The invention relates to a preparation process of a co-crystal made of sugar and a natural sweetener and, eventually, another aggregate and with said product. The process is further related with co-crystallizing sucrose and a natural sweetener in a vacuum pan under controlled pressure and temperature conditions and separating the crystal from the sugar juice. At the end of the process, the co-crystallized sub-products are used for producing a low calorie content liquid sweetener such that in a high percentage all the stock material is used.
