【正文】 例如加入到油抗氧化劑能阻止氧化變臭，防腐劑阻止食品的腐敗，著色劑是食品具有更吸引人的外觀等等。這個過程包括了攝入消化食物，和吸收與應(yīng)用，或者代謝食品中的營養(yǎng)素。8. Thus we can describe them in terms of their primary, secondary, tertiary, and in many cases, quaternary structure. They are long chains of amino acid units held together by peptide bonds, looped and folded into secondary and tertiary (and often quaternary) structures by disulfide bonds, hydrophobic interactions, and salt bridges.這樣我們能從蛋白質(zhì)一級，二級，三級和四級結(jié)構(gòu)方面來描述酶：它們是由氨基酸通過肽鍵結(jié)合的單位所組成，以纏繞折疊的方式，由二硫鍵，疏水鍵，鹽橋而構(gòu)成二級和三級結(jié)構(gòu)的許多長鏈。2. Saturated fats have a uniform shape that allows them to pack together in a crystal lattice. Unsaturated fats have double bonds that introduce kinks into the hydrocarbon chain making crystal formation more difficult.飽和脂肪有一個均一一致的形狀，這使得他它們能夠在晶格中聚合起來。s structure adjusts to the substrate39。 we would have to study each individual on the earth in a hospital setting to find such requirements.然而，我們每個個體都是不同的，那如何去確定每個不同個體的營養(yǎng)素確切的攝入量呢？答案是確切的攝入量是不可以被計算出來的；我們必須在醫(yī)院的設(shè)備環(huán)境下來找到這個需求量。28. The intakes for eight agesex groups are pared with the acceptable daily intakes (ADI) as established by the Food and Agriculture Organization/ World Health Organization of the United Nations. (The ADI is the acceptable daily intake of a chemical that, if ingested over a lifetime, appears to be without appreciable risk.) 8個年齡性別組的攝入量被拿去與由世界糧農(nóng)組織和世界衛(wèi)生組織建立的每日允許攝入量（ADI）作比較。Perhaps the most obvious, and certainly the most prevalent problem of food safety is microbiological food poisoning. This is a serious in nearly every country, but another aspect of food safety is primarily concerned with chemicals.食品安全的概念包含很多方面，最顯而易見和最普遍的食品安全問題是微生物食品污染，這是在每個國家都有的重要問題，但其他方面的食品安全主要和化學(xué)藥品有關(guān)。13. They are called essential nutrients because we cannot get along without them .We need them for energy for building and maintaining body tissue, and for regulating body process—the three essential functions of food in the body. 因為我們的生存離不開它們，所以被認(rèn)為是必須的營養(yǎng)素。 catalysts do lower the energy barrier between reactants and products.這意味著任何一個催化劑既可以催化一個反