The present invention relates generally to functional sweetener compositions comprising non-caloric or low-caloric natural and/or synthetic high-potency sweeteners and methods for making and using them. In particular, the present invention relates to different functional sweetener compositions comprising at least one non-caloric or low-caloric natural and/or synthetic high potency sweetener, at least one sweet taste improving composition, and at least one functional ingredient, such as rubisco protein, rubiscolin, rubiscolin derivatives, ACE inhibitory peptide, and combinations thereof. The present invention also relates to functional sweetener compositions and methods that can improve the tastes of non-caloric or low-caloric high-potency sweeteners by imparting a more sugar-like taste or characteristic. In particular, the functional sweetener compositions and methods provide a more sugar-like temporal profile, including sweetness onset and sweetness linger, and/or a more sugar-like flavor profile.