Zucchero Fornaciari was discovered ten years ago in a national show and during this period of time has sharpened and refined his music.

refined 是动词 refine 的过去分词形式。refine 由前缀 re-（表示"再次"）和 fine（"精细的"）组成，字面意思是"使更加精细"。在这里 refined 表示"经过改进和完善的"，指音乐作品经过不断打磨后变得更加精良。