What is the scientific reason of why a white piece of bread grows fungi before wheat bread does?

Please don't answer something like,';Do your own work.'; or ,';Because of its appearence.'; for your answer. Thank you very much!! =)What is the scientific reason of why a white piece of bread grows fungi before wheat bread does?
Digestibility of the nutrients in wheat are increased with increased processing of the wheat flour. Whole wheat flour has the same actual calories of processed wheat flour. However, the processed wheat flour is more digestible than the whole wheat flour and consequently has less digestible calories than processed wheat flour. This affects the way animals (and fungus) can utilize the flour as a food source. The more processed the flour is the more rapidly it can be utilized for animal (and fungus) growth.What is the scientific reason of why a white piece of bread grows fungi before wheat bread does?
i think it may be because there is more yeast and sugar in white bread.
White bread is basically pure starch and useable carbohydrates for fungi while wheat bread contains alot more fiber which the fungi can't break or at least makes it harder to break down
I have no proof, however I think it's because the whole wheat is more acidic.
because it's easier to break down.