Twin-Screw extrusion of hairtail surimi and soy protein isolate blends

Abstract

In this study, hairtail surimi (HS) and soy protein isolate (SPI) blends were extruded using a co-rotating twinscrew extruder. The effects of feed moisture, screw speed, and barrel temperature on the texture and water-holding capacity of the extrudates were investigated using response surface methodology. HS and SPI were mixed at a ratio of 1:4; the screw speed was tested at three levels between 80 and 120 rpm; the barrel temperature was set between 140? and 160?, and the feed moisture was set between 30% and 50%. The digestibility and microstructure of the extrudate produced by optimum condutions were also studied. The results demonstrated that the physical properties were significantly (p < 0.05) affected by the three process variables. Water-holding capacity and extrudate texture were found to mainly depend on barrel temperature and feed moisture, respectively. In vitro protein digestibility of the blends was improved by the extruding process. Copyright © 2014, Japanese Society for Food Science and Technology.