Evaluation of autochthonous adjunct cultures in the ripening of goat cheeses

OLISZEWSKI, RUBEN; CANDIOTI, MARIO C.; MERCANTI, DIEGO J.; WOLF, I.VERÓNICA; PEROTTI, M.CRISTINA; BERGAMINI, CARINA V.; HERRERA, V.; GONZÁLEZ, SILVIA; ZALAZAR, CARLOS A.

San Miguel de Tucumán - Tucumán - Argentina

Simposio; III International Symposium on Lactic Acid Bacteria. II Argentinean LAB Net Meeting.; 2009

Centro de Referencia para Lactobacilos (CERELA-CONICET)

The last twenty years shown a great increase in Argentinean goat cheeses production, with the emergence of commercial farmers that joined to subsistence farmers. In addition, the Northwest region of Argentina has the largest stock with 1,240,000 goats, that represent 31% of the total. On that basis our working group developed autochthonous adjunct cultures. In the present study we assessed adjunct cultures and their interactions with a commercial starter to characterize the cheeses ripening. Three batches of semi-hard cheese were made with adjunct cultures strains Lactobacillus plantarum ETC17, Lactobacillus rhamnosus ETC14 and Enterococcus faecium ETC3 (CRL collection). Each one was tested separately using as starter a commercial culture (Chr Hansen) whose composition was Streptococcus thermophillus (60%), Lactobacillus bulgaricus (20%) and Lactobacillus helveticus (20%). The starter was inoculated at 1% and the adjunct cultures at 0.25%. All batches were manufactured in duplicate. Cheese made only with the commercial starter was used as a control. The cheeses were ripened 60 days. Insoluble nitrogen fractions analysis were made by electrophoresis; ripening index by soluble nitrogen at pH 4.6, proteolysis by HPLC; lipolysis by gas chromatography, detection of aroma compounds by solid phase microextraction analysis and sensory analysis by organoleptic panel. Cheeses showed low differences in the degradation of insoluble nitrogen fractions and ripening index. HPLC chromatograms showed no significant differences, being the main source of variation cheese replicas, influenced by the composition of milk used. Fatty acid profile showed differences mainly in cheeses produced with Enterococcus faecium, besides being the only cheeses that differ statistically from control in the sensory analysis. Aroma analysis characterized the main released compounds, predominated among those: a-ketones (2-propanone, 2-pentanone + diacetyl and acetoin); b-alcohols (ethanol, 3-methyl 1-butanol, 2,3-butanediol), c-esters (ethyl butanoate); d-aldehydes (acetaldehyde), e-acids (acetic, isovaleric, hexanoic, butyric, 2-methyl propanoic) and other compounds such as limonene. The present work allowed to characterize the ripening profile of goat semi hard cheeses produced with autochthonous adjunct cultures.