Snack Science: The Weird Truth Behind Everyday Foods
Written by Lindsay Grohs
In today’s article, we’re going to be debunking some of your favorite snack-related questions. What makes popcorn pop? Why do onions make you cry? These answers are rooted in the fascinating science behind these foods. In just a few minutes, impress your friends at movie night by explaining exactly how a little kernel transforms into a fluffy piece of popcorn. You’ll have the answers to some of the most common food mysteries. Let’s get into it, food nerds!
Why Onions Make You Cry
Did you know the reason onions make you cry is actually a defense mechanism? Onions sprout out of the ground, so they are surrounded by hungry little bugs in the dirt who are looking for a snack. The onion’s protection from these creatures lies in its chemical composition. Each onion cell holds a sealed vacuole. This sealed vacuole contains enzymes that break open when an onion is cut or bitten into. When the enzymes break, they “mix with other chemicals inside the onion cells,” and form “syn-propanethial-S-oxide molecules” (Singh, 2016). These molecules are very small. They float up into the air and get into your eyes, making you shed some tears. So next time you cry when chopping an onion, just know it’s not you; it’s really just the onion trying to protect itself.
Why Soda Fizzes & Explodes
Have you ever wondered why your soda makes that hissing sound when you crack it open? Or why it explodes when you open it right after dropping it on the ground? It’s because of those little bubbles that float around in your soda, called carbon dioxide, CO2. Soda and other carbonated drinks are “infused with this colorless, odorless gas at high pressures during production” (Choi, 2022). After infusion, the soda gets bottled at very cold temperatures, allowing the CO2 to better dissolve into the beverage. Bottling also creates a little area of trapped gas that sits between the beverage and the opening of the can.
Here’s the twist: following the infusion process, the gas escapes the soda. You may be confused by this, considering I just told you the reason soda hisses and fizzes is because of the gas. Let me explain a little rule called Henry’s Law that makes this make more sense. Henry’s Law tells us that “the amount of gas dissolved in a liquid is proportional to the pressure of that same gas in the liquid’s surroundings” (Choi, 2022). Meaning that because of the CO2 in the drink, combined with the CO2 that makes up the space between the liquid and the opening of the can, “the carbon dioxide that's dissolved in the beverage stays within the fluid.” So that’s why your Diet Coke or Sprite taste crispy when you take that first sip.
When you open the can, the pressure releases. And when you decide you want to shake your soda up and open it immediately after to see if it will explode –even though you already know it will– this creates even more concentrated pressure in the gas that remains in the space between the liquid and opening. Hence, why it explodes.
What Makes Popcorn Pop?
Friends over, a movie is queued up, and popcorn is in the microwave. As you watch the kernels burst into little white clouds, you might wonder: What actually makes popcorn pop?
The answer boils down to water! There’s a small drop of water in every kernel, “inside a circle of soft starch” (The Popcorn Board, n.d.). As the kernel heats up, the water expands and turns to steam, all while the starch alters into a jelly-like consistency. Eventually, the pressure inside the kernel becomes so intense that–well, you know what happens–POP! The steam is released, and the starch expands and “spills out, cooling immediately,” giving us the one and only popcorn (The Popcorn Board, n.d.)!
Can Certain Foods Change Your Mood?
The answer is yes. Let me introduce you to a little something called the “gut-brain connection”. There are a few key biological processes that are directly correlated with this connection, including: inflammation, glucose, and the gut microbiome.
Inflammation can disrupt serotonin and dopamine levels, affecting your mood—for better or worse—depending on the foods you eat.
Blood sugar (glucose) can “spike and dip in response to the things we eat,” influencing our energy, focus, and mood (Xiong et al., 2023). When glucose is stabilized, it helps better control mood swings. Eating balanced meals with protein, carbohydrates, and healthy fats can help reduce energy crashes and support a steadier mood throughout the day.
The gut microbiome affects the brain and mental health by regulating neurotransmitters such as serotonin and dopamine. A healthy, diverse gut microbiome may support regulated emotions and overall well-being, while an imbalance in gut bacteria may contribute to mental health conditions. Different foods support a more diverse gut microbiome than others; a few of these foods are shown in the image below.
Does the Color of Your Food Affect the Way it Tastes?
The short answer: yes. It comes down to a few different factors, with the major one being perception. We all have this inner instinct where our brains associate certain colors with certain flavors: red means cherry, purple means grape, orange means orange –you get the point. We also connect a food or drink’s appearance with certain characteristics, such as whether it will be salty, sweet, savory, or umami.
You set an expectation of what the food or drink will taste like before it even enters your mouth. When those predetermined expectations aren’t met, it can throw your brain for a loop. Like when the blue ice cream tastes like blueberry instead of blue moon, or when a mousse is savory, as opposed to being sweet. The disconnect can change the way you view that food or drink entirely.
Here’s another little twist: You know that experiment where someone is blindfolded, and they have to taste different Skittles or M&Ms to see if they can correctly guess the colors? This is where that brain-eye perception comes into play –but in the opposite way. Without being able to see the color, your brain doesn’t have that “bias” or expectation of what the candy should taste like before you eat it. Kind of crazy, right?
Conclusion
Congratulations –you’re officially a snack science expert! The next time you’re eating popcorn, chopping an onion, or tasting colorful candy, you’ll know there’s more happening than meets the eye. While food may be delicious, the science behind it makes it that much more fascinating!
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