Currently, the fruits with lesser value in terms of size and shape are considered waste, and poorly paid as they are used in the production of fruit juices or in the energy supply chain. The production of snacks with high nutritional functionality could be a valid alternative to use the kiwifruit waste, with positive economic impact on the entire production chain. Therefore, in this work, osmotic dehydration (OD) and pulsed electric field (PEF) were combined as pre-treatments for the subsequent air drying to obtain snacks with a high functional content. Yellow kiwifruits slices (5 mm thick) were subjected to OD process (40% trehalose, 35°C, 2.5h). PEF pre-treatment was performed by using lab-scale PEF unit (Model S-P7500, Alintel, Italy), with the electric field strength of 200 V/cm and 1000 near-rectangular shaped pulses, with fixed pulse width of 10 μs. PEF was applied before and/or after OD. The differently treated samples were subjected to air drying at three different temperatures 50, 60 and 70°C. The total polyphenol content, vitamin C content and antioxidant activity (DPPH and ABTS method) were investigated. The results showed that all measured parameters were strongly depended on the type of pre-treatment applied and, on the drying temperature. Vitamin C content was the highest in non-treated and PEF treated kiwifruit samples when dried at low temperature. Total polyphenol content and antioxidant activity by DPPH were the highest at the temperature of 60 °C in non-treated and OD treated samples. However, when lower (50°C) and higher (70°C) temperatures were used the antioxidant activity of PEF and PEF/OD treated samples were at a comparable level as control samples. Concerning the antioxidant activity measured by ABTS the samples treated with PEF and PF/OD showed the highest values of this parameters, suggesting the contribution of other bioactive compounds with high antioxidant activity.
Application of non-thermal pre-treatments (PEF and/or OD) to develop yellow kiwifruit dried snack with high nutritional functionality
Cinzia Mannozzi
;Urszula Tylewicz;Jessica Genovese;Santina Romani;Pietro Rocculi;Marco Dalla Rosa
2018
Abstract
Currently, the fruits with lesser value in terms of size and shape are considered waste, and poorly paid as they are used in the production of fruit juices or in the energy supply chain. The production of snacks with high nutritional functionality could be a valid alternative to use the kiwifruit waste, with positive economic impact on the entire production chain. Therefore, in this work, osmotic dehydration (OD) and pulsed electric field (PEF) were combined as pre-treatments for the subsequent air drying to obtain snacks with a high functional content. Yellow kiwifruits slices (5 mm thick) were subjected to OD process (40% trehalose, 35°C, 2.5h). PEF pre-treatment was performed by using lab-scale PEF unit (Model S-P7500, Alintel, Italy), with the electric field strength of 200 V/cm and 1000 near-rectangular shaped pulses, with fixed pulse width of 10 μs. PEF was applied before and/or after OD. The differently treated samples were subjected to air drying at three different temperatures 50, 60 and 70°C. The total polyphenol content, vitamin C content and antioxidant activity (DPPH and ABTS method) were investigated. The results showed that all measured parameters were strongly depended on the type of pre-treatment applied and, on the drying temperature. Vitamin C content was the highest in non-treated and PEF treated kiwifruit samples when dried at low temperature. Total polyphenol content and antioxidant activity by DPPH were the highest at the temperature of 60 °C in non-treated and OD treated samples. However, when lower (50°C) and higher (70°C) temperatures were used the antioxidant activity of PEF and PEF/OD treated samples were at a comparable level as control samples. Concerning the antioxidant activity measured by ABTS the samples treated with PEF and PF/OD showed the highest values of this parameters, suggesting the contribution of other bioactive compounds with high antioxidant activity.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
