Scientific journal
Journal of Food and Nutrition Research
Summary No. 2 / 2019
Tomáška, M. – Čaplová, Z. – Sádecká, J. – Šoltys, K. – Kopuncová, M. – Budiš, J. – Drončovský, M. – Kolek, E. – Koreňová, J. – Kuchta, T.
Microorganisms and volatile aroma-active compounds in “nite“ and “vojky” cheeses
Journal of Food and Nutrition Research, 58, 2019, No. 2, s. 187-200
Tomáš Kuchta, Food Research Institute, National Agricultural and Food Centre, Priemyselná 4, P. O. Box 25, SK-824 75 Bratislava, Slovakia. E-mail: kuchta@vup.sk, tomas.kuchta@nppc.sk
Received 19 January 2019; 1st revised 8 April 2019; accepted 8 April 2019; published online 24 April 2019
Summary: “Nite“ and “vojky“ are various string-like forms of a traditional cheese in Slovakia. These products are manufactured by shaping of pasteurized or raw cows’ or ewes’ milk-based lump cheeses after melting in hot water. Unsmoked versions of these cheeses from three producers were studied regarding the contents of microorganisms and volatile aroma-active compounds in four seasons during a year. Culture-based microbiological analysis was carried out using selective media. Because eukaryotic microflora was found to be negligible, culture-independent analysis was focused to prokaryotes, using 16S rDNA amplification coupled to high throughput sequencing on Illumina MiSeq platform (Illumina, San Diego, California, USA). Aroma-active compounds were extracted by headspace solid-phase microextraction and subsequently analysed by gas chromatography-olfactometry supported by gas chromatography-mass spectrometry. Microflora was found to be dominated by Lactococcus spp. with significant levels of Streptococcus spp., Lactobacillus spp. and Enterococcus spp. Dominant aroma-active compounds comprised butanoic acid, diacetyl and 3-methylbutanoic acid, the latter being profound in “nite“ produced from unpasteurized ewes’ milk. Traditionally produced cheeses contained a more diverse prokaryotic microflora and had a stronger aroma profile containing a rich complex of volatile aroma-active compounds, while “nite“ produced from pasteurized cows’ milk by industrial process contained a uniform microflora and had a weaker aroma profile.
Keywords: cheese; lactic acid bacteria; high throughput sequencing; gas chromatography-olfactometry
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