Abstract: The present invention provides a process for the manufacture of a leavened foodstuff, such as a leavened or heat treated leavened foodstuff, and apparatus for the same, wherein in said process an ingredient composition comprising a food structurant, water and a leavening agent is treated with ultrasound from an ultrasound source during at least a part of a leavening step, and/or an ingredient composition comprising a food structurant, water and a leavening agent or a leavened ingredient composition, typically obtained therefrom, is treated with ultrasound from an ultrasound source during at least a part of a heat treating step.