Strawberry aroma substance

Strawberry flavor The strawberry aroma is made up of caramel-like [ impact compounds Furaneol, mesifuran (see Furaneol )], fruity [ fruit esters, 4-decanolide (see alkanolides)], green [( )-2- hexen-l-ols, ( )-2- hexenals, 2-hexenyl acetate (see fruit esters)], and flowery notes ( linalool, methyl anthran-ilate). Particularly important fruit esters are ethyl butanoate and hexanoate as well as the corresponding methyl esters. Free acids such as 2-methylbutanoic acid (C5H,o02, Mr 102.13, CAS [116-53-0]) and trace substances, e.g., dimethyl sulfide and vanillin, round off the aroma. 

Pineapple Ananas comosus, Bromeliaceae) aroma consists of about 200 alcohols, esters, lactones, aldehydes, ketones, monoterpenes, sesquiterpenes and other volatiles. About 80% of the total volatile substances are esters. The main components in the green fruit are ethyl acetate, ethyl 3-(methylthio)propionate (8-189) with a distinctive pineapple aroma and ethyl 3-(acetoxy)hexanoate (8-190). The ripe fruit contains, as the main esters, ethyl acetate, (2J ,3i )-butane-2,3-diol diacetate (8-191) and ketone 3-hydroxy-butan-2-one. An important compound for the typical character of pineapple aroma, as in strawberry aroma, is 2,5-dimethyl-4-hydroxy-2//-furan-3-one (furaneol), present as a glycoside, and 2,5-dimethyl-4-methoxy-2H-furan-3-one. 

The aroma substances that comprise flavors are found in nature as complex mixtures of volatile compounds. A vast majority of volatile chemicals that have been isolated from natural flavor extracts do not provide aroma contributions that are reminiscent of the flavor substance. For instance, n-hexanal is a component of natural apple flavor (1) however, when smelled in isolation, its odor is reminiscent of green, painty, rancid oil. Similarly, ethyl butyrate has a nondescript fruity aroma although it is found in strawberries, raspberries, and pears, it does not uniquely describe the aroma quality of any of these individual fruits. It has long been the goal of flavor chemists to elucidate the identity of pure aroma chemicals that have the distinct character impact of the natural fruit, vegetable, meat, cheese, or spice that they were derived from. Often, these are referred to as character impact compounds (2). 

Cyclopentenolones with a planar vicinal enol-oxo configuration are known to be powerful aroma active substances with distinct caramel notes. By methylation of the enolic function, this flavour impression is changed drastically to a sweet, mildew, and mouldy odour in the case of 2,5-dimethyl-4-methoxy-3-[2H]-furanone (2). This so-called mesifurane as well as pineapple ketone (1) were stereodifferentiated with modified cyclodextrin [103], Although (1) and (2) can be stereoanalyzed without any racemization, both compounds were detected in strawberries, pineapples, grapes and wines as racemates (Fig. 6.43). 

Furaneol and norfuraneol are significant sensorially active substances with low threshold concentrations. They are synthesised and added to numerous aroma compositions with a pleasant sugary, jammy, fruity and caramel flavour reminiscent of cooked strawberries and pineapple, which is where furaneol was identified for the first time (see Section 8.2.11.1.1). 

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