Bobby Brown -- Leaving Bobbi Kristina's Side For the First Time

Bobby Brown is leaving Bobbi Kristina for the first time in more than 2 months -- boarding a jet for Los Angeles to fulfill a contractual obligation to soul food ... TMZ has learned.

According to our sources, Brown is flying Friday afternoon to appear at the Soul Food Festival near downtown L.A. It may sound crass for Bobby to leave his daughter's bedside for the festival -- but it was out of his hands.

We're told the deal to perform at the event -- along with Salt-N-Pepa, El DeBarge and Stephanie Mills -- was signed long before Bobbi Kristina was hospitalized. As we first told you, Bobby has the same situation with an upcoming mini-tour in Australia ... where the promoter is demanding he perform.

Bobby's not just singing and dancing, by the way -- he's also cooking with his own line of BBQ sauce. No joke.

Original, sweet & spicy, or maybe Boston blend ... it's your prerogative!