Stripping unwanted components from a material to raise its purity, one of food science’s core operations. It covers refining crude oils through degumming, neutralizing, bleaching, and deodorizing; polishing water for processing; isolating food-grade enzymes, colors, and additives; and depurating oysters and mussels in clean seawater so they purge pathogens picked up from polluted beds. Each application pairs a separation principle, filtration, adsorption, crystallization, or biological cleansing, with analytical proof that the target purity was actually reached. Validation with analytical testing confirms each purification step achieved its target.