Proteolysis of milk heated at high temperatures by native enzymes analysed by trinitrobenzene sulphonic acid (TNBS) method

CHOVE, M.

doi:10.5897/ajfs13.0987

Cited by 6 publications

(4 citation statements)

References 24 publications

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“…The spectrophotometric and fluorometric assays used for AprX activity measurement are based on the detection of either the hydrolysis of milk proteins, or the hydrolysis of externally added substrates. Trinitro-benzene-sulfonic acid (TNBS) and ophthaldialdehyde (OPA) methods have been widely used for determining the degree of hydrolysis of milk protein (Chove, Abdulsudi, & Lewis, 2013;Marchand et al, 2009a;Zhang et al, 2018), by determining the number of free amino groups. Compared with the TNBS assay, the reagents used in the OPA method are more stable and less toxic (Nielsen, Petersen, & Dambmann, 2001).…”

Section: Aprx Detection Approachesmentioning

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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Section: Aprx Detection Approachesmentioning

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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“…and Escherichia coli ; however, few studies have described the presence of Enterobacter, Klebsiella , and Serratia species, particularly with regard to the presence of these genera in foods and milk products. In addition, although most studies performed with these bacteria have focused on quantification and identification, some studies have also explored antimicrobial resistance (Samaržija et al, 2012 ; Zhang et al, 2015 ) and other virulence factors, such as biofilm (Cherif-Antar et al, 2016 ), proteolytic enzymes (Chove et al, 2013 ), and lipolytic enzymes (Masiello et al, 2016 ).…”

Section: Introductionmentioning

confidence: 99%

A Highlight for Non-Escherichia coli and Non-Salmonella sp. Enterobacteriaceae in Dairy Foods Contamination

Amorim

Nascimento

2017

Front. Microbiol.

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“…UHT milk was used because it was concluded from previous studies that processing at higher temperature lowered proteolysis and hence susceptibility of UHT milk to spoilage (Chove et al, 2013(Chove et al, , 2014. This is probably through denaturation of enzymes responsible for proteolysis, hence decreased proteolysis.…”

Section: Effect Of Proteolysis Of Uht Milk At 25 °Cmentioning

confidence: 99%

Preliminary Study on the Role of Ionic Calcium in Gelation and Proteolysis of UHT Milk

Mlipano

Michael²

2017

JFS

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A study was conducted to determine the influence of ionic calcium on gelation and proteolysis in milk. Raw milk was heated to 142 °C for 2s followed by cooling to 5 °C to make UHT milk. Two sequestering agents, Trisodium citrate (TSC) and Sodium hexametaphosphate (SHMP) were added at 0.04 -0.08% (w/v) to the processed UHT milk to reduce the ionic calcium levels. Proteolysis and gelation were induced by addition of trypsin (248 BAEE units), 0.03% (v/v) chymosin and 10 6 cfu/mL Pseudomonas fluorescens NCIMB 702085 (Ps. fl. 416) to UHT milk. Samples were stored at 25 °C for 2½ weeks to monitor gelation and Ca 2+ and some were incubated at 37 °C for 2h to monitor proteolysis. SHMP reduced more Ca 2+ than TSC. Ca 2+ reduction was accompanied by an increase in pH, most evident with TSC at 25 °C. Gelation was not observed in samples inoculated with Ps. fl. 416 (with sequestering agents) even after 9 days of storage, suggesting the importance of calcium in gelation. Chymosin treated samples gelled on day 0, whereas other samples gelled after 4 days. Trypsin increased Ca 2+ to levels higher than originally present in control UHT skim milk. Although in the current study, proteolysis was higher in samples inoculated with Pseudomonas fluorescens 416, no clear relationship was established between proteolysis and gelation in UHT milk. This observation Journal of Food Studies

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Proteolysis of milk heated at high temperatures by native enzymes analysed by trinitrobenzene sulphonic acid (TNBS) method

Cited by 6 publications

References 24 publications

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

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

A Highlight for Non-Escherichia coli and Non-Salmonella sp. Enterobacteriaceae in Dairy Foods Contamination

Preliminary Study on the Role of Ionic Calcium in Gelation and Proteolysis of UHT Milk

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