What mayo brand do chefs love most? In the South, Duke's is king. Hellmann's is popular in the North.Credit: Design elements: Getty Images. EatingWell design.Key PointsMayonnaise brands — and loyalties are regional, Hellmann's is preferred in the North and Duke's in the South. Hellmann’s is mild-tasting, while Duke’s has a more pronounced acidity, and its flavor pops. As a boy growing up in Charlottesville, Virginia, Mason Hereford—chef-owner of…