Characterization of alkali-modified soy protein concentrate

Abstract

To study the influence of the preparation mode, including mild alkali modification, of soy protein concentrate on soluble protein content and composition, some of its nutritive and functional properties were investigated. Soy protein concentrate prepared by aqueous alcohol leaching was modified in mild alkaline solutions (pH 8.0) at 40, 50 and 60° C for 60 minutes and compared with two principal types of commercial soy protein concentrate. Soluble protein content, composition and properties of soy protein concentrate, as well as their potential use are essentially determined by the preparation mode. Limited mild alkali hydrolysis increased protein solubility by 40-71%, while emulsion stability was increased by 18-56%. Major storage soybean proteins exhibited different stability to alcohol denaturation and mild alkali modification. The most susceptible were acidic -A3 - and -A5- subunits of glycinin.

U okviru ovog rada ispitivan je efekat načina pripreme, uključujući i efekat alkalnog modifikovanja na sadržaj i sastav rastvorljivih proteina i neke funkcionalne karakteristike tradicionalnog koncentrata proteina soje. Tradicionalni proteinski koncentrat (dobijen ispiranjem neproteinskih komponenti 65%-nim etanolom) modifikovan je u alkalnoj sredini (pH 8,0) pri temperaturi od 40, 50 i 60ºC u toku 60 minuta. Sadržaj, sastav i funkcionalne osobine, a time i moguća primena sojinog proteinskog koncentrata određeni su načinom njegove pripreme. Alkalnim modifikovanjem sadržaj rastvorljivih proteina tradicionalnog koncentrata se povećava za 40-70%, dok je stabilnost emulzije obrazovane ovim uzorcima povećana za 17,8-56,1%. Dominantni proteini soje ispoljili su različitu osetljivost pri alkoholnoj ekstrakciji i alkalnom modifikovanju.