Orange flavor, components important

In this chapter, we present some specific evidence on certain components important to citrus flavor. The interrelationship of certain volatile components to orange flavor is described and the flavor of grapefruit and the importance of specific compounds to the flavor of mandarin and tangerine are related to recent taste panel studies at our laboratory. 

In tests to better define this mixture of components (and their proper proportions) necessary for good orange flavor, volatile components believed from prior analytical studies to be important to orange flavor were examined (5). Individual taste and aroma thresholds in water were determined on the compounds selected. Then, the influence of nonvolatile juice constituents on the taste threshold of certain of the volatile components was studied. Finally, selected individual compounds and mixtures containing from two to six components were evaluated in a bland juice medium for their contribution to orange flavor. 

Optical rotation is commonly used as in QC for essential oils and oleoresins. The most important flavor constituents in these oils very often are optically active. Therefore, optical rotation may be used to quantify specific flavor components in the oleoresin or essential oil (e.g., AOAC Official Method 920.142 for orange and lemon oils). 

Importance of Selected Volatile Components to Natural Orange, Grapefruit, Tangerine, and Mandarin Flavors... 

The essence of citrus flavor is a complex mixture of volatile alcohols, aldehydes, esters, hydrocarbons, ketones and oxides. Alcohols are the largest class and ethanol is the main organic constituent of the essence. Esters and aldehydes are considered to contribute most to the characteristic flavor and aroma. In these two classes ethyl butyrate and acetaldehyde were shown to be important components of high quality orange juice (1). 

Aliphatic esters in various combinations play a major part in many flavors, particularly fruit flavors 441), Hexyl acetate develops the strongest and most typical odor in Cox s Orange Pippin apples (279). Hexyl 2-methylbutyrate contributes highly to the flavor of Golden Delicious apples (265). Methyl and ethyl esters of ( )-3-hexenoic, (Z)-4-decenoic (32) and )- and (Z)-4-octenoic acids have some importance in the flavor of pineapple 408). Methyl (Z)-4-decenoate (32) and methyl thiohexanoate account for about 56% of the odor provided by the components of the oxygenated fraction of hop oil 202). Ethyl (jE, Z)-2,4-decadienoate (35) is considered as the character impact compound in the aroma of Bartlett pears (227) (Table 2). The application of this pear ester in reconstitution work has been facilitated by the development of highly stereospecific syntheses 405, 407, 457). Isobutyl an-gelate is considered as an essential constituent of Roman camomile oil 85). 

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