## 3 Results and Discussion
### Omission Test  
Omission experiments were performed to investigate the importance of odorants with OAV \(\geq\) 1 on the aroma profiles of distilled peach spirit and pervaporation produced peach spirit. Seventeen omission models and 25 omission models were prepared based on omission of a compound or a class of compounds to compare to the reconstituted models of distilled peach spirit and pervaporation produced peach spirit, respectively (Table 3). For distilled peach spirit, the absence of all esters was just identified by 9 from 16 panelists (\(p<0.05\)). The absence of esters one by one in the omission models was also assessed. The results showed that lack of ethyl hexanoate (1-8) had the most significant effect on the aroma profile (\(p<0.001\)), and removing 3-methylbutyl acetate (1-1, \(p<0.01\)) or ethyl octanoate (1-5, \(p<0.05\)) also had an obvious effect on the overall aroma. However, there was no significant difference when omitted ethyl acetate (1-2, \(p>0.05\)) and ethyl butyrate (1-7, \(p>0.05\)). Combined with the OAVs, ethyl hexanoate, 3-methylbutyl acetate and ethyl octanoate were critical aroma compounds for distilled peach spirit. And it was speculated that aroma interactions, including masking and inhibition, exist among esters. As for alcohols, when 3-methyl-1-butanol (3-1, \(p<0.01\)) and 1-hexanol (3-2, \(p<0.01\)) were omitted individually, there was significant difference from the complete reconstitution. In addition, it was more easily to identify the omission solution when both of 3-methyl-1-butanol and 1-hexanol were removed (3, \(p<0.001\)). Although the FD factors and OAVs of (E)-\(\beta\)-damascenone and citronellol were markedly high, the mixture models without (E)-\(\beta\)-damascenone (4-1, \(p<0.05\)) or citronellol (4-2, \(p<0.05\)) was just slightly significantly different in 'floral' aroma from the complete recombinant. The same phenomenon was also reported in wine and whisky [55; 56; 57]. Compared to the aroma properties of complete reconstitution, omissions of 1,1-diethylacyethane (2, \(p<0.001\)), \(\gamma\)-butyrolactone (7, \(p<0.05\)) or phenethyl acetate (9, \(p<0.05\)) was evaluated as a significant difference, while mixture models without 3-methylbutanoic acid (5-1, \(p>0.05\)) or furfural (6, \(p>0.05\)) had no effect on the aroma. For pervaporation produced peach spirit, several aroma compounds influenced the aroma profile significantly according to the results of omission tests. The omission models without all esters were significantly different from the complete recombination of pervaporation produced peach spirit. Lack of 3-methylbutyl acetate (1-1, \(p<0.001\)), ethyl isobutyrate (1-3, \(p<0.001\)), ethyl isovalerate (1-4, \(p<0.001\)), ethyl octanoate (1-5, \(p<0.001\)), or ethyl hexanoate (1-8, \(p<0.001\)) presented highly significantly lower fruits aroma. While the mixture models absence of ethyl acetate (1-2, \(p>0.05\)), ethyl butyrate (1-7, \(p>0.05\)) or ethyl decanoate (1-6, \(p<0.05\)) could not be recognized easily by panelists in the triangle tests. Compared to distilled peach spirit, the above results indicated esters played a more prominent role in the aroma profile of pervaporation produced peach spirit, contributing to stronger fruity property. It was also easy to be identified by panelists when all alcohols (3, \(p<0.001\)), 3-methyl-1-butanol (3-1, \(p<0.01\)), 1-hexanol (3-2, \(p<0.001\)) or isobutanol  
Figure 3: Radar diagram of aroma profiles of original spirit and its reconstitution solution. (**a**) Aroma profiles of DS and its reconstitution. (**b**) Aroma profiles of PS and its reconstitution. (3-3, \(p<0.01\)) was removed from the complete reconstitution. Although the OAVs of terpenoids and acids were not high enough, it was proved that they were critical to the aroma profile of pervaporation produced peach spirit.