[Enzymatic modification of proteins of commercial sesame meals (Sesamum indicum, L.)].
Sesame (Sesamum indicum, L.) is one of the most important oilseed crops in Venezuela. However, the low solubility of the flour made of commercial meals does not allow its use in the preparation of fluid foods. To solve this situation, the alternative of solubilizing the sesame proteins by an enzymatic method, using commercial proteases, was studied. Hydrolysis was carried out with two types of bacterial proteases: neutrasa 0.5L, and alcalase 0.6L. Basically, the process consisted of milling and sieving the sesame cake (60 mesh), concentrating the proteins by solubilizing them at a pH of 9.5, and then precipitating at a pH of 4.5. Proteins were hydrolyzed by an enzymatic method, and the hydrolysates freeze-dried and spray-dried. Optimal conditions of hydrolysis using neutrase 0.5L at a pH of 7 were: 6% substrate concentration, 3% enzyme:substrate ratio, temperature 50 degrees +/- 1 degree C, and hydrolysis degree of 8%. When alcalase 0.6L was used at a pH of 8, optimal conditions were: 8% substrate concentration, 2.3% enzyme:substrate ratio, temperature 58 degrees +/- 1 degree C, and hydrolysis degree of 10%. The enzyme affinity (Km) was best at temperatures near the optimal temperature for the hydrolysates. Dried hydrolysates had protein values which ranged between 66.3% and 66.9% and a nitrogen solubility in water, of approximately 85%. Hydrolysis yields referred to the concentrate dried mass were 42% for the atomized hydrolysate, and 56% for the freeze-dried one. In conclusion, the enzymatic hydrolysis process improved the nitrogen solubility in water of the sesame proteins.