# Effect of Organic and Conventional Production on the Quality of Lemon \"Fino 49\"
## 1 Introduction  
Since 1970, organic foods have gained interest on a global scale [1]. Today, many farmers implement organic practices to attract consumers and increase their income. In turn, these agronomic practices promote crop rotation, biodiversity, etc., and they ban synthetic pesticides and fertilizers [1]. However, despite the fact that organic systems produce smaller volumes of food [2, 3], some authors have shown that organic foods are more nutritious than conventional ones, presenting higher contents of vitamin C or total antioxidants, among other things [2, 4, 5, 6, 7, 8, 9]. In general, organic farming is considered to be more respectful of the environment than conventional farming, since it reduces the use of mineral fertilizers and pesticides, although the use of some non-synthetic pesticides, such as sulfur, copper sulphate, potassium permanganate, etc., are allowed [10]. Currently, they have increased the number of organic farms and therefore the extent of farmland. In the EU, the total area devoted to organic farming continues to increase, covering almost 13.8 million hectares of agricultural land in 2019 [11]. Likewise, the funds allocated to organic farming have also been increased [12].  
Worldwide, the lemon (_Citrus limon_ Burm.) is the third most cultivated citrus species, after orange and mandarin [13]. Since the end of the 20 th century, the consumption of citrus fruits began to increase among the world population [14], reaching a production of more than 20 million tons in 2019 [15]. Spain is the second lemon producer country [16],and the two most cultivated varieties in this country are \"Fino\" and \"Verna\", occupying almost the entire growing area destined for lemon. Lemons of the \"Fino\" variety are of high quality and are also used for international exports from October to February when prices are highest. \"Verna\" variety is harvested once the \"Fino\" harvest has finished and allows exports to be maintained during almost the entire period of the year [17].  
Consumers are not only looking for a visually attractive fruit (size, color, firmness, etc.), but are also looking for internal quality (flavor, volatile compounds, functional compounds, etc.) [14; 18]. Although citrus flavor and aroma are important factors in quality, consumers buy a lemon product based mainly on their perception of product quality and value for money [19].  
In general, lemon is a fruit with an important content of bioactive compounds (vitamins, phenolic compounds, fiber, organic acids, mineral salts, etc.) responsible for beneficial health effects [20; 21; 22]. Several authors have reported its healthy properties on various types of cancer, cardiovascular diseases, obesity, cholesterol, etc. [20; 23; 24].  
The flavor of a lemon depends on the concentration of organic acids and sugars and the relationship between them. Both are the main compounds in citric fruits. [25; 26]. However, the main quality characteristic of citrus fruits is aroma [27]. Most of the volatile compounds of lemon are found in the skin of the fruit presenting 85-90% of the entire essential oil fraction of the lemon [28; 29; 30]. Citrus essential oils are used in the food industry as flavorings in beverages and alcoholic beverages, jams, jellies, sweets, ice cream and dairy products [31; 32; 33]. It is possible to determine direct relationships between the odor or flavor of a sample and the responsible volatile compounds in two ways: (i) comparative sensory analysis, using GC-MS to detect volatiles and find associations or (ii) using GC olfactometry ports -MS to detect and identify the responsible compounds [34].  
On the other hand, the flavor, aroma, and functional quality of lemon depends on the agronomic practices, as use of rootstock, ripening, irrigation, etc., [18; 19; 25; 35; 36; 37].  
Therefore, the objective of this study was to determine if the type of cultivation (organic or conventional) affects the chemical, physical and volatile composition of \"Fino 49\" lemon.