Umami flavor is a savory taste that adds depth and richness to food. It's often described as a delicious and satisfying flavor that enhances the overall taste of dishes. Full definition
They impart the savory umami flavor of tomatoes without the inflammatory lectins and saponins that disrupt intestinal tight junctions — leading to pathologic paracellular intestinal permeability, the precursor to all autoimmune disease (Fasano, 2012). (empoweredautoimmune.com)
It sounded lowbrow and disgusting, but instead it was a minor miracle: tart, slightly sweet and salty with umami flavor from the Maggi and funk from the Clamato. (bonappetit.com)
I think this would still be pretty good without, but if you can I'd recommend adding something else — the tomato paste is there for umami flavor. (yupitsvegan.com)