The Bloke On Who Wants To Be A...
Film, Media & TV0 min ago
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For more on marking an answer as the "Best Answer", please visit our FAQ.Possible I suppose, the red and yellow are different varieties of the same family so maybe the colours relate to some chemical content. However peppers can be the subject of artificial speeding up of growth as stated in the article below and I am sure that some of the chemical used can't good for you (as usual)!!
The question of whether ethylene (C2H4) treatment - a natural plant hormone involved in ripening - will work comes up frequently. While we can't answer this question for every situation, there is some research that provides guidance for further evaluating the use of ethylene on peppers.
Preharvest Treatments
The application of ethephon (phosphonic acid) - a synthetic form of the ripening hormone ethylene - on bell peppers is not recommended.
Several studies done in the '70s and '80s, however, demonstrated the effectiveness of ethephon treatment for accelerating processing of color development. A high level of optimization for air temperature and variety are needed to prevent injury. In each field, fruit will vary from mature to immature green pods.