The content of aroma compounds in fermented milk products.

abstrakt

angličtina

Fermented milk products are dairy foods that have been fermented with lactic acid bacteria such as Lactobacillus, Lactococcus, Leuconostoc and Bifidobacterium. The fermentation process increases the shelf-life, improves the digestibility and contributes to the taste and aroma (flavour) of the product. The bases of flavour are the aroma active compounds, which are created during fermentation process and thermal treatment of foods from their precursors. The understanding of conditions and regularities of aroma compounds creation and their influence on sensory perception of flavour is necessary for production of high-quality products. Technological process of production consists of several steps. The fermentation phase, where not only characteristic taste and aroma, but also structure and consistence of product are developed, is the most important. Taste and aroma active compounds arise by enzymatic decomposition of lactose, proteins and fat in milk. The anaerobic transformation of saccharides to lactic acid is the basic biochemical pathway during production. The produced lactic acid imparts fine refreshing acid taste to these products and extends their durability. It also precipitates milk proteins, which are then easier to digest and improves utilization of calcium, phosphorus and iron. The proteolytic activity of lactic acid bacteria changes physico-chemical properties of casein, which influences rigidity, texture and viscosity of coagulate. Arisen peptides and free amino acids are precursors for enzymic reactions producing taste compounds. Similarly aroma compounds can arise by lipolytic activity. Released fatty acids are precursors for methyl ketones, alcohols, lactones and esters, which also impart characteristic flavour to product. The aim of this work was to identify and quantify several aroma compounds in various types of fermented milk products using SPME-GC-MS method and to judge their influence on flavour of products. In total 18 types of products (7 types of flavoured creamy yogurts, 3 types of drinking yogurts, 4 types of acidophilic milk, 2 types of kefirs and 2 types of clabbered milk) with various flavourings were analysed.

fermented dairy products, flavour, SPME, GC, sensory analysis

SKLENÁŘOVÁ, K.; LOUPANCOVÁ, B.; DIVIŠOVÁ, R.; VÍTOVÁ, E.; BABÁK, L.

17. 8. 2011

ČSCH

Brno

0009-2770

Chemické listy

105

18

Česká republika

s1044

s1044

1