# Aromatic Profile of Hydroponically and Conventionally Grown Tomatoes
## 1 Introduction
Hydroonics is becoming an increasingly popular way of growing crops, as it has several advantages compared to the traditional way of growing tomatoes [15]. In agriculture, hydroponic cultivation is a common cultivation method in greenhouses, or more precisely in hydroponic environments, where plants are grown in an inert substrate (such as perlite or rockwood) using crop fertilization (irrigation with a nutrient solution) [16]. In a hydroponic system and in soil cultivation, before the elements are bioavailable to the plant, the inorganic and organic parts must be dissolved and decomposed in water. In soil-grown plants, the elements stick to the soil particles and pass into the soil solution where they can be absorbed by the roots of the plant. In hydroponically grown plants, the nutrient solution containing the elements comes into contact with the plant roots, where the roots can then take up the minerals and water [15]. According to some data, tomatoes represent the largest share of hydroponically grown crops, as this method of cultivation can produce red and juicy tomato fruits with a variety of flavors, colors and can contain health-promoting ingredients such as lycopene, which helps maintain a healthy cardiovascular system and provides a wide range of other health benefits. [PERSON] et al. [17] stated that hydroponically grown tomatoes had higher lycopene and \(\upbeta\)-carotene content compared to conventionally grown tomatoes. It is from these substances that the volatile compounds that contribute to the typical tomato aroma are produced metabolically. These authors report that they have been able to produce cropsof similar or better quality in the hydroponic way compared to food grown in soil, using significantly less water. It is clear that hydroponic tomatoes can taste as good as tomatoes grown in rich soil outdoors, or even better [18; 19]. Tomatoes grown in this way should have a more pronounced aroma and flavor, and the fact that they are harvested at the ripe stage should be reflected in the fresh red color and adequate sensory characteristics of the fruit. Although the hydroponic system has many advantages, it does not automatically guarantee a high-quality product. As the technology advances, it is important to consider the sensory characteristics of the hydroponic product [20]. The aroma of tomato has been the subject of research, and the two main techniques have been the most commonly used for aroma assessment--sensory analysis and conventional gas chromatography-mass spectrometry (GC-MS). These methods are generally time consuming and difficult. A good application of these methods is important to obtain adequate results. In recent years, electronic nose systems (e-nose) have been designed to address the need for routine quality testing in the food industry. Electronic nose devices are designed to simulate the human olfactory system and are devices that can detect and recognize odors and flavors using an array of sensors. The use of the e-nose consists in the analysis of volatile organic compounds and single emerging odors that are released as gases or vapors from solids or liquids. Since the day the first prototype was developed, the e-nose has become a useful device in several applications in solving urgent problem situations, finding relevance in various industrial fields such as healthcare, automotive, food industry, environmental monitoring, food storage, and even military industry. Especially in the food industry and medicine, traditional methods of object recognition are too slow, expensive, and mostly subjective, which can result in fatal mistakes. Instead, e-nose technology offers a fast, sensitive, low-cost, and objective alternative. Moreover, the potential of this new sensing method continues to grow rapidly with new developments in sensor and computer learning technologies [21; 22; 23]. There are many different types of tomatoes to choose from on the shelves of supermarket chains.