Rice Germ Oil

Base Oil
INCI: Oryza sativa (Rice Germ) Oil
Comedogenicity: 2
Composition: Oleic acid (up to approx. 48 %), linoleic acid (up to approx. 42 %), palmitic acid (up to approx. 23 %), stearic acid (up to approx. 3 %), linolenic acid (up to approx. 2 %), behenic acid (up to approx. 2 %), γ-Oryzanol (up to approx. 2 %), phytosterols, tocopherols.
Iodine number: 89 – 108.
Cosmetic use: Dry, sensitive skin.
Shelf life: Up to 12 months in dark and cool storage. Unrefined oil, however, becomes rancid more quickly.

Plant

The cultivated rice plant Oryza Sativa grows between 50 and 160 cm tall and can form up to 30 stalks. Each stalk carries a narrow overhanging panicle with 80 to 100 uniflorous ears, on which the hard lemmas (rice shell) sit. A plant can thus bear almost 3000 fruits. The lemma forms the outermost shell of the rice grain. Under the husk lie the intergrown fruit and seed shells. The fruit is a caryopsis and the rice grain itself consists almost exclusively of pure rice starch. At its narrow end is a seedling, which is responsible for the development of a new plant and contains the most nutrients.

Extraction of rice germ oil

The yellow to light brown rice germ oil is obtained by extraction with hexane from the rice bran, which contains the seedlings or outer layers of the rice grain. Rice germ oil that is processed for cosmetics is clear to pale yellow and odorless. Among other enzymes, the rice bran contains so-called lipases, which cause the decomposition of proteins and carbohydrates. These are deactivated by heating the mass to at least 130 degrees Celsius. This can lead to an increased proportion of free fatty acids, which harms the quality of the rice germ oil. In this state, the raw oil cannot be used for medical purposes or as a food product, since it contains approximately 3-20% free fatty acids and 5-8% unsaponifiable. These must first be removed, which is why the oil is cleaned and deacidified after extraction.

Cosmetic use of rice germ oil

Rice germ oil is considered a traditional beauty product in Japan. The oil is used as an additive to cosmetic products for all skin types. It is considered to be a rather light, low-grease oil that soothes irritated and dry skin. The composition of linoleic and palmitic acid, vitamin E, and oryzanol has a highly antioxidant effect and is also suitable as natural protection against sunlight. The contained Gamma-Oryzanol is able to absorb UVA and UVB radiation. The oil is therefore often used in sun protection products and daycare products.

In natural cosmetics, rice germ oil is also frequently used in the production of soaps. Homemade soaps made from this oil have similar properties to soaps made from olive oil. They are very soft and develop a creamy foam.

Benefits of rice germ oil for skin

very skin friendly
soothes irritated and dry skin
has softening abilities
light natural sun protection
has antioxidant effects
suitable for making soaps

Internal use of rice germ oil

Rice germ oil is said to have a positive effect on the cardiovascular system and an anticancerogenic (cancer preventing) effect due to the different components such as γ-oryzanol, tocotienols, tocopherols and squalene. These components have antioxidant properties.

The oil has been used for a long time in Asia as a cholesterol-lowering agent because it contains phystosterols (including a lot of ß-sitosterol), which can inhibit the synthesis of cholesterol. In addition, y-oryzanol, which is mainly extracted from rice germ oil, can be found in dietary supplements in the sports sector. It is speculated that it increases testosterone levels.

Buy rice germ oil – what to consider?

Rice germ oil is offered in different qualities. These differ mainly in processing and their content of gamma-oryzanol. Also the content of lecithins, phytosterols and tocopherols is very variable.

When buying rice germ oil you should therefore pay attention to these ingredients. The refined cosmetic oil contains only 1% of gamma-oryzanol, 66% of tocopherols and 95% of phytosterols. Lecithins are no longer present, but about 99 % of the unhealthy fatty acids are destroyed.

There are also cheaper oils for dogs and horses, but these have not been further investigated. These should therefore not be used as food or for cosmetic purposes.

Sources

Sources: Krist, Sabine (2013): Lexikon der Pflanzlichen Öle und Fett. Vienna: Springer Verlag. | Braunschweig, R. (2020): Pflanzenöle - über 50 starke Helfer für Genuss und Hautpflege. Wiggensbach: Stadelmann Verlag.