Ribes nigrum L. - Grossulariaceae - blackcurrant, **Schwarze Johannisbeere**

Deciduous shrub, up to 2m tall, native to northern Europe and northern Asia, widely cultivated and naturalized; leaves 3-5 lobed, broadly triangular, margin serrate; racemes arching or nodding, 4-12-flowered, flowers green-red; fruit black, subglobose, up to 1cm diam. \\
[[http://www.efloras.org/florataxon.aspx?flora_id=2&taxon_id=241000646]]

"Blackcurrants can be eaten raw but are usually cooked in a variety of sweet or savoury dishes. They are used to make jams, jellies and syrups and are grown commercially for the juice market. The fruit is also used in the preparation of alcoholic beverages and both fruit and foliage have uses in traditional medicine and the preparation of dyes." [[http://en.wikipedia.org/wiki/Blackcurrant]]

"S.nigrum flower buds extract is used in perfumery industry. Small amounts of this extract impart a fruity note." \\ [[http://de.wikipedia.org/wiki/Ribes_nigrum]]

The most important compounds to the quality of black currant juice aroma were diacetyl, methyl butyrate, ethyl butyrate, eucalyptol, and a compound present in trace quantities which has a 'catty' odour. \\
[Latrasse, A. "L'arôme du cassis (Ribes nigrum L.) odeur principale et notes secondaires." Sciences des aliments 2 (1982), 145-162]

"An important flavor-active sulfur component, 4-methoxy 2-methyl-2-mercaptobutane was identified and synthesized by Rigaud et al. Its threshold value is 2x10⁻4 ppm in a blackcurrant liquor. This component is responsible for the predominant catty note of the blackcurrant buds." \\
[Latrasse, A. L. A. I. N. "Fruits III" Volatile compounds in foods and beverages (1991): 329-387] \\
[Rigaud, Jade, et al. "Le méthoxy-4 méthyl-2 butanethiol-2, un constituant majeur de l'arôme du bourgeon de cassis (Ribes nigrum L.)." Sciences des aliments 6.2 (1986): 213-220]

{{:4-methoxy-2-methylbutane-2-thiol.jpg|}}  4-methoxy-2-methylbutane-2-thiol (4-methoxy 2-methyl-2-mercaptobutane; '4-MMP')

"The essential oils of 23 varieties of blackcurrant buds were investigated for chemical composition and
chemosystematic studies.... The most important compounds for the aroma of the oils (Latrasse et al., 1982; Latrasse, 1983) were present in the polar fractions, even though they were found in very small amounts. Thus, the sulfur compound 4-methoxy-2-methyl-2-mercaptobutane responsible for the characteristic catty note was found in small amounts varying from trace to 0.04%, the highest level, however, being found in aromatic varieties (eg Noir de Bourgogne, Burga, Royal de Naples). Concentration of eucalyptol (1,8-cineole), important for its characteristic balsamic note, varied from trace to 0.01% of the total oils, and 1-octen-3-ol, with its mushroom odor, was only found in trace amount. More abundant in these polar fractions, monoterpene alcohols, such as linalool or citronellol, generally give off typical floral notes, while sesquiterpene alcohols and oxides, such as spathulenol, caryophyllene oxide, or isospathulenol, afford conifer like odors. Monoterpene acetates have been found particularly important for their characteristic floral or lemony notes." \\
[Composition of the essential oils of black currant buds (Ribes nigrum L.)., Le Quere, J.L., Latrasse, A., Journal of Agricultural and Food Chemistry, 38(1), 1990, 3-10]

"The first use of the 'Bourgeons de Cassis' note in a prominent perfume was certainly Amazone (Hermes 1974), and that set the fashion. Silences (Jacomo-1978) followed, together with many others. The absolute harmonizes well with green floral notes while accentuating its own characteristics and bringing out its fruity side. Its use has been restricted because of cost, and perfumers have turned to the essential oil of buchu, which unfortunately does not possess all the qualities of the 'Bourgeons de Cassis' absolute." \\
[The Overdose, Martin Gras, Dragoco 1990; Perfumer & Flavorist 15.2, 1990, 25-28]

"The impact of an aroma compound can be estimated by the GC-sniffing method. Latrasse et al. (1982) used
this method to differentiate between volatile compounds of primary and secondary importance in the typical
black currant aroma. Primary notes were diacetyl, methyl and ethyl butanoate, eucalyptol, and 4-methoxy
2-methyl-2-mercaptobutane [4-methoxy-2-methylbutane-2-thiol]. The methoxymercaptobutane contributed with a strong note of cat urine, and Latrasse et al. concluded that this is probably the most important black currant aroma enhancer, although it is present in only a very low concentration in bud extracts. Methoxy-2-methyl-2-mercaptobutane has not yet been identified in black currant juice or nectar." \\
For the fruits, quantitatively dominating compounds in the headspace of black currant nectar / juice are esters (93% of the volatile compounds) such as (ppm approx.) ethyl acetate (2), ethyl butanoate (73), methyl butanoate (350), methyl hexanoate (29), ethyl hexanoate (5), methyl octanoate (3), ethyl octanoate (1), methyl decanoate (0.7) and ethyl decanoate (0.4) along with many others. Other major components are α-pinene, δ-3-carene, myrcene, α-terpinene, limonene, β-phellandrene, (Z)-ocimene, 4-terpineol, (E)-2-hexenal, and nonanal.\\
[Aroma Changes during Black Currant (Ribes nigrum L.) Nectar Processing. Carsten K. Iversen, Henrik B. Jakobsen, and Carl-Erik Olsen, J. Agric. Food Chem. 1998, 46, 1132−11366] 

Major components of the essential oil of blackcurrant buds, berries and leaves were α-pinene (1-2%), sabinene (1-2%), δ-3-carene (20-26%), α-terpinene (1-2%), (Z)-β-ocimene (2-11%), limonene (2-4%), (E)-β-ocimene (1-7%), β-phellandrene (2-11%), terpinolene (6-10%), p-cymene (up to 4%), (E)-β-caryophyllene (4-9%), germacrene B (1-4%), and caryophyllene oxide (0.5-9%). \\
Minor components are eg. 1,8-cineole, 1-octene-3-ol, terpinene-4-ol, decanal, myrtenal, 1-p-menthen-9-al, α-terpineol, isoborneol, borneol, bornyl acetate, nerol, citronellyl acetate, perilla aldehyde, ethyl decanoate, geranyl acetate, bicyclogermacrene, δ-cadinene and butyl cinnamate. \\
[Composition of blackcurrant aroma isolated from leaves, buds, and berries of Ribes., Orav, A., Kailas, T., Miiiirisepp, M., In Proceedings of the Estonian Academy of Sciences, Chemistry Vol. 51(4), 2002, 225-234]

Static headspace GC-O showed the top five most potent compounds of black currant juice aroma to be ethyl butyrate, diacetyl, ethyl 2-methylbutyrate, methyl acetate and ethyl hexanoate. Very important compounds for black currant berry juice aroma were methyl butyrate, ethyl butyrate, eucalyptol, 3-methyl-1-butanol, ethyl hexanoate, 1-octen-3-one, 2-methoxy-3-isopropylpyrazine, linalool, 4-terpineol, and β-damascenone. \\
[Varming, Camilla, Mikael A. Petersen, and Leif Poll. "Comparison of isolation methods for the determination of important aroma compounds in black currant (Ribes nigrum L.) juice, using nasal impact frequency profiling." Journal of Agricultural and Food Chemistry 52.6 (2004): 1647-1652]

"Nine black currant varieties cultivated in Lithuania were studied. The highest amount of ascorbic acid was established in fresh berries from cv Minaj Smyriov and Kupoliniai: these varieties contained 220.5 and 186.7 mg 100 g−1 of ascorbic acid in berries. The highest amount of anthocyanins was found in cake produced from berries cv Kupoliniai and Kriviai: 14.65 and 15.42 mg g−1, respectively. The major pigment determined in Kupoliniai variety was delphinidin-3-rutinoside; in Ben Lomond, Minaj Smyriov, Kriviai and Gagatai cultivars, cyanidin-3-rutinoside. The composition of the identified pigments was the following: cyanidin-3-rutinoside (33-38%), delphinidin-3-rutinoside (27-34%), cyanidin-3-glucoside (8-10%) and delphinidin-3-glucoside (8-10%). Impact of storage, thermal treatment and addition of sweeteners were studied. Cyanidin-3-rutinoside was the most stable to the effect of thermal treatment at 95 °C, while cyanidin and delphinidin rutinosides were the most stable during storage for 12 months at 8 °C. Fructose has a greater effect on anthocyanin degradation compared with glucose and aspartame." \\
[Impact of various factors on the composition and stability of black currant anthocyanins., Rubinskiene, M., Viskelis, P., Jasutiene, I., Viskeliene, R., Bobinas, C., Food research international, Vol.38(8), 2005, 867-871]

Although identified several decades ago in blackcurrant buds, an unambiguous identification of 4-methoxy-2-methylbutane-2-thiol (methoxy-2-methyl-2-mercaptobutane) in blackcurrant fruits has been lacking. This now has been achieved by vacuum-headspace-extraction, enriching on mercurated agarose gel, and identification via GC-MS. Of seven blackcurrant cultivars, concentration in Andega (4.5 µg/kg) was significantly higher than those in the other cultivars (0.16-0.72 µg/kg). OAV calculation showed that 4-methoxy-2-methylbutane-2-thiol contributes to the aroma of blackcurrant berries. The concentration of this compound in blackcurrant buds (800 - 2,000 μg/kg) are several orders of magnitude higher than those in the berries. \\
(Z)-hex-3-enal, (E)-hex-2-enal, methyl butanoate, and ethyl butanoate showed highest concentrations among the key aroma compounds of fresh blackcurrant berries. Ethyl butanoate, 2-isobutyl-3-methoxypyrazine, 2-isopropyl-3-methoxypyrazine, (Z)-octa-1,5-dien-3-one, 4-methoxy-2-methyl-2-butanethiol, oct-1-en-3-one, and geraniol had FD values > 64. The most important aroma active compounds (OAV >1) were (Z)-hex-3-enal, 4-methoxy-2-methyl-2-butanethiol, ethyl butanoate, oct-1-en-3-one, 1.8-cineole, hexanal, α-pinene, 2-isopropyl-3-methoxypyrazine, methyl butanoate, 2-isobutyl-3-methoxypyrazine, 2-sec-butyl-3-methoxypyrazine, (E)-hex-2-enal, pent-1-en-3-one, (E)-non-2-enal, (Z)-rose oxide , and (Z)-hex-3-en-1-
ol. When the compounds (20) with an OAV ≥1 were used as a basis for reconstitution experiments, the recombinate was reminiscent of blackcurrant berries, but the aroma of fresh blackcurrant fruits could not be fully achieved. \\
[Jung, K., Fastowski, O., & Engel, K. H. (2016). Occurrence of 4‐methoxy‐2‐methyl‐2‐butanethiol in blackcurrant (Ribes nigrum L.) berries. Flavour and Fragrance Journal.] \\
[Jung, Kathrin. Analysis and sensory evaluation of volatile constituents of blackcurrant (Ribes nigrum L.) and redcurrant (Ribes rubrum L.) fruits. Diss. Technische Universität München, 2018] 
[[https://mediatum.ub.tum.de/doc/1427712/file.pdf]]

{{:ribes_nigrum.jpg?600}} \\
Lindman, C.A.M., Bilder ur Nordens Flora, vol.2, t.281 (1922-1926) \\
[[http://www.plantillustrations.org/species.php?id_species=882056]]

{{http://www.botanische-spaziergaenge.at/Bilder/Lumix_70/P1100267.JPG}} \\
Ribes nigrum,  Bad Leonfelden © Rolf Marschner (2016) [[http://botanische-spaziergaenge.at/viewtopic.php?f=572&t=4504| www.botanische-spaziergaenge.at]]

VIDEO: [[https://www.youtube.com/watch?v=nCWGGpUj52I|Blackcurrant buds from France]] (IFF-LMR)