by Jovita Turan, December 2, 2020
Strawberry tree (Arbutus unedo L.) belongs to Ericaceae family and is one of the most important species economically compared to the other 20 species of the genus Arbutus. The plant is found to be grown in rocky and well-drained soils and it is native to Ireland, southern Europe, and the western Mediterranean basin, and other areas that have hot summers and mild rainy winters.
Description, Importance, and Usage
Strawberry tree is an evergreen plant that is usually described as a small tree or shrub, smaller than 4 m (1.5-3 m, sometimes can reach up to 9-12 m), that has a gray-brown bark. The flowers of the plant are small blueberry-like and fruits are spherical, red-orange in color, it can be 1-3 cm in diameter and it takes a year for them to ripen. During some months of the year, you can find both flowers and fruits presented on the same tree. Strawberry trees can grow in groups, in uniform populations but most commonly they grow together with other trees, mostly with the ones from Fagaceae family.
The strawberry tree can be propagated by seeds, however, this method cannot assure genetic stability, some special characteristics may be lost, and that means that plant will not be identical to the plant that you collected seeds from. Another method to propagate the plant is by vegetative propagation that can be done in two ways: rooting of cuttings (relatively low, determined to be less than 65%) and/or micropropagation.
The plant has high importance in the Mediterranean ecosystem as it maintains the biodiversity of fauna, it helps to avoid erosion, it regenerated quite strong after fires, and it grows well in poor soils, low temperatures, and dry conditions.
Young branches of the strawberry tree are used in floriculture in floral compositions. The bark of Arbutus unedo can be used to tan leathers, flowers have high amounts of nectar for bees.
The fruits of Arbutus unedo are edible and being collected from October to December. One tree can produce about 7-10 kg of fruits. Before consumption, fruits are usually being processed. Processed products of strawberry tree fruits include jams, marmalades, jellies, cider, aromatic distillate, wines, spirits, and liqueurs.
Nutritional and Medicinal Properties
Fruits and leaves in traditional medicine have been used as an antiseptic, diuretic, astringent, antirheumatic, antidiarrheal, and to fight urinary infections.
High consumption of the fruits lowers the risk of cardiovascular diseases, cancer (lung, oesophagus, and colon), and other diseases referred to as oxidative stress. Quercetin in the fruit had shown hypolipidemic and antiatherogenic properties, while anthocyanins have shown antioxidant and potential to regulate adipocytokine gene expression.
High concentrations of sugar (42-52%) were found in the fruit. The fruit has vitamin C and a high amount of calcium and is believed to be a good source of other minerals. Acids such as lactic, malic, suberic, fumaric, gallic, protocatechuic, gentisic, p-hydroxibenzoic, vanillic, and m-anisic phenolic were identified as well. The bitter taste might be associated with the presence of tannins and other phenolic compounds. The red color of the fruit is correlated with high amounts of anthocyanins and cyanidin. Other found flavonoids in the fruit are the anthocyanin delphinidin-galactoside and the flavonol kaempferol. Moreover, high tannin content is present in leaves.
References
Ayaz, F. A., Kucukislamoglu, M., & Reunanen, M. (2000). Sugar, non-volatile and phenolic acids composition of strawberry tree (Arbutus unedo L. var. ellipsoidea) fruits. Journal of Food Composition and Analysis, 13(2), 171-177.
Celikel, G., Demirsoy, L., & Demirsoy, H. (2008). The strawberry tree (Arbutus unedo L.) selection in Turkey. Scientia Horticulturae, 118(2), 115-119.
Gomes, F., & Canhoto, J. M. (2009). Micropropagation of strawberry tree (Arbutus unedo L.) from adult plants. In Vitro Cellular & Developmental Biology-Plant, 45(1), 72-82.
Morgado, S., Morgado, M., Plácido, A. I., Roque, F., & Duarte, A. P. (2018). Arbutus unedo L.: From traditional medicine to potential uses in modern pharmacotherapy. Journal of ethnopharmacology, 225, 90-102.
Oliveira, I., 2010. Phytochemical characterization of leaves and fruits of Arbutus unedo L., Master thesis in food quality and safety, Polytechnic Institute of Bragança, Portugal
Özcan, M. M., & Hacıseferoğulları, H. (2007). The strawberry (Arbutus unedo L.) fruits: chemical composition, physical properties and mineral contents. Journal of Food Engineering, 78(3), 1022-1028.
Pallauf, K., Rivas-Gonzalo, J. C., Del Castillo, M. D., Cano, M. P., & de Pascual-Teresa, S. (2008). Characterization of the antioxidant composition of strawberry tree (Arbutus unedo L.) fruits. Journal of Food Composition and Analysis, 21(4), 273-281.
Picture: http://www.tropikmeyveci.com/siradisi-meyve-agaclari/kocayemis-dag-cilegi-sandal/ access: 2020.12.02