In this work we evaluated different varieties of garlic. All varieties of garlic are rated from one harvest year. Compared samples were different in shape, taste, aroma and characteristics, which were likely to impact on consumer choice and deciding on purchases garlic. Selected indicators were part of internal sensory evaluations, which were evaluated by experts in the sensory laboratory. External part of the preference mapping was conducted among consumers relying on different varieties of garlic under their consumption. Using the internal part of the preferential mapping we summarize randomly selected characteristics within the textural properties and characteristics of taste in which we consider the possible impact on consumer´s choice. In the sensory evaluation assessors used 9 point scale to evaluate 15 selected properties across the texture, taste and aroma on 10 selected varieties according to the degree of preference. Garlic odour and textural properties were evaluated by the normal procedure, though the taste because of intense lingering aftertaste of has been evaluated in a prepared mixture after cooking. For external evaluation, we designed a questionnaire in which consumers can express their preference for individual samples based on photo and variety characteristics, using a hedonic scale from 1 to 9. Obtained data from sensory evaluation and a questionnaire survey were evaluated using statistical software XLSTAT. Preferential map summarise results from internal and external evaluation. We identified characteristics affecting the degree of consumer preferences according to the visualization of our results.
Preferential mapping is a way to statistically combine analytical sensory results, consumer information and product perception. Using analytical sensory data and consumer technology, it is possible to obtain a complete product image (
Garlic (
The aim of the study was to determine consumer preferences to selected varieties of garlic. By selecting different varieties, we wanted to highlight the diversity of garlic offered on market and identify the properties that are decisive for the consumer.
We evaluated ten samples (Figure
Samples of winter garlic varieties.
Apples were used as a neutralizer for odour determination. We have included the odour neutralizer in the review due to the intense sensory burden of the evaluators that we have been alerted to during the trial evaluation. Similarly, due to the extreme sensory load and the long-lasting aftertaste when using a raw garlic sample, we chose to evaluate the taste properties of the mixture. The prepared appetite blend comprised: 250 g of chicken, 15 extruded garlic, 2 g of salt, 1 g of pepper and 2 g of red pepper. The mixture was heat treated. Garlic was added to the mixture 2 minutes before the end of the heat treatment. The external part of the evaluation was done by using a questionnaire. The questionnaire included a description of the characteristics of the varieties with the attached photographs. The evaluators had the opportunity to express their preferences on a 9 point hedonic scale. 150 respondents were involved in the evaluation.
The data obtained from sensory evaluation and questionnaire survey, were evaluated using the XLSTAT statistic software (v. 2019.1.2, Addinsoft). Internal data sets from the sensory analysis were evaluated by principal component analysis (PCA). External data sets were evaluated by agglomerative hierarchical clustering (AHC). By combining these data set we have obtained preference map.
From the PCA (Figure
Evaluation using principal component analysis (PCA).
High values have been observed in the evaluation of the earthy taste, spicy odour, earthy odour and colour. In general, these samples, along with sample 2, had high ratings in all selected properties. Sample 2 recorded slightly lower ratings when assessing the odour intensity, spicy, sour odour and colour.
By processing the survey data for the 150 respondents (Figure
Preference map.
Samples placed in the lower consumer preference zone 5, 9 and 1 received average ratings in assessing the shape, size, appearance after cutting, hardness, sweet and earthy odour, sweet and earthy taste. Low ratings have received these samples in evaluating colour, odour intensity, spicy and sour odour, authentic taste, spicy and sour taste. Samples 3, 7, 8, and 10 were placed in the lowest consumer preference zone (0 – 20%). These samples were evaluated based on a PCA of average rating for colour, sour and earthy odour, authentic taste, spicy and sour taste. Samples 3, 7, 8, and 10 received a low rating in assessing the shape, size, appearance after cutting, hardness, sweet and earthy taste. In consumer studies on tomatoes, the consumer's emphasis on commodity appearance was more pronounced than the taste of subsequent tasting (
In a similar study comparing the importance of external and internal properties of tomatoes on the market, the colour was the most significant attribute, followed by size and juiciness (evaluated after slicing), followed by strength after hand pressure, the taste itself was much less important (
Eight clusters (Figure
Agglomerative hierarchical clustering.
Consumers focus on textural features when buying (
Kitchen garlic is a plant which is very often used in traditional and modern gastronomy. It is part of many foods and food products. Garlic with its distinctive taste and odour characteristics is a diversification of every meal. There are many varieties of garlic in the world that differ from those native to garlic, which are significant in addition to the taste and smell indications of their broad-spectrum positive health effects. Evaluators of garlic are very demanding, and it is necessary to select a sensitive methodology to achieve the desired result. Especially the intense smell and the long-lasting aftertaste of garlic, which prevents the ingestion of multiple samples in a row in the raw state, is a complication in sensory analysis. For this reason, we evaluated the scent neutralizer and the taste evaluation in the mixture after the heat treatment to evaluate the flavour intensity and its overwhelming after ingestion. By processing the data, we found that the evaluators in the internal evaluation section, as well as the respondents involved in the external part of the preference mapping, were key features for decision-making colour, hardness, size and appearance after cutting, and thus predominantly textural features of the evaluated plant commodity. In the highest consumer preference zone (80 – 100%), samples 2, 4 and 6 was placed on the basis of the specific characteristics of the products included in the survey. These samples, based on the analysis of the PCA of the evaluation of the characteristics examined, showed the following characteristics: shape, size, colour, appearance after cutting, hardness, odour intensity, spicy, sweet, sour and earthy odour, authentic taste, spicy, sweet, sour and earthy taste. The lower scoring was observed for sample 2 when evaluating colour and odour intensity. Sample 4 reported a lower rating for the sweet odour and sweet taste. Sample 6 did not report a low score in either of the endpoints, however, it received moderate evaluations in assessing hardness and spicy taste.
Samples placed in the lower consumer preference zone 5, 9 and 1 received average ratings in assessing the shape, size, appearance after cutting, hardness, sweet and earthy odour, sweet and earthy taste. Low ratings have received these samples in evaluating colour, odour intensity, spicy and sour odour, authentic taste, spicy and sour taste. Samples 3, 7, 8, and 10 were placed in the lowest consumer preference zone (0 – 20%). Based on the PCA, these samples received average ratings for colour, odour, sour and earthy odour, authentic taste, spicy and sour taste. Samples 3, 7, 8, and 10 received a low rating in assessing the shape, size, appearance after cutting, hardness, sweet odour, sweet and earthy taste.
Based on the results we would like to state that the samples with attractive appearance are partly overestimated by the assessors in all evaluated properties. The findings from the internal part of the evaluation were confirmed by the analysis of the clusters, which suggests that the vast majority of respondents in the research focus on garlic based on the perception of textural properties of garlic, especially shape, colour, size and hardness. The observations also show that the basic indicative characteristics of the evaluation are the sweet and spicy taste and odour as well as the degree of acidic and earthy taste and aroma in evaluating the taste and odour characteristics of garlic.