What are the saponins in soybeans?

It's a class of chemical compounds. They are naturally found in plants, and have a foamy appearance.

soybeans are little beans usally grown in a farm and they can reduce the risk of heart diseaseby Serena Henry

No it is not

Eastern half of North China in the eleventh century B.C. or perhaps a bit earlier.

No, although if you have a gluten allergy eat pickles before you eat them.