A process for preparing a free alkylphenol flavor concentrate, comprising the steps of reacting an aqueous solution comprising a raw material containing bound alkylphenol conjugates with a mineral acid, and the use of free alkylphenols and free alkylphenol concentrates as flavor enhancers in a wide variety of food products. An effect of light exposure is to generate photo-induced charges. Pressure developed in the gas passage when the orifice is at each gauge point is detected whereby the geometry of the passage is established. The method also provides a means for controlling the shape of the resultant nanoparticles. Each shaft has a plurality of paddles mounted thereon, each paddle being mounted at an angle to the shaft to raise washed aggregates up the inclined trough to a discharge hopper or conveyor belt.