# Predicting Fruit's Sweetness Using Artificial Intelligence--Case Study: Orange
## 1 Introduction  
Oranges are one of the most popular and most commonly cultivated fruits in the world and they predominate in citrus production [1]. According to 2020 statistical data, orange production amounted to 76.29 million tonnes. Brazil is the world's leader in orange production (17.07 million tonnes). Spain is the leader in Europe (3.23 million tonnes), for which orange production contributes 4% of the worldwide production. Egypt ranks sixth among the largest producers of oranges worldwide and it is the largest exporter of oranges in the world [2]. According to the data of the Central Agency for Public Mobilization and Statistics, the Egyptian orange is one of the most important exported fruits in Egypt's trade, with its exports amounting to about EGP 493.28 million, which represents 11.3% of the value of all Egyptian agricultural exports. There are specific conditions for the growth of oranges, they grow in a wide variety of soils but deep-rooted clay soils are most ideal for growing oranges and a soil pH of 6.5 to 7.5 is also preferred. Orange fruit harvesting in Egypt usually begins during the months of December and January [3]. Due to the increased preference for a high level of immunity in the body, society is increasingly looking for natural vitamins and minerals. According to research, oranges are characterized by a high content of ascorbic acid (vitamin C), phytochemicals, carotenoids, flavonoids [4], and a little dietary fiber [5]. Consuming oranges or orange juice is recommended due to the varied amounts of bioactive compounds that they contain that contribute to the prevention of cardiovascular diseases and cancer [6; 7]. Regular consumption has been shown to have a health-protective effect, for example against stomach cancer [8], and utility in slowing aging [9]. Appearance is the first factor that consumers focus on when they are deciding whether to accept or reject a product and, among this, color is the main appearance characteristic that is assessed. The color of a food product has, historically, provided information about other food qualities or even the safety of a certain food [10; 11; 12]. Flavor and color are important factors in evaluating fruits. More precisely, the appearance of fruits may cause a change in the perception of their flavor. If the appearance of the fruit is acceptable, then the flavor is the main sensory characteristic that is used to judge the quality of that fruit. Thus, the role of color and flavor in the assessment of the quality of fruits and the controlling factors in maintaining these characteristics must be taken into account [13]. The flavor quality of fruits and vegetables is affected by their genetics as well as pre-harvest, harvest and post-harvest factors. The longer the period between harvest and consumption, the greater the loss of the characteristic flavor (taste and aroma). The post-harvest period that begins to influence the flavor and nutritional quality of a fruit is shorter than that which begins to influence the fruit's appearance and synthetic quality. Thus, it is necessary to ensure good flavor quality in the future by selecting the best production genotypes, using an integrated crop management system, harvesting at the ripening or ripeness stage that will improve the quality of eating at the time of consumption and using post-harvest procedures that will maintain the optimum flavor and the nutritional quality of fruits and vegetables between their harvest and consumption [14]. After transporting the fruits to warehouses for packaging, different operations need to be performed, such as sorting, grading, washing, packing and storage. The classification of fruits according to their characteristics, including their color, increases their marketing value [15]. There is a connection between the color and flavor, as green fruits are less sweet as compared to more richly colored fruits [10]. Support for this notion was obtained by [PERSON] in 1974 [10], who discovered a decrease in the perceived sweetness of sucrose solutions when they were stained green.