Effect of soybean protein isolate, transglutaminase, and konjac glucomannan on the cooking and eating quality and digestibility of rice noodles

Abstract In this study, rice noodles were developed with the goal of improving texture, cooking quality, sensory attributes, and reducing glycemic impact by adding transglutaminase (TG), soybean protein isolate (SPI), and konjac glucomannan (KGM) to indica rice flour using a single-screw extruder. Compared to the control group without these additives, the textural analysis results showed that the addition of 0.5 % TG, 0.5 % KGM, and 3 % SPI significantly improved chewiness. For cooking and sensory quality, this formulation exhibited the lowest cooking loss rate (CLR), a reduced iodine blue value, the highest water absorption rate (WAR), and superior overall acceptability in comparison to the control. In terms of color properties, this group showed a 1.66 % increase in L* (lightness) and a 0.78 % decrease in a* (red-green value) compared to the control. Furthermore, the in vitro digestion results revealed a decrease of 3.87 % in estimated glycemic index (eGI) and an 8.03 % reduction in glycemic load (GL) for the 0.5 % TG + 0.5 % KGM + 3 % SPI group relative to the control. This study demonstrates the potential to enhance rice noodle quality while lowering glycemic impact.