Development Of A Low GI Rice Noodle Formulation Based On RS2 And Buckwheat

Rice noodles,rice products made from rice,dominate the rice products because of their unique taste and popularity among consumers.At present,rice noodles in the market are mainly white rice noodles,and there is still relatively little research on functional rice noodles.However,the main component of traditional white rice noodles is starch,which is very likely to increase the postprandial blood glucose concentration in human body after consumption,and is a high GI food,which can easily induce chronic metabolic diseases such as type II diabetes with long-term intake.Therefore,by regulating the digestive rate of starch and controlling the digestibility of rice noodles,it is important to develop a low-GI rice noodle suitable for people with high blood glucose and lipid needs to regulate blood glucose levels.The effect of different additions of RS2(Hi-maize^TM260)and buckwheat on the quality characteristics and digestive properties of rice noodles was first investigated,and then the two ingredients were compounded with rice flour to make rice noodles,with GI and cooking characteristics as indicators.The final formulation of low GI rice noodles（rice:buckwheat:RS2=4:4:2）with a GI of 54.45 was determined by screening.The relevant studies and results are as follows:（1）RS2 was able to significantly reduce the GI of rice noodles.The content of fast-digesting starch（RDS）in rice noodles was significantly reduced and the content of slow-digesting starch（SDS）was significantly reduced RS content was significantly increased（p<0.05）,and when the addition amount reached 40%,the GI of rice noodles decreased from 78.36 in the control group to 65.62,a reduction of 16.3%.The addition of RS2 at 5～20% maintained the sensory evaluation of rice noodles while also improving the cooking characteristics such as cooking loss and breakage rate of rice noodles.（2）Buckwheat was able to significantly reduce the GI of the rice noodles,the content of RDS in the rice noodles was significantly reduced,the content of SDS was not significantly changed,while the content of RS was significantly increased（p<0.05）,the overall starch hydrolysis rate of the rice noodles was reduced,the GI value was reduced from 81.44 to 67.07,a reduction of 17.6%（p<0.05）.The paste viscosity of the mix decreased significantly,the paste temperature increased significantly,the enthalpy of paste（ΔH）decreased significantly,the crystallinity of the rice noodles decreased,the hardness and chewiness of the rice noodles decreased significantly,the cooking loss and breakage rate decreased significantly（p<0.05）,the colour of the rice noodles became darker and the overall acceptability of the rice noodles became lower.（3）Different ratios of RS2 and buckwheat were compounded with rice flour to make rice noodles,and the GI and cooking characteristics determined a low GI rice noodle formulation（rice:buckwheat:RS2=4:4:2）with a GI of 54.45.The peak viscosity,minimum viscosity,attenuation value,final viscosity and rebound value of the compounded rice noodle ingredients all decreased significantly,and the starting temperature of pasting（To）,final temperature（Te）and enthalpy of pasting（ΔH）decreased significantly and the peak pasting temperature（Tp）increased significantly;the hardness,viscosity,chewiness and adhesiveness of the compounded rice noodles decreased significantly,the elasticity did not change significantly,the reversion increased significantly,and the breakage rate and cooking loss of the compounded rice noodles increased significantly.The experimental results of E-nose and GC-IMS showed that there were more volatile flavour substances in the different groups of rice noodles compared to the raw material powder,where RS2 had little effect on the volatile flavour substances of the rice noodles and buckwheat had a large effect on the volatile flavour substances of the rice noodles.（4）Compared with white rice noodles,the low-GI rice noodles before and after in vitro simulated digestion both had good antioxidant properties and inhibitedα-amylase and α-glucosidase.After in vitro simulated digestion,the total flavonoid content of the rice flosses were all decreased.The flavonoid extract of low GI rice noodles had significant inhibitory effects on α-amylase and α-glucosidase,and there was a dose-dependent inhibition of α-amylase by the flavonoid extract of rice noodles.The results of fluorescence spectroscopy experiments showed that the GI rice noodles flavonoid extract had a significant burst effect on α-amylase,while there was no significant change in the white rice noodles group.The scavenging rates of DPPH and ABTS radicals of low GI rice noodles were much higher than those of white rice noodles,which had good antioxidant activity;after in vitro simulated digestion,the scavenging rates of both DPPH and ABTS radicals of rice noodle extracts were reduced.