# Utilization of Yacon Damaged Roots as a Source of FOS-Enriched Sweet-Tasting Syrup
## 3 Results and Discussion
### Syrup Production
#### 3.2.1 Effect of Citric Acid Concentration on Syrup Properties
Regarding the texture properties of 0.25% CitA Hualqui and Crespo syrups (Table 5), surface stickiness and stringiness decreased by 7% and 92%, respectively. For stringiness, this decrease was between 7% and 82%. These changes were due to the increase in the free sugars/inulin ratio. The introduction of 0.5% CitA to the yacon juice decreased the juice pH to about 3.8 (Table 3). When compared to the 0.25% CitA syrups, the 0.5% CitA Hualqui and Crespo syrups presented an orange color (Figure S1) and an increase in Glc content from 2-21%, as well as in Fru content to 24-51% (Figure 4c,e and Table S3). Model systems, which attest to the hydrolysis of FOS and inulin [49], support the conclusion that the increase in free Fru is associated with the depolymerization of short-chain FOS. This FOS decreased by 91% and 52% in the Hualqui and Crespo syrups, respectively, compared to the 0.1% CitA syrups. Furthermore, inulin almost entirely disappeared, indicating its depolymerization into FOS, which is corroborated by the lower recovery of polymeric material from the Crespo syrup (30 g/kg, Table 4). Consequently, the proportion of inulotype FOS increased to 55-60% (Figure 4d,f). These results align with the trend observed for the syrups made with 0.25% CitA and 0.1% CitA. The lower proportion of Fru molecules in \begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Syrup**} & **Yield** & \multicolumn{6}{c}{**Carbohydrate Composition (Molar \%)**} & \multirow{2}{*}{**Glc**} & **Total** & **Protein** \\  & **(\%)** & **Rha** & **Fuc** & **Ara** & **Xyl** & **Man** & **Gal** & **Glc** & **UA** & **(g/kg)** & **(g/kg)** \\ \hline
0.1\% & 21 & - & tr & \(1\pm 0\) & \(1\pm 0\) & \(32\pm 0\) & \(1\pm 0\) & \(60\pm 1\) & \(5\pm 0\) & \(510\pm 43\) & \(12\pm 2\) \\ CitA & 10 & - & tr & \(1\pm 0\) & \(2\pm 0\) & \(32\pm 2\) & \(1\pm 0\) & \(57\pm 1\) & \(7\pm 0\) & \(493\pm 28\) & \(14\pm 2\) \\ CitA & 3 & - & \(1\pm 0\) & \(2\pm 0\) & \(2\pm 0\) & \(30\pm 1\) & \(3\pm 1\) & \(53\pm 0\) & \(10\pm 2\) & \(502\pm 91\) & \(23\pm 0\) \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Yield (%), neutral sugar, and uronic acid composition of the polymeric material obtained from the dialysis of the Crespo syrups with 0.1% CitA, 0.25% CitA, and 0.5% CitA using dialysis membranes with a molecular weight cut-off of 12 kDa. CitA—citric acid; AA—ascorbic acid. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Syrup**} & **Additive** & **Surface Stickiness** & **Stringiness** \\  & & **(g)** & **(mm)** \\ \hline \multirow{2}{*}{**Yacon (Hualqui)**} & 0.1\% CitA & 7.57 \(\pm\) 0.25 & 9.54 \(\pm\) 0.30 \\  & 0.25\% CitA & 7.01 \(\pm\) 0.14 & 8.89 \(\pm\) 0.18 \\  & 0.5\% CitA & 9.06 \(\pm\) 0.39 & 10.36 \(\pm\) 0.26 \\ \hline \multirow{2}{*}{**Yacon (Crespo)**} & 0.1\% CitA & 69.21 \(\pm\) 5.72 & 43.18 \(\pm\) 3.42 \\  & 0.25\% CitA & 5.81 \(\pm\) 0.33 & 7.36 \(\pm\) 0.11 \\  & 0.5\% CitA & 4.70 \(\pm\) 0.08 & 6.91 \(\pm\) 0.07 \\ \hline \hline
**Yacon (commercial)** & & 8.59 \(\pm\) 0.27 & 10.06 \(\pm\) 0.26 \\ \hline
**Agave (commercial)** & & 7.44 \(\pm\) 0.08 & 9.14 \(\pm\) 0.08 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Surface stickiness (g) and stringiness (mm) of yacon syrups produced from Hualqui and Crespo-damaged roots and of commercially available yacon and agave syrups. CitA—citric acid. the 0.5% CitA syrupps (Figure 5) also suggests the occurrence of side reactions that might influence syrup properties. These reactions may include caramelization processes that yield, among other products, dirtucoselianhydrides known for their reported sweet taste and prebiotic properties [50]. Additionally, the occurrence of protein, accounting for 0.75 g/kg in the syrup, can contribute to Maillard reactions [51]. One of the most relevant products generated during syrup production is hydroxymethylfurfural, a compound known to influence flavor [38; 52], and likely affect perceived sweetness.