Extrusion conditions as pretreatment factor for sunflower meal enzymatic hydrolysis
Sunflower meal extrusion cooking process was investigated as pretreatment method for enzymatic hydrolysis. Effect of moisture content and screw speed on changes of specific mechanic energy and quality of subsequent hydrolysis of extruded sunflower meal with protease and cellulase was studied using central composite orthogonal design. The results obtained showed absence of significant influence of extrusion cooking conditions on the hydrolysates dynamic viscosity and protein hydrolysis degree. Average value of the extrudates protein hydrolysis degree increased by 18.6% compared with hydrolyzed non-extruded samples. Extrusion cooking at favorable processing conditions provided the increase of reducing sugars concentration by 73% and 280% compared with hydrolyzed non-extruded meal and unprocessed raw material, respectively. Extrusion cooking of sunflower meal was found to increase hydrolysis degree of protein and non-starch polysaccharides and reduce the hydrolysates viscosity.