Fatty acids green aroma from

Cg and Cg aldehydes generated enzymlcally from n-3 fatty acids (23-27) are responsible for much of the plenty, green-type aromas encountered In very fresh fish and seafoods. 

Alkenals. A. are formed from fatty acids by autooxidation or enzyme action and are widely distributed in essential oils and aromas. The Cs-Cu-A. (see also hexenals) have sensory effects even in low concentrations. Odors of (0-2-A. resemble those of the alka-nals but are stronger and less fatty Ci citrus, orange C,2 orange, mandarine. Clearly different are the odors of the (Z)-A. (see table, p. 20). C, green, fatty cream C9 cucumber, melon C, citrus, flowery. ... 

D-2-Hydroxy saturated 16 0 to 25 0 fatty acids with both even and odd numbers of carbons in their chains occur in lipids in green leaves of a great number of vegetables. y- or (9-Lactones are obtained from 4- and 5-hydroxy carboxylic acids (Cg to C16) by the elimination of water. 5-Lactones have been found in milk fat and fruits. They are very active aroma components (cf. S.3.2.3). 

Termination reactions may lead to the formation of both high and low molecular weight products of the peroxidation reactions. Depending on the lipid, some of the low molecular mass compounds may be important flavours (or aromas) of foods (section 5.2.3). For example, short to medium chain aldehydes formed from unsaturated fatty acids may give rise to rancidity and bitter flavours on the one hand or more pleasant attributes such as those associated with fresh green leaves, oranges or cucumbers on... 

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