本文選題：奶粉 + 脂肪酸分子��； 參考：《鄭州大學》2017年碩士論文

【摘要】：由于奶粉單分子脂肪酸碳氫穩(wěn)定同位素的數(shù)據(jù)及系統(tǒng)評價鮮見報道,本研究主要以不同產(chǎn)地及適應不同人群的15種奶粉為研究對象,采用多種測試方法(GC,GC/C/IRMS及GC/TC/IRMS),對脂肪酸進行化學定性及定量分析,并測定其穩(wěn)定碳氫同位素組成,為判別奶粉產(chǎn)地建立新方法,并為建立參考奶粉數(shù)據(jù)表庫提供基礎數(shù)據(jù),本次試驗研究結果如下:(1)本次試驗共識別發(fā)現(xiàn)的32種脂肪酸,總體奶粉脂肪酸的含量有如下趨勢:C18:1C16:0C18:2C14:0≈C12:0C18:0,并且在嬰幼兒奶粉中,單不飽和脂肪酸占主要優(yōu)勢;在成人奶粉中,飽和脂肪酸占主要優(yōu)勢。(2)月桂酸,肉豆蔻酸及反式脂肪酸的總量及奶粉的SFA:MUFA:PUFA比值都符合國家及營養(yǎng)學規(guī)定,但多不飽和與飽和脂肪酸的比值與營養(yǎng)學家推薦值相差較大,且除亞油酸,ARA外,?-亞麻酸,DHA、EPA與DPA與外包裝嚴重不符。(3)建立以下判別指示:當C18:1/C18:2值小于5時,或者UFA/SFA比值大于1,可以認為此種奶粉是嬰幼兒奶粉;當C18:1/C18:2值大于10時,或者UFA/SFA比值小于0.5,可以認為此種奶粉是成人奶粉。(4)脂肪酸的碳氫同位素總體上隨著碳鏈的延長,其13C同位素在貧化,2H同位素在富集,兩種同位素變化趨勢正好相反。各個脂肪酸的平均δ13C變化趨勢:C14:0C16:0≈C18:0C20:0C22:0C24:0,C14:0C12:0C10:0C8:0,各個脂肪酸的平均δ2H變化趨勢:C12:0C14:0C16:0C18:0。(5)動物體內的C16:0是合成其他脂肪酸的重要前體,也就是說C18:0、C20:0、C22:0、C24:0等脂肪酸是通過C16:0碳鏈的延長形成的,而C8:0、C10:0、C12:0、C14:0是由C16:0的碳鏈斷裂形成的,并且C18:0脂肪酸除了是碳鏈的延長得到的,也有可能部分是由C18:1,C18:2氫化得來的,氫化后δ2H值會變得更加貧化,可能是瘤胃微生物的氫化作用的結果。(6)偶數(shù)碳的δ13C值明顯比奇數(shù)碳的δ13C值相高,且與含量具有一定的關系:當含量足夠高時,就在一定程度上加劇了δ13C值的富集或貧化,同時也會在一定程度上減緩碳鏈延長或縮短帶來的δ13C值的變化。(7)氫同位素在碳鏈的延伸過程中,分餾很少或為零,在加氫過程中2H值會變得更加貧化。氫同位素分餾過程中,可以使不飽和脂肪酸的δ2H值更加升高,這就說明?2H取決于相對代謝通量,不同脂肪酸δ2H值的差異可以成為生物合成過程中定量通量和方向的有用工具。(8)C3或C4植物的δ13C差異在奶粉的地域性差異上得到反映,長鏈脂肪酸的δ2H值也與區(qū)域特征有明顯記錄。
[Abstract]:Because the data of monolayer fatty acid hydrocarbon stable isotopes and systematic evaluation of milk powder were rarely reported, 15 kinds of milk powder from different producing areas and adapted to different population were studied in this study. The chemical qualitative and quantitative analysis of fatty acids and the determination of their stable hydrocarbon isotopic compositions were carried out by using various testing methods such as GC / C / C / IRMS and GC / TC / IRMS, so as to establish a new method for judging the origin of milk powder, and to provide basic data for the establishment of reference milk powder data sheet. The results of this experiment are as follows: (1) there are 32 kinds of fatty acids identified and found in this experiment. The total fatty acid content of milk powder has the following trend: C18: 1C160C18: 0C18: 0 鈮，

本文編號：1864120