(585t) Enzymatic Hydrolysis Changes Induced for Thermoplastic Extrusion and Protease Supplementation in Red Sorghum, Decorticated Sorghum and Maize: Reducing Sugars Yield, Free Alpha Amino-Nitrogen Compounds and Proteins Fractions Distribution

The growing demands for efficient processes and a variety of cereal commodities have been the driving force for the implementation of thermoplastic extrusion in food and bio-fuel industries.  This technology allows a quick starch gelatinization and promotes important structural changes in the food matrix. The objective of this research was to compare the extruded cereal with dried ground meals in terms of reducing sugars yield, free alpha amino-nitrogen (FAN) compounds profile and protein fractions distribution during the starch hydrolysis to produce sorghum worts. A split plot design was proposed with three replications to evaluate the enzymatic hydrolysis. The main plot treatment comprised the cereal type while the sub plot treatments were milling, extrusion conditions, and the protease supplementation. The proteins fractions were studied with a modified Landry-Moreaux protocol changing the polarity of solvent applied to the hydrolyzed samples The protein fractions considered in this study were globulins, prolamins, crosslinked prolamins and glutelins; these fractions are important to differentiate the protein matrix that entraps the starch granules and cause certain differences in hydrolysis efficiency.

The extruded treatments increased sugar production (185 g/L) compared with the ground treatments (165g/L), maize presented a better yield (185g/L) respect to red sorghum (168g/L).However, the FAN presents higher production in the ground treatments (130mg/L)compared to the ground ones (90mg/L) during the first 50 minutes of hydrolysis (140 g/L) in comparison with the grounded treatments (45 g/L). Preliminary results have shown that extrusion yields a decrement in the protein content in red sorghum. Protease increases the FAN compounds in extruded treatments which can be correlated with starch breakdown in the first 25 minutes of the process. The research has demonstrated that the use of extrusion  modifies the protein matrix, increases the hydrolysis yield and affects the FAN profile.