Flavour formation by lactic acid bacteria and biochemical flavour profiling of cheese products

Abstract

Flavour development in dairy fermentations, most notably cheeses, results from a series of (bio)chemical processes in which the starter cultures provide the enzymes. Particularly the enzymatic degradation of proteins (caseins) leads to the formation of key-flavour components, which contribute to the sensory perception of dairy products. More specifically, caseins are degraded into peptides and amino acids and the latter are major precursors for volatile aroma compounds. In particular, the conversion of methionine, the aromatic and the branched-chain amino acids are crucial. A lot of research has focused on the degradation of caseins into peptides and free amino acids, and more recently, enzymes involved in the conversion of amino acids were identified. Most data are generated on Lactococcus lactis, which is the predominant organism in starter cultures used for cheese-making, but also Lactobacillus, Streptococcus, Propionibacterium and species used for surface ripening of cheeses are characterised in their flavour-forming capacity. In this paper, various enzymes and pathways involved in flavour formation will be highlighted and the impact of these findings for the development of industrial starter cultures will be discussed.

Multifactorial diversity sustains microbial community stability

“…Fluctuations in the community members during cheese manufacturing have an effect on the functionality of the starter such as acidification or flavor formation (Smit et al, 2005). Therefore, relative abundance of each genetic lineage during cheese Community stability through genetic diversity O Erkus et al manufacturing was quantified by amplified fragment length polymorphism typing of randomly picked single colony isolates to reveal the community dynamics (Figure 6).…”

Physicochemical and microbiological evaluation of corrientes artisanal cheese during ripening

“…This biodiversity generates particular flavors in these cheeses contributing to the increase in global demand over the last few years (WOUTERS et al, 2002;SMIT;SMIT;ENGELS, 2005). Therefore, the wild strains of lactic acid bacteria (LAB) with particular technological characteristics are really required for new collections for industrial applications.…”

Microbiology of Cheddar cheese made with different fat contents using a Lactococcus lactis single-strain starter

“…Similar to many other internally bacterial ripened cheeses, Cheddar must be stored at low temperature (5-13°C) for months and sometimes years to attain desired flavor and body attributes. During this period, microorganisms and enzymes trapped in the cheese matrix act on curd substrates in a manner that is heavily dictated by the curd microenvironment (e.g., cheese pH, water activity, salt content, redox potential, and temperature), producing a heterogeneous mixture of volatile and nonvolatile flavor and aroma compounds that eventually confer mature cheese flavor (Fox et al, 1993;Fox and Wallace, 1997;Marilley and Casey, 2004;Smit et al, 2005;Ardö, 2006).…”

“…Given the causal role of LAB in cheese flavor development, research to define the biochemical basis for flavor changes in cheese has logically focused on the microbiology and physiology of species present in cheese (for reviews, see Beresford et al, 2001;Marilley and Casey, 2004;Smit et al, 2005;Ardö, 2006;Broadbent and Steele, 2007;Cogan et al, 2007;Drake, 2007). Those efforts have identified several important biochemical and chemical processes that occur during maturation, and demonstrated that starters, adjuncts, and NSLAB can have an intimate role in those processes.…”