Sensory analysis flavor descriptions

Flavor Description. TypicaHy, a sensory analyst determines if two samples differ, and attempts to explain their differences so that changes can be made. The Arthur D. Litde flavor profile (FP), quantitative descriptive analysis (QDA), and spectmm method are three of the most popular methods designed to answer these and more compHcated questions (30—33). AH three methods involve the training of people in the nominal scaling of the flavor quaHties present in the food being studied, but they differ in their method for quantitation. 

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. 

Figure 3. Descriptive sensory analysis of beef flavor attributes. Flavor attributes are examined as a function of storage time (days) postmortem.

Flavor can be evaluated by chemical and sensory evaluation methods. Descriptive methods of sensory evaluation are applied frequently to profile this important quality aspect (Jackson, 2002). To analyze flavor profile, the technique of descriptive analysis has been applied to a variety of beverages including vermouth. 

Table I. Mean Scores for Descriptive Sensory Analysis of Mild and Harsh Carrots with Added Terpene Flavor Mixture...

Alasalvar, C., Shahidi, R, and Cadwallader, K.R., Comparison of natural and roasted Turkish Tombul hazelnut (Corylus avellana L.) volatiles and flavor by DHA/GC/MS and descriptive sensory analysis, J. Agric. Food Chem., 51, 5067-5072, 2003. 

Alasalvar, C., Odabasi, A.Z., Demir, N., Balaban, M.O., Shahidi, E, and Cadwallader, K.R., Volatiles and flavor of five Turkish hazelnut varieties as evaluated by descriptive sensory analysis, electronic nose, and dynamic headspace analysis/gas chromatography-mass spectrometry, J. Food Sci., 69,... 

Modified Atmosphere Stored Broccoli Florets. Since TBHQ and caraway seed flavonoid components exhibited the same effect on depletion of methanethiol in model systems, they were examined for efficacy in suppressing methanethiol-related off-flavors in broccoli florets stored under modified atmospheres. Freshly prepared broccoli florets (ca 3 cm long) were treated by dipping them in cell-free cni caraway seed extracts or aqueous TBHQ solutions (100 ppm), and allowing excess liquids to drain off. Control samples were dipped in distilled water. Broccoli samples were placed in the heat-sealed Curlon 850 pouches described earlier (70 g/pouch), and then held under refrigeration at 4°C until used for GC-FPD and descriptive sensory analysis 8 days later. 

Food flavor, taste, and texture sensations are perceived over time during consumption, and intensity of flavor perception can change over time. The temperature of the product, after time, equilibrates with the mouth temperature. Physical manipulations such as tongue movements, mastication, and salivary dilution affect the product and its sensory characteristics over time. The classic methods of descriptive sensory analysis do not take into account this temporal dimension. For that purpose, dynamic methods such as time-intensity analysis were developed [13]. 

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... 

Preliminary GC analysis revealed that there are more number of peaks in roasted samples compared to plain cashews. Also selective extraction method was found to be slightly superior to the SDE method under the conditions of the experiment adopted in this study. However, the compounds in oven-roasted and oil-roasted samples did not differ much, qualitatively and quantitatively. In total, 26 compounds have been identified in plain cashews and 3 compounds in roasted samples. The identified peaks constituted 70 percent of the total peaks registered in GC analysis of the individual samples. The descriptive flavor profile of the eluting peaks of the plain and roasted samples were studied. Since the flavor isolate from oven roasted cashew nuts contained the flavor components of plain cashews also and since analysis showed that there was not much difference between the flavor constituents of oven-roasted and oil-roasted samples, the aromagram of the oven-roasted cashew nuts (SDE) was taken as representative. Fig.l gives the GC profile of oven roasted cashew nuts and the sensory properties of the numbered peaks are included in Table III. 

Samples were reheated at full power for 1 minute in a microwave oven prior to proceeding with flavor volatile analysis (60 C internal temperature). A reproducibility study was carried out on 5 identical, 100 g samples that had been stored for 3 days after cooking, except that they were not reheated in the microwave prior to analysis. An ad hoc panel convened for these experiments consisted of two trained meat flavor panelists who scored the samples for characterization of MFD according to descriptive sensory methods described by Johnsen and Civille (12) and Love (13). The panelists were also active members of a twelve member descriptive sensory panel at the Center. Two duplicate repetitions were carried out for each experiment (4 samples studied). 

Figure 3 plots intensity changes perceived by gd hoc descriptive sensory panelists in intensity analysis for character notes involved in meat flavor deterioration during storage of the grilled beef samples reported in Figure 2 and Table II (12, 13). The loss of intensity for certain descriptors in Figure 3 is in accord with sensory panel experience that the positive notes such as cooked-beef brothy diminish with formation of new off-flavor compounds represented as cardboard and painty. 

I believe the future of sensory evaluation will involve an expansion of the use of descriptive analysis in many different situations, such as in plant quality control, as well as product development and research applications. Because of the increased competition in the flavor industry, flavor companies are increasingly expanding their sensory work and sensory capabilities. This is necessary, not only for the flavor company to understand the products they are producing but to be able to satisfactorily service their client companies. 

Abbott, N.A., Coombe, B.G. and Williams, P.J. (1991) The contribution of hydrolyzed flavor precursors to quality differences in Shiraz juice and wines. An investigation by sensory descriptive analysis, Am. J. Enol. Vitic., 42, 167-174. 

New developments in glycoside research of grapes and wines are a) the use of formal sensory descriptive analysis to investigate the precise role of glycosides in flavor expression, and b) the possibility of grape and wine quality evaluation through the quantification of glycosides. These developments are discussed here. 

To assess the effect of the juice treatments on wine flavor, sensory descriptive analysis was undertaken by a trained panel of 11 judges, scoring a subset of the samples fix)m these experiments in duplicate. There was insufficient volume of sample... 

There are six or seven other descriptive analysis methods described in the sensory literature. The methods include Flavor Profile (CairuCTOSS and Sjdstrom, 1950) or its current version. Spectrum Analysis (Meilgaard et al., 2006), Texture Profile (Brandt et al., 1963), Free Choice Profiling (Williams and Arnold, 1985), and its successor Hash Descriptive Analysis (Dairou and Sieffermann, 2002). There are other methods described in the literature, but all appear to be based on methods previously described. 

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