Good result buddy
This is just my opinion but I doubt it was the anything in the 'white bits' which constituted as to why you had a good response from the carp when you introduced them. I don't know the water in question but it sounds like a fairly 'no fuss' water, however, if everyone is using the chummies day in, day out throughout the warmer months, the fish will soon start showing caution if their gettin' nailed each time on them.
I'm guessing it was simply the change of shape (I'm assuming these white bits are smaller than a standard chum mixer) that made the difference mate. Get yourself a bag of 6mm floating trout pellets or something and I bet you'll have the same response, just fish the white bits on your hook amongst the floating trouties
Be a dam site cheaper and easier than selecting out the little bits from a bag of puppy chum