# Olfactory Impact of Terpene Alcohol on Terpenes Aroma Expression in Chrysanthemum Essential Oils
## 3 Results and Discussion
### Organoleptic Effect of Terpene Alcohols on Quantitative Perception
#### 3.2.3 Sensory Effect of Terpene Alcohols on Aroma Expression  
The aromatic strength of the mixture was not simply the totality of its component strength [36; 37; 38]. Perception depends not only on the concentration of the stimulus, but also on factors such as memory, mood, expectation, age, or cross-pattern interactions [39]. The researchers divided the interactions between aromatic components into four categories [40]. In order to proof if there were quantitative contributions of terpene alcohols was due to synergism, simple addition phenomenon, or a hyper-addition effect, we have evaluated the effect by comparing the measured threshold with theoretical threshold calculated on the basis of [PERSON]'s additive model. Meanwhile, detection probability for isoborneol at high, medium, and low level in _Chrysanthemum_ essential oils individually have been tested by [PERSON]'s additive model.  
The TR detecting probabilities in the presence of isoborneol with different concentrations (Figure 3) are higher than values tested by the [PERSON]'s model. In the high concentration, the olfactory threshold measured by [PERSON]'s additive model is 13.24 mg/L, the experimental olfactory threshold is 1.68 mg/L, the threshold is reduced by 7.88 times (\(p<0.001\)), similarly, the threshold is reduced by 6.14 (\(p<0.001\)) and 1.49 times (\(p<0.001\)) at medium and low concentrations, revealing an addition effect when different concentrations of isoborneol were added to the TR. Depending on isoborneol addition tested, the addition of isoborneol had significant effects on the olfactory threshold of the mixture. This was consistent with the triangular test results.  
Figure 3: _Cont._  
According to the terpene alcohols tested in Table 5, the addition of BL, EL, or BEL led to a 9.53 (from 30.69 to 3.22 mg/L, \(p\) < 0.001)-, 1.42 (from 30.69 to 21.63 mg/L, \(p\) < 0.05)-, and 17.05 (from 30.69 to 1.80 mg/L, \(p\) < 0.001)-fold decrease, respectively, in the olfactory threshold of the TR, indicating a additive effect for each of these compounds in TR. And the addition of BE led to a 2.26 (from 30.69 to 69.34 mg/L, \(p\) < 0.001)-fold increase in the olfactory threshold of the TR, revealing a subtraction effect after the addition of BE to TR.  
Adding different concentrations of isoborneol led to a 9.70-fold at high level (_p_ < 0.001), 18.27-fold at medium level (_p_ < 0.001), and 6.73-fold at low level (_p_ < 0.001) decrease (from 30.69 to 3.22 mg/L at high level, 1.68 mg/L at medium level and 4.56 mg/L at low level), respectively, and the result was showed at Figure 4. These results indicate that the addition of isoborneol leads to a decrease of TR olfactory threshold. Similarly, [PERSON] [41] found that ethyl phenol at concentrations of 365 and 375 mg/L increased animal aromas to varying degrees. In the wood wine model, subjects were able to detect aroma differences, even if the amount of higher alcohol added was trace, such as 17 mg/L and 22 mg/L. The perceptual interaction when Higher Alcohols were added to the Fruit Recombination was due to the complexity of the mixture, and devotion of a certain component to the overall aroma of aroma recombination is concerned with its concentration [42]. The presence of each compound resulted in a change in the olfactory threshold of the TR, reflecting an individual quantitative contribution of these compounds to overall aroma intensity.  
Figure 3: Comparison of detection probabilities of aromatic recombinations by experiments and by feller’s model. OT\({}_{\text{Feller}}\), olfactory threshold measured by [PERSON]’s additive model; OT\({}_{\text{Exp}}\), experimental olfactory threshold. (**a–c**) Adding isoborneol at high, medium, and low level respectively.  
Figure 4: Aromatic effect of alcohols at different concentrations added to terpenes recombination. I, isoborneol. (**a**–**c**) Adding isoborneol at high, medium, and low level respectively.