Improving soybean processing using ultrasound

Introduction. Soy protein has properties similar to the protein of animal origin. The main disadvantage of soy is the content of a significant number of specific protein-inhibitors, forming stable complexes with proteolytic enzymes of animal origin. Inhibitors reduce the efficiency of protein absorption, causing growth suppression and pancreatic hypertrophy. There is a need to reduce the activity of digestive inhibitors and neutralize urease by various methods based on hydrothermal treatment. However, currently used technologies have low indicators of soy bean processing efficiency. The product of processing is of poor quality and high cost. The aim of the study was to improve the quality of soy protein by intensifying the process of extracting soluble inhibitors of proteases by ultrasound. Materials and Methods. Caseinolytic method of M. L. Kakeyd (in modification of I. I. Benken) was used to determine the inhibitory effect on the digestive tract enzymes. The method is based on a comparison of the proteolytic activity of enzyme solutions in the presence of inhibitor and without it. The viscosity of the water-soybean suspension was detected on Brabender rotational viscomer. Optimal regime parameters of ultrasonic treatment, the degree of soybean grinding and the concentration of hydrogen peroxide in soybean processing were proposed based on the results of the study. Results. As a result of theoretical studies, factors influencing the efficiency of soybean treatment in an intense ultrasonic field were formulated: degree of grinding; concentration and amount of oxidizing solution; viscosity of water-soybean suspension; dynamics of extraction and design features of the unit for ultrasonic treatment of soybean grain. Experimental studies allowed to determine the design parameters of the plant for ultrasonic treatment of soybean grain and rational technological regimes ensuring effective neutralization of substances of anti-nutritional orientation: speed of mixer is 10-20 min-1; frequency of ultrasonic radiation is 18-20 kHz; capacity of installation is 120 kg/h; degree of neutralization of urease enzyme during oxidation is 92 %; degree of extraction of water-soluble inhibitor is 86 %. Conclusions. A production check of soybean processing technology in an intense field of ultrasonic waves was developed and carried out. This technology provides neutralization of harmful compounds by 80-90 % with an average increase in protein efficiency by 33 %. The payback period for investment in the introduction of technology and equipment is 1.17 years.