MALDI-TOF analysis of seasonal dynamics of Lactic Acid Bacteria from Algerian Goat Milk suggests predominance of Enterococcus Genus

Abstract

The goat milk is considered as nutraceutical due to its several beneficial com-pounds that increase its value. The purpose of this study was to investigate the variation of the goat milk’s lactic profile during winter and spring (2015). Several tests were realised. First, the isolation of the lactic acid bacteria con-tained in goat milk was realised by three specific media: the MRS, the M17, and the MSE. Second, a screening by the study of the proteolysis at two different concentration of casein (2%, 5%) and the study of aroma production were made to highlight performing isolates. These performing isolates were identified by using a precision spectrometry method which is called the Matrix Assisted Laser Desorption Ionisation Time-of-flight (MALDI-TOF). The identification with mass spectrometry «MALDI-TOF» technique revealed that those seasons had a more quantitative effect than a qualitative one. As a result, an average of 48% of lactic acid bacteria was identified for both sea-sons with a decrease of 6% observed in winter. In addition, it was revealed that Enterococcus was the most dominant genus in the Algerian goat milk. Therefore, lactic strains of this milk were proved to be technologically com-petent in terms of proteolysis and aroma production.