Anodal Galvanic Taste Stimulation to the Chin Enhances Salty Taste of NaCl Water Solution

Galvanic taste stimulation (GTS) is a non-invasive electrical stimulation of sensory nerves that induces, inhibits, and enhances taste sensation. It has been shown that the cathodal GTS taste enhancement effect occurs when only cathodal electrodes are attached in or near the mouth, while anodal GTS, whose anodal electrodes are attached in or near the mouth, induces an electrical taste sensation rather than taste enhancement. In the present study, we focused on the taste enhancement effect of anodal GTS, enhancing the salty taste produced by a sodium chloride (NaCl) aqueous solution during stimulation. In this study, GTS was applied to the chin rather than the inner mouth so as not to disturb natural eating and drinking behavior, according to a previous study. To demonstrate and quantitatively evaluate its enhancement effect, we conducted two psychophysical experiments in which subjects were asked to indicate the intensity of the saltiness perceived during electrical stimulation by adjusting the concentration of aqueous NaCl to achieve a solution of equivalent saltiness. We discovered that the perceived intensity increased as the current intensity applied to the chin increased. Moreover, the magnification ratios against the baseline exceeded 1 under all conditions of the NaCl aqueous solution. These results indicate that anodal GTS is effective in enhancing the salty taste of NaCl aqueous solutions.

Modulation of taste sensitivity by the olfactory system in Drosophila

An animal's sensory percepts are not raw representations of the outside world. Rather, they are constructs influenced by many factors including the species, past experiences, and internal states. One source of perceptual variability that has fascinated researchers for decades is the effect of losing one sensory modality on the performance of another. Typically, dysfunction of one sense has been associated with elevated function of others, creating a type of sensory homeostasis. For example, people with vision loss have been reported to demonstrate enhanced tactile and auditory functions, and deafness has been associated with heightened attention to visual inputs for communication. By contrast, smell and taste - the two chemosensory modalities - are so intrinsically linked in their contributions to flavor that loss of smell is often anecdotally reported as leading to deficiencies in taste. However, human studies specifically examining taste are mixed and generally do not support this widely-held belief, and data from animal models is largely lacking. Here, we examine the impact of olfactory dysfunction on taste sensitivity in Drosophila melanogaster. We find that partial loss of olfactory input (hyposmia) dramatically enhances flies' sensitivity to both appetitive (sugar, low salt) and aversive (bitter, high salt) tastes. This taste enhancement is starvation-independent and occurs following suppression of either first- or second-order olfactory neurons. Moreover, optogenetically increasing olfactory inputs reduces taste sensitivity. Finally, we observed that taste enhancement is not encoded in the activity of peripheral gustatory sensory neurons, but is associated with elevated sugar responses in protocerebrum anterior medial (PAM) dopaminergic neurons of the mushroom bodies. These results suggest a level of homeostatic control over chemosensation, where flies compensate for lack of olfactory input by increasing the salience of taste information.

Gender effects on odor-induced taste enhancement and subsequent food consumption

Purpose The purpose of this paper is to test for gender-specific effects on odor-induced taste enhancement and subsequent food consumption in olfactory food marketing. Design/methodology/approach Lab experiments conducted among female and male participants using vanillin as a stimulus and ratings of sweetness, taste pleasantness and eating of sugar-free food as measures. Findings Odor-induced taste enhancement is gender-specific. Female consumers outperform male consumers in olfactory reaction and sweetness perception. While men outperform women in food consumption. Research limitations/implications Odor intensity was set to the concentration level of 0.00005per cent according to the findings from (Fujimaru and Lim, 2013). The authors believe that this intensity level is appropriate for both men and women. Still, there may be some gender effects on intensity levels, which are not explored here. The author’s test for the effects of one personal factor, gender and odor-induced taste enhancement of sugar-free food. The authors think that investigating the combined effects of more personal factors such as age, culture and so on adds to the accuracy of the results. Practical implications It seems that the stronger sensory capacities of women in terms of odor detection and recognition already confirmed in the literature extends to the cross-modal effects of this sensory detection and recognition on taste enhancement. It seems appropriate to tailor olfactory food advertising according to the gender of the target audience. Originality/value Odor-induced taste enhancement is still a novel subject in marketing. While most of the research has investigated the effects of smelling congruent odors on taste perception and food consumption among mixed groups of men and women, the value of this paper lies in the investigation of the potential moderating effects of gender on this relationship.

Odour-induced Taste Enhancement and Consumption of Low-sugar Pastry

This paper describes a study that tests for the enhancement of low-sugar pastry via olfaction and examines its effects on pastry consumption. Olfactory taste enhancement preserves the nutritional benefits of low-sugar pastry while retaining the pleasure of full-sugar pastry. Willingness to reduce sugar intake and eat healthily is stronger today than at any time before in western societies, and low-sugar pastry can be effective in reducing sugar intake among consumers in these markets. The challenge, however, is that consumers' liking of pastry is driven by the sweet taste pastry eating procures; reducing pastry sugar content makes it healthier but probably less tasty and thus of a low market acceptability. Results from laboratory experiments show that smelling clearly perceivable sugar-associated odour significantly enhances perceived sweetness and pleasantness, and leads to the higher consumption of low-sugar pastry. These findings have implications for pastry makers and retailers as well as for social marketers. Odour-induced taste enhancement enables food makers and retailers to achieve the goals of selling both tasty and healthy pastry. It can be also a vector to promoting healthy pastry by converting the ‘healthy = untasty’ attitude into a ‘healthy and tasty’ attitude.