# Study of the Utilization of Spent Grain from Malt Whisky on the Quality of Wafers
## 3 Results and Discussion
The total dietary fiber content was higher in the wafer sample (11.64% \(\pm\) 0.04%) compared to the control sample (9.82% \(\pm\) 0.03%) due to the addition of spent grain that contains a higher amount of fiber; the same trend was observed in study reported by [PERSON] and [PERSON], 2022 [36]. The ash content was found to be highest in the control sample (7.35% \(\pm\) 0.01%) followed by the spent grain sample (6.22% \(\pm\) 0.01%), in accordance with [PERSON] et al., 2020 [26]. The force measured at the first maximum point of the first significant change of the first curve is the force recorded at the breaking or destruction of the sample, i.e., the fracturability. If under stress a material can be fractured then it is considered to be a fragile material [23]. The fracturability of dried wafers decreases with the increase in the addition of spent grain (control sample 5.47 \(\pm\) 0.09 N, spent grain wafers 3.86 \(\pm\) 0.07 N), the same result obtained by [PERSON], 2020 [32], and with a decrease in pasta fracturability with the increase in the content of whey powder and corn starch and by [PERSON] and [PERSON] [23] in their study about spent grain pasta. Baking loss can be influenced by several factors: baking temperature, batter moisture, or leaving agents used. The values for baking loss were 50.15% for the control sample and 56.12% for the spent grain sample, respectively, compared to 19.52-27.48% baking losses in the case of waffle [18], which is to be expected because the wafer humidity is much lower than that of waffles. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Determination**} & \multirow{2}{*}{**Control Sample(\%)**} & **Spent Grain Wafer** & \multirow{2}{*}{**\(p\) Value**} \\  & & **Sample(\%)** & \\ \hline Proteins & 9.66 \(\pm\) 0.35 \({}^{\text{a}}\) & 11.17 \(\pm\) 0.21 \({}^{\text{a}}\) & 0.001 \\ Lipids & 16.03 \(\pm\) 0.02 \({}^{\text{a}}\) & 17.69 \(\pm\) 0.03 \({}^{\text{b}}\) & \textless{}0.001 \\ Fibers & 9.82 \(\pm\) 0.03 \({}^{\text{a}}\) & 11.64 \(\pm\) 0.04 \({}^{\text{b}}\) & \textless{}0.001 \\ Carbohydrates & 51.28 \(\pm\) 0.06 \({}^{\text{b}}\) & 47.40 \(\pm\) 0.05 \({}^{\text{a}}\) & 0.003 \\ Ash & 7.35 \(\pm\) 0.01 \({}^{\text{b}}\) & 6.22 \(\pm\) 0.01 \({}^{\text{a}}\) & \textless{}0.001 \\ Moisture & 5.86 \(\pm\) 0.02 \({}^{\text{a}}\) & 5.88 \(\pm\) 0.02 \({}^{\text{a}}\) & n.s. \\ \hline \hline \end{tabular} Mean values with different letters in the same column are significantly different (\(p\) < 0.05), n.s.—not significant.  
\end{table} 
Table 3: Proximate analysis of spent grain wafer. Water activity (Aw) is a simple instrumental measure of crispness in wafer, making it an excellent way to monitor crispness over time and from batch to batch [37]. Traditionally, crispness intensity decreases as Aw increases. In their study, [PERSON] et al., 2007, found values for ice cream cones between 0.387 and 0.520, in agreement with this study (0.4302 for the control sample and 0.4350 for the spent grain sample) [37]. The acceptability of a product given by consumers is also influenced by the color of the product. The lightness of the spent grain wafer sample decreased compared to the control sample (Figure 1), a process due to the addition of spent grain, which has a specific dark color. There is a decrease in yellowness (b*) and an increase in redness (a*) in the spent grain wafer sample compared to the control sample (Table 4), in accordance with a study made by [PERSON] and [PERSON], 2021 [23]. The total content of polyphenols increased in the spent grain wafer sample (6.46 ug GAE/g) compared to the blank sample (5.29 ug GAE/g), which means that spent grain has a polyphenol intake in the finished product. Spent grain had a contribution of polyphenols also in the case of pasta with the addition of spent grain flour, where the polyphenol content increased with the percentage of added spent grain (17.21 \(\pm\) 0.19 ug GAE/g--23.06 \(\pm\) 0.11 ug GAE/g) [23].