Sensory Terms Research Articles

Foam Characteristics and Sensory Analysis of Arabica Coffee, Extracted by Espresso Capsule and Moka Methods

The coffee extraction methods modify the structure of the foam (when it is present) and the sensory profile of the beverage. In this research, three ways of extracting and two varieties of 100% Arabica were compared. Nineteen bars and fifteen bars were applied to the coffee thanks to the use of compatible capsules and machines. The method with the moka was considered, which acts at low pressures and does not allow the formation of foam (crema). In addition, the Brazil and Guatemala Arabica varieties were considered to understand the extent to which Arabica coffee can respond in structural and sensorial terms to the extraction techniques applied. The results show that 19-bar espresso coffees have a very stable crema with very small bubbles, which give a uniform and fine structure to the coffee crema. On the contrary, the pressure at 15 bars generates more unstable foams and bubbles that tend to be disproportionate, with more marked effects in the Brazil variety. The sensory profiles of the coffees respond to the extraction techniques applied. While the coffee extracted with the moka has sensory descriptors with rather low values, those obtained at 19 and 15 bars have much wider profiles. In conclusion, different pressure intensities to the coffee extraction affect the quality of crema and the solubilization of organoleptically active compounds.

The Stevens law and the derivation of sensory perception

The Stevens law, S = k I n , is commonly accepted as a landmark achievement in the field of sensory psychophysics and has been widely applied in food sensory research. The theory effectively links the two parameters of very different nature, the intensity of sensory perception ( S ) and the intensity of physical stimulus ( I ). However, the Stevens law suffers from two major drawbacks. The equation was self-inconsistent in terms of the units, which makes equation questionable in principle. The Stevens law was also found inapplicable when multiple physical stimuli are involved in the perception of a sensory attribute. To solve the first drawback, we propose to replace the absolute stimulation intensity in the Stevens law with a relative intensity, S = k( I / I 0 ) n . The modified Stevens law becomes self-consistent when both sides of the equation are dimensionless and the theory is applicable regardless of the unit of the physical stimulus. To solve the second drawback, a concept of sensory derivation is introduced and so sensory properties can be categorized as primary sensory and derived sensory. The former can be described effectively by the Stevens law, while description of the latter is beyond the applicability of the Stevens law because of the involvement of multiple sensory stimuli or multi level sensory derivation. Furthermore, a sensory hierarch is constructed with sensory perception of different nature at different levels, including the primary sensory at the basic level and derived sensory perception at progressing levels. The modified Stevens law provides a self-consistent model for psychophysical analysis of sensory perception. The proposed sensory hierarchy helps to streamline sensory terms and attributes and may be used as a useful guide in establishing instrumental analysis of sensory perception.

Effect of the type and degree of alkalization of cocoa powder on the physico-chemical and sensory properties of sponge cakes

Alkalization is a crucial process during cocoa processing to reduce its bitterness, improve solubility and develop color. Alkalization can be performed out at several points of the process (nib or cake), with different agents and at various intensities. All these variables may affect cocoa properties, but also physico-chemical and sensory properties of derived products (i.e. cakes). This work aims to evaluate the impact of alkalization type (nib vs. cake), alkalizing agent (K2CO3, NaHCO3 and KOH) and process intensity (mild and strong) on the physico-chemical and sensory properties of sponge cakes. For this aim, 8 different alkalized powders were industrially produced and used in the preparation of sponge cakes. Alkalizing conditions significantly affected cocoa properties (pH, color, sensory properties) and those of the corresponding cakes (cake doughs color and rheology, as well as baked cake color and texture). In general, doughs prepared with cocoas alkalized under strong conditions were a 55 % darker and a 15 % less elastic. After baking, the corresponding cakes were a 17 % darker (L*) and a 12 % harder in texture. Despite these differences, all the cakes were equally rated by consumers in sensory terms demonstrating that for this application, alkalization variables do not condition consumer acceptability.

Differences in citation proportions in CATA questions can be interpreted as differences perceived intensity of sensory attributes

AbstractCATA (check‐all‐that‐apply) questions enjoy high popularity for sensory product characterization with consumers. Amidst extensive methodological characterization, the meaning of term citation frequency has received modest attention only, possibly hindering further uptake. The present research performed a more detailed exploration of the relationship between CATA responses and perceived intensity of sensory attributes. In addition, the following question was addressed: How many consumers are necessary to interpret differences in CATA citation proportions as a proxy of differences in perceived intensity? The present research includes new empirical data from four consumer studies conducted in New Zealand and China under central location test conditions and a re‐analysis of one consumer study. When dealing with samples with clear differences, the percentage of consumers selecting a sensory term for describing samples tended to be linearly correlated to average intensity ratings. A median of 15 consumers was needed for CATA to show good linear correlations with average intensity ratings, and the minimum number of consumers needed to reach the threshold for a good correlation was generally lower than 30.Practical ApplicationsResults add to existing guidelines and say that for sets of sample sets with at least moderate differences in a specific attribute, a minimum of 50 consumers is necessary to obtain reliable sensory characterizations using CATA questions and interpret differences in citation proportions as a proxy for differences in the perceived intensity of that attribute. However, practitioners should be aware of the limitations of CATA questions for measuring attribute intensity, such as studies involving complex terms or samples with subtle intensity differences.

Sensory Lexicon and Major Volatiles of Rakı Using Descriptive Analysis and GC-FID/MS

Rakı is a traditional and Protected Designation of Origin (PDO) alcoholic beverage that is distilled from grape distillate with Pimpinella anisum L. in copper pot stills in Turkey. This study focused on the development of a sensory lexicon, a sensory wheel, using a consensus approach and the determination of major volatiles by GC-FID/MS for Rakı. A total of 37 Rakı samples representing all producers were used for volatile and sensory evaluation. The experts identified 78 attributes and references for the lexicon. The main attributes were spicy, anise, sweet, resinous, fruity, dry fruit, floral, head&tail aroma and white colour. The Rakı sensory wheel was created to provide a graphical display of its sensory attributes. For validation of the lexicon, 18 samples were evaluated using descriptive analysis. The results were subjected to PCA to examine the relationship of the samples with the defined sensory attributes. The PCA results show that there is a significant relationship between the Rakı categories and sensory terms and flavour intensities. The GC-MS analyses depicted the following major volatile compounds n-propanol, 2-methyl-1-propanol, 2 and 3-methyl-1-butanol, ethyl-acetate, acetal, acetaldehyde, trans-anethol and estragole. The characterization of the product using its most distinctive sensory descriptors are important tool and can be used for the industry, marketing, consumer education and scientists.

Development of pineapple and wine flavored fermented dairy product

The objective of this work was to take advantage of buttermilk and whey for the development of a pineapple and wine flavored fermented dairy product and to characterize the product in physicochemical, microbiological and sensorial terms. The experiment was carried out through four treatments with the following formulations: T0 (70% UHT skim milk and 30% whey), T1 (70% buttermilk and 30% whey), T2 (60% buttermilk and 40% whey), T3 (50% buttermilk and 50% whey). The average treatment values did not differ among themselves, at a 5% level of significance, regarding pH, acidity, viscosity and color. The protein and fat levels decreased with the increase of the amount of buttermilk in the treatment formulations. There was no significant difference, at a 5% level of significance, in the average acceptance values of the 57 judges for flavor, texture, aroma, color and overall impression, with values above 8.0 (9 point scale) for all attributes. In the purchase intention test, there also were no differences, with averages superior to 5.4 (7 point scale) for all formulations. All formulations had counts of total coliforms and E. Coli within the acceptable range, taking into consideration the legislation for fermented dairy beverages. Regarding the lactic acid bacteria, the counts were superior to 1.3 x 107 CFU g-1 and also in accordance with the legislation. It was concluded that the use of buttermilk in the production of fermented dairy products is technologically feasible.

Different psychophysiological and clinical symptoms are linked to affective versus sensory vicarious pain experiences.

For some people, seeing pain in others triggers a pain-like experience in themselves: these experiences can either be described in sensory terms and localized to specific body parts (sensory-localized, or S/L) or in affective terms and nonlocalized or whole-body experiences (affective-general, or A/G). In two studies, it is shown that these are linked to different clinical and psychophysiological profiles relative to controls. Study 1 shows that the A/G profile is linked to symptoms of Blood-Injection-Injury Phobia whereas the S/L profile shows some tendency toward eating disorders. Study 2 shows that the A/G profile is linked to poor interoceptive accuracy (for heartbeat detection) whereas the S/L profile is linked to higher heart-rate variability (HRV) when observing pain, which is typically regarded as an index of good autonomic emotion regulation. Neither group showed significant differences in overall heart rate, systolic blood pressure (SBP), or skin conductance response (SCR) when observing pain, and no overall differences in state or trait anxiety. Overall, the research points to different underlying mechanisms linked to different manifestations of vicarious pain response. Affective-General pain responders have strong subjective bodily experiences (likely of central origin given the absence of major differences in autonomic responsiveness) coupled with a worse ability to read objective interoceptive signals. Sensory-localized pain responders have differences in their ability to construct a multi-sensory body schema (as evidenced by prior research on the Rubber Hand Illusion) coupled with enhanced cardiovagal (parasympathetic) reactivity often indicative of better stress adaptation.

Influence of wine traits and context on liking, intention to consume, wine-evoked emotions and perceived sensory sensations

Wine consumption is a sensory experience that can evoke a wide range of emotional responses and heterogeneous hedonic reactions, that also depend on the circumstances in which the product is consumed. The recent literature has extensively addressed emotions elicited by wine consumption; however little research has been done on the effect of the context of consumption. This study focuses on how testing contexts and Chianti wine traits impact on liking, desire to consume again, wine-evoked emotions and perceived flavour, by comparing measurements recorded in a standard sensory laboratory (CLT), in an evoked consumption situation (images and self-description of their own habitual context of consumption) (CLT-evoked) and in a home use test in natural testing conditions (HUT), on commercial Chianti wine samples by regular consumers of red wine.The results of this study show that liking and intention to consume did not vary significantly among the test settings. This finding would suggest that the testing conditions have low relevance compared to the wine samples. However, the context influenced emotion and sensory terms. In the home use test a lowering of scores was found, both for positive and negative emotions and for sensory terms. In the HUT context a longer time for testing resulted in a better product separation.Pleasure of Chianti wine was associated with the emotions: pleasant, peaceable, joyful, amusing, and best correlated with the sensory attribute sweet. Unpleasantness was associated to the emotions: aggressive, disgusting, and overwhelming, and with the sensory terms acid, dry, astringent. Level of arousal was positively associated with euphoric, passionate, and keen, and well correlated with spicy and persistent as sensory characteristics.

“It Feels Right to Me”

Focusing in particular on how affect theory has been informed by art practice, this article develops the concept of the “sovereignty of the senses” through queer and feminist installation projects by Rachael Shannon and Zoe Leonard, as well as Alison Bechdel’s account of retreat from the social in her graphic narrative memoir Are You My Mother? (2012). Aiming to articulate notions of sovereignty, democracy, and freedom in affective and sensory terms, it conceives of sovereignty as an embodied practice and something that must be learned and experienced collectively over time rather than a fixed condition of a discrete individual or nation. It explores tensions between Indigenous notions of sovereignty and queer notions of the antisocial or non-sovereign, as well as recent discussions of the commons as an affective category, to offer an anti-racist and decolonial account of queer feminist affect theory and cultural politics.

Culinary quality and sensory profile of cassava varieties harvested at different ages

Sweet cassava must be rapidly cooked and meet the sensory and technological requirements of consumers. The objectives of this study were to evaluate the culinary quality of sweet cassava varieties harvested at three ages and obtain the sensory profile of these varieties using the check-all-that-apply method (CATA). Roots of three cassava varieties released or recommended by Embrapa (BRS Aipim Brasil, BRS Dourada and Saracura) and the commercial variety Eucalipto, harvested at nine, 12 and 15 months of age, were evaluated for physical, chemical and sensory aspects. At nine months of age, the Saracura, BRS Aipim Brasil and BRS Dourada varieties did not differ in cooking time, averaging 41.62 min. The Eucalipto variety had similar cooking times at the three harvest ages, averaging 21.83 min. There was a difference between the four varieties at nine months, with Saracura exhibiting the lowest acceptance score (5.0) and differing from the Eucalipto variety, which showed an average score of 6.3. At 12 months of age, there was a significant increase in the acceptance of the Saracura and BRS Aipim Brasil varieties, which did not differ from Eucalipto and had an average score of 6.4. Consumers perceived differences between the sensory characteristics of the cassava varieties using CATA. The sensory terms “creamy”, “soft” and “sticky” can be associated with greater acceptance of cooked cassava roots, whereas terms such as “floury”, “slightly bitter”, “no taste”, “hard” and “fibrous” can be associated with less acceptance and are therefore undesirable from the consumer’s point of view. Principal component analysis showed that the age at which the roots were harvested had a great effect on the culinary quality of cassava, regardless of the evaluated variety. The commercial variety Eucalipto was well-accepted by the consumers irrespective of root age and can be harvested at any of the evaluated ages. For the Saracura, BRS Aipim Brasil and BRS Dourada varieties, harvesting is recommended at 12 or 15 months so that better quality roots are obtained.

Utilizing Consumer Perception of Edamame to Guide New Variety Development

Consumption of edamame (vegetable soybeans) has increased significantly in the U.S. over the last 20 years. Although market demand has been increasing, most edamame is still imported from Asian countries. A team of multistate plant-breeding programs in the mid-Atlantic and Southeast U.S. has focused on developing new breeding lines that grow well in the U.S. and deliver what domestic growers, processors and consumers need and expect from their edamame. In our study, sensory evaluation was used to identify edamame genotypes and sensory attributes preferred by consumers to support breeding selection criteria. In the first year (reported as our “screening study”), 20 edamame genotypes were grown in three locations: Newport, AR, and Blacksburg and Painter, VA. In the second year (reported as our “validation study”), 10 edamame genotypes selected after our screening study were grown in Blacksburg and Painter, VA, Portageville, MO, and Stoneville, MS. In both years of research, untrained participants (adults; vegetable consumers not allergic to soy; N ≥ 50) used a traditional 9-point acceptability (hedonic) scale (1 = “dislike extremely”; 9 = “like extremely”) to evaluate overall-liking, aroma, appearance, taste, and texture, and a 5-point scale (1 = “not sweet,” 5 = “extremely sweet”) to evaluate sweetness intensity. Next, participants used a check-all-that-apply (CATA) list of selected sensory terms to describe the sensory characteristics of each edamame sample. Overall acceptability of edamame genotypes was significantly different among all genotypes (p < 0.05). Samples described as “bitter,” “sour” (flavor) or “starchy” (texture) were associated with lower acceptability scores while “salty” and “sweet” (flavor) were correlated with higher acceptability. Sensory data from the screening study were used to select the best genotypes by use of a defined decision process based on the consumer data. The validation study tested the selection decisions and further supported the genotype choices. Sensory evaluation is a powerful tool to direct breeders to improve market acceptability and develop new edamame genotypes. Both screening and validation studies illustrate the significant role of consumer sensory data in support of genotypes targeted for domestic (U.S.) production.

Access to wine experts' long-term memory to decipher an ill-defined sensory concept: the case of green red wine

The present study aims to understand an ill-defined sensory concept by a long-term memory-based strategy with Spanish winemakers from four wine regions using “green wine” as a case study. A total of 77 Spanish winemakers from four Spanish wine regions carried out a non-tasting free description task. The description task yielded terms belonging to two main categories including origin-related terms as well as sensory terms. Sensory terms belonged to aroma, taste, trigeminal, colour, multimodal and hedonic subcategories, which elucidates the multidimensionality of the studied concept. The most cited specific terms were “vegetal aroma”, “bitter” and “unpleasant”. Despite these commonalities, a certain idiosyncrasy linked to taste (“excessive sourness”) and trigeminal (“astringency”) subcategories as well as to wine components (“tannins”) was evidenced as they were cited distinctly by experts belonging to separate wine regions. The capacity of approaches based on long-term memory to decipher multidimensional and ill-defined concepts is highlighted. The regional effect is also explained in terms of cognitive processes (i.e., knowledge and experience), which is linked to the use of sensory concepts by wine experts.

EXPLORING SENSORY EXPERIENCE OF THE DUBAI CREEK

Tourism is the fastest growing sector of the global economy and one of the key driving force of growth and development of the country. Current tourism literature highlights the sensory aspects of destinations is crucial to facilitate positive and memorable tourist experiences. The paper aims to investigate how tourists perceive, sense, think, and record their particular destination and also to understand how their feelings about that particular place have elicited in the form of emotional expressions and create positive memories. The objective is to investigate whether the Khor Dubai (Dubai Creek in English) acts as cultural heritage landscapes and an integral component of city and whether it offers sensory based memorable experiences. The results suggest that Dubai Creek has a lot of emotions to offer: the photos and sensory terms used in the actual survey brings the sensorial emotional appeal, and its history offers nostalgia-laced place-making specific spots like the Old Town, Souq (Souk) Al Bahar which offers the tourists sense of exhilaration and a deep sense of enjoyment and reinforce positive memories able to retain tourists for ages. This study describes the novel method of not only measuring the tourist experience, but also helps to develop branding initiative and to build a unique destination identity to Dubai.

Optimization of pretreatment and enzymatic hydrolysis conditions of tomato pomace for production of alcohols and esters by Kluyveromyces marxianus

Tomato pomace (TP) is generated as a natural by product in a significant amount in the tomato processing industry, and it is a good source of lignocelluloses to produce some high-value products from fermentable sugars (FS). The present study was performed to produce FS by using either ultrasound-assisted dilute acid (UADA) or heat-treated dilute acid (HTDA) pretreatments of TP followed by enzymatic hydrolysis (EH). When HTDA and UADA were compared in terms of FS (g/L) concentration, HTDA pretreatment generally produced more FS content than UADA. The optimum conditions for HTDA pretreatment were the application of 2.5% H2SO4, 10% (w/v) solution of TP, and heating at 121 °C for 6 min, which yielded 31 g/L FS concentration. Beside the optimized conditions for EH of HTDA, pretreated TP required 1.5% of enzyme concentration and 6 h of hydrolysis time. In conclusion, the most abundant volatile organic compounds (VOCs) produced by K. marxianus in final tomato pomace hydrolysate (TPH) were isoamyl alcohol, phenyl ethyl alcohol, ethyl acetate and phenyl ethyl acetate in a 5-L bioreactor. Nine descriptive sensory terms were developed to characterize fermented TPH. The rose and sweet floral aromas were defined as aroma characteristics for TPH fermented by K. marxianus.

Formation and Retrieval of Associative Memory for a Complex Signal in Mice: Specific Involvement of Hippocampal Field CA1 Neurons

Most important events in the environment are complex in sensory terms. Integration of multimodal information relating to such complex signals by the brain is regarded by many investigators as a biological function of very early forms of consciousness. We report here use of a model of associative learning in mice in which electrocutaneous stimulation was combined with a complex conditioned signal consisting of simultaneous presentation of light and sound stimuli. These studies showed that mice successfully learned and formed long-term memory in a task consisting of conditioned reflex freezing in response to a complex conditioned stimulus. Immunohistochemical mapping of the neuronal expression of the c-fos gene in the hippocampus and associative retrosplenial cortex was performed to study the neural substrates of this memory. We found that only hippocampal field CA1 and not other areas of the hippocampus or the retrosplenial cortex underwent activation on retrieval of the associative memory for the complex conditioned signal, while its components produced no hippocampal activation. In addition, field CA1 showed a strong positive correlation between the level of freezing on retrieval of the memory and the number of neurons activated by retrieval of the memory. Thus, it can be suggested that hippocampal field CA1 is specifically involved in forming and retrieving associative memory for complex signals in the natural environment.

Using stepwise backward elimination to specify terms related to tactile sense for product design

The tactile sense plays a crucial role in the evaluation of products by providing important information pertaining to the material properties of the products. Designers must reach a consensus with target consumers regarding the perception of touch and the terms used to describe it. In this paper, Cronbach’s alpha (used in reliability analysis) and the Kaiser-Meyer-Olkin test (used in factor analysis) are proposed to consider in assembling a reliable set of sensory terms applicable to the description of consumer products. Stepwise backward elimination is used to eliminate ambiguous and imprecise terminology in order to derive highly specific words that are representative of the tactile sense. Factor analysis is then used to assign the resulting terms to two categories: material strength and surface texture. These two categories are classified to the evaluation dimension proposed by Osgood et al. (1957) [1]. This study departed from many previous works in eliminating the visual sense from all analysis. The resulting terms provide a valuable reference for the selection of materials and act as a guide to communication with potential consumers.

Kelly’s repertory grid method applied to develop sensory terms for consumer characterization (check-all-that-apply) of omega-3 enriched bologna sausages with reduced sodium content

This work aimed to apply the Kelly’s Repertory Grid methodology to obtain sensory terms to be applied in the Check-all-that-apply (CATA) question to describe bologna sausages enriched with omega-3 through the addition of Echium oil. Three formulations of bolognas were processed: Control (100% pork back fat), T25 and T50 (with 25 and 50% replacement of pork back fat by Echium oil, respectively). The sensory terms characterizing the sausages, developed by Grid method, were evaluated by CATA questionnaire. Results showed that Control and T25 samples were considered sensorially similar, differing from T50 (p < 0.05). One can conclude that the Grid method could be a good option to develop reliable terms to describe bologna sausages through CATA. In addition, it is possible to replace 25% of pork back fat with Echium oil to produce a healthier meat product with desirable sensory characteristics.

Application of the CATA methodology with children: Qualitative approach on ballot development and product characterization of innovative products

There is an increasing importance of the role of children and adolescents in the food market and to successfully develop food products intended for them, it is necessary to apply proper sensory evaluation methodologies. Although children can execute traditional methods for food liking and preference evaluation, traditional sensory descriptive methods may not be suitable for them and it is necessary to assess their ability to perform novel sensory profiling methods. Thus, this study aimed to assess children’s acceptance of an innovative food product – cookies incorporating fermented grass pea (Lathyrus sativus) flour – and their ability to describe a sensory profile using a Check-All-That-Apply (CATA) approach. Two different types of cookies (salty and sweet) were developed, differing in the level of substitution of wheat flour by fermented grass pea flour (between 0 and 40%). The cookies were evaluated by two sensory panels of 60 children (8–12 years), who assessed the overall liking using a 7-point facial hedonic scale and the sensory profile of the samples using a CATA ballot with 21 sensory terms previously developed through focus groups with children. Children showed the ability to discriminate the different samples with the hedonic scale and according to their sensory profile. Results revealed that the focus-group with children is an adequate way to generate CATA ballots and that the CATA approach is adequate to evaluate how children discriminate the sensory profile of food products. Furthermore, the food neophobia level of the children negatively impacted their acceptance of the food products.

Risk of hedonic bias in sensory co‐elicitations: Comparison of CATA questions and applicability ratings

AbstractCo‐elicitation of hedonic responses and sensory responses is now common. Against this background, this research compared the risk of hedonic bias from sensory check‐all‐that‐apply (CATA) questions and sensory term ratings from unstructured line scales (RQ1) and evaluated if the risk of hedonic bias is independent of the sensory terms of the CATA question (RQ2). Seven studies with 137–293 participants each were conducted, using different product categories. Between‐subjects experimental designs were used and allocated consumers to one experimental condition (EC). For RQ1, these were hedonic, hedonic immediately followed by a CATA question, and hedonic immediately followed by a rating of term applicability (“not at all” to “extremely”). In RQ2, both ECs involved hedonic ratings followed by a CATA question, but the sensory terms differed. Results showed a significant effect of EC on hedonic ratings in three of five studies for RQ1, suggesting that hedonic bias may or may not occur. For RQ2, the terms of the CATA question influenced hedonic ratings in two of three studies, and a negative hedonic effect was seen when CATA terms drew attention to particular characteristics of individual samples. Collectively, the results suggest that likelihood of bias depends on interactions between product category, samples, and terms.Practical applicationsResults from the present work suggest that hedonic bias in sensory co‐elicitations using CATA questions and scales may occur depending on the type of sensory attributes considered in the study. The consideration of terms that trigger attention to specific sensory attributes of the samples may lead to changes in hedonic ratings. Rating scales appear more likely to be associated with hedonic bias compared to CATA questions due to their more analytic approach to sample evaluation.

Modelling the Cult of Thomas Becket in Canterbury Cathedral

As part of an AHRC project, a team at the University of York created digital models of the major spaces of St Thomas Becket’s cult in Canterbury Cathedral in the early 15th century. This article explains the reasoning behind the choices made in planning and constructing the models, and details much of the underpinning research. The models offer as much, if not more, an argument about the use and experience of space within the cathedral, as they do ‘accurate’ depictions of architecture and furnishings. Focusing particularly on the shrine in the Trinity Chapel, but also explicating the scenes in the Corona, Martyrdom and tomb chapels, the article explores the ways in which access and exclusion, in both physical and sensory terms, shaped the nature of the cult and pilgrimage experience in medieval Canterbury.