A machine including a supply of gelling agent (45), a supply of acidic buffer solution (47), a third supply of food inlet (51) connected to a source of food (53), a mixer (27) connected to the gelling agent and acidic buffer solution supplies, for delivering a mixture of gelling agent and acidic buffer solution, and a co-extruder (31) fed with food (51) and with said mixture, for extruding the food at the center and the mixture at the periphery, so as to obtain the expected food product at the outlet.
