【摘要】：煎炸體系中極性物質(zhì)的含量是評(píng)價(jià)煎炸油脂品質(zhì)的重要指標(biāo)。本論文以煎炸過程中產(chǎn)生的極性物質(zhì)及不同極性組分為研究對(duì)象,討論其在煎炸介質(zhì)以及煎炸食品(薯?xiàng)l)中的分布規(guī)律,分析不同煎炸介質(zhì)的脂肪酸組成對(duì)極性物質(zhì)形成過程的影響,探索其在煎炸過程中的產(chǎn)生途徑,同時(shí),討論極性物質(zhì)對(duì)煎炸食品中丙烯酰胺含量變化的影響,以評(píng)價(jià)其對(duì)煎炸食品品質(zhì)的影響。在此基礎(chǔ)上通過小鼠喂養(yǎng)實(shí)驗(yàn)研究煎炸棕櫚油及其極性物質(zhì)對(duì)昆明小鼠能量代謝以及肝臟功能的影響,進(jìn)一步從分子水平上研究極性物質(zhì)在小鼠體內(nèi)干擾脂質(zhì)代謝的原因。本論文為闡明煎炸過程中極性物質(zhì)的形成機(jī)制以及極性物質(zhì)對(duì)動(dòng)物體能量代謝過程的影響提供了理論依據(jù),為進(jìn)一步控制煎炸體系中極性物質(zhì)的產(chǎn)生及其對(duì)煎炸食品品質(zhì)的影響奠定基礎(chǔ)。主要研究?jī)?nèi)容包括:(1)本論文以棕櫚酸型(棕櫚油)及月桂酸型(精煉棕櫚仁油及精煉椰子油)油脂為研究對(duì)象,全面研究了煎炸過程中煎炸介質(zhì)及煎炸食品中極性物質(zhì)的含量與分布。結(jié)果表明:煎炸體系中極性物質(zhì)及不同極性組分的含量隨煎炸時(shí)間的延長(zhǎng)而增加,極性物質(zhì)含量的變化與所用油脂類型不相關(guān)。進(jìn)一步研究表明極性物質(zhì)在煎炸介質(zhì)以及煎炸食品中的分布不同。煎炸介質(zhì)中的極性物質(zhì)含量略高于煎炸食品中的極性物質(zhì)含量。在煎炸末期(第50 h),煎炸棕櫚油,煎炸棕櫚仁油以及煎炸椰子油中極性物質(zhì)含量分別為31.65%,38.23%以及38.28%,但是,在對(duì)應(yīng)煎炸薯?xiàng)l油脂中極性物質(zhì)含量分別為29.42%,32.88%以及30.54%。隨后,借助高效凝膠排阻色譜(HPSEC)技術(shù)進(jìn)一步分析發(fā)現(xiàn),極性物質(zhì)中不同極性組分在煎炸介質(zhì)與煎炸食品中的分布情況差別明顯:氧化甘油三酯寡聚物及甘油三酯二聚物在煎炸食品中的含量高于煎炸介質(zhì)中的相應(yīng)組分的含量。以煎炸第50 h的煎炸棕櫚油以及煎炸薯?xiàng)l為例,薯?xiàng)l中甘油三酯寡聚物及甘油三酯二聚物分別達(dá)到6.79%及6.54%,高于對(duì)應(yīng)煎炸棕櫚油中這些物質(zhì)的含量(2.05%及5.49%)。但是氧化甘油三酯以及甘油二酯表現(xiàn)與之相反,在煎炸薯?xiàng)l中氧化甘油三酯及甘油二酯含量分別為5.55%及9.02%,這一含量低于對(duì)應(yīng)煎炸棕櫚油中氧化甘油三酯及甘油二酯的水平(7.41%及15.12%)。說明不同極性組分與煎炸食品中碳水化合物之間的相互作用強(qiáng)度不同,從而影響不同極性組分在煎炸體系中的分布。煎炸體系中極性物質(zhì)及不同極性組分的含量與煎炸油脂肪酸組成中的反油酸(trans-C18:1)含量的變化呈正相關(guān)。另一方面,在棕櫚酸型油脂中,極性物質(zhì)及不同極性組分含量的變化還與亞油酸(C18:2)含量的變化高度相關(guān),然而,在月桂酸型油脂中,極性物質(zhì)及不同極性組分含量變化與C18:2含量變化的相關(guān)性小(相關(guān)系數(shù)低于0.8)。(2)本論文借助核磁共振(~1H NMR)的方法分析了煎炸過程中煎炸油脂的組成變化(含不飽和脂肪酸的�；鶊F(tuán)、醛類化合物、環(huán)氧化合物、羥基化合物以及甘油二酯等),通過電子自旋共振(ESR)方法監(jiān)測(cè)高溫處理?xiàng)l件下不同油品中自由基的產(chǎn)生情況,進(jìn)一步闡明了煎炸過程中不同煎炸介質(zhì)體系內(nèi)極性物質(zhì)的產(chǎn)生過程。結(jié)果表明:與新鮮棕櫚仁油和新鮮椰子油相比,新鮮棕櫚油中烯丙基�；鶊F(tuán)含量分別是前者中對(duì)應(yīng)含量的3.04以及5.96倍,且在煎炸50 h以后,棕櫚油中烯丙基酰基基團(tuán)含量下降了37.05%。棕櫚油在熱處理過程中烷基自由基的產(chǎn)生更占優(yōu)勢(shì)。因此以其為介質(zhì)的煎炸體系中首先產(chǎn)生非極性甘油三酯二聚物,再進(jìn)一步被氧化得到氧化甘油三酯二聚物。雖然在煎炸棕櫚油、煎炸棕櫚仁油以及煎炸椰子油中檢測(cè)到的環(huán)氧化合物以及羥基化合物含量相差不大,但是醛類化合物在煎炸棕櫚油中的含量顯著高于其在另外兩種煎炸介質(zhì)中的含量。以煎炸第30 h為例,煎炸棕櫚油中醛類化合物含量分別是煎炸棕櫚仁油以及煎炸椰子油的5.28以及2.88倍。而且棕櫚油、棕櫚仁油以及椰子油在熱處理過程中能夠產(chǎn)生強(qiáng)度相當(dāng)?shù)耐檠踝杂苫Ｒ虼嗽谝陨鲜鋈N油脂為煎炸介質(zhì)的煎炸體系中都存在脂質(zhì)氧化產(chǎn)物(氧化甘油三酯單體)的聚合,而且在以棕櫚仁油和椰子油為煎炸介質(zhì)的煎炸體系中,氧化甘油三酯二聚物的來源主要是脂質(zhì)氧化產(chǎn)物的聚合。(3)本論文系統(tǒng)研究了煎炸過程中煎炸油脂的品質(zhì)對(duì)煎炸食品中丙烯酰胺含量變化的影響,以討論其對(duì)煎炸食品品質(zhì)的影響。首先,完善了煎炸食品中丙烯酰胺的快速檢測(cè)方法:在預(yù)處理操作中的氮吹復(fù)溶階段,需要預(yù)先加入一定量超純水,以保護(hù)待測(cè)物質(zhì),防止丙烯酰胺發(fā)生聚合反應(yīng)影響其回收率;同時(shí),在丙烯酰胺色譜分析階段,Chrome-Matrix C18色譜柱(2.6μm,2.1×100 mm)的使用不但改善了丙烯酰胺峰形,而且節(jié)約了分析時(shí)間,提高了檢測(cè)效率。其次,通過測(cè)定不同食品基質(zhì)中丙烯酰胺含量評(píng)價(jià)了該方法的重復(fù)性及準(zhǔn)確度,結(jié)果表明該方法的日內(nèi)精密度范圍為0.04-2.38%,其日間精密度范圍為2.34-3.26%。進(jìn)一步研究了不同煎炸介質(zhì)中煎炸食品內(nèi)丙烯酰胺含量隨煎炸油脂使用時(shí)間的變化:以棕櫚油、棕櫚仁油以及椰子油為煎炸介質(zhì)的煎炸體系中,在前30 h的煎炸過程中,煎炸薯?xiàng)l中的丙烯酰胺含量隨煎炸介質(zhì)使用時(shí)間的延長(zhǎng)而增加。與第一批次(第0.25 h)煎炸薯?xiàng)l中丙烯酰胺含量相比,第30 h煎炸薯?xiàng)l中的丙烯酰胺含量分別增長(zhǎng)了6.63倍、0.21倍以及2.21倍。但是在第30 h以后,煎炸薯?xiàng)l中的丙烯酰胺含量隨煎炸介質(zhì)使用時(shí)間的延長(zhǎng)而下降。與第30 h煎炸薯?xiàng)l中丙烯酰胺含量相比,第50 h煎炸薯?xiàng)l中的丙烯酰胺含量分別下降了62.28%、34.88%以及28.81%。通過分析煎炸過程中煎炸油脂中水分含量及煎炸薯?xiàng)l中極性物質(zhì)及其組分含量的變化發(fā)現(xiàn):在煎炸初期,煎炸食品中丙烯酰胺的含量與體系中水分含量相關(guān),即丙烯酰胺含量隨煎炸體系中水分含量的減少而增加,而且,丙烯酰胺的產(chǎn)生與煎炸油脂中游離脂肪酸的含量呈正相關(guān)。但是,在煎炸后期,隨著煎炸體系中極性物質(zhì)含量的增加,由于其與煎炸食品中碳水化合物的相互作用限制了煎炸體系中美拉德反應(yīng)的進(jìn)行,因此煎炸食品中丙烯酰胺含量明顯下降。(4)本論文進(jìn)一步探討了煎炸棕櫚油以及從其中分離得到的總極性物質(zhì)對(duì)小鼠健康的影響,尤其是對(duì)脂質(zhì)代謝以及糖代謝和肝臟的影響。結(jié)果表明,高能量攝入能夠促進(jìn)小鼠肝臟細(xì)胞中脂肪的堆積,但是,極性物質(zhì)的攝入對(duì)小鼠肝臟中脂肪的堆積影響并不明顯。另一方面,極性物質(zhì)的攝入雖然沒有造成小鼠肝臟中脂肪聚集,但是,其對(duì)小鼠的血脂水平、肝臟酶活力以及機(jī)體抗氧化能力的影響與其他高脂飼料喂養(yǎng)的小鼠表現(xiàn)一致,表明極性物質(zhì)的攝入能夠干擾小鼠體內(nèi)脂質(zhì)代謝過程,降低機(jī)體抗氧化能力,并且造成肝臟損傷。對(duì)小鼠肝臟中參與脂肪酸代謝的相關(guān)基因表達(dá)的測(cè)定結(jié)果顯示:極性物質(zhì)的攝入抑制了小鼠肝細(xì)胞中參與脂肪酸合成的相關(guān)基因(SREBP-1c)的表達(dá),與低脂對(duì)照組相比其表達(dá)量下降了15.34%;與高脂對(duì)照組相比,極性物質(zhì)喂養(yǎng)組小鼠肝細(xì)胞中脂肪酸去飽和酶(SCD1)的基因表達(dá)量下降了29.54%,說明極性物質(zhì)的攝入影響小鼠肝臟中脂質(zhì)代謝過程。另一方面,極性物質(zhì)的攝入使得小鼠肝細(xì)胞中乙酰輔酶A氧化酶(ACOX1)的基因表達(dá)增強(qiáng),是低脂對(duì)照組小鼠肝臟中相應(yīng)基因表達(dá)量的2.07倍,表明極性物質(zhì)促進(jìn)小鼠肝細(xì)胞中過氧化物酶體上的脂肪酸氧化反應(yīng);但是極性物質(zhì)的攝入對(duì)小鼠肝臟中肉毒堿棕櫚�；D(zhuǎn)移酶(CPT1α)的基因表達(dá)沒有顯著影響,說明脂肪酸在線粒體中的氧化反應(yīng)并沒有隨極性物質(zhì)的攝入而改變。極性物質(zhì)對(duì)小鼠體內(nèi)葡萄糖代謝過程的影響表現(xiàn)為:低劑量極性物質(zhì)的攝入有助于改善小鼠體內(nèi)由高脂飲食引起的葡萄糖耐受量變差的情況,然而,高劑量極性物質(zhì)的攝入明顯損傷小鼠的葡萄糖耐受量。因此高油脂基質(zhì)中極性物質(zhì)的攝入能夠改變昆明小鼠體內(nèi)的脂質(zhì)代謝以及葡萄糖代謝過程。
[Abstract]:The content of polar substances in frying system is an important index to evaluate the quality of frying oil. In this paper, polar substances and polar components produced in frying process were studied. The distribution of polar substances in frying medium and fried food (French fries) was discussed. The formation of polar substances by fatty acid composition in different frying medium was analyzed. In order to evaluate the effects of polar substances on the content of acrylamide in fried food and the quality of fried food, we studied the effects of fried palm oil and its polar substances on energy metabolism and liver function in Kunming mice by feeding experiments in mice. This paper provides a theoretical basis for elucidating the formation mechanism of polar substances and the effect of polar substances on energy metabolism in mice during frying, and for further controlling the production of polar substances in frying system. The main research contents are as follows: (1) The content and distribution of polar substances in the frying medium and the frying food during the frying process were studied comprehensively with palmitic acid (palm oil) and lauric acid (refined palm kernel oil and refined coconut oil) oils as the research objects. The content of polar substances and different polar components increased with the prolongation of frying time, and the change of polar substances content was not related to the type of oil used. At the end of frying (50h), the contents of polar substances in fried palm oil, fried palm kernel oil and fried coconut oil were 31.65%, 38.23% and 38.28%, respectively. However, the contents of polar substances in corresponding fried potato chips oil were 29.42%, 32.88% and 30.54% respectively. Subsequently, high performance gel exclusion chromatography (HPSEC) was used for further analysis. It was found that the distribution of different polar components in frying medium and fried food was obviously different: the content of triglyceride oxide oligomer and triglyceride dimer in fried food was higher than that of corresponding components in fried medium. Triglyceride oligomers and triglyceride dimers reached 6.79% and 6.54% respectively, which were higher than those in the corresponding fried palm oil (2.05% and 5.49%). The levels of triglyceride and diethylene glyceride in fried palm oil (7.41% and 15.12%) showed that the interaction strength between different polar components and carbohydrates in fried food was different, thus affecting the distribution of different polar components in the fried system. The content of trans-C18:1 in fatty acid composition was positively correlated. On the other hand, the content of polar substances and different polar components in palmitic oil was also highly correlated with the content of linoleic acid (C18:2). However, in lauric acid oil, the content of polar substances and different polar components changed with the content of C18:2. (2) In this paper, the composition of frying oils (acyl group, aldehydes, epoxides, hydroxyl compounds, glycerol diesters, etc.) during frying was analyzed by means of nuclear magnetic resonance (~1H NMR), and the high temperature was monitored by electron spin resonance (ESR). The production of free radicals in different oils under different physical conditions was further clarified. The results showed that the contents of allyl groups in fresh palm oil were 3.04 and 5.96 times higher than those in fresh palm kernel oil and fresh coconut oil, respectively. The content of allyl acyl group in palm oil decreased by 37.05% after 50 h of frying. The generation of alkyl radicals was more dominant in the heat treatment of palm oil. The contents of epoxides and hydroxyl compounds in palm oil, fried palm kernel oil and fried coconut oil were similar, but the contents of aldehydes in fried palm oil were significantly higher than those in the other two media. Palm kernel oil and fried coconut oil are 5.28 and 2.88 times as strong as those of palm oil, palm kernel oil and coconut oil, and they can produce alkoxy radicals of the same strength during heat treatment. Therefore, lipid oxidation products (triglyceride monomers) can be polymerized in the frying system in which the above three oils are used as frying media, and in which triglyceride monomers are oxidized. In the frying system with palm kernel oil and coconut oil as frying medium, the source of triglyceride oxide dimer is mainly the polymerization of lipid oxidation products. (3) The effect of the quality of frying oil on the content of acrylamide in fried food during frying process was studied systematically in order to discuss the effect on the quality of fried food. A rapid method for the determination of acrylamide in fried food was developed. In the stage of nitrogen blowing and resolving in the pretreatment operation, a certain amount of ultra-pure water should be added in advance to protect the substance to be tested and prevent the polymerization of acrylamide from affecting its recovery. The method not only improved the peak shape of acrylamide, but also saved analysis time and improved detection efficiency. Secondly, the repeatability and accuracy of the method were evaluated by determining acrylamide content in different food substrates. The results showed that the intra-day precision range of the method was 0.04-2.38%, and the inter-day precision range was 2.34-3.26%. The changes of acrylamide content in fried food in different frying media with the use time of frying oil were studied. In the frying system with palm oil, palm kernel oil and coconut oil as frying media, the acrylamide content in fried French fries increased with the use time of frying media during the first 30 hours. The content of acrylamide in fried potato chips increased by 6.63 times, 0.21 times and 2.21 times at 30 h, respectively. But after 30 h, the content of acrylamide in fried potato chips decreased with the prolongation of frying time. The content of acrylamide in fried potato chips decreased by 62.28%, 34.88% and 28.81% at 50 h, respectively. Amine content increases with the decrease of water content in the frying system, and the production of acrylamide is positively correlated with the content of free fatty acids in the frying oil. The content of acrylamide in fried food decreased significantly as a result of the Rudd reaction. (4) The effects of fried palm oil and the total polar substances isolated from it on the health of mice, especially on lipid metabolism, glucose metabolism and liver, were further investigated. The results showed that high energy intake could promote the liver of mice. On the other hand, the intake of polar substances did not cause the accumulation of fat in the liver of mice, but the effects of polar substances on blood lipid level, liver enzyme activity and antioxidant capacity of mice fed with other high-fat diets were not significant. The results showed that the intake of polar substances could interfere with lipid metabolism, reduce antioxidant capacity and cause liver injury in mice. The expression of related genes involved in fatty acid metabolism in mice liver showed that the intake of polar substances inhibited fatty acid synthesis in mice liver cells. The expression of related gene (SREBP-1c) was decreased by 15.34% compared with the low-fat control group, and the expression of fatty acid desaturase (SCD1) in the liver cells of mice fed with polar substances decreased by 29.54% compared with the high-fat control group, suggesting that the intake of polar substances affected the lipid metabolism in the liver of mice. The gene expression of acetyl coenzyme A oxidase (ACOX1) was 2.07 times as high as that of the low-fat control group, suggesting that the polar substances promoted the oxidation of fatty acids in the peroxisome of the liver cells, but the polar substances increased the carnitine brown in the liver of the mice. The gene expression of palmitoyl transferase (CPT1alpha) was not significantly affected, suggesting that the oxidation of fatty acids in mitochondria did not change with the intake of polar substances. However, high doses of polar substances significantly impaired glucose tolerance in mice. Therefore, the intake of polar substances in high-fat matrices can alter lipid metabolism and glucose metabolism in Kunming mice.
【學(xué)位授予單位】：江南大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2017
【分類號(hào)】：TS221

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本文編號(hào)：2226769