Effect of processing, fermentation, and aging treatment to content and profile of phenolic compounds in soybean seed, soy curd and soy paste

► Forty-three phenolics in soybean seed decreased to ∼50% in soy curd and <1% in soy paste. ► Heating/filtering/coagulation in soy curd are key factors for loss of phenolics. ► Steaming/fermentation/aging in soy paste are key factors for loss of phenolics. ► Aging period affects the decrease of phenolic acids contents in the soy paste. ► Soy paste contains more useful phenolics than those in soybean seed and soy curd.