A 'Mouth-feel Wheel': terminology for communicating the mouth-feel characteristics of red wine

A hierarchically structured vocabulary of mouth-feel sensations elicited by red wines has been produced. Represented as a wheel, this structured vocabulary should assist tasters in their interpretation and use of terminology relating to 'in mouth' sensations produced by red wines. These terms and their definitions were generated by consulting the opinions of experienced wine tasters following exposure to an extensive range of commercial red wines. Logical relationships among the derived terms were formulated by analysis of 'sorting data' provided by a combined group of experienced winemakers and wine-tasters.     

Olfaction and taste: Human perception, physiology and genetics

Drinking wine is a manifestly sensuous experience. Wine stimulates most of our senses; particularly smell (olfaction) and taste, and, to a lesser extent, sight and touch. These sensory inputs interact with the limbic system in our brain which is associated with emotions and memory. Agreeable smells can thus evoke feelings of enjoyment and nostalgia. But how are tastants and aromas detected? Over the past few years a great deal has been learnt about how small tastant and odorant molecules are detected by specific protein receptors located in our mouth and in nasal cavities, respectively. Indeed, we have a vast array of olfactory receptors encoded by a group of genes that represent a significant part of the human genome. Interestingly, many more aroma compounds can be detected and discriminated than can be accounted for by the number of olfactory receptors that are encoded by our genes. Such disparity implies a level of complexity in this system which is not yet fully understood. Sophistication in olfaction is something that winemakers (and drinkers!) have long appreciated, and now scientists are beginning to unravel some of the underlying mysteries. Discovering why some individuals are more receptive to different tastes and smells than others will help wine producers understand variation in consumer preferences between different parts of the world, and possibly capture new opportunities in a changing global marketplace. Given such prospects, this present review offers a timely summary of some key developments in our understanding of odorant and tastant detection. We also consider how genetic components in human olfaction might be utilised to develop a ‘biosensor’ for aroma detection and discrimination.     

Sensory Detection and Population Thresholds for Sodium Tripolyphosphate in Cooked Ground Turkey Patties

Sodium tripolyphosphate (STP) at levels of 0.1, 0.2, 0.3, 0.4, and 0.5% by weight was added to ground turkey meat to determine if a flavor difference could be detected when STP was present. Detection thresholds for STP in ground turkey meat were determined for 30 female respondents. Two population thresholds were determined using information from the detection thresholds. Two-thirds of the respondents detected a difference between samples with no STP and those with 0.5% STP or less. STP added at less than 0.3% was undetected by more than 50% of the tested population.     

Lactose Crystallization from Whey Permeate in an Ethanol-Water Mixture

A 30% concentrated permeate of a whey ultrafiltration process was used for producing crystalline a-lactose monohydrate. Effect of pH (2.75–5.5 pH units) at solvent to solute ratio 10:1 v/w, agitation and seeding (0.004–0.02%) on rate of lactose crystallization were examined. Conditions which were favorable in terms of crystallized lactose yield, and time of crystallization were: pH 5.5, agitation with or without seeding and 22°C. The first-order reaction-rate constant for crystallization ranged from 0.0178 to 0.200 hr^?1 depending on conditions.     

FILTER INLET VELOCITY REDISTRIBUTION WITH FILTER LOADING

ABSTRACT

Previous flow visualizations and laser Doppler anemometer velocity measurements have shown that clean engine air filters are presented with very non-uniform velocity distributions when tested in the SAE universal panel Filter test housing. Experiments were conducted to measure the changes that occur in the velocity distribution in the plane 12.7 mm upstream of the filter as it is loaded with dust. Laser Doppler anemometer measurements of velocity profiles were performed for a production engine air Filter in the SAE universal panel filter test housing. Test conditions corresponded to a clean Filter, and dust-loaded Filters at additional pressure drops corresponding to 50 percent, 100 percent, and 150 percent of the design terminating pressure value. The results show that dust loading does make the velocity profiles less non-uniform, but that the changes are not dramatic. The inlet velocity profiles for the design capacity Filter remain very non-uniform.     

Free and Bound Volatile Secondary Metabolites of Vitis Vhifera Grape cv. Sauvignon Blanc

Free volatiles, and those hydrolytically released from glycosidic forms, were analyzed for Sauvignon Blanc juices from three successive vintages. Most of the 213 compounds identified were in one of the bio-genetic categories: norisoprenoids, benzene derivatives, monoterpenes or aliphatics. Several have not been previously reported as grape components. Monoterpenes were in lower concentration than normally found in floral grape varieties, but at higher levels than reported in Chardonnay juices. A notable proportion (40–50%) of the bound monoterpenes were monocyclic. Hydration of α-terpineol at pH 3 gave c-4-(1-hydroxy-1-methyIethyl)-1-methyl-r-1-cyclohexanol (cis-p-men-thane-1,8-diol) and t-4-(1-hydroxy-1-methylethyl)-1-methyl-r-1-cy-clohexanol (trans-p-menthane-1,8-diol) as the main products and a low yield of t-4-(1-methylethyl)-r-1-methylcyclohexane-1,4-diol (trans-p-menthane-1,4-diol). These were confirmed as major components of the acid hydrolysates of the bound fraction.     

Wine bottle closures: physical characteristics and effect on composition and sensory properties of a Semillon wine 1. Performance up to 20 months post-bottling

A Semillon wine was bottled using 14 different closures: a screw‐cap type, two grades of conventional natural cork, two ‘technical cork’ closures (natural cork with a synthetic component), and 9 closures manufactured from synthetic polymer material. Closure performance was evaluated for physical aspects (e.g. extraction force and energy, change in closure diameter, and ease of closure reinsertion), and for wine composition and sensory properties. Wine under the screw cap closure retained the greatest concentration of sulfur dioxide (SO₂) and ascorbic acid and had the slowest rate of browning. For other closures the trend of SO₂ loss relative to the screw cap closure was apparent from an early stage of testing, and was most evident in the group of synthetic closures, intermediate in the conventional corks, and least evident in the technical cork closures. The loss of SO₂ was in general highly correlated with an increase in wine browning (OD₄₂₀) and the concentration of SO₂ in the wine at six months was a strong predictor of future browning in the wine, particularly after eighteen months. Neither the concentration of dissolved oxygen at bottling (0.6–3.1 mg/L), nor the physical closure measures were predictors of future browning. For several closures upright storage tended to accelerate loss of SO₂ from the wine, but in many cases this effect was marginal. The closures differed widely in regard to physical characteristics, and in general synthetic corks appeared least ‘consumer‐friendly’ in terms of extraction forces, energies, and ease of closure re‐insertion, but there was a trend for natural cork closures to exhibit larger variability in physical characteristics than technical cork and synthetic closures. Sensory analysis indicated large differences in wine flavour properties, with closures which tended to result in the best retention of free SO₂ having wine sensory scores for ‘citrus’ that were generally high whilst scores for the attributes ‘developed’/‘oxidised’ were low. The situation was reversed for wine under closures that performed poorly in the retention of free SO₂. It was found that below a critical level of free SO₂ remaining in the wine, closures exhibited substantially higher ‘oxidised’ aroma. Whilst trichloroanisole‐type (TCA) taint was a noticeable problem for some cork and technical cork closures, any plastic‐type taint appeared not to be a problem with most synthetic closures.     

Exclusion of sunlight from Shiraz grapes alters wine colour, tannin and sensory properties

The aim of this study was to determine how changes in grape composition brought about by artificial shading (sunlight exclusion) influence wine properties including colour, flavonoid composition and sensory attributes. Prior to flowering, bunches of Shiraz grapes were enclosed in boxes designed to eliminate light without altering bunch temperature and humidity. This artificial bunch shading had little effect on berry ripening and accumulation of sugar but at harvest the shaded bunches had smaller berries and higher seed weight, juice pH and titratable acidity. The amount of anthocyanins in the fruit was not changed significantly but anthocyanin composition in the shaded berries was shifted towards dioxygenated anthocyanins (the glucosides of cyanidin and peonidin derivatives). Shaded fruit had increased seed tannins and decreased skin tannins but the largest relative change in flavonoids was a marked decrease in flavonols in the shaded fruit, similar to previous studies. Wines made from shaded fruit had lower wine colour density, total phenolics, anthocyanins and tannins when the wine was bottled and after ageing for up to three years. Analysis of potential flavour compounds following acid hydrolysis indicated that the wines made from shaded fruit had decreased levels of glycosides of β-damascenone and 1,1,6-trimethyl-1,2-dihydronaphthalene (TDN). Sensory analysis of the wines indicated no significant difference in aroma attributes but the wines made from shaded fruit were rated lower for astringency, fruit flavour and flavour persistence in-mouth sensory attributes. The results indicate that extreme shading of Shiraz fruit can decrease wine colour, anthocyanins and tannins as well as altering sensory attributes.