The effect of pulsed electric fields, ultraviolet light or high intensity light pulses in combination with manothermosonication on selected physico-chemical and sensory attributes of an orange and carrot juice blend

Abstract

A blend of orange and carrot juice was processed by three selected treatments combining pulsed electric fields (PEF) (24kV/cm, 18Hz, 93μs), ultraviolet light (UV) (10.6J/cm2) or high intensity light pulses (HILP) (3.3J/cm2), in each case, with manothermosonication (MTS) technology (400kPa, 35°C, 1000W, 20kHz). Treatment effects on selected physico-chemical and sensory properties of the juice were evaluated. No significant changes were found in non-enzymatic browning (NEBI) or antioxidant activity compared to an untreated control. However, the treatments increased all the Hunter Lab colour values, while total phenolics were significantly decreased. Each combination achieved on average 78% inactivation of pectin methyl esterase (PME). Sensory analysis showed that the colour of the product processed by hurdle combinations was preferred to that of a pasteurised sample (72°C, 26s), while the flavour was adversely affected by all of the non-thermal treatments. Panellists did not perceive differences in the odour, sweetness or acidity of the product. Results indicate that, under the current experimental conditions, the application of the selected combinations of non-thermal technologies resulted in a product in which certain quality attributes were somewhat inferior to those of a lightly pasteurised control juice.