Effects of infrared treatment on urease, trypsin inhibitor and lipoxygenase activities of soybean samples.

In this study, infrared (IR) treatment at different powers (814W, 1003W, 1208W, 1342W) and times (10min, 15min) were applied to unsoaked and soaked (30min, 45min) soybeans (cvs. Adasoy, Nazlican). Effects of IR treatment on urease, trypsin inhibitor, lipoxygenase-1 and lipoxygenase-3 activities were investigated. Infrared treatment caused a substantial reduction in urease and trypsin inhibitor activities and considerable decrease was observed as the IR power increased. Urease inactivation in unsoaked samples was achieved at even lower power (1208W). In contrast to urease activity, IR treatment had a more pronounced effect on trypsin inhibitor and lipoxygenase activities of soaked soybeans as compared to unsoaked counterparts. Maximum trypsin inhibitor reduction in IR-treated samples was 95% for cv. Adasoy and 97% for cv. Nazlican. IR power of 1003W was sufficient for complete inactivation of lipoxygenase-1 and lipoxygenase-3, regardless of the moisture contents of the samples.

Effects of extrusion variables on the properties of waxy hulless barley extrudates.

The objective of this research was to investigate the extrudability of waxy hulless barley flour under various extrusion conditions. Waxy hulless barley flour was processed in a laboratory-scale corotating twin-screw extruder with different levels of feed moisture content (22.3, 26.8, and 30.7%) and die temperature (130, 150, and 170 degrees C) to develop a snack food with high beta-glucan content. The effects of extrusion condition variables (screw configuration, moisture, and temperature) on the system variables (pressure and specific mechanical energy), the extrudate physical properties (sectional expansion index, bulk density), starch gelatinization, pasting properties (cold peak viscosity, trough viscosity, and final viscosity), and beta-glucan contents were determined. Results were evaluated by using response surface methodology. Increased extrusion temperature and feed moisture content resulted in decreases in exit die pressure and specific mechanical energy values. For extrudates extruded under low shear screw configuration (LS), increased barrel temperature decreased sectional expansion index (SEI) values at both low and high moisture contents. The feed moisture seems to have an inverse relationship with SEI over the range studied. Bulk density was higher at higher moisture contents, for both low and high barrel temperatures, for samples extruded under high shear screw configuration (HS) and LS. Cold peak viscosities (CV) were observed in all samples. The CV increased with the increase in extrusion temperature and feed moisture content. Although beta-glucan contents of the LS extrudates were comparable to that of barley flour sample, HS samples had generally lower beta-glucan contents. The extrusion cooking technique seems to be promising for the production of snack foods with high beta-glucan content, especially using LS conditions.

Effects of irradiation on protein electrophoretic properties, water absorption and cooking quality of lentils.

Effects of gamma irradiation at doses of 1 kGy, 5 kGy, and 10 kGy on water absorption properties, cooking quality and electrophoretic patterns of insoluble proteins of red and green lentil samples were investigated. The densitometric analysis indicated that the effects of irradiation on sodium dodecyl sulfate-polycrylamide gel electrophoresis patterns of red and green lentil proteins were not significant. Generally, a 1 kGy irradiation dose did not significantly affect the water absorption properties of the lentil samples while significant increases were observed at the 5 kGy level. The dry and wet cooking times were found to be significantly decreased, as the irradiation level increased in all red and green lentil samples.