Carambola (Averrhoa carambola), often called starfruit, does seem like a fruit that is out of this world. This beauty is a member of the Oxalidaceae family, and is considered a slow growing, fast producing tree with evergreen foliage. The foliage is light sensitive and most often folds in upon itself as the sun goes down. The carambola is thought to have originated in Sri Lanka and Indonesia, but is also considered a native to the Philippines, Malaysia, Nepal, Vietnam, and India. Carambola has also been cultivated in other areas such as Australia, Hawaii, Central and South America, and even in southern portions of North America.
What makes this fruit unique is that when cut at the cross section it resembles a star. Plus, the citrus-like flavor this fruit offers comes in two forms, either sweet or sour. The more flavorful and sour variety is typically smaller, and contains more oxalic acid, while the sweeter and mild flavored variety is usually larger and has less oxalic acid. The importance of being aware of the oxalic acid in any food is that foods that are high in oxalic acid can cause problems for those that are susceptible to developing kidney stones composed of calcium oxalate. Plus, in some people that suffer from impaired kidney function, carambola can be deadly, even in very small amounts.
If carambola is something that works in your diet, know that in one medium sized fruit (91 grams) you will receive 28 calories, 0 grams of fat, 1 gram of protein, and 6 grams of carbohydrates (3 grams of which is dietary fiber). Carambola is an excellent source of Vitamin C, and also offers Vitamins A, E, and all the B’s, except for B-12, and the minerals calcium, copper, non-heme iron, magnesium, manganese, phosphorus, potassium, selenium, and zinc. Carambola also contains flavonoids, including quercetin, epicatechin, and gallic acid. These flavonoids help reduce inflammation, reduce risks of certain types of cancer, improve insulin sensitivity, and in some instances, improve allergies.
To grow carambola, use plump and fully developed seeds planted in damp peat moss, preferable in loamy soil, allowing the seeds to germinate. You can start a seedling indoors, and move it later to an area in full sun, in a location where the soil can adequately drain. While the roots due exhibit antimicrobial properties, which protect the tree, consistently flooded areas can still cause rot. These tropical and sub-tropical classified plants can tolerate freezing temperatures down to 27° F for limited periods of time, and can thrive in elevations up to 4,000’ in warm enough climates. Carambola does need abundant rainfall or watering. In areas like Australia, it’s reported that fruit quality is best when rainfall reaches 70”/year.
When planting trees be mindful that they need to be spaced 30’ apart to allow for adequate growing space and nutrient availability in the soil. You may plant just one tree and it will still bear fruit, but planting additional trees of different varieties allows for cross-pollination resulting in increased crop production. These charming trees produce delicate pinkish-red to lavender flowers and will produce fruit usually within 10-14 months after planting. The fruit is considered to be ripe when it’s bright yellow, with just a slight green tinge, and the ridges have a hint of brown. Typically, when fruit is ripe it will naturally fall to the ground. Not much bothers this tree, except for fruit flies. Wrapping the fruit can help prevent damage from these flies.
When you have harvested some of your ripe fruit, you can eat the fruit fresh or use it to make some wonderful recipes. Carambola can be added raw to salads, used to make baked goods, or used to create delicious jams. One of my favorite ways to use carambola is for making bread!
1½ cups almond flour
½ cup coconut flour
2 cups pureed carambola (sweeter carambolas work better in this recipe)
½ cup butter – softened
4 eggs – slightly beaten
½ teaspoon vanilla extract
1 teaspoon baking powder
½ teaspoon cinnamon
1 cup shredded unsweetened organic coconut
½ teaspoon salt
Preheat oven to 350° F
Grease bread pan
Place a cut piece of parchment paper that fits flat onto the bottom of the pan
In a large bowl, place butter and beat with a mixer until whipped
Add eggs, carambola puree, and vanilla and beat with mixer until combined
Add in all dry ingredients, except coconut
Stir together, blending thoroughly
Stir in coconut
Mixture should be slightly pourable but not runny. If it’s runny add a bit more of each flour
Pour mixture into prepared bread pan
Bake for 45 minutes or until an inserted toothpick comes out clean
Let bread cool in pan for 2-3 minutes
Run a knife along the edges to unstick the sides of the loaf
Invert pan onto a wire rack and then flip right side up
Let it cool for 20-30 minutes
Slice and enjoy!
Star of the Show!
Carambola or starfruit, no matter what you call it, is an unmistakable and distinctive looking fruit. Its delicious flavor enhances any dish it is added to or tastes great all on its own. With beautiful flowers, fruit, and foliage this tree is exactly what your garden landscaping needs to add the perfect exotic flare!
Choose My Plate.gov. US Department of Agriculture. SuperTracker. https://www.choosemyplate.gov/tools-supertracker
Crane, J. 2015. University of Florida IFAS Extension. Carambola Growing in the Florida Home Landscape. Publication #HS12. https://edis.ifas.ufl.edu/mg269
Dobbs, J., et al., February 12, 2012. Department of Human Nutrition, Food and Animal Sciences, College of Tropical Agriculture and Human Resources, UH-Manoa. Star Advertiser. Health Options. Oxalic acid in star fruit can kill kidney patients. https://www.nutritionatc.hawaii.edu/HO/2012/488.htm
Payal, G., et al., May 01, 2012. International Research Journal of Pharmacy. Phytocemical and Pharmacological Profile of Averrhoa carambolaLinn: An Overview. ISSN: 2230-8407. V: 3 (1). https://www.irjponline.com/admin/php/uploads/796_pdf.pdf