Lecture 5: Demystifying your Ingredients - Sugar Substitutes (Part II)

In our last lecture, we began our journey into the world of sugar substitutes.  Our study of how sugar alternatives were discovered and created left us with a storied history that is so complex that we've been forced to spread the richness across a trio of lectures.  In Part I, we discussed a couple sweeteners that are no longer in use because of their mind-numbing toxicity or alleged carcinogenicity.  Here, we will take a much more conservative approach and look into how other natural sugars, besides glucose, have been used to sweeten foods over the years.

Corn Syrup

Figure 1. Most carbonated drinks contain corn syrup...and so
do most sweet food items you find in the grocery store

Everyone is familiar with corn syrup.  It is the choice sweetener for most food manufacturers, as the commercial food industry has decided that cane sugar is too expensive to use in their products.  Corn syrup is used in mass quantities to sweeten everything from soft drinks to canned foods to candy (Fig. 1).  It definitely has a different taste than real sugar - have you tried Coca Cola Life, Pepsi True, or Berghoff or Goose Island Root Beer, which are all made with real sugar?  If you compare a drink sweetened with corn syrup and one sweetened with cane sugar, you will notice right away that the one with the real sugar is much sweeter.  In fact, sucrose is 2-4 times as sweet as corn syrup.

Why is corn syrup less sweet than pure cane sugar?  Corn syrup is made up of many different
saccharides (sugar molecules) that your taste buds are simply not that sensitive to.  Corn syrup starts as starch, the long, interconnected glucose chains that pasta is made of - if you've had pasta before, you'll know that starch is not sweet.  Through a process called acid hydrolysis, corn starch is broken down from polysaccharides (made of many glucose molecules) into oligosaccharides (chains of 3-5 glucose molecules). While closer to glucose in structure - these smaller glucose chains also aren't perceptibly sweet.  Following more hydrolysis, these oligosaccharides are broken down into single glucose molecules.  Finally, something your taste buds can recognize.

Manufacturers can control how thick and sweet the syrup will end up by controlling how much the starch molecules break down: the more oligosaccharides that are left behind, the thicker and less sweet the syrup will be.

Because of how thick it is, corn syrup is used not only for its sweetness, but it is also used as a thickening agent.

Figure 2. Glucose is converted to fructose to make HFCS

Now you can see why corn syrup isn't as sweet as pure sugar.  So what do food manufacturers do when they want a sweetener as cheap as corn syrup but as sweet as sucrose?  They convert corn syrup into the ever-notorious high-fructose corn syrup.  To synthesize high-fructose corn syrup, the regular corn syrup is subjected to complicated chemical process that converts glucose to fructose (see Figure 2).  High-fructose corn syrup is sweeter than regular corn syrup because fructose is sweeter than glucose.  Pretty straightforward, right?

 Until recently, high-fructose corn syrup was the sweetener of choice in most prepared foods because of its low price and high sweetness (which means that less has to be used).  Despite this advantage, high-fructose corn syrup has been targeted as a primary cause of obesity and heart disease, and therefore has been removed from many foods in favor of "healthier" sweeteners.  However, similar to the attacks on other sweeteners, the veracity of these health claims have been called into question, and it is still not known for sure whether or not high-fructose corn syrup is worse for you than normal corn syrup.  As scientists, we recommend that if you need something sweet but you don't want to use real sugar, use non-caloric artificial sweeteners.

Figure 3. Clockwise from above: Glucose, mannitol, and sorbitol.

Sorbitol

Now we will step farther away from glucose and look at a couple sugar alcohols (Figure 3). 

Sorbitol is a common sugar substitute that is primarily used in mass-produced ice cream, sugar-free gum, and candy for diabetics.  Sorbitol is called a "nutritive sweetener" because it provides dietary energy (i.e. calories), albiet not as much as sucrose (table sugar).  Sorbitol can be found in nature, for example, in fruits, but most of the sorbitol that is used in manufacturing is derived from corn syrup.  As we mentioned above, corn syrup is composed of a glucose chains of different sizes.  To make sorbitol, the sugar chains in corn syrup are further broken down into single glucose molecules, and these are converted into sorbitol through a different chemical process called hydrogenation.  Glucose and sorbitol are very similar in structure, but this little difference accounts for a big change in how the body reacts to it. Sorbitol is used as a sugar substitute in sugar-free candy because, unlike sucrose, it is not easily absorbed through the intestines, and therefore doesn't reach the blood stream. This aspect of sorbitol is very helpful for diabetics.

In healthy people, when one's blood stream contains too much sugar, the pancreas releases insulin. Insulin causes one's cells to take sugar up and store it.  Diabetics, however, do not have insulin (or their bodies are insensitive to it), so if a diabetic's blood cells are full of sugar, they do not have a mechanism to release it into the blood stream and dispose of it.  Since sorbitol never makes it into the cells of the body in the first place, it is a safe and healthy sugar alternative for diabetics.

Unfortunately, there is a downside to consuming a sugar that cannot cross the intestinal wall - it can cause diarrhea.  To explain this phenomenon requires a little background in biochemistry:

All of the fluids in your body (including the food mush that your stomach makes out of what you eat) contain mostly water (called the solvent), and also some proteins, sugars, and fats (called solutes).  All of these fluids are separated by membranes (for example, the membranes that compose the cells that make up the wall of the intestine).  These membranes are sometimes permeable to water, and are sometimes permeable to different proteins, sugars, and fats. 

Your body wants to keep the concentration of water and these solutes equal on both sides of these membranes.  For instance, if the water to sugar ratio inside your intestines is 1000:1, then the water to sugar ratio on the outside of your intestines is going to be 1000:1.  If you take some sugar away from the outside of the intestine, some sugar will move (or diffuse) from the outside to the inside of the intestine to balance the sugar-to-water ratio across the intestinal wall (See Fig. 4).

Figure 4. A an example of the diffusion process.  If you dump a
bunch of sucrose into the intestine (top) , over time, it will
 diffuse into the wall of the intestine (bottom) until the sucrose 
concentration is the same on both sides of the membrane.

Another example: when you eat sucrose, the sugar concentration in your intestines goes way up, so a lot of it will diffuse to the outside of the intestines to balance out the sugar concentration across the intestinal wall (Fig. 4).  Sorbitol, however, cannot cross the intestines that easily.  Therefore, when you eat sorbitol, the sugar concentration in your intestines goes up, yet most of it will not cross the intestinal wall, and therefore the sugar-to-water ratio across the intestinal wall will not balance out.

So how does your intestine rectify this problem?  Since the intestines cannot kick out sorbitol, they pull in water in order to balance out the sugar to water ratio across their wall.  What does excess water in the intestine cause?  Diarrhea!  Yes, diarrhea is a common side of effect of eating too much sorbitol, which is why it is recommended that individuals with disorders of the gastrointestinal tract avoid sorbitol.

Okay, now that I've ruined your appetite (ironic for a food blog, right?), I think its about time to move on to another sugar.

Mannitol

Mannitol is another sugar alcohol that is found everywhere in the grocery store.  Chemically, mannitol is very similar to sorbitol, but it is derived from a different sugar, mannose.  Mannitol is found widely in nature as well, most notably in tree sap and mushrooms.  Like sorbitol, mannitol provides energy to the body (although, not nearly as much as sucrose).  Mannitol also does not cross the intestinal wall very easily, and it has a high melting point, which is why it is used in chocolate (chocolate is heated and cooled several times to smooth it out).  For these two reasons, mannitol is an ideal sugar choice when manufacturing chocolate for diabetics.  However, just like sorbitol, the fact that it does not cross the intestinal wall means that it causes diarrhea, a side-effect that causes many diabetics to avoid "sugar free" chocolate.

Figure 5. The powdered stuff you see
on your gum is mannitol

Unlike sorbitol, mannitol is a desiccant, which means that it does not hold onto water.  Even when the humidity outside is 98%, mannitol still stays dry!  Food manufacturers take advantage of this amazing property when packaging hard candies and gum: mannitol provides a natural barrier against water, therefore candy and gum that are coated in mannitol do not stick to their wrappers (Fig. 5).

***
Another advantage of sorbitol and mannitol: unlike sucrose, mannitol and sorbitol cannot be broken down by the bacteria in your mouth.  When sucrose is broken down, the remaining byproducts increase the acidity of your saliva.  In the mouth, acidic saliva can wear away at the enamel on your teeth.  Since sorbitol and mannitol are not broken down by oral bacteria, they do not increase the acidity of your mouth, and therefore they do not rot your teeth.

References and Further Reading:

Figure 4 was borrowed from biologyguide.net
 http://sweetsurprise.com/hfcs-myths-and-facts
http://www.wisegeek.org/what-is-sorbitol.htm
http://www.caloriecontrol.org/sweeteners-and-lite/polyols/mannitol

Lecture 5: Demystifying Your Ingredients - Sugar Substitutes (Part I)

A while back, when we baked our unbelievably sweet Pumpkin Cinnamon Rolls, we told you a little about the magic (and science) of sugar.  Sugar is the compound that makes us sense sweetness, the stimulus that, in its purest sense, signals the presence of nutrition in food.  This is why sugar tastes so good - it encourages use to eat foods that will provide us with energy.

Figure 1.  The molecular structure of sucrose.  The hexagon
on the left is glucose, and the pentagon on the right is fructose.
 Each corner of each shape is a carbon (except for the two
oxygens).  The two sugars are connected by an oxygen
atom.  This atomic grouping (C-O-C) is called an ether group.

Sugar comes in many forms.  Glucose is the most basic sugar - through a series of biochemical and electrochemical steps, our bodies convert it into ATP, our body's molecular batteries.  Sucrose, or table sugar, is a disaccharide (composed of two sugar units), made of glucose and fructose, another natural sugar.  There are two major problems with sucrose.  First, it has a lot of food energy, or calories.  Another issue: it's converted to glucose in the body, which in diabetics can thicken the blood, increase blood pressure, and cause tissue damage in delicate areas such as the fingers, toes, and eyes.  Over the years, scientists have therefore come up with several sugar substitutes that solve one or both of these issues...and some have worked out better than others.

We are going to start our venture into the world of sugar with a study of those that you won't be able to find anywhere because they're either horribly toxic or just outright banned by the FDA.

Lead Acetate

Figure 2. Lead (II) acetate.  DON'T EAT THIS.

Surprisingly, lots of lead salts (lead + acid) taste sweet.  The ancient Romans noticed this, and they came up with the bright idea of using lead (II) acetate, the same compound in those paint chips you're not supposed to eat, to sweeten their wine.  Sure, at the time, they didn't have many sweeteners at their disposal, so it is understandable they they'd use any remotely sweet compound that they could get their hands on to obtain their sugar fix.

But, as you can probably guess, the Romans ran into problems.

Lead is a poison - it binds to most of the enzymes (the "workers") in your body and renders them nonfunctional.  It's half-life in the body is about a week, so repeated exposure will cause it to build up in the body, which leads to neurodevelopmental impairments and organ failure.  Now, it is still under debate whether lead poisoning was a significant public health issue in the Roman Empire, and if it was, whether lead acetate was responsible (they used lead pipes, too, remember), but it is known that lead acetate led to the deaths of Pope Clement II, the painter Albert Christoph Dies, and possibly Ludwig van Beethoven.  Don't worry, lead acetate has been banned from foods in the US and Europe for a looong time (but not some hair dyes; FDA 2002)


Cyclamate

Figure 3. A juice powder packet from the early seventies.

Cyclamate's sweetness was accidentally discovered by a student at the University of Illinois after he synthesized it in 1937 (what's with everyone tasting random compounds??).  Its patent was bought by Abbott Labs and was used to mask the taste of some of their bitter antibiotics.  In the 50's and 60's, cyclamate was sold in tablets and was used as tabletop sweetener for diabetics (similar to how Splenda is used today).  In 1969, a study came out showing that cyclamate caused bladder cancer in rats, and this study led to the FDA to ban the sweetener (FDA 2014).  However, it turns out that this study was plagued with problems.  For instance, the researchers used an extremely high dose of cyclamate in a species that was already highly susceptible to bladder cancer.  Since then, dozens of studies have come out that demonstrated the safety of cyclamate.  Consequently, an application has since been submitted to the FDA to get cyclamate re-approved.

As we all know, the government moves very slowly, so it might be a while until you see cyclamate back on the table at your local deli.

Stay tuned for Part II - Natural Sweeteners

Figure 4.  Yummy donuts.

Sources:
FDA, 2002: http://www.fda.gov/Cosmetics/ProductsIngredients/Products/ucm143075.htm
FDA 2014: http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=189.135

Experiment 17: Pumpkin Gingersnaps

Figure 1.  Pumpkin gingersnap cookies, cracked on top, with a coat of sugar on the surface.

November 2013

Introduction

Well, we're nearing the end of pumpkin season.  Times like these demand that we devise a use for every last bit of canned pumpkin before it is deemed “so last season.”  In an effort to combine our proclivity for making sugary desserts and our desire to absolve our aforementioned pumpkin dilemma, we chose to bake chewy pumpkin gingersnap cookies.  This recipe is super fantastic because it's chewy, unlike most gingersnaps, which are so crunchy they could crack your teeth.  Spoiler alert: Fantastic recipe, definitely try this one at home!

NFPA Ratings

Figure 2. Our NFPA ratings for pumpkin gingersnap cookies.

Difficulty: One point for mixing, one point for rolling.  Just remember to mix your dough before your roll, or else you'll have a big mess on your hands and your floor...especially over carpet.

Baking Time:  If you could fit all of your cookies in the oven, this recipe would take you about 30 minutes to complete.  However, if you are like us and only have one baking sheet or have an apartment-sized oven, you'll have to build more time into your schedule for rotating your cookies in and out of the oven.  The good news is that if you run out of time, you can stuff the extra cookie dough in the refrigerator until you have time to make more cookies.
 

Course:  Dessert, of course!  Not a bad midnight snack either.  And breakfast, if you're not to strict on that whole "balanced breakfast" thing.

Materials

Figure 3. Dry ingredients.  Wet ingredients not shown
due to gross aesthetics.

0.5 cups butter at 22º C (room temperature)
1 cup granulated sugar (+ more in a small bowl to the side for rolling onto the dough)
0.5 cup pure pumpkin
0.25 cup molasses
1 large egg
1 tsp vanilla extract
2.33 cup all-purpose flour
2 tsp baking soda
2 tsp cinnamon
1.5 tsp ground ginger
1 tsp ground cloves
0.5 tsp salt

Methods

1) Preheat oven to 350º F.  In a bowl or stand mixer, beat the butter and sugar together until smooth
2) Add the pumpkin, egg, molasses, and vanilla extract and mix until...you know...mixed
3) In a medium bowl, whisk together flour, baking soda, spices, and salt

Figure 4. Raw dough

4) Add wet ingredients to dry ingredients and mix
5) Refrigerate for at least an hour but no more than 3 days (Who leaves cookie dough in the fridge for 3 whole days??)
6) Line baking sheet with parchment paper.  Bring back the little bowl of sugar that you placed off to the side earlier.
7) Roll tbsp-sized balls of dough in the sugar and place onto the baking sheet, about 2 inches apart
8) Bake for 10-12 minutes, until the cookies look crackled and set on the edges
9) Let the cookies cool for 2-3 minutes after you take them out of the oven (they will still be soft).  Then, transfer them to a wire rack to cool them completely.

Makes A LOT (30-36) of cookies.

Results

Figure 5. The finished product

These cookies were scrumptious. (n > 35...so tasty) They were sweet but not too sweet, they were pumpkiny but not too pumpkiny.  You could taste the bite of the cloves and the tartness of the ginger.  Every ingredient showed through and hit its mark.  We surprised ourselves and others with the quality of the taste.  In addition, they looked amazing.  It is all too common that a finished baking product does not look like the pictures, but this time, our cookies looked like they came straight out of the blog that had the original recipe.  Super easy, super delicious.  So good we made a second batch.

These cookies were also very soft.  Straight out of the oven, they did not seem fully cooked; however, they finished cooking on their own, and they remained soft and chewy.  

Discussion

Molasses.  It is sold next to syrup at the grocery store, it's brown like syrup, it's thick like syrup...but it does not smell or taste as sweet as syrup.  (Trust us on this.  Please do not dip your finger in to taste molasses by itself.)  What exactly is this unusual pseudo-syrup?  Our initial hypothesis, given its proximity to maple syrup in its consistency, color, and geographical location, was that molasses fell somewhere in the liquid plant product spectrum between maple syrup and tree sap.

Figure 6. Jar of Molasses
(photo credit: somewhere on google.com)

But we were wrong.  Unlike syrup, in the cooking ingredient family tree, molasses is not related to tree sap.  Did the grocery store mis-categorize molasses, or were we tricked?  That's a question for a different blog.

Let's chat about the etiology of molasses.  For the sake of analogy, molasses is to sugar as whey is to curds.  That is, molasses is the byproduct of the sugar-making process.  To purify sugar from sugarcane, the cane is chopped up and mashed, and the leftover sugary juice is boiled multiple times.  Boiling promotes the crystallization of sugar, which is extracted from the mixture.  The leftover juice from each boil is sold as its own product - molasses.  Light molasses, the byproduct of the first boiling, is sweet but does not have a very complex flavor.  This is what we used.  Robust molasses, the byproduct of the second boiling, has a rich flavor and is moderately sweet.  Blackstrap, the leftover syrup from the third boiling, has the lowest sugar content but the richest flavor.  Light molasses is sometimes "sulphured" to preserve it and add flavor, but this is not what you want...really ever.

Figure 7. Molasses on a Spoon
(photo credit: google.com)

Why is molasses used in baking?  Sure, molasses is healthy (it’s fat-free and full of B vitamins, iron, calcium, magnesium, and potassium), but that’s not its purpose in desserts.   Molasses has a rich, complex flavor that arises from its low sugar content.  This flavor lends itself to the rich flavor of everything from gingerbread cookies to barbecue sauce.

Interestingly, molasses is also used as the base for making rum (instead of, for example, hops for beer), and it is added to garden soil to promote microbial growth.

References

1. http://www.takepart.com/article/2013/08/28/its-sugar-thats-bad-you-not-sugarcane

2. http://www.dominospecialtyingredients.com/?pageId=1090&rowId=11207

Figure 6.  YUM.  YUM YUM YUM!!

Experiment 16: Sea Salted Caramel Brownies

Figure 1. Sea Salted Caramel Brownies

Introduction
It has become obvious that we are better at baking desserts than cooking healthy stuff.  While contemplating which sugar-packed recipe to make next, we happened upon this recipe for salted caramel brownies.  Though we had planned to make a sophisticated meal that day, we abandoned that idea as soon as we saw these brownies in a recipe online.

Figure 2. Our NFPA ratings for Sea Salted Caramel Brownies

NFPA ratings:
Difficulty: 4
Not too difficult, but you have to read the directions.  The results are well worth it!

Prep. Time: 2 hours.  This is an estimate, as we baked these some time ago and neglected to watch the clock.  About a quarter of this time will be spent with your tuchus glued to a chair waiting for the brownies to cook.  You will really need to use some strong glue because these brownies need to bake in peace.

Course:  Midnight snack for students.  Dessert for everyone else.  Also a decent breakfast!

Materials
Brownies
1) Unsweetened chocolate, roughly chopped - 3 ounces (85 grams)

Figure 3. Sizzling caramel

2) Unsalted butter - 1 stick
3) Granulated sugar - 1 cup

Figure 4. It's much easier to break off pieces of caramel than to cut it.

4) Eggs - 2
5) Vanilla extract - 1 teaspoon
6) Flaky sea salt - 0.25 teaspoons, heaping
7) Flour - 0.67 cups

Caramel
1) Granulated sugar - 0.5 cups
2) Unsalted butter - 4 tablespoons
3) Flaky sea salt - 0.25 teaspoons, heaping
4) Heavy cream - 3 tablespoons

Methods
Caramel
1) Melt sugar in a medium, dry saucepan.  This takes about 5 minutes.  Don't stop stirring!!  The sugar should turn brown.
2) Remove from heat.  Stir in butter, then the cream and salt.
3) Return to medium-high heat.  Simmer and melt any remaining solid butter.  The mixture should bubble.  When it darkens, pour it onto a parchment paper-covered plate and freeze it until it solidifies.  This will take about 30 minutes.

Brownies
1) Pre-heat oven to 350 ºF.  Line the bottom and sides of an 8 x 8 inch (ish) pan with parchment paper.  Butter or spray the paper so nothing sticks to it.

Figure 5. Mix the brownies and fold in the caramel.

2) This step requires a frying pan and a pot.  Boil water in the pot.  Put the chocolate pieces in the pan, and rest the pan on top of the pot.  This method is fit for students like us, but if you're a traditionalist, you could use a heatproof bowl.  Stir until the chocolate is fully melted.  Alternatively, you can microwave and stir (another option fit for the average student).
3) Add the sugar, eggs, vanilla, and salt.  Stir in the flour.
4) When the caramel is solid, remove it from the freezer and chop it into one-inch squares.  The caramel will be sticky and difficult to chop.  We found it easier to just pull it apart into pieces.
5) Fold most of the caramel pieces into the brownie batter and mix gently.
6) Pour the batter into the parchment paper-covered pan.  Place the remaining caramel pieces on top of the batter.
7) Bake for 30 minutes.
8) Eat and marvel at your neurochef skills!

Results
So delicious.  Fantastic taste, and not too difficult.  These brownies balance caramel with chocolate in a way that is sweet, but not tooth-rottingly sweet.  The flavors actually balance really well. You can keep your leftover brownies in the refrigerator or freezer, but make sure to heat them up before you dive back in, both to maintain the structural integrity of your teeth, and to prepare melted caramely goodness for your deserving palette.  Also, plop a scoop of vanilla ice cream on top, and you will forget you are eating reheated frozen brownies.

In cooking this recipe, we learned that folding something into a mix is different from just mixing.  Previously, we just thought it sounded like some pretentious cooking term for fancy mixing.  However, this recipe required us to fold our caramel bits (that we broke because they were too sticky to cut) into our batter.  Folding (a similar motion as folding paper) really seemed to help here.  It helped distribute the caramel more evenly than plain mixing would have.

Discussion
This recipe, while dominated by a plethora of sweet tastes, e.g. sugar, caramelized and not, incorporated sea salt as a primary ingredient.  Of course, these brownies would have baked perfectly fine without the salt; it provides no structural or chemical support of the brownies themselves.  However, without the dash of sea salt, the brownies would simply taste different: the salt (sea salt or regular salt) actually alters the sensitivity of your tongue to other tastants.

One such tastant that benefits from the presence of sodium is glucose.  There's a reason why your caramel corn tastes so good.  The biological mechanisms that underlie the gestalt effect of combining sweet and salty tastes have only recently been elucidated.

It has been proposed that the sodium-glucose receptor/transporter (SGLT1) is responsible for the interaction between glucose and sodium.  SGLT1 is a transport protein, which means it floats around on your cellular membranes and pumps atoms or molecules across membranes into or out of cells.  It was originally thought to only reside in your stomach, but it has recently been found in the taste cells on taste buds as well (Toyono et al. 2011).  Transport proteins are very important, because just like how a water pump pumps water up against gravity to reach your shower, transport proteins work for you by pumping ions and molecules opposite from where their electrical and chemical gradients want them to go.

Figure 6. Sodium Glucose Transport - From Frank Boumphrey (2009)

SGLT1 is a co-transporter (Figure 6; blue).  It pumps one ion (sodium; yellow) and one molecule (glucose; orange) across your taste cell membranes (periwinkle).  However, it can only pump glucose into your taste cells when sodium is present.  The receptor begins open to the outside of the cell membrane.  Once the receptor receives both sodium and glucose, it change its conformation and opens to the inside of the cell, releasing the sodium and glucose.  Since both the sodium and glucose are required for passage into the cell, the salt in your brownies actually makes your taste buds accept more glucose, and in turn causes you to perceive a greater level of sweetness.  Who knew?

References
1) Salted Caramel Brownies. smittenkitchen.com. Feb. 2013
Toyono T, Seta Y, Kataoka S, Oda M, Toyoshima K. Differential expression of the glucose transporters in mouse gustatory papillae. Cell Tissue Res. 2011;345(2):243-52.

Experiment 15: Roasted Corn, Red Pepper, & Tomato Chowder

Figure 1.  See the little dots in the soup?  That's perfection.

Introduction
A little while back, we tried our hands at tomato soup.  As you hopefully don't remember, it wasn't one of our proudest moments (we provide you with the link to the associated article not to remind you of our results, but merely for the sake of continuity).  It was a bit of a disaster.  It took a good day or two to admit it, but we screwed up the recipe pretty badly.

But alas!  We are graduate students!  We are used trying and failing!  We can't give up!  Without the discipline of our graduate education in our back pockets, we may have succumbed to defeat.  But no, for us, the next logical step was to try something even harder, and prove to ourselves that it can be done.  Yes!  We can make tomato soup!  Tomato, roasted red pepper, corn, delicious!  LET'S DO IT!

Don't stop reading!   We didn't write this to flaunt our achievements.  We promise this one is a better story.  Actually, this soup was actually pretty delicious.  We even had a third, unbiased person taste it, and she loved it.

NFPA Ratings:

Figure 2. Our NFPA ratings for roasted corn, red pepper,
and tomato chowder.

Prep time: 2 hours.  This recipe took forever.  For something disarmingly complex despite its simple appearance, as this soup was, we felt that it took more time than it should have. Tons of chopping, too many steps, lots of places to mess up.  Fortunately, after all that, the result was super delicious.

Difficulty: 7.  Perhaps this ties into our rant over taking two entire hours to cook this.  It felt like a never-ending recipe with a million steps.  And then the blender issues....Oh, the blender issues.  Maybe we should take the difficult up to 8 or 9.  On the other hand, it might be better to just get a blender that has a lid (See Results).

Course: Dinner, lunch, whatever.  Soup is a side.  We tried eating this as a main course because we didn't feel like cooking anything else after putting so much effort into this soup.  Honestly, it was lucky that we also made sea salted caramel brownies that evening, because soup, no matter how many veggies you stuff into it, is not a main course.

Materials

Figure 3.  Photo cropped on purpose to hide pathetic grill.

Red Bell Peppers - 3 halved and seeded
Shucked Corn - 3 ears
Tomatoes - 1.5 lbs (about 4) halved, seeded, and peeled
Extra-Virgin Olive Oil - 2 tbsp
Chopped Onion - 4 cups (about 2 medium)
Fat-Free, Low-Sodium Chicken Broth - 3 14 oz. cans
Salt - 0.25 tsp
Freshly Ground Black Pepper - .25 tsp
Crumbled Blue Cheese - 0.25 cup (1 oz)
Chopped Fresh Chives - 2 tbsp

Methods
1) Set your grill on to medium  heat.
2) Arrange bell peppers, skin side down, and corn in a single layer on the grill rack.  Grill for 5 minutes, turning occasionally.
3) Add tomatoes to the grill, skin side down.  Grill for 5 more minutes, or until the vegetables are slightly charred.
4) Remove from heat, cool for 10 minutes.
5) Coarsely chop the tomatoes and peppers and place them in a medium bowl.  Cut the kernels from the corn and add them to the bowl.
6) Heat oil in a large Dutch oven (or pot with a well-fitting lid).
7) Add the onion and cook for 7 minutes or until the onion is tender.  Add the tomatoes and cook for 3 more minutes, stirring occasionally.

Figure 4. Tomato, corn, pepper, onion, sliced and seeded.

8) Increase the heat to high and stir in the broth.  Bring to a boil.
9) Reduce heat and simmer for 30 minutes or until the vegetables are tender.  Cool for 20 minutes.
10) Place 1/3 of the tomato mixture in a blender, PUT THE LID ON, and process until smooth.  Put the pureed mixture into a large bowl.
11) Repeat step 10 twice (until the whole mixture is pureed).
12) Wipe Dutch oven (or pot) clean with paper towels.
13) Push the tomato mixture through a sieve/colander/strainer and discard the solids.
14) Place Dutch oven (or pot) over medium heat and cook thoroughly
15) Stir in the salt and pepper

Yield: Six 1.5 cup bowls of soup
Top each with 2 teaspoons of cheese and 1 teaspoon of chives (optional...aka we forgot this part.  We bought chives, but then forgot to use them.)

Results
Here's a useful tip: when you're cooking something, read the entire recipe carefully before you start.  When the recipe asks for a blender, don't just say "oh, I have that."  Make sure you have all of the components, including the lid.  When we reached step ten, we casually pulled out the blender, set it down on the counter, then stepped back in horror upon realizing that the lid was not present.

Figure 5. The effect of lid presence on the total kitchen
surface area splattered with boiling hot tomato-infused
chicken broth, as a function of the angular velocity of the
blender blades.

See, this is where being a scientist doesn't help.  Engineers build working systems from scratch, but as biologists, we are taught to take
the opposite approach, that of taking a whole working system and manipulating it in some way to see what changes.  Therefore, in this case, our graduate education does not apply to this sort of dilemma.  Don't worry, we don't lack quite enough common sense to "test" what happens when you use a blender without a lid and swirl sharp blades at a very high velocity through a boiling hot mixture contained within it (See Figure 5 for the predicted results from such an experiment).

No, we tried to come up with other kitchen supplies to substitute for a lid.  It was definitely one of our worst ideas thus far.  Enter: cutting board.  A small, smooth (minus a few slice marks), thick, plastic, board with rubber edges for a no-slip grip.  A perfect substitute for a blender lid?  Not hardly.

It was a beautiful piece of teamwork: one of us applied pressure to the cutting board while the other managed the controls.  Bzzz..bzzz..bzzzzzzzz.  It was working.  With every turn of the blade came greater confidence in our last-minute lid substitute.  But all of the sudden, "SPLOOSH!"  The blender hiccuped, and sprayed boiling hot tomato corn pepper soup puree through the air onto every surface in a two foot radius.  None hit the skin though, fortunately.  No, that happened during the first repetition of the first part of step 10.  It was only a minor burn.  It's all better now.

Don't try this at home.  Seriously, don't.

Figure 6.  Yummy in our tummies!

Where there is no harm, there is no foul.  Who is thinking about 1st degree burns anyway when they're eating such a delicious chowder?  It provided the taste buds with an immaculate mixture of flavors, with each ingredient making its presence known in a subtle but succulent fashion.  We forgot to peel the tomatoes, which produced a bit of a texture in the soup.  It wasn't bad; in fact, it added a little character to the dish (bowl?).  All in all, we feel that we redeemed ourselves from our previous effort at cooking tomato soup from scratch.  While the process itself could have used much refinement, the final product outscored and conquered our first iteration, wiping it clean from our minds (but not from the counter).


Discussion The kitchen is full of hot surfaces and substances, e.g. the pots on your stove, the racks in your oven, the boiling hot oils in your frying pan, and the silverware straight out of your dishwasher.  It is sometimes a wonder that we made it this far in the first place.   In this case, the burn came from transferring boiling hot chicken broth from a pot on the stove to a blender sitting a foot away.

So...this is kind of gross, but if you follow our recipe exactly, then it's only fair that we tell you a little about how to deal with a burn.  First of all, a first degree burn is a surface burn of the skin, and it can be caused by heat, radiation, chemicals, friction, or electricity.  In this case, the burn result from concentrated heat exposure.  Generally, with a minor burn, the affected skin will turn red and hurt.  Rest assured, these minor burns should heal in 2-3 days (Granger 2009).  For anything more serious, you would probably need medical attention.  However, unless you pour the entire pot of soup on yourself, you shouldn't worry about that.

Figure 7. Layers of the Skin

Your skin layers include the epidermis, which is the outermost layer, the dermis, which is the middle layer, and the hypodermis, which is the innermost layer of skin (Figure 7).  First degree burns usually only affect the epidermis.  Anything lower than the epidermis (muscles, blood vessels, etc.) would only be affected by a more severe burn.  Throughout these layers, for example in your fingertips, you have sensory receptors that help you feel things you touch.  These receptors indicate properties like temperature, texture, and pressure.  These properties are integrated in your brain, which allows you to identify things by touch alone.  Some receptors give you information about the onset, offset, and changes of these properties, and still others respond to prolonged, ongoing stimulation.

In the case of painful extreme temperature contact, the role of these receptors is to help you move away from painful stimulus in order to prevent injury.  The process is pretty cool, and doesn't even require your brain to get involved until after you're safely away from harm.  For example, think about accidentally touching a hot frying pan.  You jump back right away without even thinking about it.  Sensing and responding to the heat of the frying pan with a retraction of your hand is all mediated in the spinal cord.  It is only later (milliseconds later) that this sensory information is sent to your brain for you to become aware of what just happened and say, "Ow!  That hurt!"  The same thing happens when you blend boiling soup without a blender lid and it goes flying everywhere.  The soup hits skin, the skin burns, and you jump back in alarm, thus allowing even more soup to escape from the blender.  Yeah...we're awesome cooks.  :)

References
1. Weir J. "Roasted Corn, Pepper, and Tomato Chowder." myrecipes.com. June 2009.
2. Granger J.  "An Evidence-Based Approach to Pediatric Burns". Pediatric Emergency Medicine Practice 6 (1). January 2009.

Experiment 14: Red Velvet Cupcakes

We're back from our hiatus!  

Figure 1. A deliciously red velvet cupcake.

Introduction
For our birthdays, it was between cheesecake and red velvet cake.  Upon finding a cheesecake pan on sale, we decided on cheesecake.  Now, even though both of our birthdays have passed, we still sort of had a taste for red velvet cake, so we decided to revisit it, but this time in cupcake form.

Figure 2. Our NFPA Ratings for red velvet cupcakes.

NFPA Ratings:

Difficulty - This recipe was pretty simple, especially for how well it turned out.  We were afraid we were doing it wrong the whole time, because our mixture looked goopy and oily until it was cooked.  Additionally, all that red made our uncooked cupcakes look like blood.  Fortunately, our cupcakes puffed up in the oven, thus validating our process.

Course - Dessert, or sugary snack if your id compels you.  Also an acceptable midnight snack.

Prep time - It took us about an hour, but looking back, we are not sure why.  The recipe just involves mixing a large variety of ingredients together, pouring the mixture into cups, baking them, and frosting them.  In reality, it will probably take you 45 minutes.
  
Materials

Figure 3. The dry ingredients.

Cupcakes
1) All-Purpose Flour - 3/4 cups
2) Cocoa Powder (no Dutch Cocoa) - 1 tbsp
3) Baking Soda - 1/3 tsp
4)  Salt -1/4 tsp
5) Buttermilk - 1/4 cup
6) Red Food Coloring - 1/2 tbsp
7) Milk - 1 tbsp
8) Olive or Vegetable Oil - 1/3 cup
9) Applesauce - 1/8 cup
10) White Vinegar - 1/4 tsp
11) Vanilla Extract -1/4 tsp
12) Cupcake foil holders

Figure 4. The wet ingredients.  This is where it starts
getting creepy.

13) Muffin Tin

Frosting
1) Unsalted Butter - 4 tbsp / 1/2 Stick, softened
2) Cream Cheese - 1/2 bar (4 oz)
3) Confectioner's (a.k.a. Powdered) Sugar 2-2 1/2 cups
4) Vanilla Extract - 1/2 tsp

 
Procedure
Cupcakes
1) Preheat your oven to 350º F.
2) Put the buttermilk in a mixing bowl.
3) Add in the food coloring, milk, oil, apple sauce, vinegar, and vanilla extract, and mix it all together (Figure 4).
4) In a separate bowl, sift the flour, cocoa  powder, and baking soda (Figure 3).  Add salt and mix in.

Figure 5. The final mixture.  Yum....NOT...yet... 

5) Combine the wet and dry ingredients in one bowl and mix with a spatula just until combined
(Figure 5).
6) Line a muffin tin with foil cupcake holders.
7) Divide the batter evenly among the wrappers (Figure 6).
8) Place your muffin tins on the top shelf of your oven.  Cook large cupcakes for about 20 minutes, and mini cupcakes for approximately 10 minutes.
  
Frosting
1) Whip the butter and cream cheese together for 3-4 minutes
2) Add the sugar in small increments and the vanilla extract.  Mix until it's not too thick, but before it becomes to soft.

Figure 6. Don't pour to the top.  Leave room for puffiness.

Cupcakes
9) Remove the cupcakes and let them cool completely (Figure 7).
10) Pipe on or spread frosting
11) Store in refrigerator.

Recipe will yield 6 large cupcakes or about 15 miniature cupcakes. 

Results
Before we get into our results, we have to admit to a tiny indiscretion.  Instead of making the frosting as described in the recipe, as easy as said recipe looks, we decided to use store-bought cream cheese frosting.  We won't lie...it was goooood.  All things considered, actually making the frosting ourselves would not have been much more of an addition to our responsibilities.  Whatever, this was faster.

Figure 7.  Baked cupcakes.
They look brown...but it's the lighting

Anyway, these cupcakes were tasty!  They were soft, moist, and delicious!  Unfortunately, they turned out a bit more rust-brown than red, even though the blog that owns this recipe guaranteed this wouldn't happen.  Regardless, steps 2-4 resulted in a murder scene-esque mess on all of our utensils.  Adding that much red food coloring into something of that viscosity makes whatever you're cooking look like a mixing bowl filled with blood.  Truly, everything before the final product of this recipe looks very unappetizing. Don't be afraid; just go with it.  It will turn out fine.

Note: While these are delicious straight out of the oven, these are equally, if not more, delicious straight out of the refrigerator the next day.

Other noteworthy points about this recipe are that 1) it has way less sugar than other stuff we've baked, and 2) you don't really need the sifter.  We don't have a sifter and our cupcakes were still light and fluffy.

Figure 8.  The final product, complete with our store-bought frosting.

Discussion

You may think that all you have to thank for the red velvet cake's rich redness is the food coloring it contains.  Big deal, right?  Add a few drops of red food coloring into anything, and voilà, you have red velvet everything you ever wanted!  Red cookies?  Food coloring.  Done.  Red pancakes?  Food coloring.  Done.  Red celery?  Food coloring.  Done.

But wait, red velvet cake contains something special that brings the redness forth independent of the food coloring.  Part of that red color comes from a chemical reaction that happens right in your mixing bowl.

Cocoa contains a chemical called anthocyanin.  Anthocyanin is an antioxidant and natural pigment that is found in plants.  It is present in all sorts of berries, purple grapes, red cabbage, pomegranates, several flowers such as violets and pansies, and, of course, the cacao tree.  The color anthocyanin emits depends on the pH of the environment in which it is found.  In low pH conditions (i.e. in acids), anthocyanin emits a bright red color.  As you raise the pH, it shifts to purple, takes a turn past blue and green, and ends up at a bright yellow (Figure 9).

Figure 9. Anthocynanin over a range of pH values.

How are you going to lower the pH to get that bright red color for your cupcakes?  The buttermilk and vinegar of course!  Buttermilk is acidic because bacteria in the milk ferment the lactose and turn it into lactic acid.  Vinegar, the prototypical acidic agent in your kitchen, is composed of acetic acid and water.  Acetic acid comes from the fermentation of ethanol.  You probably thought it was weird that this recipe called for vinegar, but now you know why it did.

It is absolutely wrong to use Dutch cocoa for your red velvet cupcakes.  Why?  Dutch cocoa is alkaline because of how it is processed.  If you use Dutch cocoa, your cupcakes will turn brown.

Figure 10.  The leftovers...

References
1. Beaird A. ""Chemistry in Cake: Putting the Red in Red Velvet Cake". ChEnected.  October 2012
2. Lassi(e) C. "Eggless Red Velvet Cupcake with Cream Cheese Frosting".  Pan Gravy Kadai Curry: Tasty Tales from a Flexitarian Foodie.  July 2012.

Experiment 13: Tomato Soup

Figure 1. Tomato Soup

Introduction
Although the year is new, the winter is not.  It's cold and dark (but not much snow!)  We wanted to make something simple and warm, just enough to bring us back from the winter doldrums.  We chose a simple tomato soup.

We dream to eventually cook a fancy and complex soup, with roasted and pureed vegetables, something that takes more than a couple steps.  However, it's winter, and it was a long day, so we decided to push our dreams off for some other day.  How's that for a cheerful, uplifting thought?

Figure 2. Our NFPA Ratings for tomato soup.

NFPA Ratings:

Prep time: One hour and 20 minutes.  Most of that time is spent dicing tomatoes and cooking.  The steps in between don't take up much time.  The recipe claimed it would take much less time than it actually did.

Difficulty: 5.  The recipe was a bit confusing.  Maybe our reiteration of the recipe will knock this rating down a point or two, but we want to report our experiences as they happened.  (Get ready to read about some weird soup.)

Course: Dinner or lunch, but it needs to be paired with a main course.  We suggest grilled cheese.

Figure 3. Simmering the Diced Tomatoes

Materials
Tomatoes - 4 cups, diced (Figure 3)
Onion  - 1 slice
Cloves - 4 whole
Chicken Broth - 2 cups
Butter - 2 tbsp
All-Purpose Flour - 2 tbsp
Salt - 1 tsp
White Sugar - 2 tsp (or to taste)

Methods 
1. In a stockpot, over medium heat, combine the tomatoes, onion,  cloves, and chicken broth
2. Bring to boil, and gently boil for about 20 minutes to blend all of the flavors.
3. Remove from heat and run the mixture through a food mill into a large bowl or pan.*  Discard leftover bits from the food mill.
4.  In the stockpot, melt the butter over medium heat.
5. Stir in the flour to make a roux,** cooking until the roux is a medium brown.
6. Gradually whisk in a bit of the tomato mixture, so that no lumps form, then stir the rest.
7. Season with sugar and salt, and adjust to taste.

*We used a strainer and mashed it through.  Big mistake.  (See Results)
**A roux is a homemade thickening agent that is common in French cooking.  Just stir until it is evenly mixed.

Results
Well...okay.  Let's talk.  It's not like we didn't try.  We were just so excited about cooking that we failed to read the recipe closely in advance.  If we had, we would have noticed that we needed a food mill.  Instead, we skimmed the directions, and as a result, were forced to improvise after we learned of the integral role of this mystical apparatus.

Figure 4. NOT a substitute for a food mill.

What is a food mill?  It's part blender, part juicer, and part strainer.  Basically, it's used to make purees by blending vegetables into a liquidy pulp. And neither of us has one.

Coming off of a string of successful cooking escapades, our hubris overcame us, and we thought we could somehow manage without the food mill.  We quite mistakenly thought we could mash our tomato mixture through a strainer and get similar results, mostly because we had not idea what a food mill was.  Don't try it.  It won't work.  Basically, 75%  of the taste of the soup came from the chicken broth, and only 25% came from the tomato mixture.  This happened because more of the tomato was supposed to be blended into the broth.  Because of our half-baked idea (pun intended) to substitute a plastic strainer for the raw power of metal blades, the chicken broth remained the dominant flavor in the soup.  Put simply, our tomato soup tasted like chicken.  Yikes!

That is not to say it did not taste good.  It was still rather tasty...but maybe a bit salty.  Actually, it only tasted good when we dipped the grilled cheese in it, which toned down the chicken flavor and put the emphasis on fried bread and cheese.  Grilled cheese was really our saving grace in this endeavor.  This recipe seemed like a lot of work for basic tomato soup, but maybe that's just because we didn't have a food mill.

Figure 5. Tomato Soup with Grilled Cheese

One last comment.  About the cleanup - it was odd.  The soup sort of gelatinized and stuck to all of the dishes.  It was very gooey and hard to scrub.

Was it worth it?  We leave that to you to decide.





Discussion
One ingredient we found surprising and problematic in this recipe was chicken broth.  Why would tomato soup use chicken broth?  Isn't tomato soup supposed to be a vegetarian dish?  Why not just use water?  So we decided to look further into the matter.

First of all, do you know what's actually in chicken broth?  It's a little gross...you might not want to keep reading.  Chicken broth is full of gelatin, which you'll know is made from hydrolyzed collagen if you read our post on thickening agents.  Remember the gummy bears?  Gelatin is a shared ingredient between chicken broth and gummy bears.  Doesn't sound so tasty anymore?  Then you should additionally know that collagen can be found in bones, tendons, cartilage, connective tissues, etc (Priest 2010).  A vegetarian's nightmare!  Good thing neither of us is a vegetarian.  Actually, don't get up-in-arms about this apparent travesty just yet.  Sources tell us that store-bought chicken broth doesn't contain as much hydrolyzed protein as homemade broth.  Yes, you read that right.  Store-bought broth has less bones, tendons, cartilage, connective tissues, etc. than the homemade stuff.

Figure 6. Chicken Broth

So, why is chicken broth so much more commonly used than vegetable broth?  At first we thought that using vegetable broth would have been nice because our tomato soup wouldn't have tasted like chicken.  However, after reading a Cook's Illustrated review of store-bought vegetable broth, we understood why it may be "disastrous" for your recipe.  According to this article, vegetable broth flavors vary widely (Cooks Illustrated 2008).  Some are loaded with salt, some are sweet, some have floating veggie bits in them, some are opaque, some are clear, some are bland, and others are overpowering and leave a weird aftertaste.  That's quite a lot of variation to introduce into your recipe, especially if you don't know which particular flavor of vegetable broth you have.  The article also points out that vegetable broth is often made from the worst vegetables just before they spoil, like KFC's chicken (Cooks Illustrated 2008).  In other words, if the vegetable isn't good enough to be sold as a vegetable, then it gets made into broth.  In terms of quality and uncertainty, vegetable broth seems like a bad choice.

Figure 7. Vegetable Broth

Our other question, "Why not just use water?"  Well, there seems to be no consensus on that.  It could either be great or disastrous.  Some people add water to their soup anyways to add more volume to it.  The chicken broth camp claims that the bits of tendons and bones and chicken guts boost the soup's flavor (Priest 2010).  To be honest though, we did not like that our tomato soup tasted like chicken. It was weird.  Next time, we will either get a food mill, or we will just try water.

References
1. Priest, C. Feb. 2010. "DIY Chicken Stock." Food/Science.
2. May 2008. "Vegetable Broth." Cook's Illustrated.