Peptidase activity of four yeast species frequently encountered in dairy products—comparison with several dairy bacteria

Klein, Nathalie; Zourari, A.; Lortal, Sylvie

doi:10.1016/s0958-6946(02)00081-x

Cited by 39 publications

(19 citation statements)

References 24 publications

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“…Little is known about the direct contribution of starter yeasts to the proteolysis during cheese ripening. Klein et al (2002) had shown that this efficiency varied depending on the strains probably because of difference in the peptidase specificity.…”

Section: Discussionmentioning

confidence: 99%

Controlled production of Camembert-type cheeses. Part I: Microbiological and physicochemical evolutions

Leclercq-Perlat

Buono

Lambert

et al. 2004

Journal of Dairy Research

115

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A holistic approach of a mould cheese ripening is presented. The objective was to establish relationships between the different microbiological and biochemical changes during cheese ripening. Model cheeses were prepared from pasteurized milk inoculated with Kluyveromyces lactis, Geotrichum candidum, Penicillium camemberti and Brevibacterium linens under aseptic conditions. Two cheese-making trials with efficient control of environmental parameters were carried out and showed similar ripening characteristics. K. lactis grew rapidly between days 1 and 6 (generation time around 48 h). G. candidum grew exponentially between days 4 and 10 (generation time around 4 . 6 d). Brevi. linens also grew exponentially but after day 6 when Pen. camemberti mycelium began developing and the pH of the rind was close to 7. Its exponential growth presented 3 phases in relation to carbon and nitrogen substrate availability. Concentrations of Pen. camemberti mycelium were not followed by viable cell count but they were evaluated visually. The viable microorganism concentrations were well correlated with the carbon substrate concentrations in the core and in the rind. The lactose concentrations were negligible after 10 d ripening, and changes in lactate quantities were correlated with fungi flora. The pH of the inner part depended on NH 3 . Surface pH was significantly related to NH 3 concentration and to fungi growth. The acid-soluble nitrogen (ASN) and non-protein nitrogen (NPN) indexes and NH 3 concentrations of the rind were low until day 6, and then increased rapidly to follow the fungi concentrations until day 45. The ASN and NPN indexes and NH 3 concentrations in the core were lower than in the rind and they showed the same evolution. G. candidum and Pen. camemberti populations have a major effect on proteolysis ; nevertheless, K. lactis and Brevi. linens cell lysis also had an impact on proteolysis. Viable cell counts of K. lactis, G. candidum, Pen. camemberti and Brevi. linens were correlated with the environmental conditions, with proteolytic products and with carbon substrate assimilation. NH 3 diffusion from surface to the cheese core during ripening was highly suspected. Interaction phenomena between microorganisms are discussed.

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Section: Discussionmentioning

confidence: 99%

Controlled production of Camembert-type cheeses. Part I: Microbiological and physicochemical evolutions

Leclercq-Perlat

Buono

Lambert

et al. 2004

Journal of Dairy Research

115

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“…hansenii shows proteolytic and lipolytic activity, but the intensity is strain specific, and consequently the influence of D . hansenii on cheese texture and flavour may vary (Corbaci et al, ; Klein, Zourari, & Lortal, ). It is generally recognized that Y .…”

Section: Role Of Yeasts In Cheese Ripeningmentioning

confidence: 99%

Cheese yeasts

Fröhlich-Wyder

Arias-Roth

Jakob

2019

Yeast

108

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Numerous traditionally aged cheeses are surface ripened and develop a biofilm, known as the cheese rind, on their surfaces. The rind of such cheeses comprises a complex community of bacterial and fungal species that are jointly responsible for the typical characteristics of the various cheese varieties. Surface ripening starts directly after brining with the rapid colonization of the cheese surface by yeasts. The initially dominant yeasts are acid and salt‐tolerant and are capable of metabolizing the lactate produced by the starter lactic acid bacteria and of producing NH3 from amino acids. Both processes cause the pH of the cheese surface to rise dramatically. This so‐called deacidification process enables the establishment of a salt‐tolerant, Gram‐positive bacterial community that is less acid‐tolerant. Over the past decade, knowledge of yeast diversity in cheeses has increased considerably. The yeast species with the highest prevalence on surface‐ripened cheeses are Debaryomyces hansenii and Geotrichum candidum, but up to 30 species can be found. In the cheese core, only lactose‐fermenting yeasts, such as Kluyveromyces marxianus, are expected to grow. Yeasts are recognized as having an indispensable impact on the development of cheese flavour and texture because of their deacidifying, proteolytic, and/or lipolytic activity. Yeasts are used not only in the production of surface‐ripened cheeses but also as adjunct cultures in the vat milk in order to modify ripening behaviour and flavour of the cheese. However, yeasts may also be responsible for spoilage of cheese, causing early blowing, off‐flavour, brown discolouration, and other visible alterations of cheese.

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“…Kluyveromyces marxianus has only endocellular proteolytic activity (Klein et al, 2002), G. candidum strongly contributes to proteolysis by its extensive enzymatic system (Boutrou et Guéguen, 2005;Boutrou et al, 2006), P. camemberti has a complex proteolytic system that is more active when the pH of the rind is at least 6.0 (Lenoir et al, 1985;Choisy et al, 2000), and B. aurantiacum is well known for its considerable proteolytic activity (Lecocq et al, 1996;Rattray and Fox, 1999). Under 98% RH at 12°C and 92 or 98% RH at 16°C, Leclercq-Perlat et al (2012) showed that (1) the death of K. marxianus begins earlier (d 25) and is more intensive than under the other ripening conditions; (2) G. candidum growth also began earlier (d 1 to 2), more rapidly reaching its maximal concentration;…”

Section: Underrind Consistency and Core Hardnessmentioning

confidence: 99%

Temperature and relative humidity influence the ripening descriptors of Camembert-type cheeses throughout ripening

Leclercq-Perlat

Sicard

Perrot

et al. 2015

Journal of Dairy Science

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Ripening descriptors are the main factors that determine consumers' preferences of soft cheeses. Six descriptors were defined to represent the sensory changes in Camembert cheeses: Penicillium camemberti appearance, cheese odor and rind color, creamy underrind thickness and consistency, and core hardness. To evaluate the effects of the main process parameters on these descriptors, Camembert cheeses were ripened under different temperatures (8, 12, and 16°C) and relative humidity (RH; 88, 92, and 98%). The sensory descriptors were highly dependent on the temperature and RH used throughout ripening in a ripening chamber. All sensory descriptor changes could be explained by microorganism growth, pH, carbon substrate metabolism, and cheese moisture, as well as by microbial enzymatic activities. On d 40, at 8°C and 88% RH, all sensory descriptors scored the worst: the cheese was too dry, its odor and its color were similar to those of the unripe cheese, the underrind was driest, and the core was hardest. At 16°C and 98% RH, the odor was strongly ammonia and the color was dark brown, and the creamy underrind represented the entire thickness of the cheese but was completely runny, descriptors indicative of an over ripened cheese. Statistical analysis showed that the best ripening conditions to achieve an optimum balance between cheese sensory qualities and marketability were 13±1°C and 94±1% RH.

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Peptidase activity of four yeast species frequently encountered in dairy products—comparison with several dairy bacteria

Cited by 39 publications

References 24 publications

Controlled production of Camembert-type cheeses. Part I: Microbiological and physicochemical evolutions

Controlled production of Camembert-type cheeses. Part I: Microbiological and physicochemical evolutions

Cheese yeasts

Temperature and relative humidity influence the ripening descriptors of Camembert-type cheeses throughout ripening

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