Enhancing the texture and modulating digestive behavior of gluten-free quinoa sponge cakes via microwave-assisted alkaline amino acid treatment

This study investigated the effects of microwave treatment combined with lysine and arginine on gluten-free quinoa sponge cakes. The results indicated that the addition of these amino acids during microwave treatment significantly increased the cakes' specific volume by 49 %. X-ray diffraction analysis revealed that cake crystallinity reached 56.23 % and 49.17 % when lysine and arginine were used, respectively. Fourier Transform Infrared spectroscopy showed confirmed the absence of new functional groups or chemical bonds under different treatments, but the absorbance ratio at 1047 cm −1 to 1022 cm −1 was higher in microwave-treated cakes with lysine compared to traditionally steamed cakes. Simulated digestion experiments demonstrated that microwave-treated cakes, especially with added amino acids, exhibited higher protein digestibility but lower starch digestibility. Confocal Laser Scanning Microscopy observations further showed that proteins formed a denser network structure around starch granules during in vitro digestion, suggesting improved protein functionality and structure in microwave-treated quinoa sponge cakes.