Original scientific paper
Optimisation of minimal media for production of aroma compounds typical for fermented milk products
Nevenka Mazić
Rajka Božanić
orcid.org/0000-0002-3387-0315
; Faculty of Food Technology and Biotechnology, University of Zagreb, Zagreb, Croatia
Abstract
The aim of this research was to optimize the composition of minimal growth media containing lactose and milk, in which lactic acid bacteria (LAB) would produce the maximum amount of volatile aroma compounds typical for fermented milk products. Ingredients used for the preparation of media were casein, tri-sodium-citrate, lactose, milk minerals, whey proteins and milk with 1.5% fat. The several prepared media differed mainly in the amount of citrate and whey proteins. Fermentation was carried out at room temperature until the media reached pH value of 5. Samples were evaluated for sensory characteristics using quantitative descriptive analysis (QDA). In all media the target pH was reached after 68-71 hours of fermentation, depending on citrate level. Fermentation and the production of aroma compounds were more intensive in media that contained whey proteins compared to media with only casein. Increased citrate level had a positive influence on the aroma production. Citrate increased the initial pH of the media and acted as a buffer during fermentation, which lead to longer fermentation and prolonged production of aroma compounds. At pH around 5, the desired cultured aroma was the most intensive, whereas sour taste was less dominant. The substrate with 0.25% citrate and 0.1% whey proteins, at pH 5, was rated as best regarding its sensory characteristics.
Keywords
fermented milk aroma; citrate; media optimization; whey proteins
Hrčak ID:
26103
URI
Publication date:
25.8.2008.
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