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Why Do Bananas Change Color?


Why Do Bananas Change Color?

Source of pictures: Pixabay.com

"I'm exhausted." Daniel was reading comic books collected by Dad in the study room, when he suddenly heard the voice of Mom outside the door. He put down the book and ran out and saw Mom walking slowly to the kitchen with a big shopping bag. Daniel went to help. Seeing such a thoughtful move, Mom said happily, "Thank you. My son. I'll cook chicken drumsticks for you tonight." Daniel smiled sheepishly as he only did a little to help Mom.

Without taking a rest after they carried the bag into the kitchen, Mom began to take stuff out of the bag and put them in the cupboards and refrigerator. Seeing some green bananas in the bag, Daniel picked them up and put them under his nose to smell. But the bananas were hard and not didn't smell fruity. Mom stopped him when he was about to have a taste, "The bananas are not fully ripe and you can't them until they turn yellow in a few days." Daniel stopped and put the banana in the refrigerator. Mom stopped him again, "Hey, bananas can't be kept in the refrigerator. They grow in hot climates and are easily damaged by cold temperature. Put them on the top of the outer cupboard. Daniel put the bananas in the place at which his mom pointed and whispered, "Bananas are so delicate."

After arranging all stuff well, mom made a glass of juice and drank with Daniel.

A few days later, when Daniel was looking for jam in the kitchen, he suddenly found the bananas on the cabinet had turned pale yellow from leaf green. He bent down and smelled the peculiar scent of bananas. Then he touched them and found that they were a little soft. Daniel ran to the table and said excitedly, "Mom, the bananas have changed their color." Mom raised her eyebrows in surprise and said, "So fast, I thought it would take at least a week."

Daniel climbed up on the chair with the jam in his hands and asked curiously, "Mom, why do bananas turn yellow from green after they were picked off the tree?"

Mom handed the bread to Daniel and said, "Bananas change color not because they are picked off the trees. They also turn yellow on the trees. This is a sign they are ripe. Green bananas are picked in advance to ensure they won't go bad in transit. Bananas have chlorophyll and xanthophyll. When bananas are ripe, the chlorophyll is broken down and the xanthophyll still exist and would turn banana yellow."

Daniel knew Mom was right but he still didn't understand, "How do bananas get ripe? We just put them there and do nothing with them. How do they become ripe by themselves?"

Mom replied, "Unlike flowers and trees that need fertilizer and water, fruits have their own way to ripen. Most fruits can produce ethylene, which serves to accelerate fruit ripening. And they produce the highest concentration of ethylene during the ripening stage. So unripe bananas can ripen by themselves by producing ethylene. Generally, fruits will change color and become soft and sweet as they ripen. The softness of a fruit is determined by its cell wall. As the fruit ripen, its cell walls break down, making the fruit soft. Besides, during ripening, there is a breakdown of starch inside the fruit. The starch is not sweet but it can produce sweet sugars, such as fructose and glucose."

After hearing Mom's words, Daniel understood finally and was quite eager to eat a ripe banana. 

Author: Huang Jing

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