Influence of growth conditions on heat-stable phospholipase activity in Pseudomonas

2001 ◽  
Vol 68 (1) ◽  
pp. 109-116 ◽  
Author(s):  
RAMARATHNA KOKA ◽  
BART C. WEIMER
Keyword(s):  
Growth Medium ◽  
Incubation Time ◽  
Milk Fat ◽  
Enzyme Production ◽  
Skim Milk ◽  
Heat Stability ◽  
Raw Milk ◽  
Growth Conditions ◽  
Psychrotrophic Bacteria ◽  
Milk Fat Globule

Many psychrotrophic bacteria contaminating raw milk produce phospholipase that withstands pasteurization and UHT treatments. This enzyme acts on the milk fat globule membrane and exposes triacylglycerides to the action of lipase. Phospholipase production by various isolates of Pseudomonas was investigated. The isolates were cultured aerobically at 8 °C in nutrient broth, McKellar's minimal salts medium, Chrisope's medium, and skim milk. Each strain produced phospholipase during the 50 h incubation. Enzyme production varied significantly (P < 0·001) with strain and growth medium. Strains varied significantly (P < 0·001) in their enzyme production in each medium and during the incubation time as well. Strain, incubation time, and the growth medium significantly influenced (P < 0·001) heat stability of the enzyme activity. Pasteurization reduced the activity, but did not eliminate it in skim milk.

Interactions between the bovine milk fat globule membrane and skim milk components on heating whole milk

1992 ◽  
Vol 59 (2) ◽  
pp. 187-195 ◽  
Author(s):  
Avis V. Houlihan ◽  
Philippa A. Goddard ◽  
Stephen M. Nottingham ◽  
Barry J. Kitchen ◽  
Colin J. Masters
Keyword(s):  
Milk Fat ◽  
Bovine Milk ◽  
Skim Milk ◽  
Milk Proteins ◽  
Raw Milk ◽  
Membrane Lipid ◽  
Milk Fat Globule Membrane ◽  
Whole Milk ◽  
Milk Fat Globule ◽  
Fat Globule

SummaryHeating raw milk at 80 °C for 2·5–20 min was found to result in compositional changes in the milk fat globule membrane (MFGM). The yield of protein material increased with the duration of heating, owing to incorporation of skim milk proteins, predominantly β-lactoglobulin, into the membrane. Lipid components of the MFGM were also affected, with losses of triacylglycerols on heating.

Effects of mechanical agitation of raw milk on the milk-fat globule in relation to the level of induced lipolysis

1978 ◽  
Vol 45 (3) ◽  
pp. 373-380 ◽  
Author(s):  
Hilton C. Deeth ◽  
Carolyn H. Fitz-Gerald
Keyword(s):  
Alkaline Phosphatase ◽  
Milk Fat ◽  
Skim Milk ◽  
Raw Milk ◽  
Mechanical Agitation ◽  
Milk Fat Globule ◽  
Fat Globule

SummaryThe amount of damage caused to the milk-fat globule by mechanical agitation of raw milk was assessed by several methods and related to the level of induced lipolysis resulting from the agitation. The results obtained by measuring the amount of ‘free’ fat formed, the percentage of fat in the skim-milk phase after separation, and the increase in the proportion of alkaline phosphatase associated with the skim-milk phase, showed little correlation with the level of lipolysis induced by agitation over a range of conditions. However, the level of induced lipolysis showed good correlation with the amount of lipolysis caused by addition of an exogenous lipase (from Candida cylindraceae) to the agitated milk. It is concluded that classical methods of assessing milk-fat globule damage are unsuitable for predicting the amount of fat available for lipase action and the lipolytic potential of raw milk subjected to mechanical agitation.

Synthesis of multivitamin-loaded heat stable liposomes from milk fat globule membrane phospholipids by using a supercritical-CO2 based system

2020 ◽  
Vol 22 (16) ◽  
pp. 5345-5356 ◽  
Author(s):  
Apratim Jash ◽  
Ali Ubeyitogullari ◽  
Syed S. H. Rizvi
Keyword(s):  
Milk Fat ◽  
Supercritical Co2 ◽  
Heat Stability ◽  
Membrane Phospholipids ◽  
Milk Fat Globule Membrane ◽  
Fat Globules ◽  
Heat Stable ◽  
System P ◽  
Milk Fat Globule ◽  
Fat Globule

Inspired by the heat stability of milk, where fat globules are coated by the milk fat globule membrane (MFGM), heat stable liposomes loaded with multivitamins were successfully synthesized from MFGM phospholipid concentrate.

scholarly journals Microfiltration of raw milk for production of high-purity milk fat globule membrane material

2020 ◽  
Vol 276 ◽  
pp. 109887 ◽  
Author(s):  
Steffen F. Hansen ◽  
Sean A. Hogan ◽  
John Tobin ◽  
Jan T. Rasmussen ◽  
Lotte B. Larsen ◽  
...  
Keyword(s):  
High Purity ◽  
Milk Fat ◽  
Raw Milk ◽  
Membrane Material ◽  
Milk Fat Globule Membrane ◽  
Milk Fat Globule ◽  
Fat Globule

Membrane material in bovine skim-milk from udder quarters infused with endotoxin and pathogenic organisms

1975 ◽  
Vol 42 (3) ◽  
pp. 401-417 ◽  
Author(s):  
M. Anderson ◽  
B. E. Brooker ◽  
A. T. Andrews ◽  
E. Alichanidis
Keyword(s):  
Milk Fat ◽  
High Speed ◽  
Skim Milk ◽  
Protein Composition ◽  
Membrane Material ◽  
Cell Debris ◽  
Relative Contribution ◽  
Milk Fat Globule ◽  
Fat Globule ◽  
And Control

SummaryThe effects of infusing endotoxin and a pathogen into different quarters of the udder of the same cow on the appearance and composition of milk membrane material were studied. Milk membrane was prepared by high-speed centrifugation of skim-milk. In samples from the control quarters only, a very thin layer covering the casein pellet was observed, whereas after the infusions it appeared as an opaque diffuse fluffy layer. The fluffy layer persisted for a maximum of 3 d after endotoxin infusion. A similar layer appeared 14 d after infusion of the pathogen and persisted, in spite of antibiotic treatment, throughout the experiment. From comparisons of (a) milk acid phosphatase activities between infused and control quarters, (b) the protein composition of milk membrane, and (c) morphological observations on the distribution of membrane material in milk, it was concluded that milk membrane originates from leucocytes, cell debris from the mammary gland, and the surface of the milk-fat globule membrane. The relative contribution made by these sources to milk membrane from healthy and infected udders is discussed.

scholarly journals Produksi Enzim Selulase Dari Bakteri Serratia marcescens KE-B6 Dengan Penambahan Sumber Karbon, Nitrogen dan Kalsium Pada Medium Produksi

2018 ◽  
Vol 19 (2) ◽  
pp. 159 ◽  
Author(s):  
Arom Septiani ◽  
W Wijanarka ◽  
MG Isworo Rukmi
Keyword(s):  
Serratia Marcescens ◽  
Growth Medium ◽  
Incubation Time ◽  
Enzyme Production ◽  
Production Medium ◽  
Cellulolytic Bacteria ◽  
Cellulase Enzyme ◽  
Randomized Design ◽  
Calcium Source ◽  
Calcium Sources

The waste of cellulose in the agro-industry can be reduced by decomposing the cellulose polymer into glucose. This process was carried out by cellulase enzyme (EC 3.2.1.4) produced by cellulolytic bacteria. Bacteria required food as nutrition to survived their life, can be obtained through growth medium or enzyme production medium. Carbon, nitrogen and calcium belong to the essential nutrients contained in growth medium and enzyme production medium. The purpose of this study is to determine the effect of the addition of carbon, nitrogen and calcium source and the time of incubation on the production of cellulase enzyme from Seratia marcescens KE-B6 bacteria. This research used Completely Randomized Design (RAL) of Factorial Pattern with two factors. The first factor is the type of medium, the first medium is the standard medium (M1) and the second medium is enriched with carbon, nitrogen and calcium sources (M2), the second factor is the incubation time with 5 repetitions. The enzyme production is measured by the reducing sugar method. The data obtained were analyzed using Anova. The results showed that the addition of carbon, nitrogen, and calcium sources and incubation time did not affect the production of cellulase enzyme by Serratia marcescens KE-B6. Keywords: Cellulose, Cellulase enzyme, Serratia marcescens

Insights into Bacterial Milk Spoilage with Particular Emphasis on the Roles of Heat-Stable Enzymes, Biofilms, and Quorum Sensing

2018 ◽  
Vol 81 (10) ◽  
pp. 1651-1660 ◽  
Author(s):  
LEI YUAN ◽  
FAIZAN A. SADIQ ◽  
METTE BURMØLLE ◽  
TONGJIE LIU ◽  
GUOQING HE
Keyword(s):  
Quorum Sensing ◽  
Biofilm Formation ◽  
Enzyme Production ◽  
Extracellular Polymeric Substances ◽  
Hydrolytic Enzymes ◽  
Heat Stability ◽  
Planktonic Cells ◽  
Psychrotrophic Bacteria ◽  
Effective Strategies ◽  
Heat Stable

ABSTRACT Milk spoilage caused by psychrotrophic bacteria and their heat-stable enzymes is a serious challenge for the dairy industry. In many studies, spoilage has been explored based on the simplistic view of undesirable enzymes produced by planktonic cells. Recently, biofilms and quorum sensing (QS) have been suggested as important factors in the deterioration of milk, which opens new avenues for investigation of the processes and challenges. Production and heat stability of enzymes are enhanced in biofilms, mainly because of inherent differences in physiological states and protective shielding by extracellular polymeric substances. QS plays a key role in modulating expression of hydrolytic enzymes and biofilm formation. To date, few studies have been conducted to investigate the complex interplays of enzyme production, biofilm formation, and QS. This review provides novel insights into milk spoilage with particular emphasis on the roles of biofilms and QS and summarizes potential effective strategies for controlling the spoilage of milk.

scholarly journals Changes in structure of the bovine milk fat globule membrane on heating whole milk

1992 ◽  
Vol 59 (3) ◽  
pp. 321-329 ◽  
Author(s):  
Avis V. Houlihan ◽  
Philippa A. Goddard ◽  
Barry J. Kitchen ◽  
Colin J. Masters
Keyword(s):  
Milk Fat ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Skim Milk ◽  
Milk Proteins ◽  
Milk Fat Globule Membrane ◽  
Whole Milk ◽  
Milk Fat Globule ◽  
Fat Globule ◽  
Membrane Components

SummaryThe effects of heat-induced interactions between milk fat globule membrane components and skim milk proteins in whole milk on the structure of the membrane were examined by isopycnic sucrose density gradient centrifugation and by using Triton X-100 as a membrane probe. Skim milk components were incorporated into all the lipoprotein fractions separated by density gradient centrifugation. High density complexes, higher in density than those found in the natural milk fat globule membrane, were formed during the heat treatment. Losses of natural membrane polypeptides from the medium and low density lipoproteins were observed on heating. Heating whole milk also altered the rate of release of membrane components by detergent, with decreases in protein released and an increase in phospholipid constituents released. Studies on washed cream indicated that some of the changes in the membrane on heating whole milk occurred due to the heat treatment alone, independent of the interactions with skim milk proteins.

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