Ester synthesis by lactic acid bacteria isolated from goat’s and ewe’s milk and cheeses

• Published in: Food chemistry 2009-11, Vol.117 (2), p.241-247
• Main Authors: Abeijón Mukdsi, María C., Medina, Roxana B., Alvarez, María de F., González, Silvia N.
• Format: Article
• Language: English
• Subjects: Alcoholysis; Biological and medical sciences; cheesemaking; cheeses; Esterification; Esters; ewe milk; food analysis; food composition; Food industries; Food microbiology; free fatty acids; Fundamental and applied biological sciences. Psychology; goat milk; Lactic acid bacteria; Milk and cheese industries. Ice creams; Ruminantia; sensory properties; strain differences; synthesis
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2009.03.105

The present work evaluates the ability of lactic acid bacteria isolated from goat’s and ewe’s milk and cheeses to synthesise short-chain fatty acid esters. In order to elucidate the mechanisms of ester synthesis involved, cell-free extracts were incubated in sodium phosphate buffer containing triglyceride plus ethanol (alcoholysis) and free fatty acid plus ethanol (esterification). After 24 h incubation at 37 °C esters were extracted and determined by gas chromatography. Strains evaluated were able to synthesise ethyl esters from 2 to 10 carbon atoms, mainly ethyl butanoate and ethyl hexanoate. A great variability amongst strains was observed. In general, higher ester-forming activities by esterification were detected. In enterococci strains the alcoholysis mechanism was also involved. These strains could be useful as adjunct cultures for small ruminants’ dairy products and would contribute to the development of fruity flavour notes. A deeper understanding of ester synthesis mechanisms involved would allow the control of flavour development.