The invention relates to a process of producing a food product by heat-treating a food material containing reducing sugars, comprising the step of blanching the food material, wherein the blanching step comprises subjecting the food product to an active blanching medium under blanching conditions in a blanching section to produce spent blanching medium, withdrawing reducing sugars from the spent blanching medium to produce active blanching medium using a sugar-withdrawing means, and reusing the active blanching medium. The process can be performed in one section, or the reducing sugars can be withdrawn in a desugaring section which is separated from the blanching section, recycling the treated active blanching medium to the blanching section. The process can also be applied to withdraw asparagine, or a combination of reducing sugars and asparagine. The sugar-withdrawing means can be a conversion agent capable of withdrawing reducing sugars such as bacteria, yeasts and moulds, in which case the selective withdrawal is called fermentation, and enzymes, or it can be a sorbent capable of selectively adsorbing reducing sugars or asparagine in a chromatographic separation.