A process for extracting phytochemicals from plants. The process generally comprises controllably slurrying a selected plant material in a volume, adding a selected enzyme the slurry while it is controllably agitated, then heating the controllably agitated slurry-enzyme mixture to a temperature from the range of 40° C. to 110° C., and then maintaining the slurry-enzyme mixture at that temperature for a selected period of time. The slurry is then separated into a solids fraction and a liquids fraction that contains extracted phytochemicals. The liquids fraction is controllably de-watered to produce a fluid extract concentrate. The liquids fraction may optionally be dried to produce a dried extract concentrate. Suitable enzymes for use with this process include α-amylases, β-amylases, endo-β-1,4-glucanases, cellobiohydrolases, cellulases, hemicellulases, β-glucosidases, β-xylosidases, xylanases, pullulases, esterases and mixtures thereof.