One red bell pepper contains:
- 11 times more β-carotene (provitamin A) than green pepper (1,2,3).
127mg vitamin C per 100g, compared to 74mg per 100g in green bell pepper
Greater concentration of B-complex vitamins, such as pyridoxine(B6) and riboflavin(B2)(2).
Greater concentration of phenolic antioxidants.
A study published in the Journal of Food Science in 2017, which compared the antioxidant levels of different colors and types of pepper showed that red pepper contained the highest concentration of β-carotene (5.4 μg/ g), capsaicin (8.0 μg/g), quercetin (flavonoids) (34.0 μg/g) and luteolin (11.0 μg/g) (3).
On the contrary, green pepper contained the lowest percentage of luteolin, while capsaicin was undetectable in it.
Sources:
1) https://web.archive.org/…/DNPA/5ADay/month/bell_pepper.htm
2) https://cronometer.com
3) https://www.ncbi.nlm.nih.gov/pubmed/17995862