Odour activity value

In the majority of the studies on the composition of food aromas, AEDA is used for the determination of the relative odour potency of the compounds detected by GC-O (reviewed in [1]). The odour potency is proportional to the odour activity value (OAV) of the compound in air. The OAV is defined as the ratio of the concentration of a compound to its odour threshold [3]. 

Odorant Concentration (pg/kg) Threshold (pg/kg water) Odour activity value ... 

Odour activity values were calculated by dividing the concentrations of the odorants by their orthonasal odour thresholds in water... 

Trace compounds without any sensorial relevance (odour activity value much less than 1) should not be evaluated in the sense of authenticity assessment, as the fraudulent addition of a sensorially ineffective compound makes no sense. 

Modern scientific tools like the so-called odour-activity value (OAV) concept were developed to unravel the quantitative and qualitative pattern of individual chemicals. Quantitation is achieved in an extremely accurate way by means of isotope dilution analysis. 

Masanetz, C. and Grosch, W. 1998b. Key odorants of parsley leaves (Petroselinum crispum [Mill.] Nym. ssp. crispum) by odour-activity values. Flavour Fragrance J. 13 115-124. 

Preininger, M. and Grosch, W. 1994. Evaluation of key odorants of the neutral volatiles of Emmen-taler cheese by the calculation of odour activity values. Lebensm.-Wiss. Technol. 27 237-244. 

Grosch, W. 1994. Determination of potent odourants in foods by aroma extraction dilution analysis (AEDA) and calculation of odour activity values (OAVs). Flavour Fragrance J. 9 147-158. 

Odour thresholds and odour activity values (OAV) of important pastry odorants (PB butter pastry PM margarine pastry) [441 ... 

Jagella, T. and Crosch, W. (1999b) Flavour and off flavour compounds of black and white pepper (Piper nigrum L.). II. Odour activity values of desirable and undesirable odorants of black pepper. European Food Research and Technology 209(1), 22-26. 

Some authors (Peinado et al. 2004a, 2004b Zea et al. 2007) have grouped aroma compounds in aromatic series based on their aroma descriptors. The overall value for each series is obtained by combining the odour activity value (OAV, which is defined as the ratio of the concentration of a compound to its perception thresholds) of the individual aroma compounds in the series. The combination of individual OAVs in order to calculate the overall value for a series cannot be interpreted as an arithmetic addition of odorant sensations. Some aspects of this classifying scheme can be subject to criticism, but in any case, the scheme is effective for comparing wines obtained with different aging methods inasmuch as the odour series always comprise the same compounds. 

With regard to chirality evaluation as an indicator for the genuineness of natural flavourings and fragrances only chiral volatiles of high enantiomeric purity and characteristic and small ranges of ee-values should be validated in relation to their total amounts (Table 4). Furthermore, it is remarkable to pay more attention to the odour activity values (OAV) of compounds analyzed [77, 78]. 

Of course, chiral compounds occurring in trace amounts and far below their odour activity values in foods investigated, e. g. y-decalactone in raspberries and gooseberries [82], have to be neglected. 

Among all the volatile compounds, only a limited number are important for aroma. According to a proposal by Rothe and Thomas [2] only those compounds actually contribute to aroma whose concentration in food exceeds their odour thresholds. To estimate the importance of a volatile compound for the aroma of a particular food, the ratio of concentration to its odour threshold was calculated. This value was denoted aroma value [2], odour unit [3] or odour activity value (OAV) [4], In the following the latter term is used. 

Kubickova, J., Grosch, W. (1998) Quantification of potent odorants in Camembert cheese and calculation of their odour activity values. Int. Dairy J. 8, 17-23... 

Fig. 3. Odour activity values (OAVs) of the odorant series (OSs) in sherry-type wines during their biological ageing.

The odour activity value (OAV) is a useful p>arameter to assess the relative importance of individual chemical components paesent in a wine. The aroma active compounds are volatiles whose concentration in wine is above their odour threshold (OAV>l). However, even when the OAV of a particular compoimd is less than 1, it still might contribute to the aroma of a wine as a consequence of some additive or synergic effect among compounds with similar aroma nature. 

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