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

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 025 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 beta-glucose in 43 and 48%, respectively. However, the content in alpha-glucose and fructose only increased (52% and 78%, respectively) when higher energies were applied (1 kV/cm for 6 ms, 86 J/kg). Industrial relevance: Results 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. (C) 2014 Elsevier Ltd. All rights reserved.