INVESTIGADORES
GONZALEZ Silvia Nelina
congresos y reuniones científicas
Título:
ETHYL ESTER PRODUCTION BY AUTOCHTHONOUS Lactobacillus AND Enterococcus STRAINS IN A GOAT MILK CHEESE MODEL
Autor/es:
ABEIJÓN MUKDSI, M.C.; WOLF, I.V.; PEROTTI, M.C.; MARGALEF, M.I.; GONZÁLEZ, S.N.; MEDINA, R.B
Lugar:
Egmond aan Zee, The Netherlands
Reunión:
Simposio; Symposium on Lactic Acid Bacteria; 2011
Resumen:
Esters
are common volatile compounds of cheese that contribute significantly to the
overall flavour. Among them, the ethyl esters of short-chain fatty acids confer
fruity flavour notes desirable in Italian, Swiss-type, goat and ewe milk
cheeses. Our aim was to evaluate the effect of autochthonous
lactic acid bacteria (isolated from goat milk cheeses) on the production of ethyl
esters in a goat milk cheese model, and the influence of ethanol on ester
synthesis. Pasteurized milk cheeses were manufactured under controlled
microbiological conditions. Lactobacillus
fermentum CRL1446 and Enterococcus faecium CRL1814, strains with
ester-synthesizing ability in vitro,
were used as adjunct culture. Cheeses containing only starter culture (mixture
of L. delbrueckii subsp. bulgaricus and Streptococcus thermophilus) were used
as control. To evaluate the influence of ethanol on ester synthesis, cheeses
were elaborated with and without ethanol addition to milk. After 30 and 60 days
of ripening at 10°C,
the concentration of volatile compounds was determined by solid phase
microextraction-gas chromatography (SPME-GC/FID), and sensory evaluation was
performed. Higher levels of ethyl acetate, butanoate and hexanoate were
detected in experimental cheeses compared to control cheeses, being ethyl
butanoate (EtC4) the most abundant. The highest EtC4 levels were detected in cheeses containing L. fermentum, whether ethanol was added to milk or not. However, in
cheeses containing E. faecium,
increases were only observed in those with ethanol addition, since this strain
produced lower ethanol concentration than L.
fermentum. Fruity
flavour notes were perceived only in ethanol-added cheeses. Our results demonstrated
that the autochthonous strains L. fermentum CRL1446 and E. faecium CRL1814 enhanced ester synthesis and fruity flavour
development in a goat milk cheese model, being ethanol concentration a determinant
factor.