Nondestructive Detection Of Fruit Quality Based On Low-field Magnetic Resonance Technology

Sugar in the fruit is the basic materials to composite synthetic vitamins,carotenoids and other nutritional ingredient, which will influence sweetness and colorof the fruit. Measuring the sugar content of fruit correctly can guild people to choosethe best fruit for themselves; Mechanical damage of fruit is one of the standards toevaluate fruit’s internal quality, and also the important studying object ofnondestructive detecting technology, detecting the mechanical damage fruit timelycan reduce the economic loss in the process of storage and selling.In this paper, the detective theory of the low-field magnetic resonance wasintroduced, and three detecting technology of the low-field magnetic resonance whichbased on signal amplitude、relaxation time and image were introduced in detail;Low-field magnetic resonance technology was used to detect fruit’s sugar content andmechanical damage: Cherry tomato and apple were taken to the research objects,firstly, discussed the influence of sugar content to magnetic resonance signal andrelaxation time by proceeding from the magnetic resonance characteristic of cherrytomatoes; With ATAGO, the linear relation of cherry tomatoes’ sugar content and perunit mass signal was found, and this correlation coefficient was0.875; Secondly, therelaxation behavior of apple’s normal and mechanical damage parts were compared,select the T2weighted imaging to detect mechanical damage according to the changesof apple’s relaxation time. After parameter optimization, repetition time was set1500ms and echo time was set200ms, then apple’s T2weighted imaging was get andalso disposed with pseudo color, finally, the mechanical damaged apple was detectedaccurately. The innovative work of this thesis includes following parts:1. Low-field magnetic resonance technology includes two main applications:component analysis and imaging. in this paper, low-field NMR was developedsecondly and then realized the comprehensive detection of sugar content andmechanical damage.2. Detection of fruit sugar content based on low-field magnetic resonancetechnology---the magnetic resonance characteristic of sucrose, glucose and fructosewas analyzed, and studied the sugar content of cherry tomatoes through discuss the relationship between the sugar content of sugar solution and per unit mass NMRsignal and T2relaxation time.3. Nondestructive detection of fruit’s mechanical damaged based on low-fieldmagnetic resonance imaging---the T2weighted images of apple was collected andused the pseudo color to process these T2weighted images.