What it is
E957 is thaumatin, a protein extracted from the katemfe fruit (Thaumatococcus daniellii) of West Africa.
Why it matters
~2000x sweeter than sugar — used in small amounts as a flavour enhancer and sweetener in chewing gum, dairy alternatives, savoury snacks. Very expensive, so usually paired with cheaper sweeteners.
What to do
Always vegan — plant-sourced.