Science Buddies: "Ask an Expert"

Does light affect how fast apples spoil is the question for my project. I am not sure how I should do this. What I was going to do is cut an apple in half and put them in 24 hour light under a lamp. put the next group in complete darness in the closet an the next group half of the day in light and half in the dark? do I measure this by hours or days? and how do i know when the apples are spoiled ?

Hi Sharon.arrigo,

You have a somewhat interersting project that you want to pursue. The thing about apples is that they will oxidize in the presence of oxygen and turn brown. The best thing to do would be to cover them in plastic wrap and put them under light. Well, since you going to put apples under a lamp for 24 hours, I would assume you would put them in the dark and half in the dark for 24 hours as well. The thing about apples is that they don't really spoil by themselves; they rot when other creatures like fungi grow on them. It might be better to determine whether the oxidation of apples (the browning of them) is affected by light.

Hope that helps!

-Sam

Hi Sharon,

Sam made a really good point ahead of me. To add to his explanation, I suggest you check out a project on ScienceBuddies very similar to yours https://www.sciencebuddies.org/science- ... p025.shtml. Light itself doesn't contribute to food spoilage, although you might see "browning". It would be interesting to compare apples to other types of fruits (pears, peaches, etc) that also "brown", and compare & contrast the sorts of vitamins/antioxidants that are in each fruit, and how that contributes to the rate of brownness (if it does).

Best of luck!

Hi Sharon,

I just want to add that the enzyme responsible for the browning of fruits is called tyrosinase, and it is a well-studied enzyme. (It's also the enzyme that speeds up the production of melanin, which turns our skin darker in the sun.) The reactions that tyrosinase catalyzes (speeds up) are light- and temperature-sensitive, so your experiment may yield some very interesting results!

If by "spoiling" you are referring to browning, then I recommend looking up tyrosinase for your background information. If you are interested more in the actual spoiling (from the growth of bacteria and other microorganisms), I recommend that you find ways to reduce browning or not use it in your measure of "spoiling." (The browning process isn't actually spoiling; it just looks bad.)

I hope that helps. Let us know if you have more questions!

Heather