Effect of Different Crown Cap Closures on Phenolics and Sensory Attributes of Bottle-Fermented Sparkling Wines

Bottle-fermented sparkling wine producers are continuously striving to increase quality and produceniche products. One production tool that could be used is a cork closure instead of a crown cap closureduring the second fermentation and maturation on yeast lees. Anecdotal evidence suggests that thisleads to stylistic differences in the wine. Six pairs of South African bottle-fermented sparkling wines(Méthode Cap Classique), closed by either a cork or crown cap, were investigated. Analyses includedbottle pressure, infrared spectroscopy, phenolic acids, sensory attributes and CO2 kinetics. Generally,there were differences between the cork-closed and crown-capped wines. Cork-closed wines tended tohave lower pressure compared to crown-capped wines, albeit still well within legal requirements. Otherdifferences were evident in the infrared spectral data and in the polyphenol profile of the analysed wines.Levels of gallic, caftaric, caffeic and p-coumaric acids could be used collectively as marker compounds todifferentiate between cork-closed and crown-capped wines. The effect of the cork was also evident in thesensory attributes and CO2 kinetics. Cork-closed wines were judged to have smaller bubbles and a longeraftertaste. It was also shown that the cork-closed wines tended to lose CO2 from the glass slower after beingpoured than their crown-capped counterparts. The data tentatively support the anecdotal evidence thatcork can be used during the second fermentation and maturation on the yeast lees to change the style ofbottle-fermented sparkling wine.

Coffee trade is a billion-dollar industry and coffee remains one of the most traded commodities of economic importance to both the countries producing, and the countries consuming coffee. To ensure demand, it is of great importance to constantly maintain and, where possible, improve its quality. Flavour is crucial to coffee quality. However, describing coffee flavour is a very complex task as it is influenced by numerous factors from the farm to cup. These factors influence compositional properties of coffee and have a large impact on the perceived flavour. The ultimate aim of this project was to understand how different components in coffee influence flavour perception. The approach involved an exploration on the sensory and physicochemical profiles of sensorily diverse 26 commercial single origin ‘specialty’ coffees. Sensory evaluation of these 26 selected coffees involves assessment on the brews while coffee ground and extracts were analysed for physicochemical profiles. An analytical method was developed and applied for rapid quantification of the targeted volatiles compounds in coffee. The results of sensory and physicochemical evaluation were modelled using a multivariate analysis to explore the relationship between attributes and to know potential sensory markers that could contribute to coffee flavour. Coffee proved to be a highly challenging matrix to study and required special preparation and presentation of individual samples at consistent temperature during sensory evaluation. Nevertheless, sensory profiles for the diverse range of coffees was achieved. Certain coffees were clearly distinctive: Ethiopian coffees registered fruity, citrus and aromatic spice sensory profile notes, Australian coffees exhibited milder profiles, while India Robusta coffees generally possess smoky, woody, earthy and cereals profile. Three analytical stable isotope dilution analysis/gas chromatography-mass spectrometry (SIDA/GC-MS) methods were developed and applied to quantify 27 key volatile compounds which were targeted due to their reported importance to coffee flavour. These methods involved a headspace-solid phase microextraction/gas-chromatography (HS-SPME/GC-MS) of coffee, steam distillation extraction of coffee followed by a HS-SPME/GC-MS and direct liquid injection of a steam distilled extract of coffee to GC-MS. The 26 medium-roasted single origin coffees investigated were quite diverse in physicochemical properties. It was clear that some coffees showed distinct physicochemical characters, for example, Robusta coffee contained doubled the caffeine content, higher concentrations of dicaffeoylquinic acids (diCQAs), higher pH, and higher L* value (a measure of lightness) but was lower in crude fat and trigonelline than the Arabica coffees. Principal component analysis (PCA) and partial least squares (PLS) regression were used as multivariate modelling techniques using compositional variables to mathematically predict coffee sensory attributes scoring. The models could be validated (Rv2≥0.4) for sensory attributes: aroma intensity, citrus, earthy, sourness, bitterness, flavour intensity and residual. For example: the prediction of sourness using caffeic acid, titratable acidity (TA), L* value and pyrazines; the prediction of citrus using ketones and aldehydes. The results indicated that those chemical components could be potential and contribute to certain sensory attributes of coffee. An additional study was conducted on the evolution of important chlorogenic acids from the green coffee beans to the coffee brews and to know the potential role to coffee flavour, specifically to volatile phenols. Chlorogenic acids were progressively lost during coffee processing with approximately only a fifth of the level in green coffee beans remains in a cup of coffee. The evolution of chlorogenic acids during coffee processing involves biochemical degradation and synthesis pathway that include acyl migration, isomerisation, lactonisation, epimerisation, hydrolysis, and polymerisation mechanism. Since there was no relationship found between the volatile phenols and chlorogenic acids, further investigation on the contribution of chlorogenic acids to coffee flavour will be beneficial. Since not all important components of coffee have been measured in this study, not every predictive model performed well. However, this is the first study to investigate sensory and physiochemical properties of a broad range of commercially diverse single-origin ‘specialty’ coffees as well as to quantify volatile monoterpenes especially geraniol. This study provided a new knowledge on an Australian coffees and specific coffee types such as Indonesia Luwak (Arabica) and Indian Monsooned Malabar. The present study also provides some interesting insight on coffee flavour. It has shown the potential for further coffee and flavour researches while offering advantages for industrial applications.

Spanish grape varieties that have been traditionally used to produce still wines were examined for their potential to make white and rosé sparkling wines. Sparkling wines manufactured from <i>Vitis vinifera</i> cv. Verdejo, Viura, Malvasía, Albarín, Godello, Garnacha, and Prieto varieties were examined for sensory attributes and for the evolution of monomeric and polymeric phenolics during different stages of winemaking and aging. Stabilization and clarification of the base wines significantly decreased the concentrations of anthocyanins and proanthocyanidins. During the initial months of aging on yeast lees, all types of polyphenols decreased, although some were released back into the wine during the final months. Garnacha rosé and Albarín white wines had high phenolic potential. Garnacha rosé sparkling wines had particularly high hydroxycinnamic acid concentrations, while Prieto Picudo rosé sparkling wines had the highest color intensity and anthocyanin concentrations. Among white sparkling wines, Albarín had the most catechin, proanthocyanidins, and, together with Viura, hydroxycinnamates. In sensory profiling, Prieto Picudo had more visual color intensity, red tones, olfactory intensity, freshness sensations, and foam quality than Garnacha wines. Albarín and Verdejo had more visual color and olfactory intensity than the other white wines, and Verdejo had better foam quality. Prieto Picudo, Albarín, and Verdejo were the most promising varieties for the production of high-quality sparkling wines.

Changes of phenolic acids and antioxidant activities during potherb mustard (Brassica juncea, Coss.) pickling

Temporal dominance of emotions: Measuring dynamics of food-related emotions during consumption

Temporal dominance of sensory and emotional sensations for chocolate

Phenolic acids are one of the several classes of naturally occurring antioxidant compounds found in sweetpotatoes. Simplified, robust, and rapid methodologies were optimized to quantify total and individual phenolic acids in sweetpotato roots. Total phenolic acid content was quantified spectrophotometrically using both Folin-Denis and Folin-Ciocalteu reagents. The Folin-Ciocalteu reagent gave an overestimation of total phenolic acids due to the absorbance of interfering compounds (that is, reducing sugars and ascorbic acid). Individual phenolic acids were quantified by high-performance liquid chromatography (HPLC) using the latest in column technology. Four reversed-phase C18 analytical columns with different properties (dimensions, particle size, particle shape, pore size, and carbon load) were compared. Three different mobile phases using isocratic conditions were also evaluated. A column (4.6 x 150 mm) packed with 5-microm spherical silica particles of pore size 110 A combined with 14% carbon load provided the best and fast separation of individual phenolic acids (that is, chlorogenic acid, caffeic acid, and 3 isomers of dicaffeoylquinic acid) with a total analysis time of less than 7 min. Among the 3 mobile phases tested, a mobile phase consisting of 1% (v/v) formic acid aqueous solution: acetonitrile: 2-propanol, pH 2.5 (70:22:8, v/v/v) gave adequate separation. Among the solvents tested, aqueous mixtures (80:20, solvent:water) of methanol and ethanol provided higher phenolic acid extraction efficiency than the aqueous mixture of acetone.

Bottle fermented sparkling wine in South Africa is known as Methode Cap Classique which is based on the method used in France for Champagne. The use of cork, instead of a crown cap during the second fermentation in sparkling wine was investigated for its effect on the phenolic profile of wines. Phenolic acids susceptible to migration from cork into wine were studied in two-disc corks from three different commercial suppliers, coded as Cork A, Cork R and Cork C and a crown cap closure. Gallic, caftaric, caffeic and p-coumaric acids were quantified in all samples using a liquid chromatographic technique. Physicochemical parameters were also measured in the wine using a spectrophotometric technique. Total acidity and pH were not significantly different among the wines. Cork R wines were however significantly different in alcohol. Residual sugar for all samples was below the limit of detection. Gallic acid was significantly highest in Cork A wines, which indicates the contribution of Cork A to the concentration of this compound in the wine. Different cork types are assumed to release different concentrations of phenolic compounds. This may be due to differences in surface roughness of cork that would increase the surface area in contact with the wine. Therefore, corks from different origins (suppliers) could be used to bring about subtle differences to the wine.

Profiling of free amino acids in sparkling wines during over-lees aging and evaluation of sensory properties

In a previous investigation, "moist incubation" was described as a novel postharvest treatment for cocoa and the aroma composition of the resulting cocoa nibs was compared to unfermented and fermented cocoa nibs. For this treatment, unfermented and dried nibs are rehydrated with an aqueous solution containing lactic acid and ethanol to adjust the pH value and are subsequently incubated at 45 °C under aerobic conditions for 72 h before drying. The aim of the present study was to investigate the sensory properties and aroma composition of dark chocolates made of these materials after roasting. Therefore, gas chromatography-olfactometry (GC-O) in combination with aroma extract dilution analysis (AEDA), quantitation with isotopically labeled standards, odor activity value (OAV) determination, and sensory analysis were performed. The three different chocolates had distinct sensory and OAV profiles. The sensory profiles showed a higher intensity of fruity aroma notes and a lower intensity of bitterness and astringency in the chocolate made with the moist incubated cocoa, while the chocolate made of fermented cocoa reached higher scores in the roasty aroma notes. Furthermore, higher OAVs were determined for the Strecker aldehydes in the chocolate made of the moist incubated cocoa, whereas higher OAVs for the pyrazines and the acids were detected in the chocolate made of fermented cocoa. In contrast, the chocolate produced with the unfermented cocoa showed low cocoa specific aroma notes and high levels of astringency and bitterness. The detected differences reveal interesting insights into the influence of different postharvest treatments on the resulting aroma composition in the final chocolate. Furthermore, the alternative postharvest treatment was demonstrated to result in chocolates with a pleasant sensory profile.

Non-Saccharomyces yeast and lactic acid bacteria in Co-inoculated fermentations with two Saccharomyces cerevisiae yeast strains: A strategy to improve the phenolic content of Syrah wine

Sparkling wines were elaborated with the nontraditional varieties Villenave, Niagara, Manzoni, and Goethe, and monitored in relation to the changes in phenolic composition, browning index, and glutathione content during 18 months of biological aging (sur lies). Important changes in the phenolic profile, browning index, and glutathione content were observed in the sparkling wines during the over-lees aging period. The major phenolic compound in the sparkling wines was tyrosol, followed by caffeic, trans-caftaric, and gallic acids, catechin and epicatechin. The biological aging led to an increase in the individual phenolic compounds, especially caffeic, gallic, and ellagic acids, and an increase in the browning index was also observed during the aging period. Caffeic acid was significantly correlated with browning and aging period in all sparkling wines, which indicates that this compound can be useful as a quality marker to monitoring the biological aging profile of white sparkling wines. The results obtained indicate that the aging period (sur lie) had an important influence on the changes in the unique phenolic profile of the sparkling wines elaborated with nontraditional varieties. PRACTICAL APPLICATION: In sparkling wines production, the secondary fermentation occurring in the sealed bottle during the vinification contributes greatly to their quality and sensory complexity. The Vitis labrusca and hybrid grapes varieties represent most of the grapes cultivated in Brazil being employed in the elaboration of juices and wines. These varieties present a great oenological potential and have not been explored yet regarding to the production of white sparkling wines. The use of these nontraditional grape varieties cultivated in South Brazil may be a viable alternative in the production of white sparkling wines with biological aging potential and particular bioactive properties.

Varietal variation in apricot causes differential changes in fruit quality during ripening. A study was executed to evaluate the effect of apricot varietal variation on fruit physico-chemical and sensory attributes during fruit ripening. Fruits of two apricot cultivars, ‘Old Cap’ and ‘Red Flesh’ obtained from Baluchistan were monitored at ambient conditions (25 ± 2 °C and 60-65% RH) during fruit ripening for physico-chemical and sensory attributes. Irrespective to days at shelf during fruit ripening, fruits of ‘Red Flesh’ apricot exhibited significantly reduced fruit weight loss with greater fruit firmness, total soluble solids (TSS), total phenolic content (TPC), ascorbic acid and antioxidant scavenging activity (ASA) than ‘Old Cap’ apricot fruits. However, titratable acidity (TA) of ‘Old Cap’ apricot fruits remained significantly higher than ‘Red Flesh’ apricot fruits during ripening. At eating soft stage, sensory attributes including fruit pulp colour, taste, flavour and overall acceptability of ‘Red Flesh’ apricot fruits were superior to ‘Old Cap’ apricot fruits. In conclusion, ‘Red Flesh’ apricot showed better fruit physico-chemical attributes during fruit ripening and fruit sensory attributes at eating soft stage than ‘Old Cap’ apricot fruits.

Sensory analysis is an important tool to control and improve the quality of food products. This study aimed to evaluate the sensory attributes and consumer preference of coffee beverages prepared from roasted ground coffee (Coffea arabica) of different brands sold in Minas Gerais, Brazil, using projective mapping and assess the relationship of sensory attributes and consumer preferences with physicochemical properties. Titratable acidity, pH, soluble solids, color, crude fat, protein, total phenolic content, caffeine, trigonelline, 5-caffeoylquinic acid and caffeic acid were determined. Physicochemical properties showed good agreement with projective mapping data. Samples associated with high acidity in the projective mapping task had the highest levels of 5-caffeoylquinic acid. Coffees associated with bitter/roasted taste and darker colors had typical physicochemical characteristics and color properties of dark-roasted coffee. The sample perceived as thin had the lowest soluble solids content. Consumers preferred traditional, dark-roasted coffee over gourmet, light-roasted coffee. Projective mapping is an effective technique for assessing the sensory attributes of brewed coffee.

Phenolic acid and condensed tannin concentrations of six cotton genotypes