IMPROVEMENT OF THE KERATIN RELEASE PROCESS BY HYDROLYSIS OF RAW MATERIALS IN THE ULTRASONIC FIELD

doi: 10.25712/ASTU.2072-8921.2021.02.025

Abstract

One of the mechanisms realizing ultrasonic extraction, which makes it possible to obtain chemically pure extracts of biologically active substances from natural raw materials of plant or animal origin, is associated with ultrasonic cavitation, which induces the appearance in a liquid irradiated by ultrasonic waves of pulsating and collapsing bubbles filled with steam, gas or a mixture of them. The use of ultrasound in production significantly speeds up the extraction process, increases the yield of target components in the extract and reduces the cost of the extracted substance. Cavitation bubbles are formed when a liquid is irradiated with powerful ultrasound and expand during half-periods of rarefaction and contract after the transition to the area of increased pressure. It is the energy released during the collapse of these bubbles that leads to such a significant acceleration of chemical reactions. The number and size of cavitation bubbles depend not only on the field parameters - intensity, frequency and sound pressure, but also on the characteristics of the liquid: viscosity, density, temperature, surface tension and pressure of the vapor-gas mixture. It seems advisable to use this technological tool to isolate such a valuable product as keratin, when disposing, for example, down-feather waste obtained in significant quantities during poultry processing. In the works where the method of alkaline hydrolysis of keratin was mentioned in order to obtain feed additives, the authors used rather stringent conditions for temperature and pressure, which led to almost complete decomposition of the protein molecule into amino acids, and even to partial degradation of amino acids. Our goal was to preserve the polymer structure of keratin while still lowering the molecular weight.