Flaxseed oil

1.1 flaxseed oil introduction
Flaxseed oil from the seeds of flax, flax was originally grown to obtain fiber, and later gradually used as oil. Linum usitatissimum L, the scientific name of linen, in the Sertic language, that is, “useful line” meaning. Flax is divided into oil flax, oil and fiber with flax and fiber with flax, the seeds can be extracted oil. Common flax seed is divided into brown, light yellow two kinds.

1.2 linseed oil composition of fatty acids and triglycerides
Linseed oil in α-linolenic acid content of 39% to 62%, usually more than 50%, linoleic acid content of 12% to 30%, oleic acid content of 13% to 39%. Compared with many oil seeds, flaxseed production, high alpha-linolenic acid content in oil, has become the first choice of omega-3 dietary supplements, can be said to be inexpensive. Flaxseed oil also has the advantage of a balanced ratio of Omega-3 / Omega-6.

Flaxseed oil has 19 kinds of content of 0.9% or more of triglycerides, almost all tri-unsaturated, diunsaturated triglycerides, while the two saturated triglycerides, tri-saturated triglycerides are very few, so its low-temperature stability is very good.

1.3 Linseed oil contains nutrients
Compared with soybean oil, canola oil, etc., flaxseed oil has only a moderate level (about 500 ppm) of total tocopherols, but its tocopherol composition is special, γ-tocopherol accounted for about 90%, and half of the plastochromanol-8, which is rare in vegetable oils, plastochromanol-8 is a kind of γ-tocopherol polyphenols, the length of the side chain of γ-tocopherol, twice the length of γ-tocopherol, which is a kind of γ-tocopherol. tocopherol and is the most potent antioxidant of all the tocopherols.

Despite its high linolenic acid content and moderate total tocopherols, flaxseed oil has good oxidative stability because of its abundance of tocopherols and tocotrienols.

Flaxseed oil contains moderate levels (2300 ppm) of phytosterols, which are abundant, mainly β-sitosterol, followed by canola stanols and oat stanols, with canola stanols in trace amounts. Rapeseed sterols are characteristic components of Oleaceae and can be used to differentiate flaxseed oil from adulterated rapeseed oil.

Whether it is the type or content of lignans, linseed are far more than common plants, the content of other oilseeds, grains, legumes, fruits and vegetables, 75-800 times, the majority of these lignans can be entered into the linseed oil, mainly open-ringed isoliquefoliols, bird fat phenol and so on. Ring-opening isoliquefol by the linseed in the ring-opening isoliquefol diglucoside (SDG) in the oil part of the decomposition and become, the oil in the ring-opening isoliquefol content of 0.03% to 0.22%.

Linseed oil also contains more than ten kinds of cyclic peptides, the total amount can reach 500-2000ppm, these cyclic peptides consist of 8-9 amino acids, they have chelating metal ions, lead exclusion, antioxidant, immunosuppression and other physiological activities and effects. Among them, cyclic peptide E is believed to be related to the characteristic bitter flavor of linseed oil, the virgin oil of fresh linseed has a low content of cyclic peptide E. With the prolongation of storage time, the content of cyclic peptide E increases, indicating that the freshness of linseed oil decreases.

Corn oil

2.1 Introduction of corn oil
Corn is the world’s most important food crop, but also China’s largest production of food crops, China’s annual production of corn up to more than 200 million tons, accounting for about 40% of the total annual production of grain. Conventional varieties of corn seeds contain only 3% oil, does not belong to the oil, but its starch system after the by-products of corn germ contains up to 30% oil, is a high-quality raw material for oil, the current market corn oil that is made from corn germ, it is also known as corn germ oil, China’s current production of corn oil is about 1 million tons.

2.2 Fatty acid and triglyceride composition of corn oil
Corn oil is a typical linoleic acid – oleic acid type fat, five major fatty acids accounted for 99.4% of the total fatty acids, including linoleic acid 34.0% ~ 65.6%, oleic acid 20.0% ~ 42.2%, palmitic acid 8.6% ~ 16.5%, linolenic acid ~ 2.0%, arachidic acid 0.3% ~ 1.0%, and other fatty acids accounted for only about 0.6%.

Corn oil, despite the high content of unsaturated fatty acids, and mainly oleic acid and linoleic acid, but only a small amount of linolenic acid, which is one of the reasons for the higher stability of corn oil.

The triglycerides of corn oil are mainly composed of more than 50% tri-unsaturated triglycerides and more than 25% diunsaturated triglycerides, so it has excellent low temperature stability.

2.3 Nutrients contained in corn oil
Corn gross oil unsaponifiables up to 2.0% to 2.5%, for other common vegetable oils, about 60% of the unsaponifiables are phytosterols, and the rest are ferulic acid sterol esters, tocopherols and tocotrienols, etc..

Corn germ oil contains more tocopherols and tocotrienols, second only to wheat germ oil, deodorized corn oil in the tocopherols still accounted for about 0.1% of the weight of the oil, containing α-, γ-, δ-tocopherol and β-, γ-tocotrienols a total of five components, of which 70% ~ 80% for γ-type, 20% ~ 25% for α-type, 3% ~ 5% for δ-type; tocotrienols are also γ-dominant, the content of 5.8 percent of the total tocopherols. 5.8% of total tocopherols. In the prevention of LDL oxidation and tumor cell formation, γ-type is superior to α-type, and the combination of the two is superior to single α-type.

The total sterols of corn germ oil are still greater than 1% after refining, higher than most vegetable oils. Whole kernel or corn with skin oil is conducive to improving the sterol content of the oil.

Its sterols include methyl sterols, 4-methyl sterols, triterpene alcohols and other 3 major categories, but the most important is sterols such as sterols, canola sterols and soy sterols, the content of sterols show sterols > canola sterols > soy sterols law.

Sterols in corn oil mainly exist in the form of sterol esters. Typical corn germ oil sterol ester / sterol ratio of 1.6, whole or with the skin oil production is conducive to improve the sterol ester content.

Corn oil and rice bran oil are rich in ferulic acid sterol ester, but the composition of the two is significantly different, rice bran oil in ferulic acid sterol ester to ring wood pineapple alcohol class ferulic acid ester as the main body and contains a moderate amount of sterol class ferulic acid ester, the general name of gluten Vitamin. Corn oil ferulic acid sterol esters, on the other hand, are dominated by methyl sterol-free ferulic acid esters, and contain less cycloartanol ferulic acid esters, which are not usually referred to as glutenin.

Canola Oil

3.1 Introduction of Canola Oil
Canola oil has long been one of the major edible vegetable oils in China, and has been known by many names throughout history, such as brassica oil, coriander oil, brassica seed oil, and so on. Now China’s annual production of more than 14 million tons of rapeseed, cultivars of mustard, cabbage and kale three categories. Canola has yellow, brown and black colors, oil content is generally 30%~40%, belongs to the high oil oilseeds, peeled canola kernel oil content is higher.

China’s canola oil production and marketing areas are wide, mainly in Sichuan, Hubei, Hunan, Anhui and other Yangtze River Basin and Inner Mongolia, Qinghai and other northwestern regions.

The national standard divides canola oil into two categories based on erucic acid content. Those with erucic acid content of 3%-60% are called general canola oil, and those with no more than 3% are called low erucic acid canola oil. Low erucic acid canola oil mainly refers to double-low canola oil, which is known as Canola oil in foreign countries, and also known as “canola oil” in Taiwan and other regions of China. Currently, canola oil accounts for about 15% of the world’s edible oil consumption.

3.2 Fatty acid and triglyceride composition of rapeseed oil
In China, canola oil is divided into general canola oil and low erucic acid canola oil with erucic acid content of 3%.
The main fatty acids of these two types of canola oil are monounsaturated fatty acids, but the former is erucic acid and the latter is oleic acid. The erucic acid content of regular canola oil, i.e., conventional high-erucic acid canola oil, is highly variable and can reach as high as 60%. The nutritional value of erucic acid is controversial, but both scientific research and a long history of consumption indicate that consumption of high-erucic acid canola oil has no adverse effects on humans and may have additional benefits.

Low erucic acid canola oils are best known for the Canadian bred double-low canola (Canola) oil, which can contain less than 2% erucic acid and replace it with oleic acid (more than 50%). Double-low canola oil, like soybean oil, contains about 7% linolenic acid, which is harder to come by, and its ratio of oleic, linoleic, and linolenic acids is more suitable for human needs, thus making it a high-quality cooking oil as well.

Generally the erucic acid in canola oil is mainly distributed in the 1 and 3 positions of triglycerides, while oleic acid and linoleic acid are mainly in the 2 positions. Although its erucic acid content can be very high, the content of tri-erucic acid triglycerides is very low. Low erucic acid canola oil is dominated by tri-unsaturated triglycerides, accounting for more than 70%, while di-saturated triglycerides and tri-saturated triglycerides are almost non-existent, so its low-temperature stability is very good, and it is very suitable for use as cooking oil and salad oil.

3.3 Nutrients contained in rapeseed oil
The total amount of tocopherols in canola oil is 430~2680 ppm, mainly α-tocopherol and γ-tocopherol, and its ratio is generally 1:2.

Canola oil contains about 100 ppm of tocotrienols–plastochromanol-8, which is a derivative of γ-tocotrienol with a longer side chain.

Canola oil is rich in phytosterols with a total content of 4,500 to 11,300 ppm, mainly containing β-sitosterol, canola stanol, rapeseed stanol, and leguminous stanol. Among them, β-sitosterol has the highest content, accounting for about 50%. Canola sterols are unique to canola oil, accounting for 5% to 13% of the total sterols, and can be used to identify canola oil adulterated with other vegetable oils. Half of the sterols in canola oil are in the form of sterol esters.

The polyphenol content of rapeseed is as high as 1.5%~3%, which is 10~30 times higher than that of other common oil seeds, including phenolic acids and tannins. Phenolic acid in the esterification type accounted for 80%, mostly erucic acid; free type 6.5%~16%, mainly erucic acid; tannins are mostly condensed tannins (proanthocyanidins), and condensed tannins are converted into anthocyanidins by acid digestion.

Erucic acid can be decarboxylated to generate 2,6-dimethoxy-4-vinylphenol, also known as Canolol, which has higher antioxidant activity than erucic acid and has physiological activities such as anti-mutagenicity in the process of rapeseed processing.

Canola oil contains 1~2mg/g of Canolol, which may not be detected in refined canola oil.
Thioglucoside is a special substance in rapeseed, which is insoluble in oil and fat and is not toxic, but its degradation products can partly enter into the oil in the process of oil making, which can give pungency and special flavor, and some degradation products such as isothiocyanate have the double effect of both favorable (anticarcinogenic) and harmful (goitre-causing).