Apple flavor index
The apple aroma index is an evaluation model for the aroma of apple juice . It provides a key figure for the objective analytical description and assessment of the degree of re-aromatization of apple juice from concentrate.
The model takes into account various aroma-active substances that contribute to the typical aroma impression of apple juice. In addition to some esters that are relevant for the apple juice aroma , the model also contains various alcohols and aldehydes . By considering different substance classes with different properties, the overall aroma of apple juice should be accurately described. The esters convey the fruity component of the apple juice aroma, the C6 aldehydes and alcohols describe the apple-like "green, grassy, fresh" smelling component of apple juice.
In detail, the flavor index model takes into account the substances ethyl 2-methylbutanoate , ethyl butanoate , 2-methylbutyl acetate , hexyl acetate , butyl acetate , hexanal , trans - 2-hexenal , 1-hexanol , trans -2-hexen-1-ol and 2-methyl -1-butanol . The contents of the individual substances are multiplied by certain normalization factors and the values obtained from them are added together. By weighting via the normalization factors , the actual contribution to the overall aroma is to be better assessed and an overweighting of individual compounds is to be prevented. Differences and fluctuations are well balanced by considering and weighting the ten substances.
|Flavor index = 2 x c (ethyl 2-methylbutanoate) + 0.5 x c (ethyl butanoate) + 0.25 x c (2-methylbutyl acetate) + 0.333 x c (hexyl acetate) + 0.1 x c (butyl acetate) + 0 , 1 x c (hexanal) + 0.025 x c ( trans -2-hexenal) + 0.017 x c (1-hexanol) + 0.05 x c ( trans -2-hexenol) + 0.033 x c (2-methyl-1 -butanol)|
The aroma index is dimensionless, since all normalization factors have the unit l / µg .
The normalization factors were determined from a database of single-origin not-from-concentrate juices, commercial not-from-concentrate juices, apple juices from concentrate and apple-flavored water phases.
- C. Wolter, A. Gessler, P. Winterhalter: Aspects for assessing the apple juice aroma , Liquid Fruit 03-2008, p. 122 ff.
- Carolin Wolter, Achim Gessler, Peter Winterhalter: Evaluation of Apple Juice Aroma . In: Flavors in Noncarbonated Beverages , Chapter 8, pp. 103-114 doi : 10.1021 / bk-2010-1036.ch008