Tasting food relies on food volatiles moving from the back of the mouth to the nasal cavity, but researchers have wondered why airflow doesn't carry them in the other direction, into the lungs. Now a team of engineers, using a 3D printed model of the human airway from nostril to trachea, has determined that the shape of the airway preferentially transfers volatiles to the nasal cavity and allows humans to enjoy the smell of good food.
"During quiet breathing, there is no valve that can control the direction of volatile transport," said Rui Ni, assistant professor of mechanical engineering, Penn State. "However, something must be controlling the movement of these particles and keeping them out of the lungs."
In the past, physiologists looked at the nasal passages, but not at the pathway from the back of the mouth to the nose. In this case, the researchers used data from CT scans and the help of two radiologists to build a schematic of the human airway from the nostrils to the trachea, including the fine structure. They then used the schematic to make a 3D model using a 3D printer.
Ni and colleagues then tested airflow into and out of the airway. They reported their results in a recent issue of Proceedings of the National Academy of Sciences.
Chewed food particles end up in the back of the mouth in a sort of side cavity to the main airflow. The researchers found that when air is inhaled through the nose, the air flow forms an air curtain to prevent volatile particles released from the back of the mouth from escaping into the lungs. However, when air is exhaled, it sweeps into the area with abundant food volatiles moving them into the nasal cavity where they are sensed by olfactory cells.
Movement of the particles is also effected by the speed of breathing.
"Smooth, relatively slow breathing maximizes delivery of the particles to the nose," said Ni. "Food smells and tastes better if you take your time."
This slow, steady breathing optimizes the unsymmetrical transport effect and allows more air to sweep particles out and up. Ni suggests that for a really good meal, taking time to slow down and breathe smoothly will deliver more smell and flavor.
Other researchers on this project included Mark H. Michalski, Gordon M. Shepherd and Elliott Brown, School of Medicine; Ngoc Doan and Joseph Zinter, Center for Engineering Innovation and Design; and Nicholas T. Ouelletter, Department of Mechanical Engineering and Materials Science; all at Yale University.
The National Institutes of Health and the National Science Foundation supported this work.
A'ndrea Elyse Messer | EurekAlert!
Hot cars can hit deadly temperatures in as little as one hour
24.05.2018 | Arizona State University
3D images of cancer cells in the body: Medical physicists from Halle present new method
16.05.2018 | Martin-Luther-Universität Halle-Wittenberg
The more electronics steer, accelerate and brake cars, the more important it is to protect them against cyber-attacks. That is why 15 partners from industry and academia will work together over the next three years on new approaches to IT security in self-driving cars. The joint project goes by the name Security For Connected, Autonomous Cars (SecForCARs) and has funding of €7.2 million from the German Federal Ministry of Education and Research. Infineon is leading the project.
Vehicles already offer diverse communication interfaces and more and more automated functions, such as distance and lane-keeping assist systems. At the same...
A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.
The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...
At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.
At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...
There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?
At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
25.05.2018 | Event News
02.05.2018 | Event News
13.04.2018 | Event News
25.05.2018 | Event News
25.05.2018 | Machine Engineering
25.05.2018 | Life Sciences