R. Imhof et al., VOLATILE ORGANIC AROMA COMPOUNDS PRODUCED BY THERMOPHILIC AND MESOPHILIC MIXED STRAIN DAIRY STARTER CULTURES, Lebensmittel-Wissenschaft + Technologie, 27(5), 1994, pp. 442-449
The potential of different commercial dairy starter cultures to form v
olatile organic compounds was assessed. Special interest was taken in
the so-called minor constituents that are present in the low mug/kg ra
nge in the aroma of the end products of the investigated starter cultu
res. Volatile organic compounds produced by the starter bacteria are f
ormed during production or within the first 24 h of storage. Quantitat
ive changes that occurred after 2 and 4 wk proved to be less significa
nt. Many of the aldehydes (pentanal and homologues up to undecanal) as
well as some alcohols (1-propanol, 1-butanol, 1-pentanol) present in
fermented dairy products were not produced by starter bacteria but ori
ginated from the milk. Only five of the compounds (dimethyl sulfide, 2
,3-butanedione, 2,2-pentanedione, limonene and undecanal) together wit
h ethanal are considered to have an impact on the resulting aroma, pro
viding odour unit values >1.5. Using multiple stepwise regression anal
ysis it was possible to differentiate between the five different cultu
re types, and to discern the age of an unknown sample independent of i
ts culture type.