300–330
Source: Chadwick 1988; Bailey and Shahidi 2005; Firestone 2006; Tan et al. 2009; Azlan et al. 2010; Neagu et al. 2013; Amira et al. 2014; Roiaini et al. 2015; Alajtal et al. 2018; Godswill et al. 2018; Xu et al. 2018; Beszterda and Nogala‐Kałucka 2019.
Table 2.3 presents the main fatty acids in oilseed oils. Linoleic acid, oleic, and α‐linolenic acids are the primarily unsaturated fatty acids accounting for 88.83% of total lipids. Palmatic acid is the major saturated fatty acid (10.42%). As reported in Ramos et al. (2009), linoleic acid (54.0%), oleic (23.9%), palmitic acid (11.3%), and α‐linolenic acids (6.1%) are the major fatty acids present in soybean oil. Canola oil, also known in Europe as rapeseed oil, has low concentrations of saturated lipids and, in line with soybean, the protein content is high. In particular, percentages of 23 and 40% have been reported in rapeseed and soybean respectively (Bauer and Kostik 2014).
2.2.4 Bioactive Properties
Phenolic, tocopherol, and sterol profiles of oilseed oils are the main important bioactive compounds reported. Palm oil is one of the potential sources of tocotrienol, part of Vitamin E, and in turn, palm oil is a great source of this vitamin helping as antioxidant protector against the oxidation of lipophilic molecules and linked to skin protection when consuming in diet (Enig et al. 1983).
Tocols are synthesized only by plants; however they are very important dietary nutrients for humans and animals (Dunford and Dunford 2004). Tocopherols are present in oilseeds, leaves, and other green parts of higher plants. In the extracted seed oil the main compounds with antioxidant activity are tocopherols and also tocotrienols, which are compounds with vitamin E activity. These compounds protect the oil from oxidative deterioration (Soldo et al. 2019). Furthermore, they prevent metabolic, proliferative, inflammatory, and oxidative damage (Galli and Azzi 2010).
Sunflower, safflower, and cottonseed oils are the richest source of vitamin E (Table 2.2). Sunflower has a high content of α‐tocopherol. Groundnut and cottonseed present balanced levels of α‐ and γ‐tocopherol. Olive oil presents a similar tocochromanol profile to sunflower, however its α‐tocopherol content is lower (Velasco and Ruiz‐Méndez 2015). The content of tocopherol in soybean at pH 6.8 is β‐, γ‐tocopherol 0.27 ± 0.02, δ‐tocopherol 0.47 ± 0.00 and α‐tocopherol 0.02 ± 0.00 mg/g neutral lipid of oil bodies (Chen et al. 2014).
Some phytosterols are important components, they are part of the steroids group, and participate in the chemical defense of the plants, as for example, triterpenoids or campesterol which is one of the most important phytosterols and has a similar structure to cholesterol. Because of this, dietary phytosterols reduce intestinal absorption of cholesterol and reduce its levels (Plat and Mensink 2005). Technologically, phytosterols increase thermal stability of oils with high levels of polyunsaturated fatty acids (Winkler and Warner 2008).
These compounds can be present in the oil in free form or esterified with glucosides, ferulic acid, or fatty acids. Ferulic acid‐esterified sterol is known as oryzanol and has been reported to have diverse health benefits, including hypolipidemic and antioxidant effects or stimulation of growth and hypothalamus activity (Dunford 2004). β‐sitosterol is the phytosterol predominant in the profile of vegetable oils. Brassinosteroids, which are plant hormones essential for normal growth and development (Bishop and Yokota 2001) are present in high concentration in rapeseed oil. Soybean decreases its content of β‐sitosterol with pH changes, at pH 6.8 0.82 ± 0.10 mg/g neutral lipid of oil bodies, at pH 9.5 with 0.73 ± 0.05 mg/g, and at pH 11.0 with 0.62 ± 0.04 mg/g (Chen et al. 2014).
Table 2.2 Composition table from Food Data Central form USDA (values per 100 g of oil).
| OILS | Energy (kcal) | Total lipid (g) | FA total saturated (g) | FA total MU a (g) | FA total PU b (g) | Vitamin E c (mg) | Vitamin K d (μg) |
|---|---|---|---|---|---|---|---|
| Sunflower oil | 884 | 100 | 10.3 | 19.5 | 65.7 | 41.1 | 5.4 |
| Canola Oil | 884 | 100 | 7.4 | 63.3 | 28.1 | 17.5 | 71.3 |
| Soybean oil | 857 | 100 | 15.7 | 22.7 | 57.7 | 8.2 | 183.9 |
| Groundnut oil | 884 | 100 | 16.9 | 46.2 | 32 | 15.69 | 0.7 |
| Cottonseed oil | 884 | 100 | 25.9 | 17.8 | 51.5 | 35.3 | 24.7 |
| Flaxseed oil | 884 | 100 | 9 | 18.4 | 67.8 | 0.47 | 9.3 |
| Poppyseed oil | 884 | 100 | 13.5 | 19.7 | 62.4 | 11.4 | ‐‐‐ |
| Sesame oil | 884 | 100 | 14.2 | 39.7 | 41.7 | 1.4 | 13.6 |
| Safflower oil | 884 | 100 | 7.5 | 74.8 | 12.2 | 34.1 | 7.1 |
| Olive oil | 884 | 100 | 13.8 |
72.9
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