Effect of PEF and heat pasteurization on the physical-chemical characteristics of blended orange and carrot juice

The effect of different Pulsed Electric Fields (PEF) intensities (25 kV/cm and 280 μs, P1; and 25 kV/cm and 330 μs, P2) and conventional HTST treatment (98 °C, 21 s, T) on quality characteristics (pH, °Brix, total acidity, turbidity, hydroxymethylfurfural (HMF), color, microbial flora, pectinmethylesterase (PME) activity, and sensory analysis) of blended orange and carrot juice were investigated. HMF, L* (luminosity) and C* (saturation or chrome) color parameters did not vary with any of the treatments. Total acidity and turbidity were slightly higher after HTST treatment. Sensory characteristics of the PEF-treated juice were more similar to the untreated juice than the HTST-pasteurized juice. Nevertheless, heat pasteurization (98 °C, 21 s) was more efficient in inactivating microbial flora and PME and preventing the growth of microbial flora and reactivation of PME at 2 and 12 °C for 10 weeks. However, the shelf-life of the PEF-treated juice was established as 4 weeks at 2 °C. This appears to be a reasonable shelf-life for this type of foodstuff.