Semi-trained Assessors Research Articles

Differences and correlations between industrial experts and semi-trained assessors in the sensory evaluation of strong-aroma baijiu using rate-all-that-apply.

Baijiu has rich and complex sensory characteristics, and how to make the sensory analysis results given by baijiu industrial experts better understood by consumers has been attracting a lot of attention. In this study, 35 strong-aroma baijiu samples were evaluated by 12 industrial experts and 21 semi-trained assessors, respectively, using rate-all-that-apply (RATA) methods, which involved 2 groups of lexicons generated by the 2 panels. The results showed that the RATA method was suitable for analyzing and distinguishing different baijiu samples by both industrial experts and semi-trained assessors. Although the industrial experts and the semi-trained assessors selected very different lexicons to describe the same strong-aroma baijiu samples, most descriptors from the expert evaluators are either positively or negatively correlated with the semi-trained assessors, such as the attributes "aldehyde," "mud," "multi-grain," and "scorched," and these attributes are effective in distinguishing different strong-aroma baijiu samples. These correlations could enable the marketing promotion and consumer evaluation of baijiu products in the future. PRACTICAL APPLICATION: The result could help baijiu market, in particular the worldwide beverage market, better understand how different baijiu samples are described and evaluated by industrial experts, and further enable the marketing promotion and consumer evaluation of baijiu products in the future.

Wild Boar Meat as a Sustainable Substitute for Pork: A Mixed Methods Approach

Sensory analysis is unusual in sustainability research, although it can offer a neoteric aspect of nature and wild animals’ perception. The study’s objective was to identify consumers’ attitudes towards plant and animal products from wild and conventional foods and put these findings into a broader social context. A blind sensory evaluation with 80 semi-trained assessors was used, segmented by gender, age, education, income, place of origin, family status, number of children, and willingness to pay. Wild boar (Sus scrofa) was chosen as an example of an overpopulated animal species occurring in the wild, which could be considered a partial substitute for pork. Statistical testing in these blind evaluations proved that wild boar meat is not considered less tasty. Therefore, wild boar meat could represent a partial substitute, complementing pork, on which consumers are willing to spend the same amount of money. Despite the mostly indifferent sensory evaluation, focus group responses showed considerable barriers to wild food. This paper concludes that possible educational and popularizing procedures are presented, including forest pedagogy, eliminating consumers’ prejudices. A mixed-methods approach within quantitative and qualitative methodology was chosen.

Seasonal Sensory Evaluation of Low Commercial Value or Unexploited Fish Species from the Portuguese Coast

Overfishing is increasing over time, and according to FAO (Food and Agriculture Organization), about one third of the world’s fish stocks are now overfished. Thus, diversifying the target species is essential for fisheries sustainability contributing to improve resource-efficient processes. Non-target species can be valuable resources for the development of new food products. However, those species are scarcely studied, and it is of high importance to trace their seasonal sensory profile as a first step towards their valorisation. Therefore, in this study, seasonal influence on sensory properties of five low commercial value or unexploited fish species, namely Trachurus picturatus (blue jack mackerel), Spondyliosoma cantharus (black seabream), Trigla lyra (piper gurnard), Serranus cabrilla (comber) and Capros aper (boarfish), was assessed in order to identify the most favourable season for catching each species. Fish samples were assessed by a panel of 16 semi-trained assessors for sensory attributes previously identified. The evaluation takes place every 2 months. Statistical differences were reported between attributes and seasons for all species, except for T. lyra, which did not present any difference in its sensory attributes throughout the year.

EVALUATION OF HETEROCLARIAS QUALITY WITH INCREASED STORAGE TIME USING QUALITY INDEX METHOD (QIM)

The quality of Heteroclarias with increased storage time using Quality Index Method (QIM) was evaluated. 140 live samples of Heteroclarias (average weight 230 + 7g) were used for the study. QIM was used to evaluate the key parameters in fish deterioration, twenty semi-trained assessors was used for the sensory evaluation. Data obtained were subjected to appropriate statistical tools using SPSS 16.0 version. Quality Index (QI) of Heteroclarias increases with increased post slaughter time when the fish was left at ambient temperatures (27 + 3°C) indicating decrease in fish quality with time. High correlation of (r=0.993) with a high coefficient of determination (R2=0.986) was obtained indicating that 98.6% of the variation in post slaughter time was explained by quality attributes; the regression equation was significant F(9, 130)=1080 (p<0.0001) indicating that it could be used for prediction and estimation of fish quality, the QI used in this study is therefore recommended to be used by relevant agencies for predicting fish quality. Practical Applications :Fish is highly perishable despite its nutritional value, consumers becoming increasingly interested in the quality of fish they consume and the physical attributes of the fish is very vital for on the spot assessment of fish quality. This study provide quality index that could be used for prediction and estimation of fish quality using sensory evaluation.

Impact of ‘free-from’ and ‘healthy choice’ labeled versions of chocolate and coffee on temporal profile (multiple-intake TDS) and liking

Product reformulation for obtaining “free-from” or “healthy choice” versions may confer significant changes in sensory characteristics which could not meet consumer expectations in terms of sensory perception. Therefore, this paper aims to evaluate the influence of formulations of different product categories on their dynamic sensory profile and consumer acceptability. A sensory panel of 23 semi-trained assessors evaluated two product categories, chocolate and milk coffee, using Temporal Dominance of Sensations (TDS) over three consecutive intakes/sips (multiple-intake TDS) on two replications. TDS allowed us to describe the dynamic profile of classic products over the three intakes and to identify differences in the sensory temporal profile compared to their 'healthier choice' reformulated versions. For the chocolate category, increasing the cocoa and the reduction of lactose content mainly influenced the dominance of sweetness, dairy, cocoa, crunchy and bitterness attributes. No sugar addition and absence of caffeine (decaffeinated version) in ready to drink milk coffee beverage modified temporal perception of sweetness, bitterness, coffee flavor and smoothness texture. Higher overall liking averages were associated with the dominant attributes of chocolate with a higher level of cacao and milk coffee decaffeinated. The obtained results of the present work suggest that the multiple-intake TDS technique can be applied for the evaluation of different food categories, helping to develop healthier products and predicting the liking.

Roasting Conditions and Coffee Flavor: A Multi-Study Empirical Investigation

This research investigates the relative importance of two roasting parameters—colour (i.e., roast degree) and time—on the sensory properties of coffee. The paper draws on data from eight studies conducted using sensory descriptive analysis with trained (in six studies) or semi-trained (in two studies) assessors, focusing on a common set of attributes. The results indicated that, while both parameters significantly affected coffee flavour, colour was the stronger predictor of the two. The effects direction for both colour and time were similar and related to the rate of non-enzymatic browning, with darker roasts/longer roasting times associated with an increase in bitterness and a decrease in acidity, fruitiness, and sweetness. With respect to roasting time, we distinguished two phases, “time to first crack”, corresponding to the time between the onset of roasting and the moment where the accumulated steam pressure causes the beans to crack, and “development time”, corresponding to the time elapsed from the first crack to the end of the roasting process. The results clearly indicated that, under the same colour, time variation also influenced flavour, and in particular, development time, rather than time to first crack, had the largest effect on coffee flavour.

Check-All-That-Apply (CATA) with semi-trained assessors: Sensory profiles closer to descriptive analysis or consumer elicited data?

Check-All-That-Apply (CATA) is a simple and fast sensory profiling tool. Yet, its application has been mainly focused on consumer studies; the aim of this study was to evaluate the application of CATA with semi-trained (ST) individuals (N = 37). ST individuals were consumers who underwent 1 h of training with physical references on the definition of attributes included in the CATA ballot. ST-CATA results were compared, on a panel level, to Descriptive Analysis (DA) with trained panellists (N = 8) and to CATA with consumers (N = 70). Moreover, the effect of training was examined, to uncover training vs. method-related variations in CATA profiling.ST-CATA and DA exhibited the highest similarity in sample configurations (94%) for two Multiple Factor Analysis factors. For all 3 factors, similarity was over 95% for all method combinations; however the RV coefficient between consumers and DA was marginally significant (P = .08). The extent of explained sensory variations in ST-CATA was not negatively affected by the smaller panel size, compared to consumers’ CATA. Training had a positive effect on attributes’ citation frequency, identification of taste, flavour and complex attribute differences among samples. CATA results did not provide the same range of differences with DA, especially for texture.Overall results support the validity of CATA with ST assessors and suggest its potential for industrial use, when a timely and cost-efficient description of products is required. Attention should be given though when a detailed quantitative profile of sample differences is required, since intensity is not well represented by CATA derived measurements due to the method constraints.

Rate-all-that-apply (RATA) with semi-trained assessors: An investigation of the method reproducibility at assessor-, attribute- and panel-level

Rate-all-that-apply (RATA) is a variant of check-all-that-apply (CATA) questions that allows assessor to rate the intensity of selected attributes. Compared to CATA, RATA has the potential to improve sample description and discrimination, and might be more useful when only a small number of assessors are available. Before advocating its use with confidence, investigations on the method validity and reproducibility are necessary.Within this context, this short paper examined the reproducibility of results obtained by RATA within a test–retest paradigm, drawing on data from a case study involving sensory assessment of common defects in chocolate production. Criteria considered were within-assessors reproducibility, attribute stability, and configurational agreement between samples spaces obtained across replicated evaluations. The results showed that although within-assessors reproducibility was moderate, RATA exhibited a very good reproducibility at panel level, as indicated by the high configurational agreement between product maps obtained from individual replicates. The method showed a good reproducibility also at the level of individual attributes. Indications were obtained that the reproducibility of RATA with semi-trained subjects might be similar to that of a simple checklist, in spite of the addition of the intensity rating step.Overall, the work presented in this short paper supports the validity of RATA as a sensory profiling tool, and suggests that its application with semi-trained assessors may be particularly advantageous for industrial applications.

Dynamic sensory characterization of cosmetic creams during application using Temporal Check-All-That-Apply (TCATA) questions

The evolution of sensory characteristics during the application of cosmetic creams has been long recognized as important. However, standard methodologies do not evaluate how sensory characteristics of products change during application, and do not determine the onset of specific sensations. In this manuscript, a new temporal methodology, Temporal Check-All-That-Apply (TCATA), is used to enable characterization of the dynamic sensory properties of cosmetic creams during application. Six cosmetic emulsions were evaluated by 22 semi-trained assessors in duplicate using TCATA. Nine sensory attributes were considered: sticky, difficult to spread, easy to spread, white residue, fresh, smooth, waxy, greasy, and oily. Data were analyzed using line plots, difference curves, and correspondence analysis. The temporal profiles of the products during application were determined and fitted expectations due to changes in their rheological properties, water evaporation, and absorption into the stratum corneum of the skin, which cause changes in the structure of the film of product left on the skin. Differences in the temporal profiles of the samples were identified and explained by differences in their formulations, which indicates the validity of the data collected using TCATA with semi-trained assessors. These results show the potential of TCATA for characterizing the dynamic sensory profile of cosmetic creams during application, which opens new possibilities to sensory characterization of other cosmetic products.

How many assessors are necessary for the Optimized Descriptive Profile when associated with training?

The number of assessors composing a descriptive analysis panel directly affects the costs for executing the sensory methodology. For the Optimized Descriptive Profile (ODP) method which uses semi-trained assessors, at least sixteen assessors are necessary to make up the panel, where the criteria magnitude of the experimental error estimate is most robust and demanding for determining the ideal number of assessors. Thus, the inclusion of training may result in reduced random variability in the data (experimental error), and therefore require fewer assessors to obtain reliable results. The present study therefore sought to evaluate the influence of training the panel to determine the ideal number of assessors for the ODP evaluation protocol. The study on determination of the number of assessors was conducted via a computer simulation, using the re-sampling with replacement technique from original data obtained by a panel of 26 trained assessors. A total of 10,000 subgroups were simulated for each number of assessors. The criteria for determining the number of assessors were: obtaining an experimental error less than or equal to the effect verified in the reference methodology (Conventional Profile); size of the effect of the interaction between the formulations and assessors less than or equal to the full panel; discrimination of samples similar to that obtained by the complete panel; and minimum loss of information in the sensory map. The discrimination criterion of the samples showed to be a more robust measure for determining the number of assessors required by the ODP technique when associated with training of the panel, with recommendation of at least eight assessors. Training of the panel had a great influence on data quality, providing a 50% reduction in the number of assessors required for the ODP.

Sensory and Instrumental Consistency of Processed Cheeses

&lt;p&gt;The objective of this study was to evaluate the instrumental and sensory texture of seven cheeses, as well as correlate sensory measurements of texture with mechanical properties. The cheeses were composed of different types of basic mass (casein and whey proteins) and emulsifying salts. Instrumental analysis of texture was performed using the universal mechanical testing machine (Instron) for determining the properties of firmness, elasticity, adhesiveness, gumminess, chewiness and cohesiveness. Data was analyzed using the principal component analysis and clustering analysis. Sensory texture was evaluated by a group of semi-trained assessors according to the ranking-difference test for texture of the products. The results were analyzed by the Friedman test; while sensory and instrumental texture measurements were correlated by the Spearman correlation coefficient. With regard to sensory and instrumental texture of the cheeses, the formation of three groups was observed: a first group consisting of cheeses with intermediate texture, another consisting of softer products and a third group formed of more consistent cheeses. Texture differences of the cheeses were determined by their protein and emulsifying agent composition. Sensory consistency presented a significant correlation (|r&lt;sub&gt;s&lt;/sub&gt;| &amp;gt; 0.90 and p &amp;lt; 0.01) with the properties of mechanical: firmness, adhesiveness, chewiness and elasticity. On the other hand, the sensory texture measurement is not correlated with the instrumental measurements of gumminess and cohesiveness, indicating that they do not reflect the human perception of cheese texture.&lt;/p&gt;

Relationship between sensory and instrumental analysis of 2,4,6-trichloroanisole in wine and cork stoppers

The effect of different corks stoppers on the sensory and instrumental determination of 2,4,6-trichloroanisole (TCA) was studied in wine and cork. A relationship between both measurements was also established. Four types of cork were used to seal white wine bottles for 8 months. The stoppers were from different raw material: a high quality commercial batch (C), slabs with yellow stain (YS) and slabs with a high musty and mouldy taint (T). Spiked samples (S) were prepared from C batch by injecting 1002 ng of TCA into the cork stoppers. TCA was determined by gas chromatography with electron capture detection after headspace solid phase microextraction in bottled wine (12 per group) and after extraction with pentane in the case of corks (six per group). Seven semi-trained assessors evaluated the different samples using a ranking test in 12 and six sessions for wine and cork stoppers, respectively. Wines and corks from S samples showed the highest TCA values in both sensory and instrumental measurements, the lowest values being for C samples. YS and T corks had intermediate values, although in general TCA concentration was higher in T. A slight tendency to increase the TCA content in stoppers with yellow stain compared to C samples was observed in wine. A high correlation coefficient ( r=0.82) was found between sensory and instrumental analysis for wine, whereas this coefficient was much lower ( r=0.56) for cork stoppers. Some hypotheses are given in order to explain these differences.

Kinetics of sensory quality changes in soymilk during thermal processing, by parametric and non-parametric data analyses

Soymilk was subjected to various heat treatments at 90, 120 and 140 °C for various lengths of time. The colour and flavour of the soymilk samples were evaluated by a sensory panel consisting of eight semi-trained assessors on (1) a 9-unit hedonic scale, with analysis based on the assumption that the units are equidistant, and (2) a 15-point hedonic ‘Smiley’ pictorial scale, the results being analysed non-parametrically. The proportion (%) of ratings higher than or equal to/higher than the overall median of the samples was used as a rigorous estimate of product quality. These values were used to determine the colour and flavour changes in heated soymilk and their temperature dependence. The Z-values derived from the parametric and non-parametric analyses were in close agreement, ranging from 31 to 33 °C and from 30 to 32 °C for colour and flavour respectively. © 2000 Society of Chemical Industry