Quality sensory evaluation

Secondly, the study of the chemical composition of foods and of its changes on processing are not the only aim (except in control analyses) the space of chemical quantities is intermediate between the cause space, which includes every parameter affecting food composition, and the effect space, where we find variables related to food properties, its quality, sensorial evaluations, nutritional value, and storage possibilities. Generally, the chemical space is described accurately and concisely. 

To predict the comfort of a material, a combination of hand evaluation, eg, using the Kawabata system, as well as deterrnination of the heat and moisture transport properties, is necessary. Often, these values are correlated with a sensory evaluation of the tactile qualities of the material by a human subject panel. A thorough discussion of the many physical and psychological factors affecting comfort is available (134,135). 

Using these rhelogical methods laboratories for quality control and research and development have good tools to characterize pectins in gels and solutions. The most important points are the reproducable handling, pretreatment, and measurement of the samples and the knowledge which information can be derived from the measured data regarding the texture, the production parameters, and the sensory evaluation of the product. 

Haglund A, Johansson L, Berglund L and Dahlstedt L (1999) Sensory evaluation of carrots from ecological and conventional growing systems . Food Quality and Preference, 10, 23-29. 

Texture is an important and complex quality characteristic. It is determined by variety and by structural and biochemical properties of tuber tissue, with some environmental influence. A considerable amount of research has been undertaken to replace subjective sensory evaluation with objective instrumental measurements (Van Dijk et al., 2002). 

Sensory evaluation of cooked potato quality is based on appearance and mouthfeel scored by trained or untrained evaluators using some form of hedonic scale on which the assessor records the perceived value of the attribute, typically on a nine-point scale, from extreme like to extreme dislike. 

Knowing the relationships between chemical and sensorial variables, objective methods can be obtained to evaluate the food quality. Juries of experts cannot be formed and used so easily as the measurement of chemical quantities can. Besides, the knowledge of these relationships will be able to retain, so to speak, sensorial evaluations and follow the evolution of taste over a long period, so that it may be foreseen as well. 

The goal of food emulsion manufacturers is to produce emulsions that meet or exceed the expectations of their clientele. As a first step, companies typically conduct market studies to determine what these expectations are. Sensory evaluations are then used to translate these expectations into product-specific criteria (e.g., emulsion color, texture, appearance) that serve as guidelines to design the emulsification process and verify the quality of the produced emulsion. If emulsion properties comply with the set standards (i.e., their values are within an acceptable range), manufacturers can be confident that their customer base will be satisfied with the product. 

There is no combination of chemical or physical analyses which can, or is ever likely to, replace human sensory evaluation completely. Sensory examination of wines employs two major approaches detecting differences and evaluating quality or, more briefly, analytical and hedonic (16,19). The former can be objective and the latter is inevitably somewhat subjective regardless of the expertise of the judges. 

The taste sensor will be applicable for quality control in food industry and help automation of the production. The sense of taste is vague and largely depends on subjective factors of human feelings. If we compare the standard index measured by means of the taste sensor with the sensory evaluation, we will be able to assess taste objectively. Moreover, the mechanism of information processing of taste in the brain as well as the reception at taste cells will also be clarified by developing a taste sensor which has output similar to that of the biological gustatory system. 

Fresh Citrus Juice. Freshly extracted commercial orange juice may contain a high peel oil content making sensory evaluation of this product very difficult because of the overriding, biting and even bitter flavor effect of the peel oil. This is one of the reasons why in certain plants, minimal attention is paid to the flavor quality of the juice until the product is standardized either in retail or bulk form (2). 

Clausen, G. (2000) Sensory evaluation of emissions and indoor air quality. Proceedings of Healthy Building 2000,... 

Berglund, B., Bluyssen, P.M., Clausen, G., Garriga-Trillo, A., Gunnarsen, L., Knoppel, H., Lindvall, T., MacLeod, P., Molhave, L. and Winneke, G. (1999) Sensory evaluation of indoor air quality. Joint Research Centre, Ispra, Italy, Report No. 20. 

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. 

In summary, headspace concentration method is the usual way of analyzing the odor quality of packaging materials and has been shown to give reliable data which can be correlated with sensory evaluation data. Oven-heated microwavable packaging materials may pose a special flavor problem in the food consumed. 

For the sensory evaluation, experienced assessors were used. Prior to sensory evaluation the purity of all flavor components was carefully checked because undesirable trace impurities may severely affect the odor quality of a component and can lead to erroneous conclusions. Different concentrations of each flavor substance in aqueous solution were used (based on their detection thresholds). Furthermore, sensory evaluation was also performed by sniffing the GC-eluate. 

The potential for smart packaging for improvement of food quality and safety is very high. Although sensory evaluation is essential in the early stages of development, there is an important role for sensory evaluation simultaneously with analytical assessments of new materials in contact with food systems. New materials or novel applications of materials may deliver value in improved sensory quality or create unexpected sensory impact that may not be interpreted from analytical chemical or physical methods of assessment. 

The sensory evaluation differentiates between the stimulation threshold (a just detectable level where a perceptible but not yet definable deviation of the sample from the standard is observed) and the recognition threshold, a level where the odor is identifiable or creates odor problems (a no longer tolerable quality deterioration caused by a definite off odor and/or taste). The difference between a perceptible and identifiable level is usually only one to two steps of a geometric dilution series. Therefore, only undifferentiated odor and taste thresholds are given in Table 13-6, because of the very different sensitivities of individual testers. The perceptible (stimulation) levels of a less sensitive tester can overlap with the identifiable (recognition) level of another more sensitive tester. 

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. 

The perceived crispiness of chips and many cereal-based products is the key determinant characterising product quality. Most crispy products are characterized by a cellular, lamellar or puffed structure often described as solid foam. The crispiness of a product is closely related to its structure and the extent of porosity. However, sensory evaluation of crispiness is difficult to correlate with instrumental parameters mainly because crispiness is not a clearly defined attribute (Roudaut et al. 2002). 

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