Descriptive analysis subjects

Sensory Analysis. Oat oils and isolates from these oils were sensorially evaluated. Oils from the Magne variety, both crude and heated, were analysed by a panel consisting of 12 to 14 persons who were selected from the laboratory staff. Most of them had previous experience with sensory analysis. Four oat oils, one from crude oats, one heated oil from crude oats and two oils from roasted oats see Figure 1, were subjected to the triangle test followed by descriptive analysis (14, 15). 

Sensory Analysis. Oils from the Magne variety were evaluated by a profile panel. Oil from crude oats (a), two oils from roasted oats (one part milled before roasting (b) and one milled after roasting (c), and heated oil from crude oats (d) were subjected to the triangle test and descriptive analysis. No evaluations were performed of oils from the Chihuauhua variety, due to lack of material and also to similarities with the various Magne oils. 

Very limited information has been published on this subject. Using a sensory panel which employed quantitative descriptive analysis, Rouseff (2 ) was able to demonstrate that heated off-flavor was the major quality factor in determining the perceived quality of the juice. Some flavor descriptors used in this study are shown in Figure 3. Panelists evaluated each flavor descriptor using a 10-cm line anchored with weak and strong on the ends, and overall quality, previously defined using a 100-point... 

Acid hydrolysates were added to a low aroma intensity white wine (ie the base wine), and the aroma properties of these samples were assessed by sensory descriptive analysis. In addition, the glycoside isolates from the Australian vineyards were subjected to glycoside hydrolase enzyme treatment, and duo-trio difference tests were performed on these hydrolysates added to a base wine. The volatile composition of each of the hydrolysates was investigated by GC/MS, and relationships between the two sets of data were determined. Finally, the glycoside concentration of each of the juices and skin extracts was determined by the glycosyl-glucose assay. 

In descriptive analysis small groups of highly trained judges with considerable experience with the commodity under study develop adjectives to characterize the qualitative properties of the product (attributes like appearance, aroma, texture, taste, etc., are analyzed). The data of sensory analysis experiments are subjected to statistical analysis to get reliable results. Instrumental methods are also used to correlate physicochemical measurements with sensory judgments (Table 5). 

Sensory resources are an integral part of most consumer products companies. By resources are meant the tools used by sensory scientists to obtain actionable information. This information may be used by technology, quality control, consumer insights, marketing, and brand managers. The resources include subjects, methods, facilities, and data capture and analysis capabilities. In Section 2.3, the methodologies are described. Section 2.5 is a more detailed exposition about descriptive analysis. More... 

Sensory scientists will agree that descriptive analysis has many applications but there is relatively little agreement as to how specific methods are developed and used. For example, subjects may or may not have been screened the number of subjects can range from as few as 5 to as many as 20 there may be a formal language development process or not the number of attributes on a scorecard may be limited references may or may not be used replication may or may not be part of the design data analysis can be simple (e.g., summary statistics such as means and variance measures) or... 

As noted previously a descriptive analysis capability attracts attention because of the results it provides for example, the ability to describe specific differences among an array of competitive products. This section provides some details on how a descriptive analysis capability can be developed and a panel made ready to evaluate products in a relatively short time period. Starting with newly recruited subjects, one can have a panel available in 2 weeks - three session days for screening, five for language, and one for a pre-test. Once operational, however, a test can be organized in a day, followed by data collection. The duration of a test depends on the number and type of products and, as always, the objective. So any discussion about rapid methods must first begin with what is meant by rapid in the context of existing methods. 

The sorting task can also be applied to achieve a selection of products prior to a descriptive analysis. Piombino et al. (2004) developed a two-step strategy for the analysis of wine flavor. The sorting of a large number of samples by untrained subjects led to the selection of a representative subset of products that were evaluated, in a second step, by descriptive techniques. 

PSP on continuous scales also enables hypothesis testing. Classical ANOVAs (Analysis of Variances) applied to descriptive analysis can be used to infer significant differences between products, which is very convenient. Ongoing studies are also looking for the apphcation of the Mixed Assessor Model (MAM Brockhoflf et al, 2012) in order to take into account the expected high scaling effect between subjects (especially untrained subjects). 

To determine the appropriate list of attributes, the glossary usually used for Descriptive Analysis can be used as a starting point to initiate the discussion with the subjects, but the attribute list for TDS is almost always different from the one used for Descriptive Analysis (at least, generally shorter). If the TDS evaluation is split into several phases (e.g. one TDS before swallowing and one TDS after swallowing), the attribute list can be different for each phase as long as there is no interest in the direct comparison of the TDS profiles across phases. 

For historical reasons, intensity has been generally recorded in the first TDS studies because the first TDS software (developed by Fizz, Biosystemes) was based on an evolution of a Descriptive Analysis module. This is, however, not reconunended because it mixes up two different cognitive processes the selection of a dominant attribute (qualitative task) and the intensity scoring (quantitative task). The use of buttons is therefore better aligned with the primary task of the subject, to identily the dominant attribute/sensation. The use of buttons is an easier alternative and was proven to be as efficient as the historical solution and simpler to handle by the subjects (Saint-Eve et al, 2011). Most of the time, it is therefore more suitable to use buttons rather than intensity scales. 

Since the TDS method aims at describing rather complex phenomena (sequence of dominant perceptions over time), published papers (Table 13.2) have generally used more subjects and replicates than for Descriptive Analysis (ISO 8586 12 subjects, no replicate). 

When the evaluation protocol is not standardized, the duration of an evaluation can vary from one product to another (and/or from one subject to another). In this case, it is useful to compare the evaluation durations between products to know whether some products generally need a longer duration to be evaluated than others. To do so, the 2-way ANOVA model usually used for Descriptive Analysis data (product as fixed effect, subject as random effect, with interaction in case there is replicates) can be simply applied to the evaluation duration variable. A multiple comparison test can also be conducted to identify which products have significantly different evaluation durations from which other products. 

First, a careful descriptive analysis of workplace discourse can contribute to the development of a generalized expert model in many important and complementary ways Because the interview process can affect a subject s beliefs and values, researchers must be particularly careful when they attempt to elicit their lay audience s beliefs and misconceptions. If interviews change a subject s knowledge, then interview results will produce a skewed conception of what audiences need to know to understand risk. When interviewers employ a conversational style, for example, they can introduce new words or ideas, but they can also overlook critical concepts. If the purpose of the interview is to discover people s mental models so that communicators can construct risk messages to affect a wider audience, the interview process must not create misconceptions or reshape the subject s mental model. When researchers employ a variety of methods, they must insure that the different forms of inquiry (questionnaire or interview, for example) do not affect their results. Morgan et al. (2002) note that designing good questions is not easy. ... 

Discriminant Sensory Analysis. Discriminant sensory analysis, ie, difference testing, is used to determine if a difference can be detected in the flavor of two or more samples by a panel of subjects. These differences may be quantitative, ie, a magnitude can be assigned to the differences but the nature of the difference is not revealed. These procedures yield much less information about the flavor of a food than descriptive analyses, yet are extremely useful eg, a manufacturer might want to substitute one component of a food product with another safer or less expensive one without changing the flavor in any way. Several formulations can be attempted until one is found with flavor characteristics that caimot be discriminated from the original or standard sample. 

The development of precise and reproducible methods of sensory analysis is prerequisite to the determination of what causes flavor, or the study of flavor chemistry. Knowing what chemical compounds are responsible for flavor allows the development of analytical techniques using chemistry rather than human subjects to characterize flavor (38,39). Routine analysis in most food production for the quaUty control of flavor is rare (40). Once standards for each flavor quaUty have been synthesized or isolated, they can also be used to train people to do more rigorous descriptive analyses. 

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