The effect of electrical discharge treatment of milk whey on partial conversion of lactose into lactobionic acid
Анотація
The article considers the scientific aspects of probable partial transformation of lactose into lactobionic acid due to the electrical discharge dispersion of magnesium and manganese conductive granules in milk whey – a traditional lactose-containing raw material. The object of this study was milk whey, defatted and with casein dust particles removed, which was treated in a discharge chamber with a conductive layer of magnesium and/or manganese granules at (20±2)°С with 120–180 s of exposure. A UPLC-MS/MS analysis of milk whey was carried out using a TSQ Vantage chromatograph-mass spectrometer (ThermoFinnigan, USA) connected to a Dionex Ultimate 3000 liquid chromatograph. The changes have been studied taking place in pH and redox potential of milk whey after electrical discharge treatment, as compared to the original whey. It has been established that electrical discharge treatment with 180 s of exposure increases the Mg content in milk whey by approximately 4 times, and increases the Mn content by 3.5 times. The dispersed metal particles are found in nano- (about 30 nm) and microscale (100 nm to 10 µm). The UPLC-MS/MS analysis of the test samples of whey that underwent electrical discharge treatment allowed identifying a chromatographic peak [M–H]–=357 m/z related to lactobionic acid. The derivative lactose content increased by 2 times in the whey samples treated for 180 s in a reaction chamber with a conductive layer of Mg between the corresponding electrodes, as compared to the original whey, and by 4 times in the samples subsequently treated in the reaction chambers with a layer of Mg and Mn granules between the corresponding electrodes, with 120 s of exposure in each chamber. The way has been presented of solving the problem of complex, economically practical and environmentally safe processing of milk whey with the prospect of obtaining lactobionic acid, a biologically valuable derivative of lactose.