油脂用途：提供热量，提供人体所必需脂肪酸和各种脂溶性维生素，重要的热媒介质。

油脂在化学概念上被定义为混脂肪酸甘油三酯的混合物，也称酰基甘油酯。

来源：水生动物油脂、陆上动物油脂、乳脂、植物油脂、微生物油脂

脂肪酸组成：乳脂类、月桂酸类、植物脂类、陆上动物脂类、油酸-亚油酸类、芥酸类、亚麻酸类、共轭酸类、水中的动物油类、羟基酸类。

可皂化类脂物：脂肪酸、甘一酯、甘二酯、蜡、磷脂、醚脂等。
不可皂化类脂物：甾醇、维生素、色素、脂肪醇等。

干燥性能：不干性油脂（碘值＜100，分子双键数＜4，空气中不能氧化成膜）、半干性油脂（碘值100~140，分子双键数4~6个，空气中能干燥成膜）、干性油脂（碘值≥140，双键数≥6个，可在空气中氧化成膜）

不饱和脂肪酸：特点：大多为偶数碳原子，所含双键多顺式，双键位置多位于第九和第十个碳原子之间。通式：CnH2n-2O2。代表性物质油酸（顺-9-十八碳烯酸）n速记法需要结构符合五碳双烯型。

二烯酸：通式CnH2n-4O2，代表性物质亚油酸（顺-9，顺-12-十八碳二烯酸）
三烯酸：通式CnH2n-6O2，代表性物质非共轭α-亚麻酸，共轭α-桐酸。

饱和脂肪酸：通式CnH2nO2。俗名：十二烷酸月桂酸、十四烷酸豆蔻酸、十六烷酸棕榈酸、十八烷酸硬脂酸、二十烷酸花生酸。正癸酸只在少数油脂中存在，十二、十四、十六、二十及二十碳以上的饱和脂肪酸都会使人体血液胆固醇值升高。

特殊脂肪酸：支链脂肪酸、异酸、羟基取代酸（典型：蓖麻酸）、酮基酸、环氧酸、炔酸

脂肪酸：天然油脂加水分解生成的脂肪族羧酸化合物的总称，属于脂肪族的一元羧酸。
特点：多数属于偶碳直链，奇数链较少，支链极少。有顺式和反式构型，重点集中在C4~C22。

脂肪酸种类、碳链长度、双键数目、几何构型都会影响性质。

学说：全随机分布学说、1-随机-2-随机-3-随机分布学说、1，3-随机-2-随机分布学说

Uses of fats: to provide calories, to provide essential fatty acids and various fat-soluble vitamins for the human body, and to provide important heat mediums.

Fats and fats are chemically defined as mixtures of mixed fatty acid triglycerides, also known as acylglycerides.

Sources: aquatic animal fats, terrestrial animal fats, milk fats, vegetable fats, microbial fats

Fatty acid composition: milk fats, lauric acids, vegetable lipids, terrestrial animal lipids, oleic acid-linoleic acid, erucic acid, linolenic acid, conjugated acid, animal oil in water, hydroxy acid.

Saponifiable lipids: fatty acids, glycoester, glyceride, wax, phospholipid, ether lipid, etc.
Non-saponifiable lipids: sterols, vitamins, pigments, fatty alcohols, etc.

Drying performance: non-drying grease (iodine value < 100, molecular double bond number < 4, can not be oxidized in the air to form a film), semi-dry oil (iodine value 100~140, molecular double bond number 4~6, can be dried in the air to form a film), dry oil (iodine value ≥ 140, double bond number ≥ 6, can be oxidized in the air to form a film)

Saturated fatty acids: general CnH2nO2. N-capric acid is only present in a few fats, and saturated fatty acids above 12, 14, 16, 20 and 20 carbon will increase the blood cholesterol value of the human body.

Unsaturated fatty acids: Characteristics: Most of them are even-numbered carbon atoms, containing double bonds and polycis, and the double bond position is mostly located between the ninth and tenth carbon atoms. General formula: CnH2n-2O2. The representative substance oleic acid (cis-9-octadecenoic acid) n shorthand method needs to be in accordance with the pentacarbon type in structure.

Special fatty acids: branched-chain fatty acids, exotic acids, hydroxy-substituted acids (typical: ricinic acid), ketogenic acids, epoxy acids, alkynes

Dienoic acid: general formula CnH2n-4O2, representative substance linoleic acid (cis-9, cis-12-octadecadienoic acid)
Trienoic acid: general formula CnH2n-6O2, representative substances unconjugated α-linolenic acid, conjugated α-tungic acid.

Fatty acids: a general term for aliphatic carboxylic acid compounds formed by the hydrolysis of natural oils, which belong to the aliphatic monocarboxylic acids.
Features: Most of them belong to the even carbon straight chain, with fewer odd chains and very few branch chains. There are cis and trans configurations, with a focus on C4~C22.

The type of fatty acid, the length of the carbon chain, the number of double bonds, and the geometry all affect the properties.

Stereospecifically numbering: sn-1:α, sn-2: β, sn-3: α'

Fatty acids: myristic acid, palmitic acid, stearic acid, oleic acid

Doctrines: The Theory of Full Random Distribution, 1-Random-2-Random-3-Random Distribution, 1,3-Random-2-Random Distribution