By Harold McGee
The oligosaccharides (“several-unit sugars”) raffinose, stachyose, and verbascose are 3-, 4-, and 5-ring sugars, respectively, all too large to trigger our sweet detectors, so they’re tasteless. They’re commonly found in the seeds and other organs of plants, where they make up part of the energy supply. These sugars all affect our digestive system, thanks to the fact that we don’t have digestive enzymes capable of breaking them down into single sugars that can be absorbed by the intestine. As a result, the oligosaccharides are not digested and pass intact into the colon, where various bacteria do digest them, producing large quantities of carbon dioxide and other gases in the process.