The Effects of CO2 Injection and Barrel Temperatures on the Physiochemical and Antioxidant Properties of Extruded Cereals

Effects of extrusion conditions on chemical properties of extruded white ginseng root hair

BACKGROUND

This study was to investigate the significant effects of extrusion process variables on chemical properties of extruded white ginseng root hair. The extrusion conditions were set as follows: barrel temperature (110 and 140 °C), moisture content (20 and 30%) and screw speed (200 and 300 rpm). The powder of white ginseng root hair was extruded as L₈ (2⁷ ) orthogonal experimental design.

RESULTS

The crude saponin and acidic polysaccharide contents of extrudate were significantly higher than those of raw material after extrusion. In addition, antioxidant properties were also increased, while reducing sugar content was markedly lower than that of raw material. Moisture content was the most significant factor affecting the reducing sugar, acidic polysaccharide and total phenolic contents, and 2,2-diphenyl-1-picrylhydrazyl scavenging activity. Barrel temperature significantly affected reducing power, and screw speed significantly influenced crude saponin content.

CONCLUSIONS

The extrusion process aided in improving the amount of beneficial compounds from white ginseng root hair. © 2018 Society of Chemical Industry.

Effects of extrusion with CO2 injection on physical and antioxidant properties of cornmeal-based extrudates with carrot powder

Carrot powder and cornmeal were extruded at ratios of 0:100, 10:90, and 20:80 with and without CO₂ injection at die temperatures of 80, 100, and 120 °C. The effects of the composition of the extrudate, die temperature, and CO₂ injection on physicochemical and antioxidant properties of extruded products were studied. The results showed that die temperature had a significant effect on expansion ratio (ER), specific length, piece density, color, water absorption index (WAI), and water solubility index (WSI) (p < 0.05). The injection of CO₂ significantly affected the ER, WAI, WSI, lightness, redness, microstructure, total phenolic content, and the 2,2-diphenyl-1-picrylhydrazyl radical-scavenging activity of extrudates (p < 0.05). Increasing the proportion of carrot powder in extrudates resulted in better antioxidant properties and higher levels of crude ash, crude fat, crude protein, and redness; however, it resulted in lower WAI, lightness, and yellowness (p < 0.05). The study demonstrated that extrusion with CO₂ injection and addition of carrot powder may improve the nutritional quality and structure-forming ability of extrudates.