Preservation of chocolate milk and rose milk by Pulsed electric field

Abstract

High voltage Pulsed electric field (PEF) technology in the pasteurization of liquid food products has shown positive results. Applying this PEF technology to food pasteurization is a promising non-thermal method, which in turn considerably reduces processing times, loss of nutrients and offers important savings in energy. This method provides consumers with microbiologically safe, minimally processed, fresh like products. PEF has been used successfully to pasteurize some liquid foods, but it is still not used commercially in milk pasteurization, although several trials have shown the positive effects of PEF milk pasteurization, which could allow for its future use at the industrial level. Very few flavoured milk stability control studies exist by Pulsed Electric Field (PEF). This study was aimed to assess the effectiveness of pulsed electric field in microbial inactivation of flavoured milk such as rose milk and chocolate milk over the electric field strength of 50 kVcm−1 and 60 kVcm−1 with 150 pulses using static treatment chamber. One such application is used for prevention of microbial growth, an effect that is based on irreversible permiabilization of cell membranes. Physicochemical parameters such as pH, acidity and protein were measured in both rose and chocolate milk before and after PEF treatment. PEF-treated flavoured milk samples showed higher stability stored at 4 °C with minor variations in physicochemical properties. PEF treatment resulted in log reduction of 6.83, 6.82 and 6.32, 6.24 log cfu mL−1 for chocolate milk and rose milk at 50 kVcm−1, 150 pulses and 60 kVcm−1, 150 pulses respectively, resulting in preservation of the products for 7 days.