Understanding 'Jejune' in Context

In the bustling city of Riverview, a renowned chef named Elena was preparing for a prestigious cooking competition. She had spent weeks refining her recipes, ensuring that each dish was not only delectable but also visually impressive. On the day of the competition, she was filled with anticipation and a hint of trepidation. As the judges tasted her creations, one remarked that there was an undeniable jejune quality to her signature dish, which surprised Elena. Despite her efforts, she sought to understand the feedback more clearly.

What does the word jejune most likely mean in this context?