Autolysis and proteolysis in different strains of starter bacteria during Cheddar cheese ripening

Wilkinson, Martin G.; Guinee, Timothy P.; O'callaghan, Daniel M.; Fox, Patrick F.

doi:10.1017/s0022029900028260

Cited by 192 publications

(203 citation statements)

References 17 publications

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“…Since we also observed that the extent of starter bacteria Iysis was related to the phage levels, we can conclude that the higher the cell Iysis, the higher was the rate of formation of small peptides and free arnino acids. These results are in agreement with previous studies (Chapot-Chartier et al, 1994;Wilkinson et al, 1994;Crow et al, 1995b) which also established a relationship between the lysis of starter bacteria and the proteolysis rate.…”

supporting

confidence: 94%

“…In the future, better knowledge of the autolytic system should help in selecting autolytic strains or constructing by genetic engineering strains with an inducible autolytic system. The influence of starter bacteria autolysis on cheese ripening has already been studied (Bie and Sjôrstrom, 1975 a,b;Crow et al, 1995a); more recently, a few studies have evaluated more precisely the natural ability of starter bacteria to autolyse in chee se and the impact of bacterial Iysis on ripening in the case of lactococci in hard and semi-hard cheese such as Cheddar (Wilkinson et al, 1994) or Saint-Paulin (Chapot-Chartier et al, 1994). It was found that the ability of L lactis to autolyse is strain-dependent and that the early Iysis of bacteria leads to a higher rate of proteolysis during ripening.…”

Section: Introductionmentioning

confidence: 99%

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Phage-induced lysis of Lactococcus lactis during Saint-Paulin cheese ripening and its impact on proteolysis

Kawabata

Vassal

Bars

et al. 1997

Lait

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Summary -The autolysis of starter bacteria during chee se ripening results in the release of intracellular enzymes, especially peptidases, into the curd and in consequence is expected to accelerate and enhance the development of cheese flavour. In the course of a series of cheese assays with the nonautolytic Lactococcus lactis NC00763 strain, the presence of a homologous bacteriophage was encountered. The phage was present at different levels which allowed us to evaluate the impact of the extent of starter bacteria Iysis on Saint-Paulin-type cheese proteolysis during ripening. We estimated bacterial Iysis by viable cell enumeration and electron microscopy observations over a 2-month ripening period. On the same cheeses, we have estimated proteolysis by measuring soluble nitrogen (SN) and phosphotun~stic acid-soluble nitrogen (PT A-N) and by quantifying free amino acids. For phage levels up to 10 0 pfu/g of cheese, the pH and dry matter values were in the standard range, whereas for a higher phage level incorrect acidification was observed. The ex te nt of starter Iysis increased with the phage level and it was also correlated with the rate of formation of small peptides and free amino acids. After 2 months of ripening, the PTA-N value was three-fold higher and the total free amino acid content was seven-fold higher in the cheese with a phage level of 10 10 pfu/g than in the control cheeses. These results confirm that the early Iysis of starter bacteria allows the release of intracellular peptidases which are active in cheese, and that the extent of starter Iysis can be correlated with the proteolysis rate.Lactococcus lactis / cheese ripening / Iysis / phage / proteolysis Résumé -Lyse de Lactococcus lactis induite par des phages au cours de l'affinage de fromages de type Saint-Paulin et impact sur la protéolyse.L'autolyse des bactéries lactiques du levain résulte en la libération des enzymes intracellulaires, en particulier des peptidases, dans le

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supporting

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Phage-induced lysis of Lactococcus lactis during Saint-Paulin cheese ripening and its impact on proteolysis

Kawabata

Vassal

Bars

et al. 1997

Lait

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“…Bacterial cell wall associated proteinases and intracellular peptidases released after cell lysis in the curd are considered to play an important role in casein hydrolysis during cheese preparation (WILKINSON et al, 1994). The differences of flavor and texture attributes can be related to the greater proteolysis of the cheese Q54 when compared to control cheese and Q14 (see Figure 2).…”

Section: Sensory Analysismentioning

confidence: 99%

“…Barros et al (2006) found that Prato cheese containing L. helveticus as adjunct culture showed a texture improvement probably due to the action of the proteolytic system of this microorganism on the casein matrix. In another study, Fenelon, Beresford and Guinee (2002) considered to play an important role in casein hydrolysis during cheese preparation (WILKINSON et al, 1994). The differences of flavor and texture attributes can be related to the greater proteolysis of the cheese Q54 when compared to control cheese and Q14 (see Figure 2).…”

Section: Sensory Analysismentioning

confidence: 99%

Assessment of proteolysis and sensory characteristics of prato cheese with adjunct culture

et al. 2012

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Influence of adjunct cultures on the chemical and sensory characteristics, and proteolysis of Prato cheese was investigated. Cheeses were manufactured using a commercial starter culture and Lactobacillus strains (Lactobacillus plantarum or Lactobacillus helveticus) as adjunct cultures. Control cheeses lacked the adjunct culture. The chemical composition was analyzed at day 5 after manufacture and the proteolysis at days 5, 25, 45 and 65 of ripening. The sensory acceptance was assessed at 60 days. A split-plot design was used and the complete experiment was carried out in triplicate. The results were evaluated by ANOVA and Tukey's test test at 5% significance level. There were no significant differences in chemical composition among the cheeses. A significant increase in proteolysis occurred during ripening period for the cheeses with adjunct culture when compared to cheeses without adjunct culture. Cheese with Lactobacillus helveticus showed higher scores for flavor, texture and purchase intent compared with the others treatments. Use of adjunct Lactobacillus suggests that the proteolysis of Prato cheese should be accelerated in order to reduce ripening period. Key words: Adjunct culture, cheese, flavor, proteolysis, sensory analysis ResumoA influência de culturas adjuntas sobre as características químicas e sensoriais, e sobre a proteólise do queijo Prato foi avaliada. Os queijos foram fabricados com cultura starter comercial e cepas de Lactobacillus (Lactobacillus plantarum ou Lactobacillus helveticus) como culturas adjuntas. Os queijos controle não foram adicionados de cultura adjunta. A composição química foi analisada no dia 5 após a fabricação e a proteólise nos dias 5, 25, 45 e 65 de maturação. A aceitação sensorial foi avaliada após 60 dias. Um delineamento de parcelas subdivididas foi utilizado e o experimento completo foi realizado em triplicata. Os resultados foram avaliados pela análise de variância e teste de Tukey no nível de 5% de probabilidade. Os queijos não apresentaram diferenças significativas em relação à composição química. Um aumento significativo na proteólise ocorreu durante o período de maturação para os queijos com cultura adjunta, quando comparado aos queijos sem adição desse tipo de cultura. Os queijos com Lactobacillus helveticus apresentaram médias das notas mais altas para os atributos sabor, textura e intenção de compra em comparação aos demais tratamentos. A utilização de Lactobacillus como cultura adjunta indica que a proteólise do queijo prato pode ser acelerada a fim de reduzir o seu tempo de maturação.

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“…It has been shown that lysis of Lactococcus lactis starter strains leads to the release of intracellular peptidases in the cheese curd, and as a result more free amino acids (which are aroma precursors) are produced and hydrophobic bitter peptides are degraded (12,35,52).…”

mentioning

confidence: 99%

Identification of Mur, an Atypical Peptidoglycan Hydrolase Derived fromLeuconostoc citreum

Cibik¹,

Tailliez²,

Langella³

et al. 2001

Appl Environ Microbiol

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A gene encoding a protein homologous to known bacterial N-acetyl-muramidases has been cloned from Leuconostoc citreum by a PCR-based approach. The encoded protein, Mur, consists of 209 amino acid residues with a calculated molecular mass of 23,821 Da including a 31-amino-acid putative signal peptide. In contrast to most of the other known peptidoglycan hydrolases, L. citreum Mur protein does not contain amino acid repeats involved in cell wall binding. The purified L. citreum Mur protein was shown to exhibit peptidoglycanhydrolyzing activity by renaturing sodium dodecyl sulfate-polyacrylamide gel electrophoresis. An active chimeric protein was constructed by fusion of L. citreum Mur to the C-terminal repeat-containing domain (cA) of AcmA, the major autolysin of Lactococcus lactis. Expression of the Mur-cA fusion protein was able to complement an acmA mutation in L. lactis; normal cell separation after cell division was restored by Mur-cA expression.Bacteria produce one or several peptidoglycan hydrolases (PGHs), which are capable of hydrolyzing covalent bonds in the peptidoglycan of their own cell envelope (for reviews, see references 46 and 49). Some of them, named autolysins, are able to trigger cell autolysis. PGHs are located in the cell wall and are involved in various cellular functions, including cell wall expansion, cell wall turnover, or cell separation. On the basis of their cleavage site in the peptidoglycan, four types of PGHs are defined: (i) N-acetyl-muramidases, (ii) N-acetyl-glucosaminidases, (iii) N-acetyl-muramoyl-L-alanine amidases, and (iv) peptidases. Most of the PGHs characterized so far have a modular structural organization with two domains: a catalytic domain containing the enzyme active site and a cell wall binding domain composed of several amino acid repeats (22,30).Autolysis of lactic acid bacteria (LAB) used as starters for cheese manufacturing plays an important role in flavor development during ripening (for reviews, see references 13 and 18). It has been shown that lysis of Lactococcus lactis starter strains leads to the release of intracellular peptidases in the cheese curd, and as a result more free amino acids (which are aroma precursors) are produced and hydrophobic bitter peptides are degraded (12,35,52).The PGH activities present in L. lactis were studied by renaturing sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), which allowed their detection after renaturation in a substrate-containing gel. Several activity bands were evidenced by this technique (9, 36, 40, 44). The major autolysin, AcmA, was characterized at the genetic level. It is an N-acetyl-muramidase that is required for proper cell separation after cell division (9) and is involved in autolysis observed during stationary phase after growth in liquid medium (10).Leuconostocs are heterofermentative LAB used as cheese starters in association with lactococci. They contribute to the development of cheese organoleptic properties by metabolizing citrate to diacetyl, an important flavor compound, an...

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Autolysis and proteolysis in different strains of starter bacteria during Cheddar cheese ripening

Cited by 192 publications

References 17 publications

Phage-induced lysis of Lactococcus lactis during Saint-Paulin cheese ripening and its impact on proteolysis

Phage-induced lysis of Lactococcus lactis during Saint-Paulin cheese ripening and its impact on proteolysis

Assessment of proteolysis and sensory characteristics of prato cheese with adjunct culture

Identification of Mur, an Atypical Peptidoglycan Hydrolase Derived fromLeuconostoc citreum

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