# Study of the Utilization of Spent Grain from Malt Whisky on the Quality of Wafers
## 3 Results and Discussion
The radical scavenging activity on DPPH was higher for the spent grain wafer sample (24.44 \(\pm\) 0.04) compared to the control sample (1.71 \(\pm\) 0.01). The water holding capacity refers to retained water that cannot be removed by ordinary drying processes, bound by electrostatic or chemical interactions. This correlates with the level of protein or ash. The water holding capacity (WHC) is often used to determine the interactions between fiber and water [6]. WHC is closely correlated with the degree of hydration of both proteins and other polar constituents, but also their hydrophilic interactions through hydrogen bonds [38]. The values of the two samples are close (301.88% \(\pm\) 9.36% for spent grain wafers and 298.22% \(\pm\) 17.16% for the control sample), with a higher WHC for the sample of spent grain wafers, which is due to the increase in fiber content, in accordance to [PERSON] et al., 2020 [24]. The high protein content could be responsible for the formation of a large number of hydrogen bonds. The oil holding capacity (OHC) is determined by the size and porosity (density) of the particles, the content of starch, and the concentration and hydrophobic nature of flour proteins [38]. The mechanism of foil absorption is mainly attributed to the physical retention of oils and their binding to the non-polar protein chain by hydrophobic interactions. The retention of oils has significant effects on the rheology of the dough and the quality of the finished product. The values for OHC are close for the two samples (135.28% \(\pm\) 11.46% \begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & **L** & **a*** & **b*** & **\(\Delta\)L*** & **\(\Delta\)E*** \\ \hline
\begin{tabular}{c} Spent grain \\ wafersample \\ \end{tabular} & 48.86 \(\pm\) 0.08 & 2.10 \(\pm\) 0.03 & 29.39 \(\pm\) 0.05 & \(-\)45.3 \(\pm\) 0.08 & 51.93 \(\pm\) 0.04 \\ Control sample & 61.6 \(\pm\) 0.21 & \(-\)6.27 \(\pm\) 0.04 & 35.65 \(\pm\) 0.21 & \(-\)32.57 \(\pm\) 0.21 & 45.67 \(\pm\) 0.01 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Wafer colors. Figure 1: Control sample (**A**) vs. spent grain sample (**B**). for the spent grain wafers and 136.02% \(\pm\) 11.88% for the control sample), these functional properties not being influenced by the addition of spent grain. The wafer sheet was examined with a scanning electron microscope (SEM) to determine the dimensions of the wafer as well as to characterize the internal microstructure, as can be seen in Figure 2.  
The samples were carefully placed inside the SEM so that the cross-section of the sample was directed towards the microscope lens. The characterization of the internal microstructure of the wafers was made using a scanning electron microscope, a suitable choice for imaging studies in that the samples are easy to use, do not require prior sample preparation, and the data acquisition is fast. The microstructure of the wafers is represented by a compact aggregate, giving it a fragile appearance. The presence of a considerable number of air bubbles and surface pores thatpenetrate the matrix is the main textural trait of tenderness and crispness. The microstructure is important because this method can understand why the viscosity and aeration of the batter are important for the quality and resistance of the wafers [39]. SEMs are also an attractive choice for imaging studies because they have an easy-to-use interface, are easy to operate, and require minimal sample preparation. The microstructure of baked wafers is usually associated with the cross-sections of the entire wafer that have dense skin and porous regions of the core, in accordance with [PERSON] et al., 2021 [3], and [PERSON], 2017 [2]. A heterogeneous distribution  
Figure 2: Wafer microstructure by scanning electron microscopy (SEM) of control sample and spent grain sample. **(a)** Control sample at magnification 100\(\times\); **(b)** Spent grain sample at magnification 100\(\times\); **(c)** Control sample at magnification 200\(\times\); **(d)** Spent grain sample at magnification 200\(\times\).