Autolysis and intracellular enzyme release from cheese related dairy lactobacilli

El-Kholy, Wedad M.; El‐Soda, M.; Ezzat, N.; Shafei, H. el

doi:10.1051/lait:1998442

Cited by 16 publications

(11 citation statements)

References 5 publications

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“…However, concurring with previous publications, the thermophilic bacteria generally disappeared in a brief time (1-3 months), thus releasing a wealth of enzymes [3,7,8,17,31]. An undoubtedly important contribution was made by the mesophilic lactic acid bacteria (essentially L. casei, L. paracasei, L. rhamnosus, pediococci) which presented meaningful counts in the fifth month of ageing, thereby showing a significantly higher level compared to what has been reported thus far in literature with specific reference to Grana Padano [1].…”

Section: Discussionsupporting

confidence: 91%

Microbiological characteristics of Parmigiano Reggiano cheese during the cheesemaking and the first months of the ripening

Coppola

Nanni²,

Iorizzo

et al. 2000

Lait

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-The aim of this work was to gain a comprehensive view of the microbiological characteristics of milk, natural whey starter, and cheese during the first months of ageing of Parmigiano Reggiano. A significant presence of different microbial groups in raw milk from the initial moments of production was rapidly substituted by various lactic acid bacteria. Natural whey starter contained a large number of thermophilic lactic acid bacteria (Lactobacillus helveticus, L. delbrueckii ssp. lactis, L. delbrueckii ssp. bulgaricus) and some facultatively heterofermentative lactic acid bacteria belonging to L. rhamnosus. Thermophilic lactic acid bacteria disappeared within 30 d. Rod-shaped mesophilic facultatively heterofermentative lactic acid microflora, consisting of L. casei, L. paracasei ssp. paracasei, L. paracasei ssp. tolerans, L. rhamnosus and pediococci, progressively increased up to the fifth month of ageing. Results showed that thermophilic lactobacilli were derived from natural whey starter whereas Streptococcus thermophilus originated from raw milk. Further, natural whey starter was the source of L. rhamnosus which was present throughout the entire period of the cheese ageing. The other components of non-starter lactic acid microflora derived from raw milk.

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Section: Discussionsupporting

confidence: 91%

Microbiological characteristics of Parmigiano Reggiano cheese during the cheesemaking and the first months of the ripening

Coppola

Nanni²,

Iorizzo

et al. 2000

Lait

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“…Cells counts on FH medium did not decrease during incubation, but it could hide a viability decrease of some strains among the population, as already observed in cheese [8]. FHL possess high autolytic activity [3,12] and peptidase activity [33,38]. The raw milk flora of Swiss-type cheese, composed of FHL and PAB has been shown to generally increase proteolysis indexes during ripening, i.e.…”

Section: Discussionmentioning

confidence: 67%

“…lactis [33]. Lysis of L. casei and L. plantarum has not yet been extensively studied but was close to L. helveticus under conditions prevailing in cheese [12]. Their intracellular peptidases could therefore contribute to increasing proteolysis in cheese.…”

Section: Introductionmentioning

confidence: 99%

Propionibacteria and facultatively heterofermentative lactobacilli weakly contribute to secondary proteolysis of Emmental cheese

Gagnaire

Thierry

Léonil

2001

Lait

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-Proteolysis is a major event during cheese ripening. In Emmental cheese, the contribution of plasmin and thermophilic lactic starters to proteolysis has been well established. Our aim was to assess the contribution of each ripening flora to secondary proteolysis. With this aim, we used the aqueous phase (or juice) of Emmental cheese as a culture medium, which contains the enzymes released by thermophilic starters. Crude juice (containing all cheese flora) and cell-free juice either inoculated with two propionibacteria (PAB) strains or uninoculated (control), were incubated under anaerobiosis at 24 o C for 20 d. Free amino groups and free amino acids, bacterial growth and organic acids were followed throughout the incubation time. Facultatively heterofermentative lactobacilli (FHL) represented the main flora growing in crude juice up to 10 d incubation. FHL and PAB respectively reached 4.0 × 10 8 and 1.0 × 10 10 cfu . mL -1 of juice and consumed citrate and lactate, in accordance with that already observed in cheese. The level of amino groups increased linearly during incubation time by a factor of 1.9 in crude juice, 1.7 in cell-free juice and only 1.5 in juice inoculated with PAB strains, showing that the enzymes of thermophilic starters are the main contributors to secondary proteolysis. FHL growth resulted in a 16% increase in free amino acids compared to cell-free juice and in exhaustion of Arg and His. Both PAB strains caused a 18-27% decrease in free amino acids and also modified the amino acid distribution, with consumption of Asp, Gly, Glu, Ser and Ile. secondary proteolysis / Propionibacterium / facultative heterofermentative lactobacilli / Emmental cheese / free amino acid Résumé -Les lactobacilles hétérofermentaires facultatifs et les bactéries propioniques ont une faible contribution à la protéolyse secondaire de l'Emmental. La protéolyse est un phéno-mène majeur dans l'affinage du fromage. Dans l'Emmental, la contribution de la plasmine et des levains thermophiles à la protéolyse secondaire a été bien établie. Le but de cette étude était de 339 * Correspondence and reprints

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“…Endopeptidases encoded by the pepE, pepE2, pepF, pepO, pepO2, and pepO3 genes and the proline-specific dipeptidase encoded by the pepR gene have already been identified and characterized in L. helveticus CNRZ32 (8,45,47). Release of these intracellular enzymes from the cell is considered to be highly important during cheese ripening, as they play a key role in biochemical processes leading to textural changes and flavor development (13). All of these genes along with other peptidase genes identified in the L. helveticus DPC4571 genome were present in all the strains analyzed by aCGH.…”

Section: Discussionmentioning

confidence: 99%

Crucial Role for Insertion Sequence Elements in Lactobacillus helveticus Evolution as Revealed by Interstrain Genomic Comparison

Kaleta

O’Callaghan

Fitzgerald

et al. 2010

Appl Environ Microbiol

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Lactobacillus helveticus is a versatile dairy bacterium found to possess heterogeneous genotypes depending on the ecosystem from which it was isolated. The recently published genome sequence showed the remarkable flexibility of its structure, demonstrated by a substantial level of insertion sequence (IS) element expansion in association with massive gene decay. To assess this diversity and examine the level of genome plasticity within the L. helveticus species, an array-based comparative genome hybridization (aCGH) experiment was designed in which 10 strains were analyzed. The aCGH experiment revealed 16 clusters of open reading frames (ORFs) flanked by IS elements. Four of these ORFs are associated with restriction/modification which may have played a role in accelerated evolution of strains in a commercially intensive ecosystem undoubtedly challenged through successive phage attack. Furthermore, analysis of the IS-flanked clusters demonstrated that the most frequently encountered ISs were also those most abundant in the genome (IS1201, ISL2, ISLhe1, ISLhe2, ISLhe65, and ISLhe63). These findings contribute to the overall viewpoint of the versatile character of IS elements and the role they may play in bacterial genome plasticity.Lactobacillus helveticus is a gram-positive, homofermentative lactic acid bacterium which is widely used in the manufacture of cheeses, such as Swiss cheese and some Cheddar-type cheeses (22,25). It is also commonly used in the production of different types of Italian cheeses, such as Parmigiano Reggiano (18) and Grana Padano, where it contributes to the formation of specific flavor compounds (42).Phylogenetic analysis of ribosomal protein sequences derived from lactobacilli and streptococci classified L. helveticus in the same group along with both gastrointestinal (GI) tract and dairy-specific species (14). Comparative analysis of the 16S rRNA of L. helveticus DPC4571 revealed 98.4% identity with Lactobacillus acidophilus NCFM and indicated that this probiotic strain was closely related to strain DPC4571, despite the different environments these two lactobacilli inhabit (4). The results of genomic analysis of L. helveticus suggested that two major events have occurred in the diversification process of L. helveticus from a common ancestor with L. acidophilus, selective gene loss and acquisition of a large number of insertion sequence (IS) elements (4). IS elements are DNA sequences capable of independent transposition within and between bacterial genomes (31). Their capacity for independent mobility demonstrates the parasitic nature of these elements (11); however, they can also be regarded as having a positive influence, as they assist in promoting genetic variation (1). Thus, even though the primal character of these elements remains unclear in that they may be considered simply as selfish DNA elements, their impact on the architecture of microbial genomes is undeniable. It has already been demonstrated that IS-related mutations occur in Escherichia coli (44), Lactococcus lactis (10)...

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Autolysis and intracellular enzyme release from cheese related dairy lactobacilli

Cited by 16 publications

References 5 publications

Microbiological characteristics of Parmigiano Reggiano cheese during the cheesemaking and the first months of the ripening

Microbiological characteristics of Parmigiano Reggiano cheese during the cheesemaking and the first months of the ripening

Propionibacteria and facultatively heterofermentative lactobacilli weakly contribute to secondary proteolysis of Emmental cheese

Crucial Role for Insertion Sequence Elements in Lactobacillus helveticus Evolution as Revealed by Interstrain Genomic Comparison

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