# Aromatic Profile of Hydroponically and Conventionally Grown Tomatoes
## 3 Results and Discussion  
### Electronic Nose  
The distribution of the samples based on the total odor profile is shown in Figure 1. This distribution was based on the volatile organic compounds released during the analysis process. We selected 12 major odorants based on discriminant strength relative to all observed samples. From this figure, we can see that samples V740 (SR), V102 (NL) and V269 (SR) have a volatile profile as they form a large triangle during the measurement time. We consider samples V297 (BE) and V512 (CZ) to be stable and least variable in the change of the odor profile. The other samples have an approximately constant odor spectrum, which means that they are almost equally extractive. The position of samples V102 (NL) and V269 (SR) suggests to us that these samples are similar. These two samples are also characterized by high odor content. Interestingly, these samples represent hydroponically (V269) and conventionally (V102) grown samples. The Slovak sample of hydroponically grown tomatoes (V801) also shows similarities with these two samples. Figure 1: Total odor profile of samples with corresponding odors. Samples (V826, V931, V188) that are in the same quadrant are similar. These samples represent tomatoes that have been stripped of their top leaves in the processing and packaging process. This figure also shows the odors captured by the e-nose during the analysis of the samples. Specific odorous substances produced by volatile organic compounds are represented by lines in the figure and their direction indicates the products that contain the most of them. At the ends of the lines are numbers used to identify the compounds that were present in the samples. We can confirm that samples V102 (NL), V269 (SR) and V740 (SR) are more extractive even though they contain fewer types of odorous compounds compared to the others. Odor compounds 26.07-1-A and 15.31.1-A (listed in Table 1) are typical of most hydroponically grown samples with strong discrimination power. In the following procedure, we discussed the most basic identifiers that occurred in significant amounts in tomato samples grown hydroponically. From the total odor profile that was detected and generated from the electronic nose database, we selected the first five basic odor markers that occurred in the greatest amount in the samples through the program. Based on this, the localization and odor spectrum of the samples were changed. This is illustrated in Figure 2. Since 98% of the 100% results obtained were evaluated, we assess that the results obtained are reliable as well as quantitatively and qualitatively adequate. E-nose was able to identify differences between the evaluated samples and classify them into two groups: hydroponically and conventionally grown tomatoes. The device assessed the hydroponic tomatoes as demonstrably similar and placed them side by side on the graph. For better clarity, we marked all these samples in the form of a triangle. Bottom left quadrant represents the samples that the device assessed as conventionally grown. This includes sample V102 (NL), but also samples V801 (SR) and V269 (SR), which are incorrectly classified in this category as they are hydroponically grown tomatoes. The erroneous categorization of these two samples can be explained by the fact that these samples represent stemless tomatoes. The device also included sample V826, which represents conventionally grown tomatoes, in the triangle representing hydroponically grown tomatoes. This sample appears to contain a similar odor spectrum to hydroponically grown tomatoes. After discounting this one sample, our study indicates that e-nose has potential to be a suitable instrumental sensory analysis tool that can be used to detect hydroponically and conventionally grown crops. Similar study indicates that there is potential for the use of the e-nose to complement routine sensory analysis of tomatoes [24].