Laser Barbecue (1) Creation of the SMAP team!

SMAP

Tell me one thing, do you like barbecues? In our lab, we are all fond of it. Sometimes we all gather around a barbecue grill in Akigase Park close to the Arakawa River, beer in hand and eat until full stomach. This is pretty cool. We feel like our skills and concentration are better in this environment than when doing experiments in the lab. Naturally, the discussions are also of a higher level of seriousness than in our usual meetings. “Don’t you dare take the meat I am reserving!”, “Why are you keeping 5 pieces just for yourself?”, “Waa, beef tongue is the best on earth”, “Let’s also do some noodles!”, “Who’s gonna eat all those peppers?” are typical examples of what you could hear if you came by us in one of those days blessed by plain summer heat and when our hearts are in full ecstasy, like floating in a Hawaiian environment.

But, wait a second! This doesn’t mean we are not in the heart of an experimental reflexions. Indeed, it is a laser barbecue experiment we are talking about. Combining successful research reflexions and barbecue delights makes the day pretty much interesting don’t you think so? Yet, if words about this kind of activity should fall in the ears of some (too) serious people, they would just sternly tell us to do some more conventional research. But the point is that we are very serious in fact. Research is a matter of doing what others don’t, right? And until now we never heard of people doing laser barbecue. This is how Super Meat by Advanced Photons (SMAP) has been invented.

But, where to begin? First we must ask the question why we cook the meat instead of eating it raw. The answer is that if one eats it raw (cf. Experiment 1), stomach ache will follow. So eating raw is to be avoided. But what really happens to the meat when it is cooked?


We all know that when meat is being cooked, its initial blood-red colour gradually faints. The operation of cooking the meat makes the water present inside it to evaporate and denatures about 15% of the proteins. This denaturation of the proteins induces transformations in their structures, causing secondary, tertiary and quaternary structures to be created without breaking the peptide bonds of amino acids. Then, the peptide chains come apart and the groups of atoms and radicals concealed in the molecules get released and can be easily operated upon by enzymes.

Said in a simpler way, this denaturation of the meat makes it easier to be digested by human organisms and facilitates the absorption of the nutriments. In addition to this, cooking the meat enables to kill the bacteria it contains. Above 60°C, most bacteria are killed. Therefore, those 2 mechanisms: protein denaturation and bacteria elimination are inherent in the cooking process.

Can we perform this by using lasers? First, we focus on the light absorption of the proteins of the meat. Most amino acids show high absorption rates in the ultraviolet region close to 230nm. Aromatic amino acids show the highest absorption rates for wavelengths close to 280nm. As for the bacteria, the pyrimidine bases and the purine bases contained in the DNA and RNA constituting the bacteria strongly absorb UV radiations close to 260nm. By irradiating DNA at those wavelengths, a change in its structure occurs due to the ionization of nucleic acids induced by this specific absorption. In consequence, the bacteria’s replication process in prevented and they end up by decaying. So we believe that by using a UV laser operating close to the 230-280nm range, protein denaturation and bacteria elimination can be performed.

Do such kinds of lasers with adaptable wavelength really exist? This is where we bring our laser skills into action. Practically, UV KrF excimer lasers emitting at 248nm exist. We have this kind of devices in our lab. But we can also mention another kind of laser, recently being intensively used in nonlinear optics research activities, known as Nd:YAG laser. Its fourth harmonic at 266nm could also fit. Although we possess Nd:YAG lasers, exciting its fourth harmonic requires a very advanced level of technology. An important factor is the output beam energy. If it is too small, protein denaturation and nucleic acid ionization cannot occur. Among the two types of lasers we mentioned, the energy provided by the KrF excimer laser is the higher. A single pulse can be powerful enough to reach several units of J/cm2. Thus the KrF excimer laser seems to be the more appropriate for a successful barbecue.

So, can we obtain protein denaturation and bacteria elimination as expected with this laser? Currently, we are comparing the energy provided by the SMAP process with the energy of the peptide bonds of the proteins. As we mentioned previously, we are only considering the problem from our familiar field of light science but we are aware that considering the mechanisms of heating processes are essential too. There are several tough points to be solved but one thing we know for certain: we are not so far from real implementations of laser barbecue! If we manage to solve the few remaining theoretical issues, laser barbecue will be soon at hand. The first person in the world to demonstrate laser barbecue might just be you!

Currently, we are recruiting people interested in the project. We are looking for people like you who like barbecues, you who, even if you don’t understand the process, show curiosity, you who don’t really understand how lasers are used, you who are fed up with your monotonous current life and you who care about those who eat too much meat and not enough vegetables. We don’t care about your origin, sex, status, age, occupation, family situation or criminal records. Our motto is 99% of curiosity and 1% of chance. Believe us, we are speaking seriously!