19 Oct. 2017
Their exceptional visual, olfactive and gustative richness make citrus fruits an extraordinary agent of enhancement and highlighting fragrances in desserts. During a visit to the corsican citrus conservatory, Pierre Hermé, pastry chef of excellence exchanged views with Yann Froelicher, researcher in citrus fruits genetics.
Over the last ten years or so, new citrus fruits have appeared in gastronomy and haute patisserie, revealing fruits that were yet unknown, such as the Buddha’s hand, with its finger-shaped claws, the yuzu, the combaya, the sudachi or the caviar lemon with its flesh like little balls that crack in the mouth, delivering an acid juice. Pierre Hermé could not avoid using these fruits: ‘to me, citrus fruits, and lemon more than any other, are part of the seasonings of pastry, just like sugar or salt. These fruits are special because of their acidity, like the lemon, but also because of their sourness and of their fragrance”. The pastry chief is indeed as much concerned by the taste inside the mouth as by the “nose” of its creations…
A fruit with infinite potentials
“Lemon is without doubt the citrus fruit I use most. I use it to add flavour to my cakes or to enhance the taste of strawberries”. Pierre Hermé obviously finds its supplies ‘à la source’ nd buys his lemons in Corsica. “We use between 300 and 400 kilos of lemon every week, depending on the time of year and on our creations. This is an ideal companion. Bergamot is exceptional, as well as lime, which I love. Its marvellous zest makes a great seasonin, like the Buddha’s hand”.
On the scientific side, Yann Froelicher, who has been working on citrus fruits in Corsica for twenty years or so and manages an innovation programme on the varieties, finds them simply “extraordinary”. “These fruits have a universe of their own with their diversity in phenotypes (visual), from the mini kumquat of half a centimetre to the 5Kg grapefruit, not to mention their extraordinary range of colours. Such a visual diversity, in the mouth or with the nose, is unique in the vegetal world and they can be used as fresh fruits, in cooking and in pastry. They are also used in perfumery, in pharmacy, in alcohols and in the juices industry.
Exactly under the sun…
If botanists do not agree on the number of species or botanic types of citrus fruits, as Yann Froelicher explains, each species includes many varieties. “Orange has about 200 to 300 varieties and new varieties are created each year. The orange tree is the one citrus tree that has known the most natural mutations, as it is the oldest. It probably appeared in South-East Asia 5,000 years ago. There exists blood oranges, half-blood oranges, with or without seeds, dessert fruits, juice fruits… The same goes for clementines, with more than 100 varieties: common, Nules, Clemenrubi, precocious or tardy”. They came from Asia with the great conquerors and through the commercial routes. The citron (of the citrus genus) came first to the West, as soon as the 3rd century BC. “Traces of it can be found in the writings of Theophrastus who mentions Alexander the Great as having brought back citron from the Indus valley”. Citrus fruits then travelled around the Mediterranean, where people like them sweet, in North America, with Christopher Columbus, and then in South America, before reaching South Africa and Australia, where they have only been grown for a century and a half. Now parading with effects of style in our plates, these fruits, “the most powerful intensity of taste” according to Pierre Hermé, are also very good to health: a true sunshine in winter, which one could not do without.
A bit of botany
Citrus fruits belong to the family of Rutaceae. There exists several genus among citrus fruits, of which Citrus is the most important as it includes most of the cultivated species.
Citrus includes 4 ancestral species: lemons, grapefruits, mandarins and
micrantha-papedas. These have crossbred by sexual hybridisation and have created numerous varieties such as the bigarade (sour orange), which is a direct crossbreed between grapefruit and mandarin or the lemon tree, which is a crossbreed of bigarade and lemon. These varieties are multiplied by cloning on rootstocks. As for the bergamot, it is the result of a return crossbreed between a lemon and a bigarade.
Truly a “seasoning” in pastry and gastronomy, citrus fruits are also an essential part of perfumery. Sour orange (bigarade), to start with: its essential oil of neroli is used in the composition of great classics, such as Eau de Cologne.
Last but not least, citrus fruits are also very beneficial to health. Ultrarich in vitamin C, they are a formidable source of energy. Not to forget their use as an excellent antioxidant agent and as a phlebotonic tanks to hesperidin, a natural flavonoid. They also assist in blood circulation and are good for the heart and arteria. One shortcoming? Their origin in subtropical and tropical areas make them sensitive to frost. They prefer the mildness of the South of France and the Mediterranean rim, to the colder regions, Corsica to start with !
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