Magnetic Resonance Imaging Experimental Study Of Peanut Milk Beverage

Peanut milk contains abundant fat and protein. Due to quality differences of rawmaterials and beverage itself is thermodynamically unstable colloidal system, peanutmilk is prone to quality change. Therefore, the national standard of peanut milk requiresfat content to be≥1.0%, protein content to be≥0.8%. Because NMR technology canquickly and accurately analyze and identify various components of the sample, and benot destructive to the sample,NMR are used more and more widely in the field of foodscience. In this paper, we use1H-NMR detection method to detect the contents andproperties of peanut milk′s major components and predict the shelf life of the products.In the NMR experiments of detecting peanut milk quality, transverse relaxationtime for MXY（T₂） and longitudinal relaxation time for MZ（T₁） were detected to peanutmilk of different concentrations and storage times. CPMG pulse sequence was used todetect T₂and the main parameters were as follows: TR=5000ms，D3=60us，TD=672168，SW=100KHz，τ=480us，EchoCnt=7000，NS=8. IR pulse sequence wasused to detect T₁and the main parameters were as follows: TR=8000ms，D3=60us，TD=336084，SW=100KHz，D1=10us，T₁IRCount=50，AddD1=160000us，NS=8.By using CPMG and IR pulse sequences to detect and inverse the peanut milksamples of different concentrations,the integration area map and data points of T₂and T₁can be accessible. T₂relaxation time was found that there are three sets of data whichare noted T₂1、T₂₂、T₂3. T₂1reflected the impact of solid material; T₂₂reflected thechanges of fat; T₂3reflected the changes of water. T₁relaxation time was found thatthere are two sets of data which are noted T₁1and T₁2. T₁1reflected the the case ofproton in layer of water molecules which combine closely with polar groups in proteinsurface; T₁2reflected the the case of proton in relatively free water environment of thesample; Therefore, according to the T₁1can indirectly reflect the changes of protein.With the continuous decrease of the peanut milk concentration, the peak integral arearatio of T₂₂and T₁1decreased linearly, the peak integral area ratio of T₂3increasedlinearly. Sample′s corresponding fat, protein content and water content can de obtainedby the fitting formula. According to theses datas can quickly and accurately determinewhether the quality of the sample in line with national standards.The shelf life of peanut milk products were predicted by combination of NMR andASLT methods. CPMG pulse sequences were used to detect the different preservationtimes peanut milk samples. Through the analysis of T₂relaxation data, it can be found that with the continuous extension of preservation time,the properties of peanut milkprotein changed and precipitated, peanut milk fat decomposed and were rancidity, andanalysis of water stratification occurred. Obtained by NMR detection, the shelf life of acertain brand of peanut milk was about12months.