What could be more natural than a cup of coffee? This seemingly simple daily routine conceals a considerable deal of intricacy, which is based mostly on the complexity of taste perception. What we term taste in everyday parlance is also known as flavor in scientific parlance, and it is based on a more complex perception than the simple sensation of taste. The flavor is a sensory perception created by the taste of food or beverages. It is based primarily on the functional integration of chemical sense information: olfaction, gustation, oral, and nasal somatosensory inputs (ThomasDanguin, 2009). Volatile molecules are retromer nasally transported from the mouth to the nasal cavity, where they are predisposed to activate the olfactory receptors on the top of the olfactory cavity as well as the trigeminal fibers that run throughout the nasal mucosa. Simultaneously, soluble chemicals are dissolved in the saliva, and some of them can be harmful.
The Craft and Science of Coffee
The gustatory cells of the taste buds and the trigeminal fibers in the oral mucosa can also detect it (Laing and Jinks, 1996; AFNOR, 1992). These three sensory modalities are activated at the same time and cooperate to create a unique perception. To help you better comprehend the sensory response induced by chemical stimuli, we’ll go over some basic anatomy and physiology of our sensory systems.
Taste or Gustation
Taste receptor cells, which are found on the tongue’s edge and anterior dorsal section, as well as the soft palate, throat, and larynx, are involved in taste perception (Breslin and Huang, 2006). These cells are mostly found in the taste buds, which are part of the papillae. Distinct types of cells play different roles in taste perception in these structures. G-protein coupled receptors detect molecules that evoke sweet, bitter, and umami perceptions, whereas ion channels detections such as Na, which elicits a salty perception, or Ca2, which elicits other taste sensations (Breslin and Huang, 2006). Aside from the scant data on taste cells that are accessible, the mechanisms behind taste coding and perception are still poorly understood and contested.
The olfactory system’s activation is responsible for odor perception. Olfaction differs from other sensory systems in that its receptors are expressed by neurons rather than specialized cells, as is the case with taste (Buck and Axel, 1991). Each of these olfactory neurons expresses a single type of olfactory receptor that may detect many odorant molecules (Nef et al., 1991). (Duchamp-Viret et al., 1999). Furthermore, a single odorant molecule can activate many olfactory neurons and, as a result, multiple types of receptors (Moulton, 1967). (Fig. 18.1). The mix of olfactory receptors that are stimulated determines the olfactory coding (i.e., the perceived odor). The population of olfactory neurons that all express the same olfactory receptor converges on a single structure.
Tactile, temperature, proprioceptive (body position, movement), and nociceptive (pain) information are all provided by the somatosensory system. The trigeminal nerve transmits these feelings to the face and mouth, and they are referred to as trigeminal sensations. It’s worth noting that the trigeminal nerve transmits chemical information as well. Thus, the trigeminal nerve’s free nerve ends detect chemical substances dissolved in saliva and olfactory mucus. When compared to the olfactory system, most odorant chemicals activate the trigeminal nerve at higher doses (Doty, 1975; Commetto-Muniz and Cain, 1994)as compared to the olfactory system. Trigeminal stimulation elicits a few qualitative perceptions such as cool, warm, burning, pungent, tingling, stinging, numbing, or irritation. However, some studies suggest broader trigeminal qualitative discrimination,
suggesting that such perception could be more complex (Laska et al., 1997). Several studies evidenced the relationship between perceived intensity and the compound potency to activate the trigeminal nerve suggesting that the trigeminal activation contributes to the perception of odor intensity (Doty, 1975; Cain, 1974, 1976; Murphy, 1987).
Construction of the Flavor Perception
Interactions between senses exist, as Verhagen and Engelen (2006) comprehensively review. Cain and Murphy (1980) found that when an odor was coupled with an irritating substance, it was suppressed, suggesting that the somatosensory system interacts with olfaction. Olfaction and taste have also been demonstrated to interact. Recently, odor-induced taste enhancement, particularly sweet enhancement generated by fragrances, has received a lot of attention. Frank and Byram (1988) demonstrated that adding a strawberry fragrance to whipped cream boosted the sweetness of the whipped cream. Other tastes have also been shown to have cross-modal perceptual interactions. Labbe et al. (2006) found that adding cocoa aroma to chocolate beverages increased bitterness while having no effect on other flavors. We can simply do this. We might easily envision that coffee would have a similar impact. A fruity fragrance, for example, could boost the perceived acidity of coffee. Similarly, we can speculate that roasted notes may contribute to bitterness.
The consistency of taste and smell cues is required for cross-modal interactions. Similarity judgment was found to be an excellent predictor of odor-induced taste enhancement by Frank et al. (1991). Incongruent or unfamiliar scents, on the other hand, diminish taste intensity (Prescott, 1999). Stevenson et al (1999) demonstrated that a sweet-smelling odor like caramel increased the sweetness of sucrose in solution while suppressing the sourness of a citric acid solution. A combination of exposure to the two experiences can be used to learn how scents acquire taste qualities (Stevenson et al., 1995, 1998).
Taste-smell interactions have pretty well-understood mechanisms. Sensory signals involved in flavor perception are “functionally connected when anatomically disparate,” according to one theory (Small and Prescott, 2005). The neuronal foundation for this unitary percept, flavor, is formed over time by repeated exposure to stimuli, according to their model.
Sensation and Perception
Sensory information is increasingly merged with other information such as memory or emotions to influence our impression of a food product, beyond the integration of smell, taste, and somatosensory responses to develop flavor perception. As a result, there should be a clear separation drawn between a sensation and a perception (Chaudhuri, 2010). Perception is the conscious experience of one or several experiences, whereas sensation is the actual bodily response to stimuli. Physiological aspects (hunger/satiation), psychological ones (personality traits, memory, past experience, emotions), environment (context), and sociocultural elements all influence our product perception and will determine our meal choices, according to Koster (2009). (culture, habits, beliefs)
Coffee, like any other culinary product, is difficult to comprehend in this sense.
Coffee experts aren’t always able to predict whether the product they create will be approved by the general public. Expert tasters, for example, place a high value on acidity, to the point where some roasters purposefully emphasize it, but the number of people who enjoy this experience has not been examined.