Baking soda raises the pH. (Low pH = acid; high pH = alkaline. Yes, they’re switched.)
Alkalinity catalyses caramelisation and the Maillard reaction, that’s why meat gets to brown more. However in acid environment both processes happen mostly the same as if they were in a neutral environment, acidity doesn’t really prevent this sort of browning. (I’m glad for this, otherwise my Sunday roast would be really sad. I often leave the pork marinading in lemon juice for a day, and it still browns just fine.)