Ser2 from Serratia liquefaciens L53: A new heat stable protease able to destabilize UHT milk during its storage

Baglinière, François; Tanguy, Gaëlle; Salgado, Rafael Locatelli; Jardin, Julien; Rousseau, Florence; Harel-Oger, Marielle; Vanetti, Maria Cristina Dantas; Gaucheron, Frédéric

doi:10.1016/j.foodchem.2017.02.054

Cited by 19 publications

(16 citation statements)

References 24 publications

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“…Of the psychrotrophic bacteria found in milk, species from the Pseudomonas genus are the most common and most widely studied in respect to UHT milk stability; however, other genera such as Bacillus (Janstova, Lukasova, Drackova, & Vorlova, ; Machado et al., ) and Serratia (Baglinière et al., ; Bagliniere, Jardin, Gaucheron, de Carvalho, & Vanetti, ; Machado, Baglinière et al., ) species can also produce heat‐stable enzymes. Several studies have attempted to isolate and characterize the specific heat‐stable extracellular proteases secreted by the psychrotrophic bacteria, especially those from the Pseudomonas genus (Bagliniere et al., ; Bagliniere et al., ; Baur et al., ; Dufour et al., ; Mateos et al., ; Mitchell et al., ).…”

Section: Age Gelationmentioning

confidence: 99%

Age Gelation, Sedimentation, and Creaming in UHT Milk: A Review

Anema

2018

Comp Rev Food Sci Food Safe

100

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Demand for ultra‐high‐temperature (UHT) milk and milk protein‐based beverages is growing. UHT milk is microbiologically stable. However, on storage, a number of chemical and physical changes occur and these can reduce the quality of the milk. These changes can be sufficiently undesirable so as to limit acceptance or shelf life of the milk. The most severe changes in UHT milk during storage are age gelation, with an irreversible three‐dimensional protein network forming throughout, excessive sedimentation with a compact layer of protein‐enriched material forming rapidly at the bottom of the pack, and creaming with excessive fat accumulating at the top. For age gelation, it is known that at least two mechanisms can lead to gelation during storage. One mechanism involves proteolytic degradation of the proteins through heat‐stable indigenous or exogenous enzymes, destabilizing milk and ultimately forming a gel. The other mechanism is referred to as a physico‐chemical mechanism. Several factors are known to affect the physico‐chemical age gelation, such as milk/protein concentration, heat load during processing (direct compared with indirect UHT processes), and milk composition. Similar factors to age gelation are known to affect sedimentation. There are relatively few studies on the creaming of UHT milk during storage, suggesting that this defect is less common or less detrimental compared with gelation and sedimentation. This review focuses on the current state of knowledge of age gelation, sedimentation, and creaming of UHT milks during storage, providing a critical evaluation of the available literature and, based on this, mechanisms for age gelation and sedimentation are proposed.

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Section: Age Gelationmentioning

confidence: 99%

Age Gelation, Sedimentation, and Creaming in UHT Milk: A Review

Anema

2018

Comp Rev Food Sci Food Safe

100

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“…Rennet coagulation of milk takes place at two steps: rennet causes proteolysis of κ-casein by breaking the Phe 105 -Met 106 peptide bond leading to destabilization of the casein micelle and the following of aggregation results in gel formation (19). Gel formation at normal pH of milk takes place after at least 85 to 90% κ-casein has been hydrolyzed (31). In this paper no gel formation was observed, since rennet activity was controlled by heat treatment, it was concluded that less than 85% of the κ-casein was hydrolyzed.…”

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confidence: 58%

“…According to the present paper, estimating the heat stability for large and small casein micelles in milk, under the same conditions is variable. This could be as a result of distribution of casein micelles size dispersion which dictates the rate of sedimentation and diffusion (31). These results were comparable with those obtained by Lin et al (2016) who studied the fortification of milk protein content with different dairy protein powders and found that the aggregation behavior of proteinfortified milk samples (125 to 142 nm) is strongly influenced by the degree of mineralisation of the protein powder used in fortification, which affects the partitioning of casein and calcium in the sedimentable and nonsedimentable phases (33).…”

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confidence: 99%

The Quality of The UHT Skim Milk as Affected by Addition of Rennet Skim Milk

Nouri

Ezzatpanah

2017

Nutr Food Sci Res

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A B S T R A C TBackground and Objectives: Consumption of whole dairy products has declined due to the awareness of possible harmful effects of fat on consumers' health. The purpose of the present paper was to investigate the possibility of substituting the Ultra-high temperature processing (UHT) whole milk with partially hydrolyzed κ-casein to manufacture a UHT skim milk. Materials and Methods:UHT skim milk samples were prepared using 0.2, 0.4, 0.6 and 0.8 % (w/w) of rennet followed by storage at 60°C for 15 minutes to inactivate the enzyme. The Chemical, physical and sensory characteristics of control and treated samples were evaluated. Statistical analysis was performed by SPSS. Results:The results showed that a higher concentration of rennet increased and decreased b * (blue-yellow) and a * (green-red), respectively (p<0.05). The regression profiles of viscosity plotted against heat stability of samples show a polynomial relationship (R 2 = 0.96). The zeta value of treatment samples was significantly lower than the absolute value of CUSM (Control UHT skim milk with 0.3% fat). There is a correlation between the appearance viscosity and average particle size (R 2 = 0.92). The skim milk consisting of 0.6% of rennet skim milk did not have any significant regarding aroma, taste and texture from those of the control UHT whole milk (p<0.05). Conclusions:The result showed that, RSM 4 (Renneted UHT skim milk with 0.3% fat and 0.8 % (w/w) rennet) has similar characteristics to whole milk and it is also clear in viscosity and sensory evaluation among other samples. It has been noted that non-dairy components were not used in RSM 4 and the new production can be a very functional and safe fat mimetic by merely changing the structure of casein micelles.

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“…Recent studies have shown that Pseudomonas is not the only psychrotrophic genus frequently encountered in raw milk with the capacity to secrete a heat‐resistant protease. The genus Serratia , especially the species Serratia liquefaciens , is also frequently found as a psychrotrophic contaminant in raw milk (Baglinière, Jardin, Gaucheron, De Carvalho, & Vanetti, ,b; Machado et al., ), and it has been shown to secrete a heat‐resistant spoilage‐inducing metalloprotease of approximately 52 kDa encoded by the Ser2 gene. The protease was therefore named Ser2.…”

Section: Relationship Between Aprx and The Instability Of Uht Milkmentioning

confidence: 99%

“…Baglinière et al. (,b) compared the hydrolysis patterns of caseins by Ser2 and AprX. They found Ser2, like AprX, could hydrolyze β‐, α s ‐, and κ‐caseins in UHT milk, thereby destabilizing casein micelles.…”

Section: Relationship Between Aprx and The Instability Of Uht Milkmentioning

confidence: 99%

The Extracellular Protease AprX from Pseudomonas and its Spoilage Potential for UHT Milk: A Review

Zhang

Bijl

Svensson

et al. 2019

Comp Rev Food Sci Food Safe

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The negative effects of proteases produced by psychrotrophic bacteria on dairy products, especially ultra‐high‐temperature (UHT) milk, are drawing increasing attention worldwide. These proteases are especially problematic, because it is difficult to control psychrotrophic bacteria during cold storage and to inactivate their heat‐resistant proteases during dairy processing. The predominant psychrotrophic species with spoilage potential in raw milk, Pseudomonas, can produce a thermostable extracellular protease, AprX. A comprehensive understanding of AprX on the aspects of its biological properties, regulation, proteolytic potential, and its impact on UHT milk can contribute to finding effective approaches to minimize, detect, and inactivate AprX. AprX also deserves attention as a representative of all extracellular metalloproteases produced by psychrotrophic bacteria in milk. The progress of current research on AprX is summarized in this review, including a view on the gap in current understanding of this enzyme. Reducing the production and activity of AprX has considerable potential for alleviating the problems that arise from the instability of UHT milk during shelf‐life.

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Ser2 from Serratia liquefaciens L53: A new heat stable protease able to destabilize UHT milk during its storage

Cited by 19 publications

References 24 publications

Age Gelation, Sedimentation, and Creaming in UHT Milk: A Review

Age Gelation, Sedimentation, and Creaming in UHT Milk: A Review

The Quality of The UHT Skim Milk as Affected by Addition of Rennet Skim Milk

The Extracellular Protease AprX from Pseudomonas and its Spoilage Potential for UHT Milk: A Review

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