Processing and preservation of apple juice by pulsed electric fields combined with cinnamon essential oils: Exploring the effect of synergism

Apple juice samples were treated by pulsed electric field (PEF) alone and in combination with cinnamon essential oils (CEO) at 0.0005, 0.003, and 0.06 μL mL⁻¹ concentrations as a function of treatment time. Results revealed 11 different compounds with the highest concentrations of 44.79% 3-propenal 3-phenyl, 34.98% trans-cinnamaldehyde, and 10.18% 4-propenal 3-phenyl in CEO. pH and total soluble solids of the apple juice samples significantly decreased; whereas total phenolic substance content of the samples significantly increased by added CEO. The same process parameters caused 3.26 ± 0.19 and 3.83 ± 0.16 log reductions on TAMB and TMY, revealing no detectable numbers after PEF treatment. Similarly, maximum 5.13 and 3.87 log reductions on Escherichia coli O157:H7 and Listeria monocytogenes were obtained on 0.06 μL mL⁻¹ CEO added samples treated after 604 μs. Moreover, increased CEO concentration, when treatment time was constant, caused significantly more microbial inactivation. Increase in treatment time resulted in an incline on ΔH of the samples. Response optimization revealed that 604 μs treatment time and 0.06 μL mL⁻¹ concentration were the optimal treatment parameters with 0.63 composite desirability.