What are these streaks on my chili fruits?

Question

I'm growing some capsicum baccatum chili in pots on my well-lit balcony, and they have grown very well, producing plenty of fruits. The leaves are healthy, with no marks of any kind. However, I've noticed that virtually all of the fruits, some time after they grow, begin to form some smudges:

As the second photo – right above – shows, these smudges eventually propagate, covering much of the fruit in a semi-even fashion.

I'm very inexperienced with chili (this is literally the first time I'm growing any), so at first I thought it was part of the natural process of changing color. But it just doesn't feel normal. I also wondered whether these are sun burns, but as the photos might reveal, the plants are behind a frosted balcony window, diffusing the sunlight.

I've tried to find information online, but none of the conditions/pests seem to match this. I also consulted questions such as this one and this one, but they don't seem relevant to my issue.

Any ideas what this could be?

Answer 1

It's hard to see for sure (more light on the peppers, and pictures of more fruits, may help), but I'm thinking it's just some pigment like anthocyanins developing on the skin in response to the UV, plant stress or something. They should be harmless. This is common on Jalapenos and Banana peppers, but it happens on at least some other kinds, once in a while. Some peppers are bred to express a lot of it all over the fruit (and that's why they're purple or black: e.g. Black Jalapeno, and Purple Beauty; note that the color is normally on the skin, and not in the flesh, and its presence doesn't mean the fruit is ripe).

The streaks should be black or purple, and shine in the sun like the rest of the pepper. If the fruit is mushy or something, I'd suspect a disease, but if the fruit is crisp, smooth, and fine as usual, it's probably just some pigment like anthocyanins. They're harmless and possibly good for you.

Streaks or more common than smudges, though. So, I'd watch out for more symptoms, just in case.