I vividly remember eating my first blood orange when in Italy and thinking that this was the only orange for me. From its brilliant crimson-red centre to its balance of sweet, tart flavours with berry notes, it puts its pale cousins to shame. Every chance I had to eat one during my time there I did.

I have the same sense of excitement when I see them in Hong Kong and find them equally hard to resist. It was the enjoyment of eating two spectacular Moro blood oranges just recently that inspired me to share my passion for this citrus wonder.

Fact and Fiction

The blood orange is a variety of orange. The blood orange is not a cross between an orange and a pomegranate (impossible) and is not the result of crossing a pomelo and a tangerine. 

It is an orange that at some point under went a natural genetic mutation resulting in it having high levels of the pigment anthocyanins. These pigments are uncommon in citrus but are found in many other fruits and flowers including purple cabbage, red grapes, and hydrangeas. The pink pigmented grapefruit is not a result of anthocyanins.

The fruit is smaller than other types of oranges and the degree of internal colour varies depending on the variety and where the orange is grown, some blood oranges also have splotches of red on the skin.

The branches of the tree are covered with thorns, which could also have contributed to the orange's name. 

Three Varieties

The Tarocco, Sanguinello and the Moro are the three most common types of blood oranges.

The Tarocco is native to Italy, in particular the area around Mt Etna in Sicily. The European Union has recognised this region as a special zone of production for the variety (sold in the United States under the trade name Volcano Oranges), and as such is geographically protected. It has a medium-sized fruit, which has little or no seeds, and is considered to be the sweetest of the three and for some the most superior. 

It is reported to be the most popular table orange in Italy; when I lived with an Italian family for several months they were always offered after lunch when in season. It is thought to be a mutation of the Sanguinello and is sometimes called "half-blood" as the pigmentation is not as prevalent as the other varieties. It has the highest level of Vitamin C of any orange. In addition to those grown in Italy, three sub-cultivators of the variety are grown in the US (Florida, California, Texas).

Discovered in Spain, the Sanguinello has a reddish skin, and is considered by Italians to be the late "full-blood" orange because of the higher levels of pigmentation than the Tarocco, and also because it ripens later in the season. Although they mature in February, they can remain on the tree until April, with the fruit in season until late May. They are mainly grown In Italy, Spain and the US. Interestingly the variety grown in California has little or no red colour to the flesh, which is said to be due to the insufficient temperature variation between day and night. 

The Moro, is the most colourful of the three, with a deep red, almost purple-black flesh, stronger flavour and aroma than the other varieties. Moro is thought to have originated in Sicily from a mutation of a bud of the Sanguigno. It is considered the true "full-blood" orange with the highest level of pigment, and its skin is often marked with red spots, patches or veins.

Due to the intense colouring, and in my view because of its superior taste with its hint of raspberry, the Moro is my favourite, followed by the Tarocco. I also prefer blood oranges grown in Italy over those grown in the US. I have seen both varieties, from both countries, for sale in Hong Kong at places like city'super. 

Good for You

The pigment (anthocyanin) is an antioxidant and as such is considered to reduce the risk of many illnesses and disease, as well as anti-ageing. Due to the antioxidant content eating blood oranges may also reduce the risk of heart disease, some cancers, cataracts and LDL cholesterol accumulation. 

Interestingly anthocyanin compounds have been reproduced by the pharmaceutical industry due to their ability to scavenge free radicals and inhibit lipid peroxidation, a key factor in the development of liver disease, diabetes, epilepsy, and heart disease.

Like all citrus they are an excellent source of Vitamin C, an average orange contains approximately 130 per cent of the FDA recommended daily intake, and are also a good source of dietary fibre. They are also a source of folate, calcium, potassium, carotene and Vitamin A.

Enjoying at Home

The blood orange can be used instead of other orange varieties in any recipe that calls for orange, although some adjustment may be needed. They work very well in salads as a counter to strong savoury flavours, such as fennel, beetroot, rocket, and purple cabbage. A popular salad in Sicily is made from blood oranges, fennel, parsley and olive oil.  Another is an orange and carrot salad, dressed with chilli vinaigrette using raspberry vinegar.

More acidic varieties, such as the Moro work well in cooked sauces. For example the Maltese or Maltaise sauce, which is hollandaise sauce with orange juice and rind. The sauce is served over vegetables, particularly asparagus and green beans.

Other popular choices for the blood orange are gelato and sorbet, and as part of a vinaigrette-style dressing. 

For more recipe ideas visit: http://simplyrecipes.com/recipes/blood_oranges, http://www.epicurious.com/tools/searchresults?type=food&search=blood%20orange