Essential oil from orange flowers
Neroli oil. The neroli oil, such called because it became famous thanks to a princess from Nerola, in Lazio region, can be found both as oil and distilled water, obtainable distillating the fresh flowers of the bitter and sweet orange.
Now, vice versa, with the denomination of neroli bigarade, we intend exclusively the oil produced by water distillation of the bitter orange flowers (Citrus aurantium L., sub. Amara var. bigardia Risso) of the family of the Rutacee, which yield is about 0,1%. A better quality and yield of the product it's obtainable with steam current modern plants. About one third of the total distilled essence (alcohol feniethylic) is water soluble.
The distillation of the bitter orange flowers was, in the past century, mainly developed in the South of France, was then diffused in other places as in Italy (Riviera di Ponente), when we obtained essence of excellent quality. Nowadays it's distilled in Algeria, Spain, Syria, Cyprus, but mainly in Sicily and Calabria regions in Italy.
Also the orange flowers, as many other flowers as jasmine, rose, sweet acacia, mimosa, tuberous, ecc., can be treated by volatile solvents (ligroin), to obtain the absolute solution, which olfactory, physic and chemical characteristics are very different from the distilled product.
In fact, while the absolute solution is reddish-brown very deep, the just distilled essence is pale yellow. By light exposition it gradually darkens because of the indol contained and with the passing of the time it assumes a brown-reddish color. The neroli oil is slightly fluorescent, has an aromatic bitter taste and has a very pleasant smell of orange flowers. The pure oil, pure, besides its olfactory characteristics must present the following constant parameters: specific weight at 15° from 0.870 to 0,881; rotator power from +1°30' to + 9°80’ (average + 7°); refraction index from 1,468 to 1,474; acetylation index not more than 1,8; ester number 16¸ 69; tenor in methyl antranilate 0,45¸ 1,10% ; 1 vol. must be soluble in 1¸ 2 alcohol vol. at 80° (the solution is turbid for ulterior addition, and after rest it's possible to collect paraffin crystals). The alcoholic solution in the neroli oil has a fluorescent reaction blue-violet, that is particularly visible when other alcohol is added to the alcoholic solution, and particularly if this has a low gradation. With a prolonged cooling below 0°, the oil makes turbid because of the paraffin separation and sometimes it coagulate in a butter mass.
Because of the high solubility, the distillation waters are treated to get an essence that actually is sold with the name of "absolute of orange flowers from water".
The data of the essence of orange flowers in Tunisia, Algeria and Morocco are similar to the data obtained from the essences coming from Sicily and Calabria. The essence the for someone is more similar to the French Riviera is the one coming from Algeria that has anyway a high rotator power and a higher refraction index.
In the neroli oil there are the following components: l- a pinene, l- canfen, dipenten, decilicaldehyde, l-linalol, linalile l-acetate, fenil etilic alcohol, geraniol and nerol, both free and as esters, a -terpineol, farnesol, nerolidol, methil antranilate, indol, traces of the following acids: fenil acetic, benzoic and palmitic both free and as esters, acetic acid. The oils, or "absolute" of the water, contain big quantities of free fenil acetic acid, methyl antranilat, indol and paraffin.
Once the neroli oil was adulterated adding essences of petitgrain bigarade, or rarely bergamot and orange essences, both as they are and saponified. Another type of adulteration consisted in the addition of flowers of the sweet quality, or fruits of the bigade orange itself, and more rarely also lemon flowers together with the synthetic constituents contained in the essence of the vegetal mass before distillation.
As the neroli oil some years had a very high price, (because of its scarcity) all the aromatic companies have one or more type or artificial neroli, all characterized by the most important specific analytic data of the neroli. These products are anyway far from the real sweet and full aroma of the pure oil, that is absolutely necessary to obtain the real eau-de-Cologne. In the luxury perfumery this general line can be given by the absolute. It's used in the distillery industry and also in the pharmaceutical industry in reduced quantities. For this last application it's preferred the distilled water that is used also in confectionery industry. The flavor of orange flower both as essential oil or distilled water is fundamental for sweet spirits as Curacao and similar.
CHEMICAL - PHYSICAL
CONSTANT PARAMETERS OF DIFFERENT NEROLI OILS
| | Absolute from water | Absolute from volatile substances | Distilled oil | | Specific weight | A 15° 0,945¸ 0,968 | A 15° 0,889¸ 0,929 | A 25° 0,906 | | Rotatory power | +1°47’ a +2°30’ | -0°5’ a –5° | -3°36’ | | Refraction index at 20° | - | - | 1,4819 | | Acetylation index | - | - | 1,4 | | Alcohol 60°solubility | - | - | 1 in 2,5 vol. | | Tenor in methyl antranilate | 11,5¸ 16% | 2,7¸ 15% | - |
| Neroli oil
Bigarade francese | Other oils | Neroli oil in Calabria region
Ancient | Neroli oil in Calabria region
Recent | | Specific weight | A 20° 0,864¸ 0,871 | A 15° 0,8696¸ 0,8812 | A 15° 0,860¸ 0,924 | A 15° 0,870¸ 0,878 | | Rotatory power 20° | Da +2°35’ a + 6°50’ | Da +0°20’ a +6°50’ | Da +2° 50’ a + 56°50’ | Da +2° 36’ a +10° 28’ | | Refraction index at 20° | 1,4707¸ 1.4741 | 1,4710¸ 1,4740 | 1,4680¸ 1,4740 | 1,4695¸ 1,4740 | | Ester index as linolile acetate | 6,9¸ 21% | - | - | 2,30¸ 14,70% | | Ester index | - | 20¸ 46,2 | 6¸ 127 | - | | Acetylation index | - | Sino a 1,8 | - | 0 a 1,35 (eccez.6,20) | | Solub. in alcohol (80°) | 1 vol. in 1¸ 2 | | -- | 1 vol. in 0,9¸ 1,8 | | Content in methyl antranilate | - | - | 0,22 | 0,60¸ 1,35 | | Total alcohol as linalol | - | - | - | 50¸ 67,5% |
Essential oil from orange peel
There are two types: the first, deriving from sweet orange is the most used one. The bitter orange trees Citrus Aurantium var. amara L. and the sweet orange trees, or Portogallo sinensis, Citrus Aurantium var.dulce L., own to the family of Rutacee and are cultivated in many areas in the south Italy, mainly along the costal zones of Calabria and Sicily regions, in all the costal zones of the Mediterranean area, specially in Spain, Cyprus and Israel. The production was developed also in the French Guinea and in Antilles, in California and in Florida. The essential oil of both types is obtained by skinning of peels (as happens for the lemon oil); the most valuable qualities are the one obtained with a sponge). The Italian production is obtained using special equipments, not by pressure as in other places.
Sweet and bitter orange oil have small differences regarding smell and composition. In Italy the production and export are mainly concentrated in the Calabric - Sicilian zones especially in the towns and surroundings of Reggio Calabria and Messina. While once the orange sweet pulp was neglected for the benefit of the bitter orange one (it was possible to extract from this one from 2 to 5% of citric acid) in some years, thanks to some very modern conservation techniques of the agro food sector it's possible to produce concentrated juices from citrus fruits with remarkable economical advantages. Even if the consumption of oils are enormously grown in every country, the exportation from south Italy did not follow the same rhythm because of the strong concurrence of the African oils, of the Florida and California production, where the essence is obtained partially by pressing and partially by steam distillation.
Sweet orange essential oil. It's the most important and actually used in every field of the perfumery industry, of the agro food sector in general (sweets , biscuits, confectionery industry) and of the drink sector (soft drinks, spirits, ecc.)
It's a mobile liquid, strongly dextro rotatory, of yellow / gold reddish or brown color, with aromatic flavor and typical smell. It has the following characteristics: specific weight at 15°. from 0.848 to 0,853; rotatory power from +95° to +98°; refraction index from 1,473 to 1,475; aldehydes decilicade from 1,30 to 2,70%; it's alcohol soluble at 95°, and in 7¸ 8 vol. of alcohol at 90°, with a turbid solution (this is due to the tenor in wax substances, insoluble that partially separate with prolonged rest). It boils at 175° at room pressure and at 180° the 9/10 of it distillate. The first fraction of the distillate (till the 50% in volume), should have a rotatory power similar, or superior, to the essence from which they derive. The distillation residue shifts from 1,50 and 2% (sometimes even till 4,50%), has a ha saponification value of 11¸ 28, and ester value of 118¸ 157.
This essence as all the other citrus fruit oils, is deterpened to render it more soluble in the low alcoholic content . All the citrus fruit oils, both deterpened or not, are difficultly preserved and so it results preferable to preserve the raw oil in a alcohol solution at 50% at 95°, while the deterpened oils in a 25% solution.
The sweet orange oil is composed mainly by: limonene dextro rotatory, with variable content in linalool, terpineol, citral, citronellal, methyl antranilate, nonilic alcohol and decilic aldehydes. It's very used in the perfumery in the preparation of eau-de-Cologne and in many qualities of fines perfumes, as in the Cyprus notes. It's normally used to aromatize the tobaccos and salutary also in the soap industry (minimum dosage) and for the toothpaste. Very used in the confectionery industry.
The deterpened industry of sweet orange is a nearly colorless liquid, sometimes pale yellow with specific weight superior (0,886¸ 0,900) to the one of the oil it's coming from. It's used in the perfumery industry for the eau-de-Cologne and in the very fine compositions.
| | Oil of sweet orange from Guinea | Oil of sweet orange from Florida | | Specific weight | A 15° 0,8485¸ 0,8510 | A 20¸ 25° 0,842¸ 0,846 | | Rotatory power | From +96° a +98° | Da +96° a +99° | | Refractory index at 20° | 1,4724 ¸ 1,4735 | 1,4723¸ 1,4742 | | Residual after evaporation | 1,5¸ 2,6 | 1,6¸ 4,5 | | Index of residual acetilation | 25¸ 36 | - | | Index of residual esterification | 130¸ 153 | - | | Index of residual solution | 140¸ 190 | - | | Tenor in decilic aldehyde (*) | 1,2¸ 2,2 | 0,8¸ 2,1 | | Solubility in 95° alcohol | 0,5¸ 4 | Not totally soluble | | Composition | Similar to the Italian oils | Prevalence. d-limonene (till 90%) aldehyde n-decilic |
Bitter orange essential oil. The bitter orange fruit plantation are developed in the same production areas of the sweet orange, especially in the area of Riviera di Ponente in Italy and in the French Riviera. In these areas the main aim of the cultivation is the production of bitter orange flowers or bigarade to get the relative essence. In Calabria and Sicily region, in addition to the production of essence the bitter orange is cultivated also for the juice and for the production of oil from the peels.
It's obtained by skinning of the peel and it's distinguished by the sweet orange because of its the aromatic bitter taste, for the rotatory power always inferior (during the distillation the rotatory power of the first one is 10% more elevated than the one of the original essence) and finally for a lower content in decilic aldehyde. Its characteristics are the following: specific weight at 15° from 0,852 to 0,857; rotatory power at 20° from +89° to +96° (can in some case decrease till +86°); refraction index at 20° from 1,4730 to 1,4750; tenor in decilic aldehyde maximum 1%; 1 vol. of essence is soluble in 7¸ 8 of alcohol at 90° with opalescence. Residual after evaporation from 3 to 5%. The essence deterpened has a higher specific weight (0.892¸ 0,908).
The bitter orange peel has weak eupeptic properties; in the pharmaceutical industry it's used especially for the preparation of the tincture, from the fluid extract and juice, and used as aromatizing elements. For this purpose also the essence it's used.
The two above mentioned orange oil qualities are put in the world market in quantities of hundreds of thousands of Kg per year.
In Brazil during the second world war was developed a remarkable production of orange essence that was destined nearly exclusively to the export in America and reached the 200 T per year. The accumulation of the stocks, that reached the quantity of 500 t, most of which had to be destroyed, implied that the production contracted till the actual level of about 60¸ 70 tons per year that cover totally the national need. Spain produces strong quantities of orange essences, and has a developed industry for the juice concentration. The orange essences, especially the sweet one are sophisticated by addition of terpens (deriving from their deterpenation), with traces of terpineol, d-limonen, linalol and citral traces, reinforcing these mixtures by addition of a certain quantity (from 3 to 4%) of decilic aldehyde. The most common adulteration of the sweet Italian orange essence is the blending with sweet orange oil importation.
Also from the chinotto an essential oil similar to the orange one is obtained.
The essential oil or chinotto essence is obtained by distillation with water steam the superficial part of the peel that is taken out from the chinotto fruits before their candy. It's a yellowish liquid with a smell similar to the orange one, but not very pleasant; D= 0,847¸ 0,848;a D at 20° from +94° to +96°; soluble in 4¸ 5 alcohols volumes at 90°, very little in the alcohol at 80°. It's constituted for the main part by limonene with small parts of aldehydes and ethers not well identified.
Its production has been executed only experimentally.
Lemon essential oil
It's the essential oil obtained by the lemon peels. The extraction of the essence once was performed manually and only by sponge, that is pushing the peel against the cut fruit with a special knife on a sponge that is itself squeezed when is full of liquid. The such obtained essential oil was of excellent quality but for economical reasons nowadays there's an industrialized production (introducing the whole lemon in a special plant called "skinner machine" that slightly scrape the surface of the fruits breaking their oil glands and collecting the essence. There are also other squeezing techniques and in fact it's used also the hydraulic press for the minced lemons, distilling then by steam current at reduced pressure the slimy mass drains from the press. The centrifugation and distillation residue is used for the citric acid production or for the calcium citrate production.
Usually about 200 Kg of lemons (1500¸ 2000 fruits) are necessary to obtain 1Kg of oil. The most fine quality derives from fruits not jet ripened, during the period end of November- starting of March for the Jonic areas, while for the Palermo zone the harvest and its relative oil production can be prolonged till April and more. Starting from these periods the quality decreases.
With a good quality it's possible to reach a value of 5% in citral, but a high percentage in cital is not necessary determining for a good quality, even if commercially is common to consider the 4% a minimum title. This tenor in citral vary strongly year by year: the essential oil have a rotatory power superior to the average.
Properties. The essential oil looks like a yellow/gold liquid, often yellow-green if recently produced; has a characteristic fresh and pleasant smell and a taste initially aromatic and then bitter. It alters evidently with the air and light, it muddies with a resinous residue nearly insoluble, that gives to the essence its resinous color. The essence of good qualities have the following characteristics: spec. weight at 15° = 0,856¸ 0,861; rotatory power at 20°: from +57 to +61°; refractory index at 20°=1,471¸ 1,476; citral tenor from 3,5 to 5%; residual after evaporation from 1,5¸ 2,2 till 4% in the oils manually squeezed and from 5 to 6,5% for the other ones; acidity of residual after evaporation from 19 to 39; ester index 100¸ 214; 1 vol. is usually partially soluble in 6¸ 8 alcohol vol. at 90° because of the presence of mucilage and waxy compounds; clear solution in alcohol 3 vol. at 95°; totally soluble in absolute alcohol, ether, chloroform, benzene and amilic alcohol. Because of the presence of small quantities of water in the oil the solutions in carbon sulfur and benzene are slightly turbid.
The above mentioned data aren't universally accepted. Nowadays the market needs the following parameters: specific weight at 20°=0,852¸ 0,858; refractory index at 20°=1,474¸ 1,476; rotatory power at 20° from +57 to +65°; residual after evaporation 1,5¸ 3,6%; maximum acidity index 1,4; tenor in carbonilic constituents expressed as citral from 3 to 5%.
The lemon deterpened and sesquideterpened essences have the following characteristics:
| | DETERPENED ESSENCES | SESQUIDETERPENED ESSENCES | | Specific weight aT 15° | 0,8935¸ 0,8990 | 0,898¸ 0,902 | | Rotatory power aT 20° | -5°¸ -8°30’ | -3°30’¸ 1° | | Refractory index at 20° | 1,481 | | | Citral tenor | 40¸ 52% | 60¸ 65% | | Ester tenor (calculated as linalile acetate) | 16¸ 24% | 15¸ 25% | | Sesquiterpens tenor | 20¸ 24% | Traces | | Solubility: 1 vol. in | 1 alcohol at 80°
3¸ 8 alcohol at75° | 1¸ 3 alcohol at 70°
6¸ 15 alcohol at 60° |
USA and Brazil are in the van among the competitors of the Calabrian - Sicilian essences, interesting production can be found also in Spain and Israel and recently also in Cipro. In the USA the main production is in California.
Spain has an irregular essence production. The characteristics of a Spanish oil - produced with the sponge method- are: specific weight at 25°=0,851; rotatory power at 25°=62°40’; refractory index at 20°=1,4748; aldehydes tenor (calc. as citral) 4,5%; regarding the industrial extraction of essence the data differ for a low-grade rotatory power (57°50’¸ 59°) and a smaller citral content (3,4%); the residual after evaporation varies from 3,7 to 4,1%.
In Brazil the lemon production has been developed quite a lot during he second world war, lacking the Italian production. The lemon plants are flourishing in San Paolo. Their essences have the following characteristics: specific weight at 25°=0,851; rotatory power at 25°=+63°5’; refractory index at 20°=1,4746; citral tenor: 2,0%; residual after evaporation 3,8%. The Brazilian quality is strongly inferior both to the Italian and Spanish qualities regarding the citral tenor.
Also in Israel and Cyprus recently a fairly good industry, which product is exported to Great Britain, has been developed. Analytic data on this essence are lacking, but it seems to correspond to the British F.U.
In the lemon essential oils the following constituents have been found: ottilen, a - e b -pinen, canfen, metileptenon, b -fellandren, d-limonen, that is the main component, g -terpinen, a -terpineol, aldehydes C8, C9, C10 e C12 (laurilic), citronellate, citral, linalil and geranil acetate, neroli and citronellolo probably as esters, bisabolen, cadinen (a primary sesquiterpenic alcohol), acetic carpinic and lauric acids; maybe methil antranilate, limettina and with this probably a phenol. The linalil acetate is present in the essences produced in the Palermo area while is absent in the ones produced in the ionic coast.
The Californian quality has the 0,5% of residual after evaporation and an inferior citral tenor that sometimes reaches the 1,50% compared to the Sicilian qualities.
Uses. The lemon essential oil is among the most important products of this kind, or maybe the most used in the different industrial sectors, from the agro food, the perfumery and the pharmaceutical sectors. The lemon essential oil is largely used particularly in the agrofood industry, so its consumption increases continuously.
Stocking and packing. The stocked essential oil must be conserved in fresh places (10¸ 12°) in big copper containers perfectly watertight and if this conservation exceeds one year it must be closed under vacuum.
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