Showing posts with label chemistry. Show all posts
Showing posts with label chemistry. Show all posts

Monday, January 6, 2014

A Candy Science Lesson!

I've been getting a lot of questions recently about my candy recipes and the ingredient list.  More specifically Corn Syrup.  I thought I would take a moment to give a fun chemistry lesson on the differences between corn syrup, corn starch, high fructose corn syrup (HFCS) and glucose syrup!

I thought I would start with a simple visual, a flowchart of corn! At the top of our flowchart we find corn.  Plain old boring yellow corn, I'm sure you've heard of it.  The first stop on the flowchart brings us to cornstarch or corn flour, depending on where you live.  Cornstarch is obtained from corn via a process of wet milling.  Basically the corn is soaked, ground and the natural starch is extracted from the mixture.  Once dried, you have a bright, white cornstarch.  You use it to thicken sauces, make soft cookies, all sorts of things.

Cornstarch can be further changed into corn syrup by the action of hydrolysis.  Hydrolysis means that you add water molecules to the cornstarch and break it down into smaller sugar molecules, specifically glucose.  Corn syrup is also called glucose syrup in some parts of the world.  Most Americans can find this at the grocery store under the brand of Karo - Light Corn Syrup.  (Light refers only to the color of the syrup, not the calorie count)  You use this in candy making and baking to add volume & soften texture.

This is where it gets a little tricky and controversial.  Corn syrup can be treated with an enzyme called glucose isomerase to convert some of the glucose to fructose. The product of this is the dreaded High fructose corn syrup.  The most common form of HFCS contains 55% fructose, 45% glucose (and a tiny percentage of other sugars).

How about a fun (okay, very sciencey) explanation of the chemistry!  In the flowchart below you'll see amylopectin, aka cornstarch.  Cornstarch is made of of lots and lots of glucose molecules all attached to each other.  Hydrolysis of cornstarch breaks apart all of those glucose molecules into individual glucose molecules, giving us corn syrup.  Treatment of glucose with the isomerase enzyme converts some of the glucose into fructose.  Some mixing and formulations later, the manufacturer produces HFCS-55, the most common HFCS in US foods.

I know, it can be a little confusing.  Especially since sucrose, table sugar, is also made up of one fructose and one glucose molecule!  So why do we see HFCS in everything?  Two reasons - Money & your Sweet Tooth.

Money - Sugar costs more than corn.  A whole lot more.  Even after you put corn through all those manufacturing processes, corn syrup still costs less than table sugar!  To keep their costs down, manufacturers of snack cakes, ice creams, sodas & cereals use HFCS to sweeten their products.

Your Sweet Tooth - If manufacturers simply substituted the sugar with natural corn syrup, the products wouldn't be as sweet.  Americans love sweet things and when it comes to sugars - not all sugars have the same sweetness.  If we randomly set the sweetness of table sugar to 1.00, the rest of the common sugars rate as follows...

0.70 = glucose (corn syrup)
1.00 = sucrose (table sugar)
1.30 = fructose (fruit sugar)

So to maintain the same sweetness level, but keep costs low, manufacturers use the sweeter HFCS in place of sugar and regular corn syrup.

There we have it, the differences between all these corn products are a few water molecules and some chemical bonds.  What's my opinion on HFCS?  Personally, I try to avoid it.  I just don't eat processed foods that often and don't drink soda at all. I don't think a small amount of HFCS in your diet will lead to life-threatening consequences. If you want to read an extremely well researched article on the fructose hypothesis, check this one out!

A whole other question about corn syrup comes up when discussing GMO's (Genetically Modified Organisms). Over 90% of corn in the US is GMO, so the majority of corn syrup produced here is made from GMO corn.  However, there is no way that corn starch from GMO corn is any different from corn starch from non-GMO corn, because chemically they are both pure amylopectin.

If you are on the side of anti-GMO, but you still want to make candy at home, you have a simple option!  I suggest buying Pastry 1 - Glucose Syrup.  It is made from non-GMO wheat!

Have any questions about corn syrup or HFCS that I have neglected to answer?  Drop your question in the comment section and I'll be doing a follow up next month!

Monday, March 21, 2011

Buffalo Sponge Candy

Sometimes, being a chemist comes in very handy in the kitchen. In my previous candy experiments you might have noticed the massive amount of molten sugar I’ve been working with. From the marshmallows to the taffy and the butterfinger bars, I’ve been going through pounds and pounds of sugar and my kitchen is getting pretty sticky. (I found some rogue purple sugar this morning while toasting a bagel!) This danger of the sugar is not what makes my PhD an asset, it is my familiarity with failure.

Failure Number 1
As a synthetic organic chemist, one gets pretty used to failure. You begin with a plan on paper and you set upon this path. A new project is exciting, you order your reagents and get everything in order.  At first things go well and your chemistry works!  Then you hit a wall. Perhaps a reaction that you expected to work one way does nothing at all, or worse, something unexpected. The reaction could even destroy all of the forward progress that you have already made, sending you months back.

Failure Number 2
Your original plan gets torn apart after a series of failures and you re-write your scheme. No matter how many failures you have there is still that end goal in sight, the completed molecule. You’ve got to finish the project! So, no matter how many failures you have and how many walls you hit you eventually find a way. Success comes to the persistent and persistence pays off (with candy).

At Last!  Sweet Success
This candy was a little tricky to make, only because I didn’t have the right recipe. Many people have sponge candy recipes, but they weren’t coming out like my sponge candy. So many recipes called for vinegar and baking soda, which turns out to be totally unnecessary for the desired reaction. This recipe was the first failure. The second failure involved a recipe that called for heating honey to 300, this causes honey to burn.

After a little research into how Buffalo sponge candy is made, I had worked out a recipe and right the method of how to put it together.  This final batch came out exactly like I remember it from Watsons and I’m sharing my recipe with you. Don’t worry, I’ve worked out all the kinks for you. These failures lead to candy gold.

Eat me
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