Leaf aldehydes

A very large number of volatile substances have been identified in fresh tea leaf.64 Substances present at the highest levels include the ubiquitous leaf aldehyde, trans-2-hexenal, and leaf alcohol, cis-3-hexenol. Both arise from cis-3-hexenal, which is biosynthesized from linoleic acid in leaf as a result of enzymic splitting.65... 

In addition to the straight-chain saturated aldehydes, a number of branched-chain and unsaturated aliphatic aldehydes are important as fragrance and flavoring materials. The double unsaturated 2-trviolet leaf aldehyde (the dominant component of cucumber aroma), is one of the most potent fragrance and flavoring substances it is, therefore, only used in very small amounts. 2-frfatty odor character is indispensible in chicken meat flavor compositions. 

The absolute is a dark green to brown liquid with a strong, green odor. The main constituent of the volatile fraction is 2-trani-6-cw-nonadienal [557-48-2] (violet leaf aldehyde) [818, 819]. 

Hexenal (leaf aldehyde) is a constituent responsible for the smell of green leafs, ( )-2-octenal a main component of the aroma of raw potatoes ( )-2-nonenal is the organoleptic main constituent of the smell of cucumbers and is found in carot root oil, tomatoes, beef and raspberries 158). ( )-2-Decenal and ( )-2-dodecenal are components of some essential oils, ( )-2-tridecenal is responsible for the bug-like smell of coriander seed oil1S8). 

Hexanol (aliphatic alcohol) ( )-2-Hexen-l-al (= tarc.y-2-Hexen-1 -al Leaf aldehyde) (aliphatic aldehyde)... 

SYNS CUCUMBER ALDEHYDE FEMA No. 3317 2,6-NONADIENAL trans,cis-2,6-NONADIENAL trans-2,ds-6-NONADIENAL VIOLET LEAF ALDEHYDE... 

Hatanaka shows in detail the reaction scheme in plants whereby linolenic acid is converted via lipoxygenase and lyase enzymes to cis-3-hexenal. This is subsequently converted by other enzyme systems to leaf aldehyde and leaf alcohol. These three aroma chemicals are important "green" aroma notes in strawberries and other berries. If these enzymes were commercially available, then the production of natural cis-3-hexenal from inexpensive vegetable oil is theoretically feasible. 

The enzymic formation of aldehydes, ketones, alcohols, and oxoacids (from linoleic and linolenic acids) on disruption of plant tissues is an important biosynthetic pathway by which fruit and vegetable volatiles are formed. Some examples are (E)-2-hexenal ("leaf aldehyde") and ( )-3-hexenol ("leaf alcohol") in tea (E)-2-hexenal in apples (E,Z)-2,6-nonadienal ("violet Teaf aldehyde") and (E)-2-nonenal in cucumber ( Z)-5-nonenal in musk melon (Z,Z) -3,6-nonadienol in water melon, and 1-octen-3-ol ("mushroom alcohol") in certain edible mushrooms and Fungi. The enzyme system is highly substrate specific to a (Z,Z)-1,4-pentadiene system (like lipoxygenase) splitting the >C = C< double bond at the W - 6 and/or W - 9 position. Therefore linoleic-, linolenic-, and arachidonic acids are natural substrates. It seems to be a common principle in leaves, fruits, vegetables, and basidiomycetes. 

E)-2-H. (leaf aldehyde) an oil with a hot, herby-green odor, pleasant fruity-green in dilute solution olfactory threshold in water 17 ppb, bp. 146 C, LD50 (rat p.o.) 0.78 g/kg. 

E,Z)-2,6-N. (violet leaf aldehyde) bp. 88 °C (1.3 kPa), LD50 (rat p.o.) >5 g/kg fatty-green odor of violet leaves in which it was first detected in 1925, ( ,Z)-structure assigned in 1944. It also occurs in vegetable flavors ( impact compound in cucumber), fruit flavors (guava, melon, mango), meat, and seafood flavors. For synthesis, see Lit.. ... 

Synonyms Hex-2-enal Hex-2-en-1-al Hexylenic aldehyde Leaf aldehyde... 

Leaf aldehyde. See 2-Hexenal Leaf green. See Chromium oxide (ic)... 

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