Taste descriptors

According to several authors, cheese taste is mainly due to the compounds found in the cheese water-soluble extract (WSE) (1, 2). Thus, to study cheese taste, the focus is usually on the cheese WSE which contains small polar molecules such as minerals, acids, sugars, amino acids, peptides and some volatile compounds produced by different processes such as lipolysis, proteolysis microbial metabolism (3). These compounds are responsible for the individual taste sensations like sourness, bitterness and saltiness which are the main taste descriptors for cheese. However, in a complex mixture they also exert otiier taste sensations due to taste / taste interactions (4). Peptides are generally considered to be the main bitter stimuli in cheese (5). However, it was shown that in goat cheese, bitterness resulted mainly from die bitterness of calcium and magnesium chlorides, partially masked by sodium chloride (6). 

Table 1 shows the taste profile obtained for crude cheese, reconstituted cheese made vnth homogenized proteins, fat with and without WSE, and WSE. Their comparison allowed the impact of each fiaction on the taste of the cheese to be evaluated. The omission of WSE led to a tasteless product, showing that WSE contained all the taste-active compounds. In reconstituted cheese where the structure of die matrix was almost totally degraded, bitterness was weaker and saltiness higher than in crude cheese (Table 2). The omission of fat and proteins from the reconstituted cheese caused an increase of saltiness and a decrease of bitterness compared to crude cheese. These data demonstrated that, in the crude cheese, the matrix structure partially masked the saltiness and increased the bitterness due to taste-active compounds. In addition, the comparison with results obtained with grated cheese in which the destructuring was intermediate between crude and reconstructed cheese for the same taste descriptors (Table 2) confirmed that the more die matrix was destructured, the more the bitterness increased and die saltiness decreased. Thus, cheese taste might be explained by the taste of die WSE containing the taste-active compounds modulated by the masking effect of both fat and proteins but also by an effect linked to the cheese mafrbc structure.

TASTE DESCRIPTOR AND THRESHOLD VALUES OF AMINO ACIDS (ADAPTED FROM O CALLAGHAN, 1994)... 

Compared to most white and red wines, Vin Santo wines, and especially the slightly sweet and sweet styles, are characterized primarily by their flavor and taste, rather than their aroma. Accordingly, in addition to sweetness and acidity, the most used descriptors to evaluate Vin Santo in relation to its perception in the mouth are alcoholicity (warm sensation), texture, viscosity, and overall taste persistence. Among the flavor descriptors, those relating to caramelization (like flavors of honey, milk-honey candy, molasses, caramel) are the most used, as these are more suitable to describe the different Vin Santo. It is estimated that these descriptors... 

Figure 3. Changes in panelists (n = 2) perceived intensity of sensory descriptors from grilled ground beef patties during storage at 4 ° C. Aromatics CBB cooked beef/brothy BRC browned caramel CBD cardboard PTY painty. Tastes BTR bitter SWT sweet.

Many materials used for food and beverage packaging have characteristic odors or sensory active compounds (Torri et ah, 2008). The intensity and description of the odor may be affected by the number and type of volatile compounds that are released under environmental conditions at the time of evaluation. Chemical composition of the material and polymer morphology may play a role in the sensory characterization. Sensory descriptors do not define a specific chemical compound but may be related to different compounds, a blend of compounds, and even a limited concentration range of a compound or class of compounds. For example, frans-2-nonenal in water changes in sensory (taste) description from "plastic (0.2 gg/1) to "woody" (0.4-2.0 p.g/1), "fatty" (8-40 pg/1), and "cucumber" (1000 gg/1) (Piringer and Ruter, 2000). Such terms are descriptive of the sensation and perception by human response to the chemical stimuli (Table 2.1). 

Marchsan and Morran (2002) found that flavor descriptions varied between chlorinated and nonchlorinated water in contact with PE and PP with stronger tastes frequently found in chlorinated samples. "Plas-tic/rubber" terms were used for chlorinated and nonchlorinated waters stored in PP and PE as well as in nonchlorinated waters from acryloni-trile/butadience/styrene (ABS). "Plastic/chemical" descriptors were used for chlorinated and nonchlorinated waters in PP and PE and polyurea materials, and in ABS materials for chlorinated waters only. Polyurethane materials contributed chemical tastes to chlorinated waters and medicinal flavors to nonchlorinated water. The "chemical" term also was applied to chlorinated water stored in PP, PE, and ABS and nonchlorinated water stored in ABS. "Medicinal" also was used to describe both nonchlorinated and chlorinated waters stored in PP. 

For aroma as for taste analysis, the approach was first to compile a sensory profile by fiequency of citation. The 3 soft cheeses used (Brie and Camembert made with pasteurized milk, respectively BP and CP, and Camembert made with raw milk, CU) could be described by the same main descriptors sulfiiry, buttery, mushroomy, salty and sour but some differences in frequency citation were observed, in particular for the sulfury note which was higher in the 2 Camembert cheeses. 

Ramos de Armas, R., Gonzalez Diaz, H., Molina, R., Perez Gonzalez, M. and Uriarte, E. (2004) Stochastic-based descriptors studying peptides biological properties modeling the bitter tasting threshold of dipeptides. Bioorg. Med. Chem., 12, 4815 822. 

The wine was scored using a modification of the descriptive analysis outlined by Stone et al. (12). Each major category of color, odor and taste was evaluated separately. For each attribute, a horizontal scale of 10 cm was provided with at least three labeled anchor points, one at each end and in the middle. Stage of color development was rated using descriptors red purple, ruby-red, ruby, ruby with amber highlights, amber and brown. 

The subsequent step consists in training assessors to rate the perceived intensity of some descriptors of foods on an evaluation scale. Panelists learn to quantify their perception, initially by ranking series of single odor or taste or texture stimuli with respect to the intensity of a particular characteristic, then quantifying the perception on the evaluation scale. The test samples used are model systems for instance, a single taste or flavor compound in water or other neutral media or solid or semisolid materials differentiated in their texture properties or samples obtained by spiking product samples with a flavor... 

Nevertheless, data can be seen another way. If we consider the poles as metadescriptors - for the taste of water, Volvic could be a metalhc and bitteT descriptor, Evian tasteless and cool and Vittel salty and astringent - data can be encoded this way from 0 for totally different taste to 10 for same taste . We now consider the intensities of each sample on several descriptors, and classical factorial analyses such as Principal Component Analysis (PCA), Multiple Factorial Analysis (MFA), Statis or Generalized Procrustes Analysis (GPA) can be processed (Fig. 10.3). 

The objective of comparative team tasting is to determine whether a difference exists between one or more samples and each given descriptor. This methodology is an internal adaptation of the difference-from-control test (Meilgaard, 20(X)). The modality of comparison should be predefined giving a quotation makes the test more difficult and is not recommended for non-expert assessors (O Mahony, 1995 Kim and O Mahony,... 

---