本文選題：奶粉 + 脂肪酸分子�。� 參考：《鄭州大學(xué)》2017年碩士論文

【摘要】：由于奶粉單分子脂肪酸碳?xì)浞�(wěn)定同位素的數(shù)據(jù)及系統(tǒng)評(píng)價(jià)鮮見(jiàn)報(bào)道,本研究主要以不同產(chǎn)地及適應(yīng)不同人群的15種奶粉為研究對(duì)象,采用多種測(cè)試方法(GC,GC/C/IRMS及GC/TC/IRMS),對(duì)脂肪酸進(jìn)行化學(xué)定性及定量分析,并測(cè)定其穩(wěn)定碳?xì)渫凰亟M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(kù)提供基礎(chǔ)數(shù)據(jù),本次試驗(yàn)研究結(jié)果如下:(1)本次試驗(yàn)共識(shí)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(shì):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(shì);在成人奶粉中,飽和脂肪酸占主要優(yōu)勢(shì)。(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(guó)家及營(yíng)養(yǎng)學(xué)規(guī)定,但多不飽和與飽和脂肪酸的比值與營(yíng)養(yǎng)學(xué)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(yán)重不符。(3)建立以下判別指示:當(dāng)C18:1/C18:2值小于5時(shí),或者UFA/SFA比值大于1,可以認(rèn)為此種奶粉是嬰幼兒奶粉;當(dāng)C18:1/C18:2值大于10時(shí),或者UFA/SFA比值小于0.5,可以認(rèn)為此種奶粉是成人奶粉。(4)脂肪酸的碳?xì)渫凰乜傮w上隨著碳鏈的延長(zhǎng),其13C同位素在貧化,2H同位素在富集,兩種同位素變化趨勢(shì)正好相反。各個(gè)脂肪酸的平均δ13C變化趨勢(shì):C14:0C16:0≈C18:0C20:0C22:0C24:0,C14:0C12:0C10:0C8:0,各個(gè)脂肪酸的平均δ2H變化趨勢(shì):C12:0C14:0C16:0C18:0。(5)動(dòng)物體內(nèi)的C16:0是合成其他脂肪酸的重要前體,也就是說(shuō)C18:0、C20:0、C22:0、C24:0等脂肪酸是通過(guò)C16:0碳鏈的延長(zhǎng)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(zhǎng)得到的,也有可能部分是由C18:1,C18:2氫化得來(lái)的,氫化后δ2H值會(huì)變得更加貧化,可能是瘤胃微生物的氫化作用的結(jié)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(guān)系:當(dāng)含量足夠高時(shí),就在一定程度上加劇了δ13C值的富集或貧化,同時(shí)也會(huì)在一定程度上減緩碳鏈延長(zhǎng)或縮短帶來(lái)的δ13C值的變化。(7)氫同位素在碳鏈的延伸過(guò)程中,分餾很少或?yàn)榱?在加氫過(guò)程中2H值會(huì)變得更加貧化。氫同位素分餾過(guò)程中,可以使不飽和脂肪酸的δ2H值更加升高,這就說(shuō)明?2H取決于相對(duì)代謝通量,不同脂肪酸δ2H值的差異可以成為生物合成過(guò)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(zhǎng)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(hào)：1864120