Alpha-linolenic acid or α-Linolenic acid (ALA) (18:3n-3) is an 18-carbon fatty acid with three double bonds at carbons 9, 12, and 15. It is an essential n-3 fatty acid which is a required nutrient for humans and can be obtained through diets including both plant and animal sources. ALA can be converted by elongases and desaturases to other beneficial n-3 fatty acids such as EPA and DHA, which contribute to normal brain development, normal vision, and decreased risk of cardiovascular diseases. Animals and mammals cannot provide ALA, while plants are the richest source for supplying it. This section summarized fruit, spice, herb, and seed oils rich in ALA.

Black raspberry seed oil

Black raspberry is a member of the genus Rubus from the Rosaceae family, which is also known as caneberries. The concentration of α-linolenic acid is 35% of the total fats, and unsaturated fatty acids comprise 98–99% of the content. linoleic acid (LA) is the predominant fatty acid but ratios of n-6 to n-3 fatty acids are very low at 1.6:1. The overall fatty acid composition of black raspberry seed oil is very similar to red raspberry seed oil.

Red raspberry seed oil

Red raspberry seed oil contains 29.1–32.4% ALA. The amounts of both LA and ALA are lower than those in black raspberry seed oil and the ratios of n-6 to n-3 fatty acids are 1.6–1.8:1.

Boysenberry seed oil

Boysenberry seed oil is similar to the oil of other caneberries (black raspberry, red raspberry, and marionberry), having a high percentage (19.5%) of ALA and a ratio of n-6 to n-3 fatty acids of 2.8:1.The total unsaturated fatty acids comprise over 91% of the seed oil and polyunsaturated fatty acids (PUFAs) are very high at 73.3%, but stearic, palmitic, and total saturated fatty acids (SFA) are higher than all the other caneberry seed oils.

Marionberry seed oil

Marionberry is a blackberry hybrid and another member of the caneberry family. The oil was shown to contain a relatively high percentage of n-3 fatty acids in the form of ALA (15.7%). This amount is lower than that of the other caneberry seed oils, such as black raspberry, red raspberry, and boysenberry seed oils. The n-6 to n-3 fatty acid ratio is 4:1, which is the highest among the caneberry group.

Blueberry seed oil

Blueberries contain high concentrations of n-3 fatty acids. ALA is the sole source of the n-3 PUFA and comprises 25.1% of the total fatty acids; which can decrease the ratio of n-6 to n-3 fatty acids (1.7:1). LA is the predominant fatty acid in the blueberry seed oil followed by ALA, oleic, palmitic, and stearic acids.

Cranberry seed oil

The amount of ALA is found to be 22.3–35% in cranberry seed oil. The ratio of n-6 to n-3 fatty acids is low between 1.2:1 and 2:1.

Sea buckthorn seed oil

The Sea Buckthorn is rich in nutrients. Hippophae rhamnoides are subspecies of H. rhamnoides L. They contain relatively high percentages of ALA, GLA, and oleic acid. Sea buckthorn seed oil has an n-6 to n-3 fatty acid ratio of 2:1. Other fatty acid constituents include palmitic, stearic, and vaccenic (18:1n-7) acids.

Basil seed oil

With regard to ALA, palmitic, and stearic acids, basil species have fatty acid profile similar to that of flax seed oil. Flax and basil seed oils have 52% and 57.4–62.5% ALA, respectively. The n-6 to n-3 fatty acid ratio of the flax seed oil is 1:3.2, while the ratio is 1:1.6–1:3.6 for basil seed oils.

Hemp seed oil

ALA, GLA (18:3n-6), and LA constitute 15.1–19.4%, up to 3.6% and 53.4–60.0% of total fatty acids of hemp seed oil. Linoleic acid is the most predominant fatty acid followed by ALA, oleic, palmitic, GLA, and stearic acids. Other fatty acids including eicosadienoic, arachidic (20:0), and behenic (22:0) acids are also detected in small quantities.

Perilla seed oil

Perilla is a member of the mint family (Lamiaceae or Labiatae). Perilla seed oil contains 51–35% oil, which is similar to flax seed oil fatty acid profile and the amount of PUFA is more than 70% of the total fatty acids. Perilla contains more than 60% ALA, followed by LA and oleic acid. The LC-PUFA of perilla is more than that of cotton.

Chia seed oil

Chia is an annual herbaceous of the mint family (Labiatae). Chia seeds contain 40–25% oil. The amount of PUFA, especially ALA, is high in chia oil, which is higher than flax seed oil. Abundance of LA in chia oil is in the second place (26–17%) and PUFA levels in chia oil reach 83%, which is the highest value among edible oils. In addition, chia oil has the lowest amount of SFA.

Camellia seed oil

Camellia belongs to Brassicaceae family. Camelina is a cruciferous plant, which is a member of the mustard family. It has fatty acid composition similar to that of flax seed. The oil content of camellia is 29–45%. The amount of camellia unsaturated oil is less than that of flax seed, but its oil level is high compared to sunflower and canola oils.

Walnut seed oil

Walnut is a member of the nut family. The fatty acid composition of walnut is 59.7% LA, 13.1% ALA, 15.9% oleic acid, 2.8% stearic, and 8.1% palmitic acid.

Echium oil

Echium seed oil has a unique ratio of ω3 to ω6 fatty acids among plants. Echium oil is mainly composed of ALA (30–33%), LA (14–18%), γ-linolenic (10–13%), stearidonic (13–15%), oleic (14–17%), and palmitic (6–7%) acids. It has been found that Echium plantagineum L. contains significant amounts of GLA, ALA, and SDA in seed lipids.

Flax seed oil

Flax seed is a member of the Linaceae family. ALA includes a high proportion of total PUFAs in flax seed oil. Due to the high content of this unique fatty acid, flax seed oil is used as a nutritional supplement. Soybean and sunflower oils contain lower amounts of SFA compared to flax seed oil.

Canola seed oil

Canola oil has low amounts of erucic acid (<2%) and glucosinolates (<30 μmol) and high amount of oleic acid. Canola is another source of ALA. Among all the oils, canola oil contains the lowest amount of SFA.

Soybean seed oil

Soybean is the most important oilseed produced in the world. The presence of relatively high amounts of ALA in soybean oil makes it sensitive to oxidation.

Rubber seed oil

The fatty acid composition of rubber seed oil comprises of saturated FA (19.12 ± 0.28%) such as palmitic (8.56 ± 0.07%) and stearic (10.56 ± 0.02%) acids and unsaturated FA (79.45 ± 0.31%) such as oleic (22.95 ± 0.15%), linoleic (37.28 ± 0.10%), and linolenic (19.22 ± 0.21%) acids.

Rose seed oil

Major fatty acids present in the rose seed oil include LA (45.38–54.58%), ALA (13.67–24.75%), oleic acid (11.97–21.08%), and palmitic acid (6.54–12.97%). The essential ratio (ω6:ω3) varies from 1.8:1 to 3.4:1 and oil content in seeds range from 1.3 to 9.0% in different sections.