My Best Date Idea Ever

Because consumers tend to have no idea how long ago a piece of fish has been harvested, it’s important to recognize good-quality fish to maximize its shelf life.  Like a potential mate, it’s more than looks and smell, there are some factors that only a reliable fish supplier can share.  They’re passionate about food too, so it doesn’t hurt to befriend that guy behind the counter! 

If you’re purchasing whole-round fish:

The belly of the fish should be clean, the skin should be firmed, and bones should not bend like rubber bands.  Signs of bacterial presence (and enzyme degradation) usually include swollen or broken flesh near the stomach. 

The eyes should be bright, black, and the lens of the eye should convex outward (imagine a dome-roof).  With time, the proteins in the eye begin to break apart and the eye lens begins to flatten out rather than extending outward.

[Source: http://media.photobucket.com/image/fish%20eyes/carolinadancer/FishEyes.jpg]

The gills should be clean and follow the naturally color of the fish.

The outer mucosal lining (The slime) should be transparent and sheen light.  With time, the proteins coagulate and dry out creating a milky or off-color appearance.  This slime may be difficult to find because most of it is washed off during cleaning. 

The natural smell should either resemble oceanic water, or of crushed leaves.  Beyond the fact that fish tend to live in the sea, the oceanic aroma (bromophenols) are synthesized by the algae that are consumed by sea life.  However, farmed fish are supplemented with bromophenols in their artificial feed.  And smell like leaves…  weird right?  Well, it’s because fish contain many highly unsaturated fatty acids that break down to smaller aromatic-carbon fragments.  These carbon-rings have a heavy green, geranium-leafy smell that plants also emit. 

I love walking through the seafood section of an Asian supermarket.  If you can spend a few hours touring the bins, playing with lobsters and geoducks, and have the dexterity to lift a crab, then my heart's almost won!  The only problem is that this dating destination would stink…and it’s largey due a chemical called TMA (TriMethylAmine).  Remember last week how I mentioned sealife structurally contain extra amino acids to combat exerted osmotic pressure?  Well there are extra chemicals such as this tasteless compound called TMAO (Trimethylamine Oxide) which breaks downs to stinky TMA once the fish is dispatched.  The TMA then converts to ammonia which attributes to the nasty smell. 

Unless you buy your fish as soon as it’s caught at Tsukiji fish market in Tokyo, there's going to be some trace odors.

[Source: http://www.nationalgeographic.com/healthyliving/gallery/japan/pic_08.jpg]

However, many cultures have combated the “fishiness” by preemptively reacting with TMAO preventing the conversion to nasty TMA.  In addition, the usage of acidity has been very successful to counter TMA.  Because acids contribute a hydrogen proton to stinky TMA, this causes TMA to become positively charge allowing water and other electric negative molecules to bond well.  Our nose never picks up the odor because TMA+ never escapes as a vapor from the surface of the fish.  The mutualistic inclusion of lemon wedges became widely popular because of this and deep frying fish with a layer of buttermilk (which is acidic) is widely popular in many fish-frys.  Vinegars also work in the same manner and I’d like to think this is why malt vinegar is served with my fish and chips. 

By the way, some freshwater fish carry an unpleasant “muddy” aroma which is present in bottom-feeding fish such as catfish and carp.  The chemical behind this is geosmin which too, breaks down in acidic conditions.  Because of this, many recipes utilizing these bottom-dwellers include vinegar, lemon/lime juice and other acidic ingredients. 

Something Fishy In Your Fridge

In between serving virtual food to avatars on facebook and calling in predator missles and harrier strikes in MW2, I caught a show on the BBC regarding food waste and sustainability.  The show depicted Britain consumerism and the effects to the environment from packaging and waste.  Though I disagree with some of their arguments correlating decomposition of food to greenhouse gases and global warming, it is very clear that we, as humans, have rather wasteful habits.  I consulted the Google gods to find an article from the NY Times that furthermore shows what a family of four throws out on an annual basis. 

It’s interesting to note that meat and fish’s spoilage weight was half of fresh fruit and vegetables.  I wonder if it has anything to do with people thinking they’re healthy because they buy veggies and apples?  Or is it because meat is expensive and we usually take extra precaution to eat that before microbes can.  Maybe both?  So expanding on last week’s post regarding refrigeration, I will share some tips to increase the shelf life of some of the most expensive proteins out there, seafood.

To prevent any confusion, I will follow the FDA terminology by defining “fish” as, any sea creature such as shellfish, squids, sea cucumbers, or squirtles.  Ok, time to dip your feet into a small biology lesson about sea creatures and their ecology.  Unlike their terrestrial brethren whom have adapted to land life, aquatic organisms are constantly immerged in an aqueous solution.  Because of the liquid milieu, there are chemical differences for a fish to survive.  To counteract the osmotic pressure of the saltwater, fish generally have a higher concentration of savory amino acids (glutamate) increasing cell rigidity.  Because of this, saltwater can’t just flow through into the body of cell like it can with humans. 

Did I lose you in all of that?  This is an example I used in my Nutri Sci reviews.  Imagine taking a bubble bath listening to Enya with pomegranate candles lit (don’t judge).  After 20 minutes, your skin is as wrinkly as a Shar Pei.  Compare this to Red Lobster who can chill in a tank all of his life without looking like a raisin.  Yes, you’re a land mammal, therefore there would be no reason for you to be immersed in water for extensive periods of time (unless you’re Michael Phelps).  What I’m trying to say is that land and ocean animals behave differently in a given environment, and it’s because of their biological chemistry.    

[Source: http://www.lasharpei.com/LaurensSharpei.jpg]

Deterioration is inevitable and it’s caused by the natural enzymes in the fish.  Primarily found in the gills, stomach, and outer-slime that coats a fish’s surface, the microbes consume the yumyum amino acids/proteins into unappealing and obnoxious compounds.  Because amino acids contain nitrogen and sometimes sulfur, bacterial digestion creates many of these foul odors that sound like a mortuary; putrescine, cadaverine and methanethiol…the same stuff skunks produce.  The warmer the temperature, the greater the activity of the fish decomposition microbes which have evolved to be most efficient when removed from their native oceanic climate (34-38° F).  So by increasing the surrounding climate, these microbes work at a quicker rate to convert those amino acids into those nasty by products. 

With that reasoning in mind, it’d only make sense to store seafood near their environmental temperature of 34.0° F.  If held at the optimal temperature, fatty saltwater fish (salmon, herring, mackerel, sardines) can be held for about a week while leaner cold-water fish (cod, sole, tuna, trout) can be held for about two.  If you’re a warm-water fish (snapper, cafish, carp tilapia or mullet) you’re given three!  But don’t forget to account for the elapsed time in transit and on the market shelves,  so you can subtract anywhere between 1-5 days.  So let’s reexamine that whole salmon fillet you bought at CostCo.

Shelflife (when held at optimal temperatures)	7 d
Transportation to market	1-2 d
Time spent on shelf	0-3 d
Days remaining in your fridge	2-6 d

Here’s more bad news, your fridge is probably around 40- 45° F (and higher if air circulation is impeded).  A 10° F increase can decrease shelf life by a half.  Suddenly, your weeklong salmon dinners diminish to only 1-3 days. 

If you can’t control the temperature of your fridge, there’s many things you can do to drop the ambient temperature.  First, wrap your fish in any foodwrap (for example, Syran) and take any deep bowl.  Then place a plastic insert that allows for drainage and fill the upper compartment with ice.  Place the nicely-wrapped fish over the bed of ice.  Any melted ice drains through to the bottom layer and the syran wrap prevents any flavors and nutrients from leaching out of your protein.  Change ice every 8-12 hours and booyahshaka, salmon burgers all week!             

Here are some tips that were shared to me by an expert in the fish and shrimp industry, if you buy your fish whole from your store’s seafood department.  First, the cavity should be visible and all organs should be removed; the gut is a breeding ground for microbes.  Secondly, pull the skin near the lining of the stomach- the bones should be rigid and the skin should stay intact.  If the bones are flexible and pull like rubberbands or the flesh splits easily, then that’s an indication that your fish has been there for a while.  Finally, smell the stomach, it should smell like the ocean or fresh crushed leaves.  Also, make sure your fish has been thoroughly rinsed prior to purchasing because the same microbes are coaxed along the surface of the fish “slime.”

[Source: http://www.gastronomydomine.com/uploaded_images/extent-of-digestive-tract-747915.JPG]

The period between shopping and the time you place your products in the fridge is as critical as storage.  Microbial activity increases (exponentially) once the temperature change occurs so Alton Brown suggests carrying a well-insulated container filled with bags of crushed ice while you shop.  After picking up your proteins, securely wrap and place in your deep-freeze vessel.  Sure, it might look weird carrying it around Safeway, but your stomach will appreciate it much more.

By the way, the U.S. FDA and the National Oceanic Atmospheric Administration require all seafood distributors to transport their products in cold-fridge transportation units either filled with ice or utilize a refrigeration system that has a non-tamperable time/temperature reading.  In addition, HACCP records and verification is required from any company that receives shipments and any temperatures above 40° F is to be documented.  However, what the company does with the product differs; some still accept while others reject the product.   

No one likes to see food go to waste (especially an Asian like me) and I hope this post has helped extend the shelf life of your shell fish.  Next week’s post will be a list of what to look for when buying seafood so look out for that! 

One of My More "Cooler" Posts

When I was little, I wanted a chemistry kit that came with beakers, test tubes, and a basic compound microscope.  I never got any of that so I had to improvise; the family freezer was my childhood laboratory.  From an early age, I was fascinated by this edifying machine that supplied me with an endless supply of Klondike bars.  For show and tell, my class was supposed to bring in something that represented an interesting animal.  I brought in a whole frozen fish. Then in sixth grade, we were to design a science experiment showing life cycles.  Most kids brought in seeds, plants, and fruit.  I one-upped the field by freezing ants and rollypollies in icecubes hoping to prove I could stop and start life-cycles; Demolition Man released a few months later.

Fast-forward a decade later where I stumbled across the wonders of Food Network, Better Homes and Garden, and my ill-attempts to win the hearts of women through cooking.  I love grocery shopping and whenever shopping needed to be done for large events, social gathers, or retreats, I naturally used the services of Restaurant Depot.  RD is very similar to CostCo, but for restaurants…and they lack samples.  Their products are sold in bulk…and when I mean bulk, I mean quantities to supply the Battlestar Galactica.  Want three pounds of onion?  No, you have to buy 50.  Want to get a 4 pack of Red Bull?  Sorry, they only come in 36.  And of course, looking to buy meat?  You can buy whole pigs, lambs, and portions of cows if you don’t mind hauling a (delicious) carcass in your trunk. 

[Source: http://www.bigredkitchen.com/2009/08/restaurant-depot.html]

After toying around the idea with my roommate, Benson and I decided to host a Roast Beef night.  So we called up a few of our friends and I began my expedition scouring the expansive aisles of RD.  Inside the 32°F meat locker are rows separating each of the fauna, and within each row are categories of cuts/grade/portions.  I fastidiously inspect each chuck cut for firmness, presence of oxidation, and a solid layer of fat that flavorfully melts penetrating the meat in a 300°F oven.  I ended up with a nice slab …28 lbs of it, but for $1.19/lb, you really can’t complain.  At home, I section off half of the roast and deliberate what to do with the rest.  Lo and behold, my childhood lab to the rescue!

If you’re like me, (or any part of my family), you eat a lot of meat.  It might not be the most sustainable, or economical way to satiate one’s self, but by far the most delicious way.  There are certain amino acids that tend to make meat more flavorful/savory/yumyum that you just can’t find in grains, veggies, or fruits (mostly the amino acid, glutamate, which is a component of MSG [MonoSodium Glutamate]).  On the flip side however, meats tend to go bad compared to other food groups out there.  The high moisture content paired with a high fat and protein content are prime conditions for bacteria to grow and oxidation to occur.  In addition, meats just expensive…and when on a college budget, sometimes you have to shop bulk to be frugal.

Freezers (and refrigerators) have mostly three components to ensure the unit becomes cold.  There’s the coolant which acts as a medium for heat to be transferred into and away from.  Then there’s a compressor which increases the pressure of the coolant (thus raising its temperature).  The heat from the coolant is then removed through a coil of thin pipes on the back of the fridge (that’s why the back is usually warm).  Finally, there’s an expansion value which drops the pressure of the gas (thus lowering the temperature) that makes the coolant,expand, cool, and turn into a gas.  The cool-coolant passes through the inside of the unit.   

One of the general rules of food safety and preservation is that the lower the holding temperature, the less chance of bacteria proliferation.  In addition, by removing more of the water activity in food, you’ll also reduce bacteria growth because…well, like all things, bacteria needs water to multiple.  The freezer won’t kill bacteria, but it does slow it’s activity by a significant factor which makes the freezer a great place to store your care-packages of meat.  However…

Meat doesn’t bathe in the fountain of youth.  Unlike dried goods which can last for a year, sometimes two depending on the moisture content, meat can still degrade in the freezer.  Most meats last anywhere between 3-6 months in the freezer, +/- depending on the amount of oxygen that’s present.  In addition, a nasty thing called “Freezerburn” can happen to meats if oxygen is present.  The freezer doesn’t do any of the cooking, but what ends up happening is that browning of meat usually occurs such as this picture

[Source: http://upload.wikimedia.org/wikipedia/commons/5/58/FreezerBurn.jpg]

Hence, the clever term called Freezerburn.

FB occurs when the water content of the meat evaporates onto the surface of your storage bag.  The remaining water in your protein then begins to migrate closer to the surface of the meat and crystallization begins to occur.  Now the matrices of the meat can be exposed to oxygen which then causes oxidation and browning to occur.  Even if you use a zip-lock freezer bag, oxygen will still be present and oxidation occurs.  Vacuum sealing helps, but with time, oxygen will enter through the plastic or will be present in the deep trenches of the protein and make its way to the surface.  Just as a side note, a lot of tuna is sold in vacuumed packed bags that are generally a dark crimson red.  Most of those packages have actually been pumped with a blend of 60/40 or 80/20 Nitrogen/CO2 gas to compete against oxygen.  By filling the surrounding air with this gas, it prevents pigmentation, which chefs and purchasers would not want.

[Source: https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgvaH48PjtRr5Kf1GO4RwcSwr694wVpy0noL4fc_dpw8WfBgylWL2pVfXLigPbaPWBpdcaZLUfzqJXGws-roryr1tAnDqXdp4wOanRM36IgHH5jxhEIifnSnG_NbLp7_nmqvj_2I2hc93Zz/s320/tuna6.jpg] 

I want to note that the FB portions of food are safe to eat, but will end up being chewy and less tasty than the non-burned portions.  In short, it’s more a food-quality than a food-safety problem.  Whenever red meats (beef, ahi tuna) are exposed to oxygen for long periods of time, browning begins to occur.  As a rule of thumb, never buy ground beef, or any types of raw red meat that have a brown cooked color to it.  It might not kill you, but it won’t be delicious either. 

Though I no longer store insects in my freezer, I’d like to think I’ve come a long way in using the freezer. Plus, I tend to injure myself a lot and nothing makes a better icepack than a frozen bag of corn…or a 14 pound chuck roast.


I think I'm going to continue with this idea by talking about ways to increase your seafood's shelflife in the next post. 

The Ultimate C-block

I’ll be revisiting reoccurring themes in the science of cooking as this blog continues to grow in content and in ridiculous pictures. Water solubility, acid/base chemisty, time/temperature, and oxygen to name a few, but perhaps the most common will be the disassociation between fats and water. This picture here isn’t of an iconic mouse, but here to explain the structure of water.

[Source" thisdayindisneyhistory.homestead.com]

Water, also known as H2O, contains two smaller Hydrogen orbs that are positively charged and bind well to the larger, negative orb, oxygen. Remember…opposites attract…which poses the question in how Match.com works…In water, there are two positive hydrogen molecules compared to one single negative oxygen molecule. Despite lacking in numbers, the renegade oxygen’s charge overpowers that of the two hydrogren and water as a whole has a negative charge, or polarity. Because of this charge, water also tends to stick to one another and form pretty structures such as this:

 

[Source: practicalchemistry.org]

Fat, on the otherhand, is generally composed of a carbon backbone and hydrogen appendages, (include oxygen if you’re talking about unsaturated fats). As opposed to water that has a strong-negative and weak- positive component, the fat molecule as a whole generally has no-charge associated with it; it is neither positive nor negative. It’s like the apathetic voter…it just sits there and chill, while water likes to comingle and get into heated debates with its negatively charged brethren, or it’s positively charged rivals. However, it dares not associate with the neutral dude that sits around twiddling his thumbs. I’m only glossing over the charge/polarity discussion, but there are many other molecular interactions occurring that I won’t bore you with (today).

So what’s this have to deal with noodles? Other than the first time where I burnt pasta (yes, it’s possible), I’ve always had a problem with my spaghetti sticking to one another after removing it from its hot bubbly bath. Even Chef Boyardee would snicker at my pool of Prego and a brick of yellow noodles floating like a Valdez accident. Well, you remember how, a long time ago (in a blog far, far away) I mentioned how dissolved starch forms on the outside of cooked pasta? The chemistry of the noodle isn’t the reason why they cling onto one another, but rather, the residual water that adheres to the carbohydrate causes the noodles to stick. Water surrounds and engulfs the starch and clings all around the noodle, and water molecules further reach out to neighboring mickey mouses to form a stronger bond.

 

Now the cool thing about oil is that it interferes with the strong interaction of the H2O bonding. In non-nerd talk, it roosterblocks water. “Yah, take that water, think you can just poke your hydrogen balls all over the place?” The negative polarity of the water molecule doesn’t sit well next to the neutral fat molecules and Mr. fatty tells water to GTFO.

 

So if you’re cooking pasta, here are some techniques to ensure your noodle doesn’t stick: You can add a small amount of oil into your boiling pot of water prior to cooking the noodle. In addition, you can some oil or butter to the pasta after draining and stirring that immediately to interfere with the water. This works wonders especially in cream-based sauces such as an alfredo or if you’re frying up the noodle like in chow mein/fun.

Out of curiosity, which topics seems more appealing to you? “Cooking without Fire” or “Freezers that Burn"?