By analyzing the physical indexes, chemical indexes and chemical components in sea buckthorn fruit oil and vegetable oils, we will find identification methods to find if sea buckthorn fruit oil is mixed with lauric acid oils, palmitic acid oils, oleic acid-linoleic acid oils.

Many pharmacological experiments confirmed that sea buckthorn fruit oil was helpful on many diseases. It is very important to identify the quality of sea buckthorn fruit oil. Besides sea buckthorn fruit oil, there is also sea buckthorn seed oil. The iodine values and fatty acids in both oils are quite different. the main fatty acids of sea buckthorn fruit oil are palmitoleic acid and oleic acid. sea buckthorn seed oil are palmitic acid, oleic acid, linoleic acid and linolenic acid.
1.1 Comparison of sea buckthorn fruit oil with common vegetable oils
By comparing the physical and chemical indexes of sea buckthorn fruit oil with common vegetable oils, it is found that the relative density values of vegetable oils are mostly in the range of 0.9100-0.9200, the relative density of seabuckthorn fruit oil is 0.9109-0.9140. Most of the refractive indexes of vegetable oils are 1.4600-1.4800, sea buckthorn fruit oil is 1.4600-1.4706 with no exception. Iodine value is an indirect reflection of fatty acids unsaturation, higher unsaturation, higher iodine value. vegetable oils with low iodine values include coconut oil and palm oil, respectively 7.5-10.0 and 14-22.

The iodine values of perilla seed oil is 192-208. The iodine value of sea buckthorn fruit oil is 31.61-72.9, which is similiar to palm oil(48-56). The saponification value reflects the average number of carbon atoms, the saponification values of coconut oil and palm oil are 250 to 264 and 245 to 255. The saponification value of the perilla oil is 170 to 180, the saponification value of sea buckthorn fruit oil is in the range of 180-200, the same as most of vegetable oils (sea buckthorn fruit oil is 182-198).

Based on the above four indexes of sea buckthorn fruit oil and common vegetable oils, there is no difference between them. The carotenoids and vitamin E levels of sea buckthorn fruit oil are significantly higher than other vegetable oils (except palm oil).

By analysing the fatty acicds of sea buckthorn fruit oil and common vegetable oils, it’s found that sea buckthorn fruit oil has two features: first, it is rich in palmitoleic acid (27.9%-38.8%), other vegetable oils contain less than 1.5% palmoleic acid; second, the main fatty acids of seabuckthorn fruit oil are palmitic acid(23.9%-38.06%), palmitoleic acid(27.9%-38.8%) and oleic acid(24.3%-30.97%). These three components account for 89%-92% of the total fatty acids.

1.2 Identification of seabuckthorn fruit oil
1.2.1 Identification by odor
Sea buckthorn fruit oil is separated from fresh fruit juice by centrifugalization, which owns characteristic odor of sabuckthorn fruits, the odor can help to identify the quality initially.

1.2.2 Identification by beta-carotene and alfa-tocopherol
Sea buckthorn fruit oil contains a lot of carotenoids and vitamin E, which can help us to identify if it’s blended with palm oil, rice bran oil, soybean oil and castor oil.

1.2.3 Fatty acids identification
It has been known that sea buckthorn fruit oil contains a large amount of palmitoleic acid, which can be used to identify seabuckthorn fruit oil.

1.3 Identification of sea buckthorn fruit oil mixed with other vegetable oils
The fatty acids of sea buckthorn fruit oil are mainly palmitic acid, palmitoleic acid and oleic acid, and the levels of the three have their specific ranges. We can use the fatty acids change to prove the presence of other oils and the types of oils mixed with sea buckthorn fruit oil. Vegetable oils are divided into lauric acid oils, palmitic acid oils, oleic acid-linoleic acid oils according to their main fatty acids percentage.

1.3.1 Identification of sea buckthorn fruit oil mixed with lauric acid oilsLauric acid oils include mainly coconut oil and palm oil, their main feature is an abundance of lauric acid(44%-52%). When lauric acid(>1.5%) is found in sea buckthorn fruit oil, which proves that lauric acid oils are added.

1.3.2 Identification of sea buckthorn fruit oil mixed with palmitic acid oils
Palmitic acid oils include cotton seed oil and palm oil. The fatty acids of cottonseed oil are mainly palmitic acid, oleic acid and linoleic acid. When sea buckthorn fruit oil is mixed with cottonseed oil, its fatty acid composition will change as follows: palmitoleic acid level decreases, linoleic acid level increases, while palm acid and oleic acid remain almost the same, the total unsaturated components increase.

The total three main fatty acids decrease. Therefore, if palmitoleic acid level is less than 27%, linoleic acid is higher than 6%, or the total unsaturated components is more than 69%, the total of the three main components is less than 88%, then sea buckthorn fruit oil may be mixed with cottonseed oil.

The main fatty acids of palm oil are palmitic acid and oleic acid. When sea buckthorn fruit oil is blended with palm oil, the following changes happen: palmitoleic acid level decreases, palmitic acid and oleic acid increase. When palmitoleic acid level is low in sea buckthorn fruit oil, it is possible that the sea buckthorn fruit oil is mixed with palm oil.

1.3.3 Identification of sea buckthorn fruit oil mixed with oleic acid-linoleic acid oils
There are 3 classes of oleic acid-linoleic acid oils: the first class is oils with higher oleic acid, including peanut oil, tea seed oil and almond oil; the second class is oils with oleic acid and linoleic acid at the same level, including sunflower oil, sesame oil, corn oil, rice bran oil, sorghum oil, grape seed oil, soybean oil and wheat germ oil; the third class is oils with higher linoleic acid and linolenic acid, including poppy seed oil, perilla seed oil, hemp seed oil, tallow seed oil and tung oil.

When the first calss oils are mixed with sea buckthorn fruit oil, oleic acid increases, palmitic acid and palmitoleic acid decrease. Therefore,if the level of oleic acid in sea buckthorn fruit oil is higher than 31%, while the level of stearic acid is higher than 2%, sea buckthorn fruit oil may be mixed with the first class oils.

When sea buckthorn fruit oil is mixed with the second class oils, oleic acid and linoleic acid content will increase, while palmitic acid and palmitoleic acid content will decline, the total three main components will decrease. Therefore, if the content of palmitoleic acid in sea buckthorn fruit oil is less than 27%, oleic acid more than 31%, or linoleic acid more than 7%, the total content of the three main components is less than 89%, then sea buckthorn fruit oil may be mixed with the second class oils.

When sea buckthorn fruit oil is mixed with the third class oils, the total amount of the three main components will decrease, while the content of linoleic acid and linolenic acid are obviously high. If the content of the three main fatty acids in sea buckthorn fruit oil is lower than 89%, linoleic acid higher than 7% and linolenic acid higher than 3.5%, then it is possible sea buckthorn fruit oil mixed with the third class oils.

1.3 4 Identification of sea buckthorn fruit oil mixed with castor oil and rapeseed oil
Castor oil is rich in ricinoleic acid (83.6%-98.0%), when sea buckthorn fruit oil is mixed with castor oil,ricinoleic acid will be found in the oil, consequently it proves sea buckthorn fruit oil is mixed with castor oil if ricinoleic acid exists. Rapeseed oil (except for rapeseed oil with low erucic acid and no erucic acid, they belong to oleic acid – linoleic acid oils) contains a large amount of erucic acid (40%-55%), sea buckthorn fruit oil mixed with raseseed oil will bring erucic acid, so as long as erucic acid is found in sea buckthorn fruit oil, it must be mixed with rapeseed oil.