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31 October 2023

Trick or Treat: The Biochemical Magic Behind Pumpkin's Orange Glow and Our Candy Cravings!

by Moderna
Media Center > Blogs > Trick or Treat: The Biochemical Magic Behind Pumpkin's Orange Glow and Our Candy Cravings! > Hero

As the autumnal hues of Halloween sweep across the landscape, the transformation of pumpkins from verdant green to vibrant orange captivates our senses. This fascinating metamorphosis mirrors the anticipation that builds in our hearts for the sweet indulgence of Halloween candy. Just as the pumpkin's color shift is a result of complex biochemical processes, our love for Halloween candy can be traced back to our innate biological preferences. This Halloween, let's delve into the science behind these cherished traditions, uncovering the secrets of nature's color palette and our own sweet-toothed predilections.

Why do pumpkins turn orange?

During the growth stage, pumpkins are green. This is due to the presence of Chlorophyll – the pigment that gives plants their green color and is necessary for plant photosynthesis.

As autumn approaches and daylight hours decrease, plants produce less and less chlorophyll, and it’s production eventually stops.

With the green pigment fading, other pigments present in the pumpkin's skin become more prominent and visible. One of these pigments is beta-carotene, a type of carotenoid that gives pumpkins their characteristic the classic deep orange color. Beta-carotene is the same pigment that makes carrots orange! The synthesis of Carotenoids, Chlorophyll, and all other plant pigments is mediated and controlled by proteins made by mRNA!

This process is not unique to pumpkins - it's the same reason why leaves change color in the fall. The changing colors of the season are a result of the complex interplay of light, temperature, and the biochemistry of plants.

Why do we like Halloween candy?

Our preference for sweet things is an evolutionary response. Our primitive ancestors were scavengers and needed to consume high-energy foods to survive – and sugary foods often indicated a source of high energy.

As such, we have an innate system that makes us like sweet foods. When we eat sweet foods, the brain’s reward system gets activated, and it triggers the release of dopamine – which can make us "feel good".  Dopamine is a neurotransmitter released by neurons that is involved in reinforcement and can signal that an event was positive.

Neurotransmitters are your body’s chemical messengers - molecules used by the nervous system to transmit messages from neurons to target cells. The synthesis of some categories of neurotransmitters is mediated and controlled by proteins made by mRNA!

In the modern world, our fondness for sweets persists, even though we no longer need to seek out high-energy foods for survival. It's a fascinating reminder of how our evolutionary history influences our present-day behaviors and preferences.

This Halloween, as you delve into your Halloween candy stash and admire the glowing pumpkins, remember the incredible science behind these traditions. It's a sweet and colorful reminder that even in our celebrations, science is always present!