葵花籽油贮藏过程理化性质与LF-NMR弛豫特性的相关性

Relationship between Analytical Indicators of Sunflower Oil and the LF-NMR Relaxation Characteristics During Storage Process

该文主要对葵花籽油分别在25、65℃避光贮藏过程的理化性质及其低场核磁共振(LF-NMR)弛豫特性的变化规律进行了研究,建立并验证了理化指标与LF-NMR检测结果的相关性模型。结果表明:65℃贮藏时,油样的过氧化值(PV)、共轭二烯值(K232)、共轭三烯值(K270)、p-茴香胺值(p-AV)、总极性化合物(TPC)含量及峰面积比例(S21、S22)随时间延长呈指数关系增加(r2>0.93),而S23峰及单组分弛豫时间(T2W)则随时间延长呈指数减小趋势(r2>0.98),通过多元回归分析可建立理化指标与弛豫特性间的相关性模型(r2>0.94)。25℃贮藏过程中理化性质及其LF-NMR弛豫特性的变化程度均相对较小,但PV、K232及TPC含量仍与贮藏时间呈良好的线性增大关系(r2>0.95),其余理化指标及LF-NMR弛豫特性则无明显的规律性变化,相关性模型亦较差。

In this paper, the evolution of several analytical indicators and the low field nuclear mag- netic resonance （ LF - NMR） T2 relaxation characteristics of sunflower oil stored at 25, 65 ℃, re- spectively, were investigated. And the correlation model between LF- NMR results and the analyti- cal indicators was established and experimentally verified. The results indicated that , when stored at 65 ℃, the analytical indicators, including peroxide value （PV） , conjugated dienes（ K232 ）, conju- gated tienes（ K27o）, p-anisidine value （p-AV）, TPC content and the LF- NMR T2 peak area（S2t, S22） all increased exponentially（r2 〉0. 93）, while the S23 and the single component relaxation time （T2w） decreased exponentially as the storage time was prolonged （r2 〉 0. 98 ）. The multiple regres- sion analysis results showed that the correlation model between LF -NMR results and the analytical indicators could be well established and successfully verified （r2 〉 0. 94）. When stored at 25 ℃, al- though the analytical indicators and the LF -NMR results changed less than those of 65 ℃, the PV, K232, TPC content increased linearly as the time was prolonged （ r2 〉 0.95 ） , while no obvious rela- tionship could be found between the K27o, p-AV, IV or T2 relaxation characteristics and the storage time. Meanwhile, the correlation of the model between LF -NMR results and the analytical indica- tors was also poor.