Citrus x junos; Citrus junos Siebold ex. Tanaka - Rutaceae - 香橙 xiang cheng (chin.), ユズ yuzu (jap.), yuzu, Yuzu
Small tree, cultivated and sometimes naturalized in Japan, Korea, China; branches often with long stout spines; petioles obovate-elliptic, 1-2.5cm long, leaf blade ovate to lanceolate, 2.5-8cm long; flowers solitary, white; fruit pale yellow, 4-8 cm in diam., surface coarse and with large oil dots, pericarp 2-4 mm thick, easily removed, sarcocarp with 9-11 segments, pale yellowish white, very acidic and bitter; seeds ca.40. The parents of this hybrid species are possibly Citrus cavaleriei and C. reticulata. http://www.efloras.org/florataxon.aspx?flora_id=2&taxon_id=250084130
„Yuzu is also known for its characteristically strong aroma, and the oil from its skin is marketed as a fragrance.“
An unusual macrocyclic ketone with a dry woody, earthy, and camphoraceous-minty odor, yuzu lactone (= (10Z)-oxacyclotridec-10-en-2-one), was found (0.04%) in the oil.
[A novel 13-membered macrolide. A flavour component of yuzu (Citrus junos) oil., Matsuura, Y., Hata, G., Abe, S., Sakai, I., Abe, A., In Proceedings of the 8th International Congress of Essential Oils 1980, (pp. 12-17). Grasse, France: Fedarom.]
„Yuzu (Citrus junos Sieb. ex Tanaka), a tree-grown fruit similar to a kind of sour orange, is widely used in Japanese food/cooking for its pleasant flavor. To clarify the odor-active volatiles that differentiate yuzu from other citrus fruits, sensory evaluations were conducted on yuzu peel oil. The results revealed that the polar part of yuzu peel oil was the source of the characteristic aroma of fresh yuzu fruit. By aroma extract dilution analysis (AEDA) of the polar volatile part of yuzu peel oil, seven odorants were newly identified as odor-active volatiles in yuzu peel oil in the highest flavor dilution (FD) factors of 128 and 32: oct-1-en-3-one, (E)-non-4-enal, (E)-dec-4-enal, 4-methyl-4-mercaptopentan-2-one, (E)-non-6-enal, (6Z,8E)-undeca-6,8,10-trien-3-one (yuzunone), and (6Z,8E)-undeca-6,8,10-trien-4-ol (Yuzuol). Among the most odor-active volatiles in yuzu, (E)-non-6-enal and Yuzunone were identified for the first time solely in yuzu peel oil and not in the peel of other citrus species, and Yuzuol was identified for the first time in nature. Sensory evaluation of yuzu aroma reconstitutions revealed that the newly identified compound, Yuzunone, contributes greatly to the distinct yuzu aroma.“
Synthetic mixtures of (8E)-undeca-6,8,10-trien-3-one (6E/6Z 50:50) and (8E)-undeca-6,8,10-trien-4-ol (6E/6Z 65:35) showed fairly low thresholds in water of 0.010 ppb and 0.042 ppb respectively.
[Novel character impact compounds in yuzu (Citrus junos Sieb. ex Tanaka) peel oil., Miyazawa, N., Tomita, N., Kurobayashi, Y., Nakanishi, A., Ohkubo, Y., Maeda, T., Fujita, A., Journal of agricultural and food chemistry, Vol.57(5), 2009, 1990-1996]
„The essential oils of six different yuzu cultivars, Kumon (KUM), Nagano (NAG), Yasu (YAS), Jimoto (JIM), Komatsu Sadao (KOS) and Komatsu Koichi (KOK), were extracted by cold-pressing method. A total of 69 compounds of the six samples were identified. Application of GC-olfactometry and aroma extraction dilution analysis technique in three-fold stepwise dilution of the neat oil for all samples indicated eight odourants with the highest flavour dilution (FD) values. Those were limonene, α-pinene, α- and β-phellandrene, myrcene, γ-terpinene, (E)-β-farnesene and linalool. ‘KOS’ was differentiated from the other oil samples by showing the highest number of components having yuzu-like odour notes and also from the PCA analysis of the FD-factor values. This is the first time the aroma characteristics of yuzu essential oils of specified cultivars were investigated.“
The total amount of monoterpenes in yuzu oil is above 90%, sesquiterpenes are 3-4%. Most important components are limonene (63-68%), γ-terpinene (11-12%), β-phellandrene (4-5%), myrcene (3%), linalool (2%), α-pinene (2%), β-pinene (1%), (E )-β-farnesene (1%) and bicyclogermacrene (2%).
[Chemical and aroma profiles of yuzu (Citrus junos) peel oils of different cultivars. Lan-Phi, N. T., Shimamura, T., Ukeda, H., Sawamura, M., Food chemistry, Vol.115(3), 2009, 1042-1047]
Cold pressed yuzu peel oil owns a typical odour between mandarin and lemon oil. In perfume creations, yuzu top notes are also achieved by blending other citrus oils, especially lemon and bergamot oil, with green odorants. „Typical for yuzu oil is its high content of linalool (2.1-4.7%)… unique amongs the citrus fruits is the occurence of yuzu lactone… Grapefruit-type connotation are provided by trace amounts of the extremely intense 4-methyl-4-sulfanylpentan-2-one. Important for the peely, fresh citrus character are the saturated aldehydes octanal (0.1%), nonanal (0.08%) and decanal (0.3%), as well as the unsaturatd (E)-non-6-enal. Two triple-unsaturated compounds, yuzunone (0.01%) and yuzuol (0.003%) are responsible for the balsamic, sweet floral aspects of yuzu peel oil.“
[Scent and Chemistry, Günther Ohloff, Wilhelm Pickenhagen, Philip Kraft, Wiley-VCH, 2012, 234-235]