Effects of raw dehydrated potato flour on properties of dough and gluten in biscuits

In this study, the effects of raw dehydrated potato flour (RDPF) on properties of dough and gluten in biscuits were investigated. Results showed that the total sulfhydryl groups content, S-S content and enthalpy (oH) of gluten proteins were significantly reduced (p < 0.05) while free sulfhydryl groups content was increased compared with the control group when RDPF increased (p < 0.05). In the 30 and 50% RDPF groups, the content of S-S reduced by 20.91% (11.61 mu mol/g) and 34.95% (9.55 mu mol/g), respectively. The secondary structure results showed that as the RDPF amount increased, the proportion of random coil significantly elevated (p < 0.05), the beta-sheet were decreased in the 30 and 50% RDPF groups, while the beta-turn were increased. There was a linear relationship between the random coil content (y) and the addition of RDPF (x): y = 5.2898 x + 51.487, R-2 = 0.94. Thermomechanical properties of the dough demonstrated that the water absorption rate increased significantly (p < 0.05) with the increase of RDPF addition, while the stability of the dough and the strength of gluten were reduced. Addition of RDPF also led to a more disordered gluten network shown by scanning electron microscopy. Confocal laser scanning microscopy results indicated that the control group and the 10% RDPF had better gluten network, the continuity of the gluten protein network could be destroyed with the addition of RDPF at a ratio of 30 and 50%.