Strawberry tree (Arbutus unedo L.; Ericaceae family) is an evergreen shrub, a native Mediterranean species that is also cultivated in other regions of Eastern Europe . Its fruits are spherical, about 2 cm in diameter, dark red, and tasty only when fully ripe in autumn. A. unedo berries are rarely eaten as fresh fruits, but have some importance in local agricultural communities where they are used for the production of alcoholic beverages, jams, jellies and marmalades .
The fruits are also used in folk medicine as antiseptics, diuretics and laxatives, while the leaves have long been employed as an astringent, diuretic, urinary anti-septic agent and, more recently, in the therapy of hypertension and diabetes . Together with its traditional applications, the wide range of antioxidants in strawberry tree fruit, such as phenolic compounds (e.g. anthocyanins, gallic acid derivatives and tannins ), vitamin C, vitamin E and carotenoids , suggest a potentially high value as a “health promoting food”. (1)
As it is noted in another study, its carbohydrate-rich fruits have a high fructose content and provide 400 kcal per 100 g of dry weight. Total antioxidant activity of strawberry tree fruits was found to be one of the highest of 28 fruits analysed by García-Alonso et al. (2004). The preventive effect of these compounds in chronic health disorders, such as cancer and neurodegenerative and cardiovascular diseases, supports the promotion of their consumption as a healthy food.
Nevertheless, their short optimum period of consumption has probably hampered their commercialization as a fresh product, as well as this species’ cultivation by large-scale agriculturalists. Strawberry tree fruits only reach a really pleasant flavour if consumed slightly overripe, when their high tannin content decreases and sugar content increases. Therefore, they spoil easily and are delicate to transport.
However, the fruits could be easily preserved by freezing or other processing techniques, extending fruit availability beyond harvest time. Although, it is stressed the fact that these fruits at an advanced stage of maturity are popularly said to cause signs of drunkenness, probably due to their high fermentable sugar content, but they haven’t found any scientific reference to their ethanol content.
New potential uses of strawberry tree fruits in the food industry have recently been studied. Alarcão-E-Silva et al. (2001) suggested their possible application as fruit pieces in yoghurt, pie and pastry filling or cereal products. This last category could include energy bars or breakfast cereals. Ganhão et al. (2010) found that the addition of fruit extracts as a functional ingredient in processed meat products prevented protein oxidation. Strawberry tree fruits could also be used as a food colorant, considering their content of β-carotene and anthocyanins. (2)
Bibliography
1. Antioxidant Properties and Neuroprotective Capacity of Strawberry Tree Fruit (Arbutus unedo). Sofia Fortalezas, 1 Lucélia Tavares,1 Rui Pimpão,1 Meenu Tyagi,1 Vera Pontes,1 Paula M. Alves,2 Gordon McDougall,3 Derek Stewart,3 Ricardo B. Ferreira,1,4 and Cláudia N. Santos1,*. s.l. : Nutrients, 2010.
2. Fruit production of strawberry tree (Arbutus unedo L.) in two Spanish forests. María Molina1, Manuel Pardo-De-Santayana2, Laura Aceituno1, Ramón Morales3 and Javier Tardío1,*. s.l. : Oxford Journals, 2011.
