Water Research In The Process Of Granulation Of Guanxi Pomelo Using High Field Nuclear Magnetic Resonance

Guanxi pomelo belongs to the subtropical evergreen tree,and is an excellent grapefruit variety in Fujian Province.Its fruit is thin,delicious,and is easy to store and transport.However,guanxi pomelo fruit is affected by granulation of juice during ripening and storage,which leads to a decrease in juice yield and a weakening of flavor.Moisture plays a crucial role in the formation of good quality of the fruit,and is even associated with many undesirable traits such as juice sacs granulation.MRI has the advantages of short measurement time and high accuracy without destroying the object.It can detect the moisture distribution and state of the fruit according to the multi-exponential relaxation characteristics of the different environments in which the protons in the fruit.Image imaging provides the conditions for understanding the water and quality of the fruit.In this paper,the fruit of ' guanxi pomelo ' was photographed by 1.5T superconducting high-field NMR spectrometer.RadiAnt DICOM Viewer(64-bit)and Photoshop CS6 software were used to introduce the RGB brightness system to image and stain the fruit.It is expected to establish an accurate evaluation system for juice sacs granulation.The results are as follows:1.Optical analysis of Dicom data generated by high-field NMR was carried out by matlab,and the RGB brightness system was introduced to accurately determine the water distribution of the juice sacs of the guanxi pomelo.The water loss status of fruit different granulation was analyzed from area value of water loss degree,water loss ratio and water loss value.2.The sagittal plane was established as the standard surface for evaluating the degree of juice sacs granulation by comparing fruit water loss with granulation of sagittal and transverse.The granulation evaluation system of pomelo was established: the ratio of fruit water loss,granulation rate and free water/combined water ratio could be used to evaluate the degree of juice sacs granulation,and the fruit water loss and granulation index could be used to evaluate the range of juice sacs granulation.At the same time,it was discovered that,from the near pedicle to the top of the fruit,the granulation of juice sacs was increasing and the most heavily granulated site was juice sacs at the distal pedicle of the fruit.3.Through the juice sac granulation evaluation system,fruits with relatively uniform granulation degree were selected and stored after 1% calcium peroxide,0.3% calcium hydroxide and 1% calcium peroxide,1% calcium nitrate and 50ug/ml polygalacturonic acid treatment.During the storage of pomelo,the correlation analysis between fruit water loss with fruit juice sac granulation degree and quality was carried out by NMR images and calculation,and the evaluation system was verified.Meanwhile,it was found that 0.3% calcium hydroxide and 1% calcium peroxide could reduce the degree of fruit juice sac granulation,and 50ug/ml polygalacturonic acid treatment accelerated the fruit juice granulation.The establishment of juice sac granulation evaluation system will provide scientific theoretical basis for fruit quality identification and classification of pomelo.