Impact of Ohmic Heating and High Pressure Processing on Qualitative Attributes of Ohmic Treated Peach Cubes in Syrup.

Stabilization of ohmic pretreated peach cubes (ohm) in syrup, representative of semifinished fruit products, was finalized by ohmic heating (OHM) and high pressure processing (HPP), proposed respectively as thermal and nonthermal pasteurization, in comparison to a conventional pasteurization treatment (DIM). The samples were then studied in terms of histological, physical (dimensional distribution, tenderometry, texture, viscosity of syrup and colour), chemical (total phenolic and ascorbic acid content), and sensorial (triangle test) properties. Severe modifications of the cell walls were observed in ohm-DIM and ohm-OHM samples, with swelling and electroporation, respectively. From chemical analyses, significant reduction of ascorbic acid and simultaneous increase of total phenolics content were observed for ohm-DIM and ohm-OHM, probably in relation to the cell wall damages. ohm-HPP showed the best preservation of the dimensional characteristics and hardness, followed by ohm-OHM and ohm-DIM. In addition, textural and colour parameters evidenced similar results, with ohm-HPP as the less different from ohm. Finally, the sensorial analysis confirmed ohm-HPP and ohm-OHM samples as the most similar to ohm as well as the most appreciated in terms of colour and consistency.

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.