# Influence of Apple Juice Type on Fermentation Process and Volatile Compounds of Hard Apple Cider
## 3 Results and Discussion
### Volatiles Analysis of Ciders
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Compound** & **RT** & **RI** \\ \hline
2-methylpropan-1-ol (isobutanol) & 2.9757 & 667 \\ \hline Isoamyl alcohol & 4.4987 & 760 \\ \hline
2,3-butanediol & 6.3514 & 819 \\ \hline Butyl acetate & 7.3854 & 836 \\ \hline
1-hexanol & 11.0754 & 891 \\ \hline Methionol & 18.5636 & 996 \\ \hline Ethyl hexanoate & 20.0131 & 1012 \\ \hline Hexanoic acid & 20.4055 & 1027 \\ \hline Limonene & 21.8124 & 1051 \\ \hline
2-ethylhexanol & 21.8124 & 1051 \\ \hline
1-octanol & 24.2737 & 1089 \\ \hline
2-nonanone & 25.3434 & 1105 \\ \hline Linalool & 25.7736 & 1111 \\ \hline Nonanal & 25.9811 & 1114 \\ \hline
2-phenylethanol & 26.4928 & 1120 \\ \hline
2-ethylhexanoic acid & 27.4337 & 1153 \\ \hline Methhone & 28.4470 & 1087 \\ \hline Menthol & 29.5033 & 1195 \\ \hline Ethyl octanoate & 30.9012 & 1222 \\ \hline Benzoic acid & 32.8055 & 1235 \\ \hline Nonanoic acid & 35.9320 & 1315 \\ \hline Eugenol & 38.0514 & 1378 \\ \hline Decanoic acid & 38.9863 & 1402 \\ \hline Ethyl decanoate & 39.2079 & 1407 \\ \hline Methyl eugenol & 39.4451 & 1376 \\ \hline Geranyl acetone & 40.5246 & 1473 \\ \hline \(\alpha\)-farnesene & 41.5781 & 1519 \\ \hline
2,4-Di-T-butylphenol & 41.7080 & 1535 \\ \hline Lauric acid & 42.5289 & 1586 \\ \hline Ethyl laurate & 42.9556 & 1611 \\ \hline Myrstic acid & 45.1320 & 1783 \\ \hline Palmitic acid & 47.2842 & 1981 \\ \hline Stearic acid & 49.2052 & 2184 \\ \hline \hline \end{tabular} RT—retention time; RI—retention index.  
\end{table} 
Table 3: List of volatile compounds identified in the cider produced. used four yeast strains which have been traditionally utilized in beer fermentation to test the theory whether yeast strain affects the quality of the final product. They produced four commercial-grade ciders and inoculated them with different yeast strains commonly used for brewing. This resulted in four significantly different sensory qualities from identical starting apple juices, which proved that the yeast strain choice is immensely important in cider making. The intention of this research was to observe if juice quality can affect cider quality when using the same cider yeast for fermentation. The data obtained in this investigation show that there are significant differences between the samples. Namely, the results of the analyzed aromatic compounds in produced ciders, displayed in Table 4, show that there are significant differences between aromatic compounds which develop during maturation. The noted changes involved fluctuations of compound concentrations during the maturation period of three weeks. The most pronounced chemical among the acids was benzoic acid, especially in Sample 1, where it reached 10,134.85 \(\upmu\)g/L after a three-week maturation period. Sample 2 contained 9970.32 \(\upmu\)g/L after a three-week maturation period, and no significant statistical difference was noted among samples for this compound. Benzoic acid, found in both samples, is probably the result of added sodium benzoate, which was used to halt further fermentation after the addition of apple syrup. However, in both samples, this compound gradually increases its value with maturation time. Another significant acid found in all of the samples is decanoic acid, which had the tendency to fluctuate over time in both samples. After fermentation, in Sample 1, its concentration was 172.96 \(\upmu\)g/L; after the two-week maturation period, it amounted to 272.39 \(\upmu\)g/L, and then it decreased after the third week of maturation to 220.12 \(\upmu\)g/L. Similarly, this occurred in Sample 2, where the starting concentration totaled 238.01 \(\upmu\)g/L and then decreased to 164.72 \(\upmu\)g/L after week 1, and 164.48 \(\upmu\)g/L after week 2. It seems to be stable for two weeks and then shows an increase after the third week and amounts to 187.75 \(\upmu\)g/L. Decanoic acid is commonly found in ciders with similar concentrations. Research conducted by [PERSON] et al.