Design and manufacturing of key lime juice processing system by pulsed electric field and evaluation of its quality characteristics

Key lime juice can be a non-fermenting product with high acidity and a rich source of ascorbic acid and phenol compound. In order to maintain the quality of the product, it is important to choose a suitable method for processing this food.
The use of modern non-thermal methods to produce high quality products should be considered. In this research, by designing and constructing a continuous pulsed electric field (PEF) system, the effect of this method on the degradation of pectin methyl esterase (PME), ascorbic acid, total phenol compound, cloudiness index, color changes and sensory evaluation in key lime juice is discussed. In this research, a bipolar square wave of 10 microseconds and a constant frequency of 1000 is used. In the processing chamber of this device, two cases of stainless steel with length and thickness of 10 and 0.5 ml, respectively, were used. Key lime juice was processed for 500, 571, 666, 800 and 1000 microseconds with Field intensity of 22.22, 33.33, 44.44 and 55.55 kV per cm. In general, by increasing the field from 22.22 to 55.55 kV / cm at a constant time, the process of reducing the degradation of PME enzyme is normally increased by 25%. Applying the highest electric field of 55.55 in 1000 microseconds caused 14% ascorbic acid degradation compared to fresh samples. With increasing pulsed electric fields, the cloudy index of the sample and browning index have increased. The use of high intensity pulsed electric field increased the degradation of PME enzyme and the cloudy index and reduced lightness compared to the fresh sample. Preservation of sensory properties of key lime juice developed with PEF during shelf life showed that the non-thermal pulsed electric field method can act as a promising approach in products with high acidity and enzyme degradation.