Self explanitory question, I guess. I was cutting up a bell pepper for dinner and got curious about the empty space inside the fruit. Are the peppers air tight? If so, is the air inside the pepper expelled pepper breath? Does it have a higher oxygen content the ambient air? Is it some naturally occuring neutral gas to prevent spoilage on the vine? Too many questions, I’ll shut up and go eat dinner now.
Nope, peppers are not air tight.
Unfortunately, it looks like getting much more detailed than that will cost thirty bucks: Varietal differences in locular gas composition in developing fruit of sweet and hot peppers, Capsicum spp., and evidence for divergent diffusion pathways
Going from your quote there, I would read it as that they are airtight, otherwise the composure of the gasses inside couldn’t flux; they would be bound to the surrounding air. Certainly the gas is coming from the outside air, but so is the air in my lungs. My lungs are perfectly air-tight (until I inhale.)
How you figure? If, say, the interior walls of the pepper are constantly emitting different types and amounts of gases at different stages of development, then the typical composition of the air inside it will change during the course of its development, even if the pepper walls are permeable to the outside air.
Think about, say, idling your car’s engine for a long time in a closed garage.* The car can put out enough exhaust gases to significantly change the composition of the air in the garage, even if the garage is nowhere near airtight.
*I mean “think about it” in the sense of a thought experiment, of course. Do not seriously consider doing this, much less actually do it.