# Physicochemical and Sensory Evaluation of Yanggaeng Treated with Roasted Guateman Coffee Extracts
## 3 Results and Discussion
### pH and Brix Values of Yanggaeng
\begin{table}
\begin{tabular}{c c c c c c} \hline  & **Roasting** & **CON** & **2\%** & **Guatemalan Coffee Extract** & \\  & Light & 6.29 \(\pm\) 0.05 \({}^{\text{dN}}\) & 6.61 \(\pm\) 0.01 \({}^{\text{cB}}\) & 6.67 \(\pm\) 0.02 \({}^{\text{bB}}\) & 6.75 \(\pm\) 0.01 \({}^{\text{aA}}\) \\ pH & Medium & 6.26 \(\pm\) 0.07 \({}^{\text{abN}}\) & 6.29 \(\pm\) 0.04 \({}^{\text{aC}}\) & 6.19 \(\pm\) 0.06 \({}^{\text{bC}}\) & 5.99 \(\pm\) 0.01 \({}^{\text{cC}}\) \\  & Dark & 6.28 \(\pm\) 0.07 \({}^{\text{cN}}\) & 6.80 \(\pm\) 0.02 \({}^{\text{aA}}\) & 6.79 \(\pm\) 0.01 \({}^{\text{aA}}\) & 6.71 \(\pm\) 0.02 \({}^{\text{bB}}\) \\ \hline \multirow{3}{*}{Brix} & Light & 3.03 \(\pm\) 0.06 \({}^{\text{dN}}\) & 3.30 \(\pm\) 0.00 \({}^{\text{cC}}\) & 3.70 \(\pm\) 0.00 \({}^{\text{aA}}\) & 3.50 \(\pm\) 0.00 \({}^{\text{bC}}\) \\  & Medium & 3.07 \(\pm\) 0.06 \({}^{\text{dN}}\) & 3.40 \(\pm\) 0.00 \({}^{\text{bB}}\) & 3.20 \(\pm\) 0.00 \({}^{\text{cB}}\) & 3.57 \(\pm\) 0.06 \({}^{\text{dB}}\) \\  & Dark & 3.07 \(\pm\) 0.06 \({}^{\text{dN}}\) & 3.50 \(\pm\) 0.00 \({}^{\text{CA}}\) & 3.70 \(\pm\) 0.10 \({}^{\text{bA}}\) & 3.90 \(\pm\) 0.00 \({}^{\text{aA}}\) \\ \hline \end{tabular} Data are presented as means \(\pm\) SD (\(n=3\)). All data were ranked and subsequently analyzed using one-way analysis of variance (ANOVA) followed by [PERSON]’s multiple range test. Means with different capital letters (A–C) in the same row and lowerse letters (a–d) in the same column differ significantly (\(p<0.05\)), \({}^{\text{N}}\) indicates not significant. CON, control (Yanggaeng treated with 0% G); 2%, Yanggaeng treated with 2% G; 4%, Yanggaeng treated with 4% G; 6%, Yanggaeng treated with 6% G.  
\end{table} 
Table 5: Changes in pH and Brix of Yanggaeng treated with various concentrations of Guatem coffee extract. pH, indicating increased acidity. Group D initially showed an increase in pH. However, at higher concentrations, the enhanced formation of quinic acid likely played a major role in the subsequent pH decline. This pattern suggests interactions between acidic and buffering compounds that vary with the roasting level. These results indicate that the degree of roasting significantly influences both the acidity and flavor profiles of Yanggaeng. Specifically, Yanggaeng with medium roast, which exhibited the lowest pH, may impart a more pronounced acidic flavor, whereas those with light or dark roasts may offer a more balanced taste profile. The Brix values, indicative of the soluble solid content, were influenced by both the concentration of G and the degree of roasting. In the L group, Brix values increased with higher concentrations of G, reaching the highest value in L4 (3.70) compared to CON (3.03), L2 (3.30), and L6 (3.50) (_p_ < 0.05). The M group showed an initial increase in Brix values from CON (3.07) to M2 (3.40), a slight decrease at M4 (3.20), and a subsequent increase at M6 (3.57). In the D group, Brix values consistently rose with increasing concentrations of G, from 3.07 in CON to 3.50 in D2 and 3.70 in D4, and peaking at 3.90 in D6. Group D consistently exhibited the highest Brix values compared to groups L and M (_p_ < 0.05). The increasing trends in the Brix values suggest that the soluble solid content in Yanggaeng was affected by both the concentration of G and the degree of roasting. In Group D, the consistent increase in Brix values can be attributed to caramelization during dark roasting, where sugars in the coffee beans break down into simpler sugars and caramel compounds that are highly soluble in water. Additionally, the Maillard reaction contributes to the breakdown of proteins and solids into soluble compounds, further elevating Brix values [37]. The loss of moisture in dark-roasted coffee beans concentrates the remaining compounds, leading to higher Brix values when these beans are incorporated into Yanggaeng.