Lol, yeah corn issue has been done and again...
It is perfectly legal to use corn. It does not mess up anything's digestive track. If you use field/deer corn then it has to be prepared but sweet corn from a can is fine. Only a handful of states don't allow the use of it, Rhode Island for one in trout waters...
Let us be honest with ourselves here...they let you shoot carp with a bow/crossbow. Do you really think they are worried about their digestion?
So it doesn't become an issue here is the link to the abstracts for our great state...
http://www.eregulations.com/massachusetts/huntingandfishing/general-fishing-regulations-advisories/
The part of interest is
FISHING PROHIBITIONS
Explosives
Jug, toggle or trot line fishing.
Lead Sinkers, Lead Weights, and Lead Jigs Weighing Less Than an Ounce. Any sinker or weight made from lead that weighs less than 1 ounce, and any lead jig (meaning any lead-weighted hook) that weighs less than 1 ounce, is prohibited for use in all inland waters of the Commonwealth. The term lead sinker shall not include any other sinkers, weights, fishing lures or fishing tackle including, but not limited to, artificial lures, hooks, weighted flies, and lead-core or other weighted fishing lines.
More than two hooks for fishing or more than five hooks when ice fishing. A hook is defined as an angling device attached to a fishing line which is designed to take one fish at a time but is not limited to devices commonly called spinners, spoons, bait harnesses, lead head jigs, or plugs.
Possession of: Sturgeon (all species), American Brook Lamprey, Atlantic (sea-run) Salmon, Bridle Shiner, Burbot, Eastern Silvery Minnow, Lake Chub, Longnose Sucker, and Northern Redbelly Dace is illegal! If caught, release immediately. This means remove hook or cut line and return fish to water immediately—do not pose for photographs, place on a stringer, hold in a net, or delay in any way the immediate return and release of the fish to the water.
Poisons
Releasing fish or spawn into inland waters, except by permit.
Rubbish in inland waters.
Sale of freshwater fish without a permit.
Snagging
Transporting live fish (except bait for personal use) without a permit.
So as you can see if it was illegal it would list it there.
That being said check out the carp forums here as there are some great discussions about bait, including quite a few recipes and such from some of the more experienced guys. To be fair most tend to chase them as Hank has said with a bit of sweet corn and/or bread. The fun part about carp fishing is it is as simple or complicated as you want to make it. I will try and answer any questions if I can, I only ask that if you chase carp you use a proper net, and try to show them some respect!