# Late Shelf Life Saturation of Golden Delicious Apple Parameters: TSS, Weight, and Colorimetry
## 1 Introduction  
Apple (_Malus \(\times\) domestica_ Borkh) belongs to the family of Rosaceae and sub-family Pomoideae and is one of the most widely produced and economically significant fruits worldwide. In 2020, the production of apples around the world reached 86,442,716 tons [1], and they are typically most appealing and health-promoting when gathered at their optimum ripeness. The apple is one of those fruits whose quality changes quickly over time while being stored, which causes variations in customer acceptance. First, it is assessed based on its appearance, including color and size, and then its total soluble solids content. Over the years, research on post-harvest storage of fruits and vegetables has focused on studying fruit's appearance, quality, and mechanical properties under different conditions such as temperature or shelf life to meet consumer expectations [2; 3; 4]. Fruits include numerous critical nutrients and phytochemicals that may help prevent and reduce the risk of, for example, chronic illnesses such as heart disease, obesity, diabetes, some forms of cancer, inflammation, stroke, and septic shock [5; 6]. It is popular among producers and consumers because of its excellent nutritional content and remarkable ecological resilience [7; 8; 9]. Fruits are a good source of water, soluble solids, sugars, organic acids, and dietary fiber [10; 11]. For instance, an apple is a \"healthy fast food\" that replenishes the body's stores of vitamins, minerals, and trace elements. Over 600 essential and intermediate chemicals beneficial to human nutrition and health are found in apple fruits. [12]. Several widespread methods are applied to evaluate fruit quality. Visual examination and destructive procedures are generally used to assess product quality. [13] In recent years, specific spectroscopic and imaging techniques have been effectively used in food quality inspection to deal with destructive methods' challenges [14]. These non-contact imaging techniques are made possible by technological advancements in cameras and robust computer hardware, software, and analysis tools. They are now a crucial instrument in applications for quality evaluation [15; 16]. Total soluble solids (TSS) are generally a crucial quality indicator linked to the texture and composition of apples and other fruits [17; 18]. Water loss causes the product's weight to drop, causing the quality of the fruit to deteriorate. On the exterior of the apple fruit, there is a natural wax coating that acts like a protective barrier or coating, preserving the fruit as it grows. Fruit weight loss is determined by the skin's structure and the waxes' composition on the fruit's surface [19]. The moisture loss decreases the visual quality and contributes to the loss of turgor pressure and subsequent softening; in industrial terms, moisture loss is also an economic [20; 21] Therefore, fruit weight measurement is critical in fruit quality evaluation too. Although fruit may be kept fresh for a long time in cold storage, fruit storage after harvesting is one of the significant difficulties in the world today. The availability of cold storage facilities is entirely restricted in contrast to fruit production, which raises the price of the produce. Additionally, customers can buy the fruits at their small local market, where they are often kept at room temperature. As a result, it is crucial to evaluate the apple's quality while it is being stored at room temperature. The non-destructive method to measure the color can help consumers to assess the quality of fruit during purchasing [22]. Consumers' first delightful experience with fruits is a healthy, fresh, and colorful appearance, influencing the remainder of the observed sensations. The color is the initial point of contact [23] between the product and the consumer, which is crucial in purchasing [24]. Using a sophisticated picture processing system and RGB and hyperspectral photography, researchers [24] carefully graded and tracked the color progression of the subjects.