Pulsed electric fields pre-treatment of carrot purees to enhance their polyacetylene and sugar contents

• Conditions at 0.25 kV/cm for 6 ms enhanced falcarindiol and falcarindiol-3-acetate content by 3-fold.
• Highest levels of falcarinol up to 1.9-fold detected at 0.25 kV/cm for 40 ms.
• Increments in soluble sugars ranging 11–53% were observed at 0.5 kV/cm for 2 ms.

The effect of PEF processing on polyacetylene and sugar extraction, colour changes and total carotenoid content in carrot purees was studied. Increase in a* values (redness) from purees treated at 0.25 kV/cm for 10 ms (7.5 J/kg) was significantly correlated with increases in their total carotenoid content. Concentrations of falcarindiol and falcarindiol-3-acetate detected in PEF-treated samples were up to 3-fold higher than untreated purees at 0.25 kV/cm for 6 ms (4.5 J/kg). Longer treatment times for 40 ms (30 J/kg) only led to 1.9 times higher the initial amount of falcarinol extracted from unprocessed purees. Processing at 1 kV/cm for 2 ms (29 J/kg) increased concentrations of sucrose and β-glucose in 43 and 48%, respectively. However, the content in α-glucose and fructose only increased (52% and 78%, respectively) when higher energies were applied (1 kV/cm for 6 ms, 86 J/kg).Industrial relevanceResults of this study show that PEF pre-treatment could be a suitable process to enhance the polyacetylene and sugar content of carrot purees, improving the over-all health and nutritional benefits of the product with relatively low input energies.