# Quality Monitoring and Analysis of Xinjiang 'Korla'
## 1 Introduction  
'Korla' fragrant pear (_Pyrus sinkiangensis_ [PERSON]), certified as China Geographic Indication Product, is appreciated worldwide by consumers for its high fructose content, rich fragrance, and tender texture [1; 2; 3; 4]. However, the long-distance transport loss rate is high due to the large span of regions where it is sold. Furthermore, fruit supply chain involves a complex distribution system, with losses of quality at the end of the chain that negatively affect profitability [5; 6; 7]. In Xinjiang, the quality of 'Korla' fragrant pear loses continuously from harvest to consumption in the supply chain. In the long-distance transportation from where Korla is located (in the border province to Eastern China), the quality deterioration and the quantity loss of pears will be considerable. Home storage is the lastbut a neglected important stage in 'Korla' fragrant pear supply chain. Room temperature storage and refrigeration storage are believed to be two of the most commonly used methods to preserve fruit quality at home [8], nevertheless improper storage of fruit may cause food safety issues. Cold chain logistics is an effective method to ensure that fruits are stored in a low-temperature environment for the whole course of transportations by using refrigeration technology and to reduce the quality loss and safety hazards of fruit [9]. Home storage is the weakest stage in the whole cold chain where inadequate temperature control and handling easily occur [10]. Though cold chain monitoring has become important and necessary, little research has been carried out on whole cold chain management, which covers from orchard to home storage. Therefore, it is crucial to conduct accurate and continuous monitoring in the 'Korla' fragrant pear cold chain, and to maintain the 'Korla' fragrant pear quality in the reliable environment throughout the cold logistics. Environmental parameters, such as temperature, relative humidity, affect the quality and safety of 'Korla' fragrant pear cold chains, and many gas microenvironments, oxygen (O\({}_{2}\)), carbon dioxide (CO\({}_{2}\)) and ethylene (C\({}_{2}\)H\({}_{4}\)), are considered to be the most important monitoring parameters [11]. The temperature and relative humidity are the key factors that directly affect the respiration intensity of the 'Korla' fragrant pear and the growth of microorganisms. In postharvest phase, C\({}_{2}\)H\({}_{4}\) concentration produced by pears varies with time [12] and exhibits a remarkable increase [13; 14; 15; 16]. Reduced O\({}_{2}\) and increased CO\({}_{2}\) slow down the rate of physiological activity and inhibit the action of ethylene such that the decay processes of quality are delayed [17]. Therefore, it is important to monitor critical microenvironment parameters in the cold chain, which affect the quality of 'Korla' fragrant pear. One of the best solutions to enable accurate and continuous monitoring is the implementation of multi-sensor technology (MST) to collect data in the cold chain logistics [18; 19]. In traditional methods, temperature and humidity recorders are the most easy-to-implement and reliable way to monitor the temperature and relative humidity [20; 21]. However, such method has high costs and devices are of a relatively large size. As for gas sensing technologies, metal oxide semiconductor gas sensors and polymer gas sensors have disadvantages of long-term instability and poor selectivity. Optical and gas chromatography methods are difficult to miniaturize for portable applications [22]. Electrochemical gas sensors have overall acceptable performance of cost and response and recover properties [23]. The MST, integrate micro-sensor technology, embedded computing, and high precision analog-to-digital conversion, can effectively sense, acquire, and record information about monitored objects in their environments [24; 25]. In brief, the MST was developed to integrate temperature, relative humidity sensor, and gas sensors and to carry out effective and continuous monitoring of 'Korla' fragrant pear cold chain.