Environmentally friendly lycopene purification from tomato peel waste: enzymatic assisted aqueous extraction

The antioxidant and anticancer properties of lycopene make it an ideal component for daily food supplements. For this reason this study investigated the possibility of extracting lycopene from tomato waste peels using a green chemistry protocol devoid of organic solvent. Cells are lysed thanks to a combination of pH changes and hydrolytic enzyme treatments. The lycopene-containing chromoplasts are then precipitated by lowering the pH and isolated through a centrifugation step. At this stage the lycopene content of the isolated chromoplasts shows a 10-fold increase (3-5% w/w, dry basis) with respect to untreated tomato peels. A further improvement in lycopene concentration is obtained by a second enzymatic treatment using a protease cocktail. This catalytic step eliminates unwanted proteins, bound to the chromoplasts, but not essential for their stability. The final product shows a lycopene content around 8-10% (w/w, dry basis), which represents a 30-fold increase with respect to the lycopene concentration of the untreated peels.