Tag Archives: Food Science

Taste, nutrients decline as size of crops grows

I wanted to write about this last week, when I first read about it, but it somehow got pushed into my story queue.

A report issued this week examined several recent studies by food scientists, nutritionists, growers and plant breeders. It found clear evidence that as the produce we eat gets larger, its vitamins, minerals and beneficial chemical compounds significantly diminish, as do taste and aroma.

Growing bigger tomatoes and ears of corn leads to a bigger yield for the producer, but the trade-off is the lower nutritional value.


Donald Davis, a senior researcher at the University of Texas, did some of the most illuminating research into the disappearing nutrients.

He compared Agriculture Department figures on nutrient content for 43 common fruits and vegetables.

Davis says historical data spanning 50 to 70 years show apparent declines of 5 percent to 40 percent or more in minerals, vitamins and proteins in groups of foods, especially vegetables.

Part of me is not really shocked that this is occurring. However, it is kind of a big deal that there is now mounting scientific evidence to support something that many of us have suspected for years (just ask the Washington Apple industry).

The next time someone points at that there is no nutritional benefit to eating organic, I’ll point them to these studies.

Splenda: Made from the selective chlorination of sucrose to taste like sugar

Splenda to Jury: Made from sugar so it tastes like sugar

Jury to Splenda: Yeah…Not so much.

The nuances of the case aside, the results are still a win for those of us who believe that processed sweeteners should not sit at the same table as natural sweeteners. McNeil Nutritionals needed to get the legal smack around in order for them to stop inferring that their product was more wholesome than other processed sweeteners when their was no evidence to support those inferences.

What causes us to cry when cutting onions?

We all know that onions can cause us to tear up when we cut them. But why does this happen?

As always, we turn to our best friend when we need a logical explanation – Science!

Within each variety of vegetables belonging to the Allium family resides a class of organic molecules called amino acid sulfoxides. These molecules help give the onions their specific bitter flavors.

Within the tissues of these same onions are enzymes called allinases. When these enzymes are released, be it through slicing, crushing, piercing, whatever, they react with the amino acid sulfoxides, converting them to sulfenic acids (RSOH). The sulfenic acids are very unstable, and often will often re-arrange their molecular structure to form syn-propanethial-S-oxide(H7O3S2). It is this chemical that causes tearing. From the Scientific American:

Its effects on the eye are all too familiar. The front surface of the eye–the cornea–serves several purposes, among them protection against physical and chemical irritants. The cornea is densely populated with sensory fibers of the ciliary nerve, a branch of the massive trigeminal nerve that brings touch, temperature and pain sensations from the face and front of the head. The cornea also receives a smaller number of autonomic motor fibers that activate the lachrymal (tear) glands. Free nerve endings detect syn-propanethial-S-oxide on the cornea and drive activity in the ciliary nerve–which the central nervous system interprets as a burning sensation–in proportion to the compound’s concentration. This nerve activity reflexively activates the autonomic fibers, which then carry a signal back to the eye ordering the lachrymal glands to wash the irritant away.

There are several ways to prevent or mitigate the causes of tearing. One, you could have brain surgery that would block any sensory information sent from the ciliary nerve. However, that may be a tad impractical.

Water is the best route. Cutting onions under water, or soaking the onions prior to slicing will work. Choosing onions with higher water content can also lessen the tearing. This means purchasing onions that haven’t been dry cured. Any “named” onions, such as “Vidalia” or “Walla Walla”, will do. Dry cured onions inlcude the generic white, yellow, and red onions.

If the only options available to you are the generic whites, yellows, and reds, it would be the white onions which should have higher water content, and red onions having the least amount.

Another way to prevent or lessen tearing is to preventing an excessive amount of allinases from being released. The best way to do that is to cut the onion in such a way that minimally damages the tissue. In other words – the sharper the knife the better.

Finally, cut the onions in a well ventilated area. The vapors released from the onion can be dispersed quickly with a fan in the area.

So all of you out there cutting red onions with a butter knife in a windowless room, cut it out. You’re only asking for trouble.

A Question for you Science types out there

The Molecular compound for Salt is NaCl.

The compound for table sugar is C12H22O11.

Can anyone tell me what the compound for High Fructose Corn Syrup would be?

Many Thanks!

The Science of Ceviche

One of the reasons I enjoy ceviche is because it challenges the notion of what we think of as “cooking”. The dish reminds me that “cooking” is not just the application of heat to a food, but rather is any method that results in the alteration of a food that makes it more palatable.

Ceviche is also one of the better food “science experiments” because it uses a process that’s in use in the majority of the world’s cuisines, but often in a different context. I’m talking about “acidification”, or the process of acids affecting the molecular structure of foods. Typically we see acidification in pickling techniques, where vinegars and other highly acidic compounds are used to store foods for extended periods of time, typically the firmer vegetables but also eggs and meats. Pickling is a process that’s in use around the world, and is very likely one of those discoveries that popped up in more than one location, as there are several types of pickling techniques out there.

While there are many pickled products meant for the long term, ceviche is a short term “pickling” process, and I cannot think of any other dish that’s out there that’s acidified in such a short period of time. Because of its quick acidification, there’s very little of the fermentation that is often found in products like sauerkraut or kim chi. This is one of the several reasons why I find ceviche interesting.

One word of note in regard to ceviche – this “short term acidification” does not kill the majority of bacteria found in whatever seafood products in the dish. This is why it’s important to purchase the best type of seafood that is available. If you can get sashimi grade tuna, that’d be your best start. In other words, if you get your seafood from the local Safeway, you probably run a higher risk of bacterial contamination.

Technorati Tags: Food Science, Ceviche,

A Quick Food Quiz

Here’s a mental exercise for you. The below list shows a product that may be mismatched with the ingredient that it’s paired with. Your job is to properly match them together.

  • Chef Boyardee Beefaroni – Soy Lecithin
  • Dannon Creamy Fruit Blends Strawberry Banana – Sodium Hexametaphosphate
  • Fig Newtons – Monosodium phosphate
  • Kool Aid Unsweetened Pink Lemonade – Maltodextrin
  • Kraft Barbeque Sauce – Calcium Lactate
  • Mr. Pibb – Guar Gum
  • Oreos – Calcium Sulfate
  • Oscar Meyer Bacon – Autolyzed Yeast Extract
  • Sunny Delight – Sodium Erythorbate
  • Wonder bread – Tricalcium phosphate

As always, there’s a point to this, and it’s not to illustrate how silly some chemicals sounds when put in context with a food ingredient list. I think we are mature enough in our knowledge of food to acknowledge that there are many chemical compounds that are perfectly okay to eat, whether they are notated as “xanthum gum” or “seaweed paste”.

The real point here is in the results of the quiz itself. How many of the above ingredients do we know off the top of our head so that when we look at , it sets off a light bulb in our head that goes “Oh yeah, that’s used in foods for controlling discoloration and off-flavor development!” If you are one of those people, I salute you.

My guess is that most folks don’t know the difference between calcium lactate and calcium sulfate (myself included), let alone know the context in which they are used in food. We instead have put our trust in the producers of these products to ensure that there’s no problems in these ingredients. For the most part, that trust is earned. But sometimes I wonder what sort of backlash there would be if people had the resources (in time and inclination) to fully research what’s going into their processed foods.

Just a thought.

But the real point that I think this test illustrates is how much faith we consumers do put into the hands of our producers. We can go to an artisinal cheese maker and generally follow how the cheese is made, and where the ingredients for said cheese comes from, although some discussion of enzymes and rennets may need to occur. I think that processed foods are a bit trickier to explain when it comes to the origins and purposes of each ingredient.

Correct answers below the jump.

Technorati Tags: Food, additives, Food Test


Fats within our Foods

Fat is somewhat misunderstood when it comes to nutrition. A person needs fat in order for their body to function properly. It is an energy source, it helps regulate blood pressure, heart rate, blood vessel constriction and blood clotting. It also is the way that various vitamins are delivered into our blood stream.

There are two ways one needs to look at fat. First, in a high level overview of fat as a whole, then a lower level look at the various types of fat. I believe this is important, because fat, at its base level, is a means in which energy is delivered to our bodies.

The issue surrounding fats is not whether it’s good or bad, but rather how much is too much. Much like everything else in life, fat is best taken in moderation. Being rather high in calories, it’s easy to overindulge. 5 grams of fat contains 45 calories. As a point of comparison, 5 grams of either proteins and carbohydrates contains only 20 calories. Fat is a very efficient means in delivering calories. Foods high in fat are probably not the best items to eat when you wish to feel “full”.

At the lower level, fats molecules can be divided into various categories -

  • Monounsaturated
  • Polyunsaturated
  • Saturated

Each of these fats provides a specific nutritional function and have both pros and cons, some more than others.

Unsaturated Fat – An unsaturated fat is a fat or fatty acid in which there is one or more double bond in the fatty acid chain. What exactly is it missing to be “un”-saturated? That’d be hydrogen atoms, some of which are eliminated when the double bonds are formed in the chain.

There are two types of unsaturated fats:

  • Monounsaturated Fat – A fat molecule is monounsaturated if it contains only one double bond. A good way to remember which fats are monosaturated is that they remain liquid at room temperature but may start to solidify in the refrigerator. Olives and olive oils, avocados, nuts and various nut oils all are good examples of monosaturated fats.
  • Polyunsaturated Fat – A fat molecule is polyunsaturated if it contains more than one double bond. Polyunsaturated fats are typically liquid at room temperature and when refrigerated. Polyunsaturated fats are considered the healthiest, and include the Omega oils (Omega 3, Omega 6)

Not all unsaturated fats are considered “healthy”. The trans fats we’ve heard so much about of late is an unsaturated fat, but deserves its own subcategory in the unsaturated fats field. I’ll discuss trans fats in a later post.

Saturated Fat – Saturated fatty acids have no double bonds between the carbon atoms of the fatty acid chain. Thus, since no hydrogen atoms are “exterminated”, they are “saturated” with hydrogen. You can recognize most saturated fats as they remain solid a room temperature. Think of bacon fat, butter, vegetable shortening, etc, etc.

This is a basic overview of fats, and I’ll discuss each individual fat in its own post later on.

Technorati Tags: Food, Fats, Nutrition