Plant oils are obtained from plants.

植物油是從植物中提取的。

These oils are found in all parts of a plant – seeds, nuts, fruit, leaves, flowers, bark, and even roots.

這些油存在於植物的各個部分--種子、堅果、果實、葉子、花朵、樹皮甚至根莖。

However, these oils must be extracted before they can be consumed or used.

不過，在食用或使用這些油之前，必須對其進行提取。

There are a few key methods to extract plant oils – mechanical extraction, distillation, and steam distillation.

萃取植物油有幾種主要方法--機械萃取、蒸餾和蒸汽蒸餾。

Olive oil is obtained from olives by mechanical extraction.

橄欖油是通過機械萃取從橄欖果中獲得的。

This method is also known as cold pressing.

這種方法也被稱為冷榨。

The olives are crushed and pressed to squeeze all the oil out.

將橄欖壓碎、壓榨，榨出所有橄欖油。

In the past, these heavy machines were operated by humans.

過去，這些重型機器都是由人來操作的。

Nowadays, most mechanical extraction is done in a factory by machines.

如今，大多數機械提取都是在工廠裡用機器完成的。

Coconut oil is also obtained using this method.

椰子油也是通過這種方法獲得的。

Note that these oils are essential cooking ingredients in certain parts of the world.

請注意，這些油在世界某些地方是必不可少的烹飪配料。

Some plant oils, such as sunflower oil and soy oil, are obtained by distillation.

有些植物油，如葵花籽油和大豆油，是通過蒸餾獲得的。

These oils are first dissolved in a solvent, and the solvent is removed via distillation.

這些油首先溶解在溶劑中，然後通過蒸餾去除溶劑。

Most impurities are also removed during this process.

在此過程中，大部分雜質也會被去除。

This method is used for oils that are more difficult to extract from their respective plants.

這種方法適用於較難從各自植物中提取的精油。

Steam distillation is used to extract floral oils, such as rose and lavender oils.

蒸汽蒸餾法用於提取花油，如玫瑰油和薰衣草油。

Steam is passed through the flower petals.

蒸汽穿過花瓣。

The oils are then able to evaporate.

這樣，油就可以蒸發掉了。

Since the oil droplets are very small, they can form an emulsion with water.

由於油滴非常小，它們可以與水形成乳狀液。

The oil can then be separated using distillation.

然後可以用蒸餾法分離出油。

We will now look at the general structure of plant oils.

現在我們來看看植物油的一般結構。

The structure can be broken down into two parts.

結構可分為兩部分。

First we have the glycerol head, which is hydrophilic or water loving.

首先是甘油頭，它具有親水性或親水性。

This head is made of three carbons.

這個頭部由三個碳原子組成。

These three carbons are each attached to three fatty acid tails, which are hydrophobic or water fearing.

這三個碳分別與三個脂肪酸尾部相連，而脂肪酸尾部是疏水或怕水的。

The length of the tail can vary from oil to oil.

不同油品的尾部長度可能不同。

It can be anywhere from 4 carbons long to 28 carbons long.

碳原子長度從 4 個到 28 個不等。

These tails can be saturated or unsaturated.

這些尾巴可以是飽和的，也可以是不飽和的。

The term saturated means that there are only carbon-carbon single bonds.

飽和的意思是隻有碳碳單鍵。

Saturated plant oils are solids at room temperature, and are also known as vegetable fats.

飽和植物油在室溫下是固體，也被稱為植物脂肪。

An example of a saturated plant oil is palm oil from oil palm trees.

飽和植物油的一個例子就是來自油棕櫚樹的棕櫚油。

The term unsaturated means that there are carbon-carbon double bonds somewhere within the structure of the fatty acid tail.

所謂不飽和，是指脂肪酸尾部結構的某處存在碳碳雙鍵。

A monounsaturated oil has only one carbon-carbon double bond.

單不飽和油只有一個碳碳雙鍵。

A polyunsaturated oil has more than one carbon-carbon double bond.

多元不飽和油含有一個以上的碳碳雙鍵。

Most unsaturated oils are liquids at room temperature.

大多數不飽和油在室溫下都是液體。

These unsaturated oils can be hydrogenated through a process called hydrogenation.

這些不飽和油可以通過一種叫做氫化的工藝進行氫化。

This hardens the oil and is a key step in the production of margarine.

這使油變硬，是生產人造奶油的關鍵步驟。

In the laboratory, one can differentiate between a saturated and an unsaturated oil by testing with bromine water.

在實驗室中，可以通過溴水測試來區分飽和油和不飽和油。

An unsaturated oil will decolorize bromine water, whereas a saturated oil would not.

不飽和油會使溴水脫色，而飽和油不會。

In summary, plant oils can be obtained by mechanical extraction, distillation, or steam distillation.

總之，植物油可以通過機械萃取、蒸餾或蒸汽蒸餾獲得。

All plant oils have the same generic structure, a hydrophilic glycerol head and three hydrophobic fatty acid tails.

所有植物油都具有相同的通用結構，即一個親水性甘油頭和三個疏水性脂肪酸尾。

The fatty acid tail can be saturated if there are only carbon-carbon single bonds, or unsaturated if there are carbon-carbon double bonds present.

如果脂肪酸尾部只有碳碳單鍵，則為飽和脂肪酸；如果存在碳碳雙鍵，則為不飽和脂肪酸。