【摘要】：甘油三酯(TAGs)是天然油脂的主要成分,由于TAGs甘油骨架上結(jié)合的脂肪酸不同以及異構(gòu)體的存在,TAGs種類非常龐大,開展TAGs分析方法研究,對監(jiān)控食用油質(zhì)量、保障食用油安全有重要意義。隨著油脂加熱時間的延長,油脂中極性組分(PC)含量增加,PC主要包括氧化甘油三酯寡聚物(TGO)、氧化甘油三酯二聚物(TGD)、氧化甘油三酯單體(ox-TG)、甘油二酯(DG)、游離脂肪酸(FFA)等,其中TGO和TGD統(tǒng)稱為氧化甘油三酯聚合物(TGP)。TGP是油脂氧化過程中產(chǎn)生的一類復(fù)雜的深度氧化產(chǎn)物,其含量增加會對人體健康產(chǎn)生不利影響。TGP總量隨著油脂氧化程度的加深而持續(xù)遞增,是可以表征油脂氧化程度的內(nèi)源性指標。本文研究了TAGs、TGP的分析方法。首先,探索了非水反相液相色譜分析植物油甘油三酯的條件,建立了非水反相高效液相色譜-質(zhì)譜聯(lián)用(NARP-HPLC-MS)分析方法,并采用該方法分析了17種植物油的甘油三酯組成及其相對含量。本研究中植物油色譜圖含有的峰數(shù)量為9-22,其中棕櫚酸型植物油的峰數(shù)量為8-10,亞麻酸型植物油的峰數(shù)量為13-22,亞油酸型植物油的峰數(shù)量為10-18,油酸型植物油的峰數(shù)量為8-11。植物油甘油三酯的當量碳數(shù)(ECN)范圍為36-56,大部分植物油中當量碳數(shù)在42-48之間的TAG相對含量較多。棕櫚酸型植物油的ECN范圍為44-50,亞麻酸型植物油的ECN范圍為36-50,其中月見草油還有極少量甘油三酯的ECN為52-56,亞油酸型植物油的ECN范圍為38-52,油酸型植物油的ECN范圍為44-52。根據(jù)不飽和程度將甘油三酯分類,各植物油中不同類型甘油三酯的含量有一些差異。甘油三酯是甘油與脂肪酸酯化的產(chǎn)物,脂肪酸根據(jù)不飽和度的多少分為飽和脂肪酸和不飽和脂肪酸,分別用“S”和“U”表示。棕櫚酸類植物油中SSU和SUU型甘油三酯含量較高,共達到94.42%;檢測的其他16種植物油均不飽和程度較高,SUU和UUU型甘油三酯總含量在88.73-99.17%之間。其次建立了非水反相液相色譜-銀離子色譜離線二維液相色譜與質(zhì)譜聯(lián)用(Ag-HPLC-MS)的方法,并分析了葡萄籽油、月見草油和辣木籽油的甘油三酯位置異構(gòu)體,及相同ECN值的甘油三酯。經(jīng)Ag-HPLC-MS分析,辣木籽油、月見草油、葡萄籽油分別被鑒定出9、12和7組TAG位置異構(gòu)體。結(jié)合一維NARPHPLC-MS的結(jié)果,辣木籽油共檢測出22種甘油三酯及其異構(gòu)體,月見草油共檢測出37種甘油三酯及其異構(gòu)體,葡萄籽油共有26種甘油三酯及其異構(gòu)體被確認。然后研究了甘油三酯氧化聚合物的分析方法。首先建立了快速柱層析-高效體積排阻色譜對TGP的分析方法,對實驗室自合成高純度甘油三油酸酯(OOO)和甘油三亞油酸酯(LLL)加熱產(chǎn)物進行了分析。通過對不同加熱時間的OOO和LLL的氧化產(chǎn)物進行分析,其極性組分含量隨著加熱時間的延長均先迅速增加后增長速度變緩,其中由于亞油酸的不飽和程度更高,LLL極性組分含量增速更大。兩種甘油三酯聚合物中TGO、TGD含量在加熱初期均較低,在10%以下,ox-TG含量在40-50%之間。隨加熱時間的延長,TGO含量呈上升趨勢,其中LLL加熱體系中TGO在36-48h含量上升最快;TGD含量呈現(xiàn)先小幅度上升后平穩(wěn)的趨勢;ox-TG含量均先迅速下降,并在36h之后保持平緩。通過不同相對分子質(zhì)量的聚苯乙烯標準物質(zhì)繪制的標準工作曲線,計算得出TGO、TGD、ox-TG和DG的平均分子量分別為3215、1787、801和605。此方法操作簡便、定量精確,定性準確。最后建立了快速柱層析-高效體積排阻色譜-質(zhì)譜聯(lián)用(PFC-HPSEC-MS)的方法,對TGP進行分析。通過質(zhì)譜檢測結(jié)果,可以看出OOO和LLL具有類似的氧化機理,經(jīng)過加熱氧化分別產(chǎn)生了單氫過氧化物、雙氫過氧化物、單環(huán)氧化物和雙環(huán)氧化物等氧化甘油三酯單體;OOO、LLL加熱體系中的TGD分子量均較小于兩倍ox-TG分子量,推測TGD由兩種ox-TG縮合而成,且分子上有一條/兩條脂肪酸鏈發(fā)生了裂解。
[Abstract]:Triglyceride (TAGs) is the main component of natural fat. Because of the different fatty acids and the presence of isomers, the TAGs are very large, and the TAGs analysis method is very important to monitor the quality of edible oil and to guarantee the safety of edible oil. As the heating time of the oil is prolonged, the content of the polar component (PC) in the oil is increased, and the PC mainly comprises an oxidized triglyceride oligomer (TGO), an oxidized triglyceride II (TGD), an oxidized triglyceride monomer (ox-TG), a diglyceride (DG), a free fatty acid (FFA), and the like, TGO and TGD are collectively referred to as the oxidized triglyceride polymer (TGP). TGP is a kind of complex deep oxidation product produced in the process of oil oxidation, and the increase in the content of TGP can have a negative effect on the health of human body. The total amount of TGP continues to increase with the deepening of the degree of oil oxidation, which is an endogenous indicator that can be used to characterize the degree of oil oxidation. The analytical methods of TAGs and TGP are studied in this paper. Firstly, the conditions of non-aqueous anti-phase liquid chromatography for the analysis of vegetable oil triglyceride were explored, and a non-aqueous anti-phase high performance liquid chromatography-mass spectrometry (NARP-HPLC-MS) analysis method was established, and the composition and relative contents of the triglyceride of 17 vegetable oils were analyzed by this method. The peak number of the vegetable oil chromatogram in the study is 9-22, wherein the peak quantity of the palmitic acid type vegetable oil is 8-10, the peak quantity of the linolenic acid type vegetable oil is 13-22, the peak quantity of the linoleic acid type vegetable oil is 10-18, and the peak quantity of the oleic acid type vegetable oil is 8-11. The equivalent carbon number (ECN) range of the vegetable oil triglyceride is 36-56, and the relative content of the equivalent carbon number between 42 and 48 in most of the vegetable oil is more. The ECN range of the palmitic acid type vegetable oil is 44-50, the ECN range of the linolenic acid type vegetable oil is 36-50, the ECN range of the monthly primrose oil and the small amount of triglyceride is 52-56, the ECN range of the linoleic acid type vegetable oil is 38-52, and the ECN range of the oleic acid type vegetable oil is 44-52. Triglycerides were classified according to the degree of unsaturation, and there were some differences in the contents of the different types of triglycerides in the various vegetable oils. Triglyceride is the product of the esterification of glycerol and fatty acid, and the fatty acid is divided into saturated fatty acid and unsaturated fatty acid according to the degree of unsaturation, and is represented by 鈥淪鈥，

本文編號：2365533