# Construction of Color Prediction Model for Damaged Korla Pears during Storage Period
## 1 Introduction  
The Korla fragrant pears belongs to the white pear system, which is a characteristic fruit and main cultivar in Xinjiang, China, and has a planting history of over 1400 years. The fruit has promising markets in China and overseas due to its dark green color, crisp and sweet taste, rich juice, thick fragrance, and high nutrient values [1; 2]. However, Korla fragrant pears can be easily affected by mechanical damages at harvest, transport, classification, and packaging due to the thin pericarp and crisp pulp. During the storage period, fragrant pears begin to rot since the damaged area can quickly expand. Alarmingly, the rotting rate can reach over 15%. To ensure quality, practitioners abandon the damaged fragrant pears directly in storage or before marketing, resulting hence in an annual economic loss of more than CNY 60 million [3]. Moreover, it has been demonstrated in the literature that the tissues of damaged fruits can increase metabolism levels, thus resulting in the quick consumption of nutrients at damaged areas and realizing self-repair functions [4; 5]. The fragrant pears with repaired damages still have the possibility to recover their commodity value, and they can be processed into commodities such as pear syrup, pear juice, and pear wine. However, abandoning the damaged fragrant pears directly is not in line with the desired improvement in the market competitiveness of the fragrant pear industry and the added value of the products. Therefore, the storage quality of fragrant pears can be accurately recognized by disclosing and predicting the variation laws of quality of the damaged Korla fragrant pears during the storage period. Along these lines, if the damaged Korla fragrant pears are adequately processed before they lose their commodity values, theeconomic benefits of the industry can be significantly increased, and practical references for the storage and scientific management of fragrant pears can be provided. Fruit color is considered one of the primary appearance factors that determine the purchase decision of consumers and is also an important reference for fruit classification [6; 7; 8; 9]. Color is even a core index to evaluate the appearance quality of Korla fragrant pears, and it has an important influence on the commodity value of fresh fruits and processing products. Many works in the literature have evaluated the quality of fruits based on colors. Good and uniform pericarp color means that the fruit is more fresh and mature and has the highest commodity value. The CIELab system is the most complete color model, which was proposed by Commission Internationale de l'Eclairage (CIE) to accurately describe all visible colors [10; 11]. It has been extensively applied to the evaluation of fruit colors. The changes in fruit colors have been also examined during the storage period. Particularly, [PERSON] et al. [12] studied the changes in L*, a*, and b* of blueberry fruits before harvest and 4 weeks after the harvest. The authors found that the color changes in the blueberry surfaces after the harvest had a strong positive correlation with the anthocyanin concentration. [PERSON] et al. [13] collected tomato images by using the RGB (Red, Green, Blue) image acquisition system, which then were transformed into CIELab color spaces for performing the color evaluation. The authors reported that the L* value of tomatoes decreased more quickly under a longer transportation distance, higher storage temperature, and extended storage time. [PERSON] et al. [14] explored the influencing laws of storage temperature on colors of the avocado and found that with the increase in the storage time and storage temperature, the chlorophyll degradation accelerated, the pigment synthesis volume increased, and both L* and b* values decreased, while the a* value increased. In other words, the brightness of the avocado was negatively affected, accompanied by fading yellow and deepening red.