TKF Science Writing

I was hanging out doing some work when I realized that I needed to tend to a bone-in turkey breast I bought at the store a few days back. I had placed in the freezer and defrosted in the refrigerator for a couple days so it was now or never. Word of caution her folks, never defrost anything at room temperature. It takes bacteria all of twenty minutes to build up enough colonies to have bad things happen to you. I wasn’t about to take any chances with salmonella either so in the refrigerator it went.

Anyway, back to the story at hand. It is too nice a day to cook it in the oven and quite frankly, I didn’t want to clean up the mess and so to the grill I went. Whoever invented the art of the barbecue should get some sort of award.

The way I cooked the turkey was low and slow. With a big enough grill, you can use the indirect heat method. It is a pretty simple concept in that one burner is turned on and the other side remains off. Heat will travel from the working burner to the other side of the grill to cook the turkey indirectly. This should keep help with any hot spots that may exist on your grill. If you have a grill with three burners, even better. Turn on the outer two burners and leave the middle one off. Place the turkey in the center and the heat will come at it from both sides but not directly underneath. By not cooking over a flame, flareups are prevented when the fat drippings start to drop from the bird. Turkey and chicken can become dry pretty quickly, so some people place a pot of water on the grill to prevent moisture loss.

Chicken and turkey obviously contain protein which are found in muscles that contain an elastic substance called collagen. Collagen is a protein that attaches muscles to bones. It takes a lot of heat energy to melt that collagen away. When cooked too long, the proteins that had previously unravelled (due to heat) now coagulate and reform but into a smaller, tightly bound bundle resulting in dry meat. Since I was cooking a turkey breast, which has minimal fat, I had to be careful. Turkey meat contains about 60% water and the longer the cooking process, the more moisture is lost. Most of that water remains bound up within the proteins themselves so my goal was to minimize moisture loss.

You may want to rub a little oil on the grill (while it is cool) first to prevent sticking. Use a high temperature oil such as vegetable or canola oil as olive oil has a low smoking point. You can also rub some oil on the bird itself. The first step is to heat up your grill on high for 10-15 minutes. After it is about 500 ºF, place the turkey on the grill. Use a meat thermometer to gauge the inside temperature of the turkey. If you have an old fashioned thermometer, place it in the meat before cooking.

The FDA recommends that turkey breast be cooked 165 ºF while the National Turkey Federation recommends 170 ºF. During the last ten minutes of cooking, you can add your favorite sauce to it (barbecue, teriyaki, etc.). Many of these sauces have sugars which can burn and char your meat if left on too long so try not to add them too early.

In a new study published in the Archives of Internal Medicine, scientists have hypothesized that increasing red meat intake leads to higher overall mortality.

The study included people aged 50-71 and were recruited from 6 states (California, Florida, New Jersey, North Carolina, and Pennsylvania).  Atlanta and Detroit were the two main metro areas studied from the above list.  For baseline purposes, the participants were asked to fill out a questionairre outlining the foods they normally ate over the last year. 

Sources of red meat included bacon, beef, cold cuts, ham, hamburger, hotdogs, liver, pork, sausage, steak, and meats in foods such as pizza, chili, lasagna, and stew.  White meat included chicken, fish, turkey, poultry cold cuts, canned tuna, as well as low fat sausages and hot dogs.  The scientists did point out that there was some overlap in the food items as there is red meat in some of the low fat options.  Their statistical models accounted for this fact as the data was analyzed.

High, medium, and low risk type diets were created based on the results of the questionairre.  Over 600,000 respondents returned the questionairre form and after excluding people for various reasons (moved away, incomplete forms, very high or very low intake of red meat), the scientists came back with almost 550,000 samples with a 60/40 ratio of men to women respectively.  The researchers found that the higher the intake of red meat, mortality rates would increase modestly.  Conversely, with a higher white meat diet, there was a small decrease in total mortality.

There were some interesting correlations that the scientists also found.  For example, they found a positive association between smokers, or former smokers, and the intake of processed meats, as it relates to cancer.  They hypothesized that it could be due to the N-nitroso compounds and carcinogens found in cigarettes. 

The N-Nitroso compounds, as you may have guessed, are derived from nitrogen and are found in bacon, fermented sausage, hot dogs, bologna, salami, corned beef, ham, and other smoked or cured meat, fish, and poultry.  They are formed from nitrogen compounds (amines and amides) as bacteria break off the acid portion of amino acid compounds.  In chemistry terms, this is known as decarboxylation.

Prior studies have shown that cooked red meat intake can create chemicals that are not present in raw meat.  These chemicals are carcinogens.  This is due to the presence of heterocyclic amines and polycyclic aromatic hydrocarbons.  Easy enough to understand right?   

Heterocyclic amines (HCAs) are found in muscle meats such as beef, pork, fowl, and fish.  These compounds are formed at high temperatures as amino acids react with creatine, a chemical found in animal muscle tissue.  Four factors come into play when dealing with heterocyclic amines; type of food, cooking method, temperature, and time.  Of the four, temperature is the most important factor.  When cooking meats, the highest temperatures occur when we barbecue on a grill, broil in the oven, or fry in oil.  Oven roasting and baking are done at lower temperatures so the formation of HCA’s is less  Cooking meats low and slow and as a friend told me, with its best days before it (instead of well done), may be the best bet for someone who is concerned about HCA formation.  Also, take it easy on the drippings on the bottom of the pan as that gravy contains substantial amounts of HCA’s as well.  

Polycyclic aromatic hydrocarbons (PAH’s) are found on the surface of meat after cooking it at high temperatures.  They are also present due to incomplete burning of coal, oil and gas, garbage, or other organic substances like tobacco.  These compounds are more prevalent when grilling whereas the heterocyclic amines usually form when pan fried.

I’ve always thought of eggs as a super food.  It is one of those foods that nutrition gurus across the world say we should eat.  In the past, due to their high cholesterol content, experts advised that eggs were best eaten sparingly.  Interestingly enough, many claim that there is no correlation between eggs and heart disease, the number one cause of death in North America.  Researchers now are saying that the egg can also help reduce high blood pressure.  Another benefit from our famed superhero, the egg.  The study was reported in the Journal of Agricultural Food Chemistry.

Eggs consist of 75% water, 12% proteins, 12% lipids (fats), and 1% vitamins, minerals, and carbohydrates.  Rich in bioactive proteins and peptides (short polymers formed from the linking of amino acids), eggs are a vehicle used to lower high blood pressure.  Scientists at the University of Alberta, Edmonton have found that the process of cooking eggs leads to more of these helpful proteins and peptides.

During digestion, the peptides are either absorbed through the intestine or locally through the gastrointestinal tract.  Antimicrobrial, anticancer, antihypertensive peptides and protease inhibitors all have been reported present in eggs.  One particular enzyme known as ACE (Angiotensin converting enzyme) was of particular interest to the researchers at the univeristy.

ACE is an enzyme responsible for regulating blood pressure.  It is part of the rennin-angiotensin system which which helps maintain stable cardiovascular functions.  ACE catalyzes the formation of angiotensin II (from angioetensin I), a potent vaso constrictor chemical which causes muscles to narrow blood vessels.  This results in the increasing of vascular resistance, decreasing blood flow, and ultimately to high blood pressure.  The compounds in the egg work to inhibit the formation of ACE.

Pharmaceutical companies have also guided efforts for antihypertensive drug development.  These drugs, aptly named ACE inhibitors, slow the activity of ACE.  Captopril, Benazepril, and Enapril are a few that belong to this category.  Often prescribed by doctors, these drugs are based on the same essential concept which is to inhibit ACE.  Side effects do occur for certain people and it is best to let a physician handle those issues.

Considering that table consumption accounts for 70% of total egg consumption in North America, differing cooking methods were addressed by the researchers.  The eggs were cooked two ways:

•  Boiling for 10 minutes, cooling for 5 under cold water, and then peeling.

•  Frying  after separating whites and yolk (each fried separately).

After cooking, they were frozen immediately and then subjected to varying scientific and metabolic processes such as changing pH and introducing pancreatic digestive enzymes.  This was done to mimic the metabolic actions in the gut.

The results showed that the fried egg had the strongest inhibitory factor.  Researchers hypothesized that this may be due to the fried egg having been cooked at a higher internal temperature (170 °C ) than the boiled egg (100 °C), which may have affected the release of bioactive peptides.

Be it fried eggs, egg salad, egg drop soup, or eggs Benedict, it seems that our superhero still belongs to the super food hall of fame.

Reference

J. Agric. Food Chem., 2009, 57 (2), pp 471–477