Experiment 6: Banana Bread

Figure 1. Banana Bread

Introduction
What happens when you buy too many bananas, and realize you can't eat all of them before they spoil? You could either invite friends over to eat them, make smoothies, or bake banana bread.  We chose banana bread.

This recipe may seem simple, and to us, slightly below our skill level (look at us, a month of cooking, and we have a skill level now!), but this happened on a Wednesday...so give us a break.  Don't worry, we've packed the Discussion with a bunch of juicy banana science to keep your mind occupied for a while.

Our NFPA ratings:

Figure 2. Our NFPA ratings for banana bread.

Prep time:  Technically, it takes several days for the bananas to become overripe once you buy them.  So, the total recipe takes a few days.  Though, if you started counting after those days, then this recipe would take about 1.75 hours.  Not too bad.

Difficulty: This isn't difficult.  You literally just mix everything and then cook it.  For us, it was a solid 2 (1 is cereal).  Just don't forget to add any of the ingredients.

Course: Banana bread is technically a dessert, though many people also enjoy it as a breakfast food.  It's more of a snack food, but doesn't seem classifiable as a midnight snack.

Materials
1) Sugar - 1.25 cups
2) Butter or margarine - .5 cup, softened
3) Very ripe bananas - 1.5 cups (3-4 medium)
4) Buttermilk - .5 cup
5) Vanilla - 1 tsp
6) All-purpose flour - 2.5 cups
7) Baking soda - 1 tsp
8) Salt - 1 tsp
9) Chopped nuts - 1 cup (optional)

Figure 4. Mixing Ingredients

Figure 3. Adding Sugar

Procedure
1) Position oven rack to low position so that the top of the baking pans will be at the center of the oven.  Heat the oven to 350 degrees Fahrenheit.  Grease the bottom of one 9x5x3 loaf pan.

2) Mix the sugar and butter in a large bowl (Figure 3).  Stir in eggs until well blended.  Add bananas, buttermilk, and vanilla.  Beat until smooth.  Stir in flour, baking soda, and salt until it is all moistened (Figure 4).  Pour the mixture into a pan.

3)  Bake 1-1.25 hours, or until a toothpick inserted in the center comes out clean.  Cool 10 minutes.  Remove from pan and cool completely, about 2 hours, before slicing.  Slice.  Wrap tightly and store at room temp up to 4 days, or refrigerate for up to 10 days.

Figure 5. Sliced Banana Bread

Results
It seems like Betty Crocker's recipes never fail.  This one was pretty tasty!  All of our taste testers enjoyed the final product (n = 11).  It wasn't nearly as special as our Pumpkin Cinnamon Rolls, but it was good.  Banana bread really can't go wrong unless it's dry, and ours wasn't dry at all.

We used regular ol' 2% milk instead of buttermilk, but it didn't seem to matter.  We also didn't include nuts due to a slight miscommunication.

The recipe calls for an obscene amount of cooling.  Pshh...  We didn't wait, and we didn't run into any problems.  Dig right in if you feel like it.

Discussion
Banana bread is best when baked with overripe bananas.  Bananas get sweeter and carry more flavor as they ripen, and it doesn't hurt to infuse the most concentrated banana flavor you can get into your banana bread.  Bananas get sweeter as they ripen because the starches in them get broken down into simple sugars (Macleod and Glassman 2012).  As discussed in our Pumpkin Cinnamon Rolls post (see Discussion), our taste buds are insensitive to starches, but once you break them down into single units of glucose (monomers), they bind to the receptors on our tongue and are perceived as sweet.

Figure 6. Chiquita Banana Plant in Costa Rica (Simmons 2005)

Did you just look over at your newly purchased bunch of bananas and sigh when you realized they're still green?  Don't despair!  There's a way to expedite the ripening process.  Lots of fruits emit ethylene gas, which speeds up the enzymes that cause ripening.  Ethylene is what browns the insides of apples if you leave them out for too long.  Ethylene is so potent that it can transfer from one fruit to another.  Therefore, all you have to do is stick your bananas in an airtight bag to suffocate them in their own ethylene.  To speed things up even further, you can put an apple in the bag with it.  The apple will still be fresh enough to eat after your bananas are ripe.

Figure 7. Chiquita Banana Plant in Costa Rica 

(Simmons 2005)

If you want to slow ripening, apply the opposite concepts.  Hang your bananas or keep them in a wire basket.  This will let their ethylene escape.

How did those bananas get from the tropical climate needed for growing to the temperate environment of your local grocery store?

Many bananas are grown in Central America and shipped, while they're still green, around the world.  Bananas must be sent to their destinations before ripening so that they will still be fresh upon arrival.  At the Chiquita Banana plant in Costa Rica, bananas are grown on the plantation, washed, and later sorted by quality (Fig. 6, Fig. 7).  Next, they are packed to be mailed.  The distributors can control how ripe bananas will be when they reach grocery stores by controlling how much air, and therefore ethylene, reaches them.  Bananas are kept in airtight vaults, where their exposure to natural ripening agents can be tightly regulated, so they can reach grocery shelves healthy and green.

Future Directions
Ideas on the table are: Deep-dish pizza, fried rice, spicy tuna sushi, and latkes.

References
1) MacLeod, T and Glassman, K.  July 2012.  "Do Brown Bananas Have More Sugar?"  Access Hollywood: Healthy Hollywood.
2) Simmons, D.  Sept. 2011.  "Belize & Costa Rica 2005 - (Part II: Costa Rica)"  Dana Goes to Madrid!
3) Upton, C.  Februrary 2010. "How to Accelerate and Slow Banana Ripening" Broken Secrets.