7.脂溶性维生素课件.pptVIP

维生素 vitamin 北京大学营养与食品卫生学系 朱文丽 维生素，vitamin 维他命，维持人体生命不可缺少的物质，维持生命的要素 是维持人体生命活动所必需的一类有机化合物 天然存在于食物中，人体不能合成 需要量甚微 既不参与机体组成也不提供热能，在机体的代谢、生长发育等过程中起重要作用 In the 1800s, it was known that people needed proteins, carbohydrates, fat and salt to stay healthy. No one had heard of vitamins. White rice can be poisonous! This was the conclusion Christiaan Eijkman declared in 1896 on his return to the Netherlands, after ten years of research in Batavia, Java in the Dutch East Indies (now Jakarta, Indonesia). One of the first to find out that food contains other things that people need was Gerrit Grinjs, who now took Eijkmans place at the institute and did more research. He understood that white rice wasnt toxic, but that it lacked something vital. In 1906, the British biochemist Frederick Hopkins demonstrated that food contains necessary accessory factors in addition to proteins, carbohydrates, fats, salts and water. In 1912, the chemist Casimir Funk thought that he had found the vital substance Eijkman called the anti-beriberi factor. Funk gave it the name Vitamine. (He coined the word by combining vital and amine.) This name later came to denote all vitamins, even if the e soon was dropped. However, Funk hadnt found the right substance. Not until 1926 was the vitamin, which was to be named Thiamin or B1, isolated in its pure form. Its structure was fully elucidated and the vitamin synthesized in 1936. In 1929, Eijkman shared the Nobel Prize in Physiology or Medicine with Frederick Hopkins. 脂溶性维生素 VitA、D、E、K 大部分贮存在脂肪组织中 过量摄入可引起中毒 水溶性维生素 B族维生素（VitB1、B2、烟酸、叶酸、泛酸）、VitC 在体内少量储存 供给不足易出现缺乏症 维生素命名 维生素命名 维生素命名 维生素缺乏 膳食供给不足 食物中原有含量，加工或贮藏过程损失 人体吸收利用降低 消化系统吸收功能障碍，或膳食成分改变 机体对维生素的需要相对增高 孕妇，乳母，生长发育期儿童，特殊生活环境条件，消耗性疾病 抗维生素化合物的存在 抗生物素蛋白 维生素A Vitamine A，又名视黄醇（Retinol），包括所有具有视黄醇生物活性的一类物质，如动物性食物来源的VitA1、A2，植物性食物来源的β-胡萝卜素（β-catotene）及其他类胡萝卜素。 理化性质 脂溶性维生素 天然存在于动物性食物中的Vit A以酯的形式存在 一般烹调和罐头加工不易破坏 高温条件下，空气中和日光下可被氧化破坏（避光，-20℃稳定） 对碱稳定，酸性环境不稳定 吸收与代谢 吸收部位：小肠 促进吸收因素 脂肪 抗氧化剂（Vit E、卵磷脂） 阻碍吸收因素 矿物油