Morcilla

Morcilla is a blood sausage built on onion — morcilla de cebolla is the common form — and onion is one of the five vegetables Muir measured highest in fructan. Rice-based versions are gentler, but the label rarely says which you are holding. Gibson and Shepherd's framework is why the quantity of onion decides the outcome: these carbohydrates deliver fermentable substrate and water to the end of the small intestine, and the framework sets no value for any food.

Morcilla: same reason as the FODMAP level: the fructans come from the onion, and fructans are oligosaccharides. The onion is the measured part: its fructans are among the densest FODMAP sources in the framework the Monash programme uses.

Morcilla is boiled rather than fermented, and that is the whole difference from a chorizo: biogenic amines build up during fermentation and ripening, which a boiled blood sausage skips. Not none, though - blood products stay on the cautionary lists for histamine intolerance. The doses behind that come from EFSA: no adverse effect at 50 mg of histamine for a healthy person - and below detectable limits for someone with histamine intolerance - against 600 mg of tyramine without an MAOI and 6 mg with a classical one. EFSA ranks fermented categories QUALITATIVELY and says outright that the available information was insufficient for a quantitative risk assessment, so read the comparison with chorizo as an ordering and not as a rate.

Pimentón is characteristic of morcilla, and paprika is one of the richest spices in salicylates. The ranking is measured: paprika is among the richest spices in Swain's survey.

The moderate oxalate here comes from the paprika and spice blend, not from the blood or the meat - animal foods carry essentially none. Spices are concentrated dried plant material, and a heavily spiced sausage differs from a plain one.

Tyramine forms while a sausage cures, and morcilla is cooked instead. The EFSA's review puts biogenic-amine formation on fermentation and ripening - which is the step this sausage skips.

It depends on the recipe. Some morcillas are bound with bread or flour, which is gluten, others with rice, and the two are impossible to tell apart without reading the list. Check the label.