Soya bean

The soya bean carries the highest GOS load of the legumes, which is why the processed forms diverge so widely. Firm tofu is pressed and the whey taken away with the sugars; tempeh is fermented and the mould eats them; soy milk from whole beans keeps them, soy milk from protein isolate does not.

The soya bean carries the raffinose family in quantity, and it explains why its products diverge so far: pressing takes them out with the whey, fermentation lets the mould eat them, and doing neither leaves them all in.

Soya beans are the highest-nickel legume measured, and the one hardest to avoid, because they enter the food supply as oil, lecithin, protein isolate and sauce as well as as a bean.

The soya bean is high in oxalate, and its products separate sharply: tofu is pressed and the whey carries oxalate away with it, while soy flour keeps everything. It is the same split as on the FODMAP axis, for the same reason - what leaves in the water is what leaves.

Soya beans carry little histamine dry, and boiling lowers it further - amines leach into the cooking water and are poured away. Sprouting does the opposite: a germinating seed produces amines as it wakes up, so sprouts are a different food here from the pulse they came from.

Soya beans are low as a dry seed, and boiling lowers it further - amines leach into the water. Germination raises it instead, which is the one preparation to watch: a sprout has spent days doing what a dry seed cannot.