Chemistry Reference
In-Depth Information
3-methylbutanal, butanoic acid, dimethyl trisulphide, hexanoic acid,
-hexa-
lactone, nonanal,
-octalactone and
-dodecalactone. Aroma recombination
studies, followed by sensory analysis, indicated that the synthetic aroma
model mixture was significantly different from the reference (direct from
manufacturing plant) but ranked the same (similarity index) as the aroma
of a commercial margarine or an unsalted fresh butter. According to Peterson
and Reineccius (2003a), sweet-cream butter was characterised by
-octalac-
tone,
-hexalactone and
-dodecalactone. In particular,
-hexalactone and
-dodecalactone had creamy and peach-like odours, respectively, but were
identified in sweet-cream butter only by Peterson and Reineccius (2003a).
Day et al. (1964) identified DMS in butter and considered it to be a
desirable component, which smoothes the strong flavour of diacetyl. In a
study by Schieberle et al. (1993), the overall odour impression of sweet-
cream butter was evaluated by a trained sensory panel and compared with
the odorants of different types of sour-cream butter. The results showed
that the concentration of diacetyl is lower without a fermentation process
as in sweet-cream butter, resulting in an overall mild and sweet odour
impression.
Schieberle et al. (1993) studied different kinds of butter: sour-cream
butter, Irish sour-cream butter, German farm sour-cream butter and
cultured butter and compared them with sweet-cream butter. AEDA on
Irish sour-cream butter, showing the most intense odour during a preli-
minary sensory analysis, revealed 18 odour-active compounds (Table
14.3). Sunflower oil was spiked with diacetyl,
-decalactone and butanoic
acid at the same concentrations occurring in cultured butter that was
chosen as standard for the most typical butter odour. The results indicated
that sunflower oil containing the three odorants exhibited an aroma note,
which in quality and intensity was very similar to the odour of the cultured
butter.
Butter generates potent odorants during heating (Grosch, 1986).
Budin et al. (2001) studied odorants in heated sweet-cream butter using
AEDA. The volatile fraction of butter, heated to 105-1108C for 15 min, was
isolated by high-vacuum distillation. The odorants with the highest aroma
dilution factors are listed in Table 14.3. The key aroma compounds of
heated butter were compared with those of fresh butter:
-decalactone,
skatole, 1-octen-3-one, (E)- and (Z)-2-nonenal, (E,E)-2,4-decadienal and
trans-4,5-epoxy-(E)-2-decenal had higher aroma dilution values in heated
butter. Schieberle et al. (1993) determined the sensory threshold of
-deca-
lactone as 120 mg/kg sunflower oil. It is present in heated butter approxi-
mately 50 times above its threshold, which suggests that it is the most
important odorant in heated butter (Budin et al., 2001). Due to their high
odour activity values (OAVs), 1-octen-3-one, methional, HDMF and trans-
