Sensory Analysis Methods Research Articles

Sensory and chemical analysis methods for earthy and musty odours in drinking water caused by geosmin and 2-methylisoborneol

Earthy and musty odours are amongst the most frequently observed objectionable odours in water supplies, and geosmin and 2-methylisoborneol are identified as the chemical compounds most closely associated with these odours. In this paper, the sensory properties, and the water matrix effects on taste and odour panel studies, as well as the chemical analysis methods for earthy and musty odours in drinking water caused by geosmin and 2-methylisoborneol, are reviewed. Insights are developed to enable better evaluation of earthy and musty odours in drinking water. Early detection of geosmin and MIB can prevent off-flavour occurrence by providing information for potential treatment.

Beer astringency assessed by time–intensity and quantitative descriptive analysis: Influence of pH and accelerated aging

pH and oxygen are usually considered as the main factors influencing the organoleptic stability of beer. Polyphenols from malt and hop contribute to several characteristics of beer flavor, but their incidence on astringency is rarely mentioned. In this work, effects of pH (3.0 and 5.0) and accelerated aging (0 or 5 days at 40 °C with low or high level of oxygen in the bottle) on astringency were measured by two sensory analysis methods: quantitative descriptive analysis and time–intensity analysis. In addition, the polymerization degree of polyphenols was determined for the different samples in this study. Whatever the sensory technique used, a trained panel showing high repeatability identified pH as the only factor having a significant effect on astringency. Accelerated aging, even with high level of oxygen in the bottle, does not significantly modify perception of this sensation compared with the 4 °C-stored beer, probably because the variation of polymerization degree of polyphenols was not sufficient to be detected by the panelists.

Implementation of Quality Control Methods (Physico‐Chemical, Microbiological and Sensory) in Conjunction with Multivariate Analysis Towards Fish Authenticity

AbstractFor Abstract see ChemInform Abstract in Full Text.

Implementation of quality control methods (physico‐chemical, microbiological and sensory) in conjunction with multivariate analysis towards fish authenticity

SummaryNowadays authenticity of foods and fish in particular has become of crucial importance because of high number of adulteration cases. Authenticity control has gained ground thanks to the development of several rapid physico‐chemical and microbiological methods aiming at distinguishing one species from another based on solid scientific evidence. It has been proven that despite the precision and accuracy of robust analytical and protein and DNA‐based techniques, detection of authenticity could not be claimed without resorting to multivariate analysis. This review summarizes both the most advanced and state of the art used techniques for detecting fish and seafood authenticity (both in terms of species and geographical origin). Another issue reported in this review is the preservation of fish and seafood through the implementation of old and novel techniques (ice, modified atmosphere packaging). Several informative tables were included in this paper referring to the employed quality control and sensory analysis methods and multivariate analysis for fish and seafood.

The mouth-feel properties of polysaccharides and anthocyanins in a wine like medium

Two fractions containing the major polysaccharides present in wine were isolated, one comprising a mixture of neutral polysaccharides, mannoproteins and arabinogalactan-proteins, and the other containing the acidic polysaccharide, rhamnogalacturonan II. A grape anthocyanin fraction was also prepared. A trained sensory panel, using formal sensory descriptive analysis methods to rate the intensity of mouthfeel attributes while the samples were held in the mouth and after expectoration, individually assessed the fractions, dissolved in a model wine at levels commonly encountered in red wines. Both polysaccharide fractions significantly increased the ‘fullness’ sensation above that of the base wine. The rhamnogalacturonan II fraction significantly decreased the attribute ratings associated with the astringency of the model wine whereas the neutral wine polysaccharide fraction had less affect on reducing the ratings for these attributes. The anthocyanin fraction tended to increase ‘fullness’ although the effect was not great enough to be statistically significant. Unlike the polysaccharides, this fraction also increased perceived astringency but this effect could be due to the presence of some derived tannins in the sample.

An AHP-based procedure for sensory data collection and analysis in quality and reliability applications

The quality of several industrial products can only be fully measured through sensory evaluation of some of its properties. Sensory evaluation is widely used in the food and pharmaceutical industry for product quality optimization. It is also used for reliability analysis of products that degrade rather than fail as judged by sensory attributes. In this paper, we propose a pairwise comparison-based method for sensory panel data collection and analysis grounded on AHP principles. Our method presents two important features that may appeal to the product development practitioner: (1) sensory panel data may be elicited from panelists not exposed to intensive training, and (2) a consistency index objectively measures how well each panelist performs. The use of the method we propose is illustrated in two case studies. The first is from the food industry and seeks to find a new formulation for a product. The second is from the plastics industry and its goal is to find an appropriate warranty policy for a product that degrades over time.

Sensory quality of minerally fortified bread

The effect of several mineral elements on the quality of fortified bread was studied through methods of sensory analysis. The sensory characteristics were established and an attempt made to measure them.

ULTRASONIC CLASSIFICATION OF MEALINESS IN APPLES

In modern agriculture, with its competitive markets, fruit quality is a significant factor, and mealiness impairs thequality of apples and reduces their market value and price. Retailers are perfectly able to distinguish a mealy product froma fresh one, describing it correctly with terms such as nonjuicy, soft, etc. However, there is a need for a reliable method,incorporating appropriate sensors, for the nondestructive testing and classification of apples according to their mealiness;it needs to be designed for use by an untrained person. Several techniques have been suggested in the literature to detect andevaluate mealiness; they include destructive tests such as tensile tests, texture profile analysis, ultrasonic examination, etc.,and some nondestructive sensory analysis methods based on, e.g., magnetic resonance, electrical impedance, and NIR. Thisarticle suggests a system based on ultrasonic energy absorbance for nondestructive determination of three mealiness levels(fresh, ripe and overripe) in Jonagold and Cox apples. The method is based on the emission of a known level of ultrasonicenergy into the fruit flesh and measurement of the attenuated signal received after transmission through the fruit tissue. Thestrength of the received signal is affected by the mechanical structure of the tissue, the physiochemical quality indices, andany change in the quality attributes of the fruit. The detected sound waves were analyzed in parallel with determination ofthe mealiness level of the fruit. The results obtained suggest that it is possible to distinguish among the three mealiness levelsin Jonagold fruits, but not in the Cox fruits.

Sensory analysis method applied to develop initial machine specifications

The International Organization for Standardization (ISO) proposed an international standard (IS) for Human-Centred Design in June 1999. However, the proposed IS does not provide detailed coverage of the method and technologies for determining the design. Given the initial lack of a specific requirement balance, interface designers are required to measure and analyse the value of a user’s comfort level. This paper discusses the sensory analysis method applied to the initial stage of new machine design. For the analysis, seven machine samples were selected as experimental Portable Information Terminal (PIT) platforms designed to meet hospital nursing care requirements. The survey participants were eleven professional nurses/therapists who were generally inexperienced computer users. The required measurement and analysis was accomplished by utilizing the Marble Method and Correspondence Analysis (CA) Through these study methods, the required PIT features for this application can be initially defined.

Delineation of the texture of Salers cheese by sensory analysis and physical methods

The 25 investigated Salers cheeses graded by the professional committee offered a large range of textures. Their texture characteristics were investigated by sensory analysis, rheological measurements and fluorescence spectroscopy. The 8 sensory attributes generated by the panel in- cluded the evaluation of mechanical, geometric and surface properties, and allowed the characterisa- tion of the texture of the investigated cheeses. The stress values at 20% compression ranged between 0.073 and 0.290 kPa. The fluorescence spectra of protein tryptophans and vitamin A were recorded directly on the samples. Principal component analysis and canonical correlation analysis were used to evaluate the data and to investigate the relationships between the different sets of data recorded on the same cheeses. All the methods used to analyse the cheeses allowed discrimination of the samples, i.e. the obtained data constituted fingerprints of the cheeses. Moreover, strong correlations were found between the sensory attribute domain and the instrumental domains. It was also suggested that the phenomena observed at molecular and macroscopic levels were related to the texture of the cheeses. cheese / texture / sensory analysis / rheology / fluorescence

Sensory analysis as a supporting method for marjoram breeding

Marjoram is one of the most important spices in Hungary, which is utilized both in phytotherapy as well as in alimentary industry. Organoleptic quality of the drugs of two Hungarian varieties of Majorana hortensis /'Francia' and 'Magyar'/ were investigated by two different methods of sensory analysis. The chemical composition of the material was checked by GC analysis of the distilled essential oil. Although their main compounds and proportions showed similar patterns, both the human and instrumental sensory tests based on the complex odour and aroma of the drug, proved a significant differentiation of the two varieties.
 On the basis of our results, sensory evaluation may be a useful tool in the practice in determination of complex aromatic values of marjoram, as a spice. At the same time it seems to be a suitable method in promotion of breeding efforts.

Genotype, Location, and Harvest Date Effects on the Sensory Character of Fresh and Frozen Red Raspberries

Fruit from three red raspberry (Rubus idaeus L.) cultivars—`Glen Clova', `Glen Lyon', and `Glen Moy'—were harvested from four sites on two harvest dates and evaluated fresh or following storage at -20 °C to determine the relative importance of genotype, harvest date, location and freezing effects on 19 sensory attributes using a trained sensory panel. Freezing and cultivar × freezing interaction effects were relatively large while site, harvest date, and other interactions were of minor importance. The cultivar × freezing interaction was caused by differential responses among cultivars for the sensory attributes purple, juicy, sweet, and raspberry aroma with less discrimination among cultivars postfreezing. `Glen Clova' fresh fruit received the highest values for juicy, fruity, sweet, and raspberry aroma; `Glen Moy' fresh fruit received the highest values for purple; `Glen Lyon' fresh fruit received the lowest values for juicy, postfreezing, `Glen Lyon' received the highest values for purple and sweet and all three cultivars were similar for the other attributes. These data suggest that selection for improved postfreezing sensory characteristics should not rely solely on fresh fruit evaluations although further study of a more genetically diverse group of genotypes would be beneficial. The significant cultivar and minimal harvest date and location effects suggest that these fruit sensory analysis methods should be useful in selecting raspberry genotypes with superior fruit quality.

Perceived texture: direct and indirect methods for use in product development

SummaryIncreasing consumer interest in texture has made it of primary concern in product development, since manipulating texture can provide product differentiation. Successful development requires both comprehensive understanding of texture as perceived by the consumer, and appropriate measurement methods. Perceived texture results from an array of sensory inputs, arising before and during consumption. Sensory analysis methods provide means to express such percepts, but can be time‐consuming and expensive. There are relationships between physiological parameters measured in individuals during food consumption, and perceived texture. Such measures can provide simple and rapid indices of texture, if validated before use, as routine tools in product development applications.

Sensory Analysis — An Alternative to Wine Tasting?

The sensory characteristics of a wine are critical in determining its acceptability, and particularly repeat purchases. Assessments of wines are often made by expert wine tasters, however the use of sensory analysis methods offers an alternative approach that is less reliant on the expertise of one individual. This paper outlines a number of different sensory analysis methods, and gives examples of situations in which the methods might be used. These include the use of triangle tests to evaluate packaging materials, the use of scaling methods to evaluate changes in particular sensory characteristics as a result of changes in processing parameters, the use of sensory profiling to characterise a wine and determine changes that occur during storage, and the use of consumer testing to determine the key sensory characteristics of importance to a particular market segment.

Development of the Flavor Profile Analysis Method into a Standard Method for Sensory Analysis of Water

The standard methods committee for the 1990 edition of Standard Methods for the Analysis of Water and Wastewater has decided to consider adding a new (provisional) method for the sensory analysis of drinking water - Flavor profile analysis (FPA). A series of issues must be addressed before FPA can become a standard method. The methodology (e.g., temperature of aroma samples, sniffing technique, use of cups vs. flasks, rest intervals between samples, maximum number of samples examined per session) must be standardized. Reference standards for odors must be developed and implemented in order to achieve consistent odor quality descriptions. Development of a flavor wheel can help aid the classification and identification of odors.

Monitoring quality changes in stored frozen strawberries with time-temperature indicators

Commercially available time-temperature indicators were examined as quality change monitors for frozen strawberries during storage. Strawberries were stored under constant (−12, −18 and −35°C) and variable temperature treatments, and quality changes were evaluated at three-week intervals by sensory and chemical analysis methods. Indicator response was strongly correlated with firmness and ascorbic acid change in strawberries stored at −12°C.

Flavor Profile Analysis: Taste and Odor Control of the Future

A standard method is needed in the drinking water industry to describe the actual flavor and aroma of a water sample in a qualitative and reproducible way, and to provide a quantitative estimate of the intensities of organoleptic (taste and odor) sensations. The method should be applicable for use in all water utilities over a wide range of problems, and each water utility should be able to train its personnel to use such a method without difficulties. The flavor profile method, a method that could be developed into a standard method for sensory analysis of drinking water, is discussed.