suggested that a relationship might exist between cocoa pulp flavour attributes and sensory traits of cocoa liquor and chocolates. A first attempt to demonstrate such a relationship was made by evaluating the following flavour attributes: volatile aroma upon opening the pods, pulp sweetness, pulp acidity, pulp astringency, pulp flavour intensity and type, overall preference for pulp taste, and degree of bitterness of the cotyledon. Blind pulp tasting was carried out by a six-person panel of ripe fruits of nine cocoa clonal varieties, representing different genetic origins, several of which are well known for their contrasting sensory traits of their chocolates. Overall pulp preference was significantly related to the known fine flavour potential of the cocoa varieties tested, whereas specific pulp flavour attributes appeared related to specific types of fine flavour of the tested cocoa genotypes. One striking example was the EET 62 clone (Nacional x Trinitario), which displayed a "jasmine" flower odour upon opening the ripe fruit, sweet pulp with an intensive pleasant flavour that was identified as floral and fruity. These flavour attributes are apparently related to the known typical "Arriba" flavour of the EET62 clone. The typical fresh-fruit Trinitario cocoa flavour of the ICS 1 clone appeared to be related to a balanced combination of relatively high acidity and sweetness and a moderate citrus-like flavour of its pulp. On the other side, the pulp of the potentially low-flavour CCN51 clone was rated as very astringent and acid, with low flavour intensity and quality. The pulp of the Pandora 1 clone from Colombia was characterised by a sour sop (Guanabana) flavour and may therefore represent a new interesting type of fine-flavour cocoa. These results suggest that a significant part of fine-flavour attributes of cocoa products (excluding basic cocoa flavour) can be related to sensory traits identifiable in the pulp of ripe cocoa pods. The effect of the pulp flavour environment on the taste of chocolates was further experimentally demonstrated by adding equal quantities of aromatic pulp of two tropical fruit species (Theobroma grandiflorum and Anona muricata) with Amelonado beans during the fermentation process. The chocolates obtained by this method revealed the 2 presence of the typical flavour attributes of T. grandiflorum and A.muricata. This shows that the added aromatic compounds are absorbed by the cocoa cotyledon during the fermentation process. An amateur public in Montpellier, France, showed high levels of preference for the chocolates that had acquired flavours of T. grandiflorum and A. muricata in comparison to that of the pure Amelonado control treatment. The combined findings suggest that: 1) Rapid screening of germplasm and of breeding populations for pulp characteristics can be attempted to select cocoa varieties that display good potential for known as well as for new fine flavor traits, 2) Chocolate flavors can be modified substantially by adding aromatic substances to cocoa beans during the fermentation process. The further development of such an innovative way to produce cocoa liquors and chocolates with enhanced and/or modified flavour profiles is expected to have important commercial applications. It would also provide new opportunities for the use of aromatic tropical fruit pulps that are often under-utilized and under-valued. (Résumé d'auteur

Predicting the composition of red wine blends using an array of Multicomponent peptide-based sensors

Differential sensing using synthetic receptors as mimics of the mammalian senses of taste and smell is a powerful approach for the analysis of complex mixtures. Herein, we report on the effectiveness of a cross-reactive, supramolecular, peptide-based sensing array in differentiating and predicting the composition of red wine blends. Fifteen blends of Cabernet Sauvignon, Merlot and Cabernet Franc, in addition to the mono varietals, were used in this investigation. Linear Discriminant Analysis (LDA) showed a clear differentiation of blends based on tannin concentration and composition where certain mono varietals like Cabernet Sauvignon seemed to contribute less to the overall characteristics of the blend. Partial Least Squares (PLS) Regression and cross validation were used to build a predictive model for the responses of the receptors to eleven binary blends and the three mono varietals. The optimized model was later used to predict the percentage of each mono varietal in an independent test set composted of four tri-blends with a 15% average error. A partial least square regression model using the mouth-feel and taste descriptive sensory attributes of the wine blends revealed a strong correlation of the receptors to perceived astringency, which is indicative of selective binding to polyphenols in wine

Wine Fining with Plant Proteins

: Fining treatments involve the addition of a substance or a mixture to wine, and are generally carried out in order to clarify, stabilize or modify the wine\u2019s organoleptic characteristics. Usually these fining agents will bind the target compound(s) to form insoluble aggregates that are subsequently removed from the wine. The main reasons to perform wine fining treatments are to carry out wine clarification, stabilization and to remove phenolic compounds imparting unwanted sensory characteristics on the wine, which is an operation that often relies on the use of animal proteins, such as casein, gelatin, egg and fish proteins. However, due to the allergenic potential of these animal proteins, there is an increasing interest in developing alternative solutions including the use of fining proteins extracted from plants (e.g., proteins from cereals, grape seeds, potatoes, legumes, etc.), and non-proteinaceous plant-based substances (e.g., cell wall polysaccharides and pomace materials). In this article, the state of the art alternative fining agents of plant origins are reviewed for the first time, including considerations of their organoleptic and technological effects on wine, and of the allergenic risks that they can pose for consumer

Investigation of taste tainting in salmon flesh in the Ribble catchment

This report presents the findings of the first phase of an investigation into the cause(s) of taints in salmonid fish in the River Ribble, commissioned by the North West Region of the Environment Agency. There have been reports of tainting in fish taken from both the estuary and the freshwater river for many years, but the contaminants involved and their source and transport pathway are unknown. Tainting by phenols has been of specific concern in the past. The work programme comprised: examination of tainting reports; collection of salmonids; their submission for taste testing; literature review; analysis of fish flesh using gas chromatography-mass spectrometry (GCMS) and analysis of river bed sediments. From enquiries, three common descriptors of the 'taint' were identified: disinfectanty; diesely; and muddy. The incidence of taints appears transient/irregular and may therefore relate to the incidence of discharges and specific threshold concentrations of pollutants. The literature review showed that a wide range of organic compounds including many industrial chemicals, and others which are naturally occurring, can taint fish flesh. Taste testing confirmed the presence of tainted salmon and trout in the Ribbie Catchment. It identified a low incidence of 'untainted' fish but demonstrated the 'taint' to be not specific to one tainting substance. Differences were found both between the species and fish from different parts of the catchment. Overall, most fish exhibited an unpleasant flavour, though this may have been influenced to some extent by the fact that most were sexually mature. The worst tainting was found in trout from the river Calder: a soapy/chemical aftertaste. An unpleasant earthy/musty flavour distinguished the salmon from the trout. Phenol was shown to have been a minor issue during the present study, whilst no hydrocarbon taints were identified. Examination of tissue from the eight salmon exhibiting the worst taints revealed the presence of aromatic hydrocarbons, but no phenolic compounds. Other notable substances present in the fish were siioxanes and benzophenone. Data from sediment analysis is presented which shows the main compounds present to be aromatic and polyaromatic hydrocarbons, that concentrations at two locations R. Darwen and R. Calder were significantly higher than at other sites, and that some phenolic compounds were detected at low levels. A paucity of fish flesh taste descriptors linked to specific compounds prevented an obvious correlation to be made between the tastes observed and the organic compounds detected. Descriptors frequently used by the taste testing panel (e.g. earthy, musty, astringency, chemical) cannot be linked to any of the compounds identified in the tissue analyses. No taste information was available from the literature on siioxanes. Aromatic hydrocarbons though present in tissue and sediments were not identified as tainting

Changes in Procyanidins and Tannin Concentration as Affected by Cocoa Liquor Roasting

Changes in cocoa procyanidins and tannin concentration as affected by cocoa liquor roasting were studied by heating up cocoa liquor of fermented beans containing 58 g kg-1 of polyphenols and the same liquor which was enriched with crude polyphenols, extracted from freeze-dried unfermented cocoa beans to a final concentration of 170 g kg-1. The liquors were roasted at 120 OC for 15, 25, 35 and 45 min with three replications. Result of the study showed that cocoa bean polyphenol was resistant against high temperature during heating of cocoa liquor 120 OC for up to 45 min. The resistance was stronger with the unfermented cocoa bean polyphenol than with fermented cocoa. High temperature promoted a small quantity of monomers up to pentamers of the fermented cocoa bean polyphenol to polymerize into higher oligomers, but did not with unfermented cocoa bean polyphenol. These results imply that the problem of lack in cocoa flavor in terms high astringency and bitterness due to high polyphenol content cannot be overcome by the application of high temperature during chocolate processing, meanwhile cocoa bean polyphenol could still give beneficial as an antioxidant even after high temperature application

A new wine tasting approach based on emotional responses to rapidly recognize classic european wine styles

Conventional tasting sheets are widely used to evaluate wine quality in wine tasting competitions. However, the higher scores are mostly obtained by international commercial wines, resulting in lower scores being awarded to the classic Europeanwines. We hypothesize that this is due to the tasting methodology that fails to recognize this wine style. Therefore, the purpose of this work was to show the implementation of a new wine tasting approach to overcome this drawback. The proposed training technique is based on the emotional responses of the taster after smelling two wines of clearly opposite styles. The first wine is characterized by high aromatic intensity but low in-mouth intensity, perceived as disappointing to the taster, here defined as an “easy” wine. The second wine is characterized as a wine with low aromatic intensity but that provides an unexpectedly positive in-mouth experience, here defined as a “difficult” wine. These emotions are explained by the wine sensorial characteristics. The “easy” wine has an intense, simple smell with short persistence while the “difficult” wine has a low intensity, complex aroma, and long persistence. The first style corresponds to the international commercial wines most prized in international wine challenges. The second, frequently rejected by untrained tasters, is consistent with the “so called” classic European wines, and is characterized by light red or yellow straw colors, weak smell intensity, and aggressive mouth-feel. After no more than four training sessions and using the OIV tasting sheet, inexperienced tasters were able to score “difficult” wines equally as “easy” wines and understand their different attributes. In conclusion, this new tasting approach may be used by wine professionals to explain the characteristics of high quality wines that are not easily recognized by untrained consumersinfo:eu-repo/semantics/publishedVersio

Correlating wine quality indicators to chemical and sensory measurements.

Twenty-seven commercial Californian Cabernet Sauvignon wines of different quality categories were analyzed with sensory and chemical methods. Correlations between five quality proxies-points awarded during a wine competition, wine expert scores, retail price, vintage, and wine region-were correlated to sensory attributes, volatile compounds, and elemental composition. Wine quality is a multi-faceted construct, incorporating many different layers. Depending on the quality proxy studied, significant correlations between quality and attributes, volatiles and elements were found, some of them previously reported in the literature