Effect of Replacing Soybean Flour by Germinated Quinoa Flour on the Physicochemical Characteristics of Vegan Burgers and Biological Activities in Diabetic Rats

Egypt has been consuming a growing amount of processed meat, which has had a detrimental impact on several environmental and health issues. The development of vegan burgers grown from germinated quinoa may be promising in Egyptian human foods for its health and nutritional benefits. This study aimed to evaluate the physicochemical properties of the vegan burgers and its effect on the biological activities of diabetic rats by using germinated quinoa seed flour (GQ) as a partial or full replacement for soybean flour (SB). Four vegan burger treatments (GQB20, GQB50, GQB80, and GQB100) were made by replacing the SB flour, which was used in the control vegan burger (SBB), with 20, 50, 80, and 100% GQ, respectively. Compared to SBB, GQB exhibited a stronger antioxidant activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2’-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid ABTS radicals; the activity increased with replacement level. Shrinkage in size and texture attributes, including cohesiveness, hardness, and springiness decreased as GQ flour replacement increased, while chewiness increased. GQB50, GQB80, and GQB100 had a pleasant flavor, an acceptable taste, and a juicy texture when compared to SB burgers. In the biological study, as the proportion of GQ flour increased, body weight gain (BWG), feed intake (FI), and feed efficiency ratio (FER) increased, but serum glucose and insulin decreased. Lipid profiles, kidney, and liver functions were all improved when GQ was added to GQB; the improvement was very comparable to the negative control. GQ content in GQB was also correlated with decreased levels of serum glutathione peroxidase and malondialdehyde. In conclusion, GQ flour can be substituted for SB flour at an 80 or 100% replacement rate to produce a vegan burger with desired sensory qualities and a strong biological effect as it can be classified as functional food.