scholarly journals Development and Validation of a Method for the Quantification of Milk Proteins in Food Products Based on Liquid Chromatography with Mass Spectrometric Detection

2011 ◽  
Vol 94 (4) ◽  
pp. 1043-1059 ◽  
Author(s):  
Petra Lutter ◽  
Véronique Parisod ◽  
Hans Weymuth
Keyword(s):  
Milk Powder ◽  
Skim Milk ◽  
Internal Standard ◽  
Milk Proteins ◽  
Skim Milk Powder ◽  
Selected Reaction Monitoring ◽  
Validation Data ◽  
Development And Validation ◽  
Protein Rich ◽  
Β Lactoglobulin

Abstract The protection of allergic consumers is crucial to the food industry. Therefore, accurate methods for the detection of food allergens are required. Targeted detection of selected molecules by MS combines high selectivity with accurate quantifcation. A confrmatory method based on LC/selected reaction monitoring (SRM)-MS/MS was established and validated for the quantifcation of milk traces in food. Tryptic peptides of the major milk proteins β-lactoglobulin, β-casein, αS2-casein, and κ-casein were selected as quantitative markers. Precise quantifcation was achieved using internal standard peptides containing isotopically labeled amino acids. For each peptide, qualifer and quantifer fragments were selected according to Commission Decision 2002/657/EC. A simple sample preparation method was established without immunoaffnity or SPE enrichment steps for food matrixes containing different amounts of protein, such as baby food, breakfast cereals, infant formula, and cereals. Intermediate reproducibility, repeatability, accuracy, and measurement uncertainty were determined for each matrix. LOD values of 0.2–0.5 mg/kg, e.g., for β-lactoglobulin, were comparable to those obtained with ELISA kits. An LOQ of approximately 5 mg/kg, expressed as mass fraction skim milk powder, was validated in protein-rich infant cereals. The obtained validation data show that the described LC/SRM-MS/MS approach can serve as a confrmatory method for the determination of milk traces in selected food matrixes.

A fluorimetric method for determination ofPseudomonas fluorescensAR11 lipase in skim milk powder, whey powder and whey protein concentrate

1984 ◽  
Vol 51 (4) ◽  
pp. 623-628 ◽  
Author(s):  
Donald Stead
Keyword(s):  
Whey Protein ◽  
Lipolytic Activity ◽  
Sodium Taurocholate ◽  
Milk Powder ◽  
Skim Milk ◽  
Milk Proteins ◽  
Skim Milk Powder ◽  
Whey Protein Concentrate ◽  
Protein Concentrate ◽  
Whey Powder

SummaryA method which was developed for assaying the extracellular lipases of psychrotrophic bacteria in milk (Stead, 1983, 1984) and which uses the fluorogenic substrate 4-methylumbelliferyl oleate has been adapted for use with skim milk powder (SMP), whey powder (WP) and whey protein concentrate (WPC). A five-fold increase in the concentration of sodium taurocholate (NaTC), in the mixture of NaTC and cetyltrimethylammonium bromide needed to dissociate lipase from milk proteins, removed the excessive sensitivity of the assay to variations in the concentrations of SMP, WP or WPC incorporated. Commercially available pancreatic lipase provided a suitable standard of lipolytic activity and as little as 1–2 μ could be detected in each assay system.

scholarly journals Effect of Egg White Utilization on the Physico-Chemical and Sensory Attributes of Protein-rich Yoghurt

2012 ◽  
Vol 1 (1) ◽  
Author(s):  
Lilian A Gogo ◽  
Kennedy O. Gogo ◽  
Peter L. Shalo ◽  
Symon Maina Mahungu
Keyword(s):  
Starter Culture ◽  
Milk Powder ◽  
Skim Milk ◽  
Egg White ◽  
Skim Milk Powder ◽  
Sensory Attributes ◽  
Physico Chemical ◽  
Whole Milk ◽  
Albumin Content ◽  
Protein Rich

High protein yoghurt was made from whole milk, fortified with egg white (30% v/v) and skim milk powder at 12% (w/v). Different yoghurt mixes, with albumin content of 15%, 30% and 45% (v/v), were prepared. The control was made from whole milk, fortified with skim milk powder at 12% (w/v). The blended premixes were pasteurized at 74ºC for 4 seconds, cooled and then inoculated with 3% (w/v) Direct Vat Set yoghurt starter culture at 45ºC. After fermentation for 3 hours in a water bath maintained at 46+-1C, product was cooled to 5ºC and then stored for 24 hours. The effect of the fortification on physico-chemical and sensory properties was investigated. Protein content increased to 8.50% at 45% egg white utilization. Susceptibility to wheying was reduced in egg-white fortified samples, without signicant difference in sensory attributes of the test samples compared to the control. Sensory analysis showed that yoghurt fortified with 45% egg white was organoleptically acceptable. The yoghurt was rated as having better sensory appeal as compared to the control.

Foaming properties of skim milk powder fortified with milk proteins

2014 ◽  
Vol 36 (1) ◽  
pp. 21-28 ◽  
Author(s):  
L.P. Martínez-Padilla ◽  
V. García-Mena ◽  
N.B. Casas-Alencáster ◽  
M.G. Sosa-Herrera
Keyword(s):  
Milk Powder ◽  
Skim Milk ◽  
Milk Proteins ◽  
Skim Milk Powder ◽  
Foaming Properties

scholarly journals Effect of β-lactoglobulin phenotype on whey protein nitrogen index and sulphydryl content of skim milk powder

1999 ◽  
Vol 79 (2) ◽  
pp. 229-244 ◽  
Author(s):  
E. Antoinette O'Sullivan ◽  
Philip M. Kelly ◽  
Richard J. Fitzgerald ◽  
Kevin O'Farrell ◽  
Matthew F. Murphy ◽  
...  
Keyword(s):  
Whey Protein ◽  
Milk Powder ◽  
Skim Milk ◽  
Skim Milk Powder ◽  
Protein Nitrogen ◽  
Β Lactoglobulin

scholarly journals Effect of Egg White Utilization on the Physico-Chemical and Sensory Attributes of Protein-rich Yoghurt

2012 ◽  
Vol 1 (1) ◽  
Author(s):  
Lilian A Gogo ◽  
Kennedy O. Gogo ◽  
Peter L. Shalo ◽  
Symon Maina Mahungu
Keyword(s):  
Starter Culture ◽  
Milk Powder ◽  
Skim Milk ◽  
Egg White ◽  
Skim Milk Powder ◽  
Sensory Attributes ◽  
Physico Chemical ◽  
Whole Milk ◽  
Albumin Content ◽  
Protein Rich

High protein yoghurt was made from whole milk, fortified with egg white (30% v/v) and skim milk powder at 12% (w/v). Different yoghurt mixes, with albumin content of 15%, 30% and 45% (v/v), were prepared. The control was made from whole milk, fortified with skim milk powder at 12% (w/v). The blended premixes were pasteurized at 74ºC for 4 seconds, cooled and then inoculated with 3% (w/v) Direct Vat Set yoghurt starter culture at 45ºC. After fermentation for 3 hours in a water bath maintained at 46+-1C, product was cooled to 5ºC and then stored for 24 hours. The effect of the fortification on physico-chemical and sensory properties was investigated. Protein content increased to 8.50% at 45% egg white utilization. Susceptibility to wheying was reduced in egg-white fortified samples, without signicant difference in sensory attributes of the test samples compared to the control. Sensory analysis showed that yoghurt fortified with 45% egg white was organoleptically acceptable. The yoghurt was rated as having better sensory appeal as compared to the control.

scholarly journals Concurrent studies of the flow of digesta in the duodenum and of exocrine pancreatic secretion of calves

1975 ◽  
Vol 33 (2) ◽  
pp. 181-196 ◽  
Author(s):  
J. H. Ternouth ◽  
J. H. B. Roy ◽  
S. Y. Thompson ◽  
Joyce Toothill ◽  
Catherine M. Gillies ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Pancreatic Enzyme ◽  
Milk Powder ◽  
Skim Milk ◽  
Milk Proteins ◽  
Skim Milk Powder ◽  
Protein Marker ◽  
Total N ◽  
Postprandial Period ◽  
Pancreatic Fluid

1. The flow of digesta through the duodenum and the concurrent secretion of the pancreas were studied in four Friesian calves given four milk-substitute diets. The diets were: reconstituted, ‘mildly’ pre-heated, spray-dried skim-milk powder with (SKF) or without (SK) margarine fat or with 50% of the skim-milk powder in diet SKF replaced by soya-bean flour (ASKF) or fish-protein concentrate (BSKF), together with dried whey. The diets were given ad lib. twice daily from 13 to 37 d of age, each diet being given for 6 consecutive days. Collections of duodenal digesta and pancreatic secretions, from cannulas, were made for 12 h after feeding the 6th and 12th meals (‘experimental’ meals) for each diet2. The diets fed as ‘experimental’ meals contained polyethylene glycol (PEG) as a fluid (whey) marker and goat's milk containing [3H]lysine as a marker for total protein; β-carotene was added as a lipid marker to the three diets containing margarine fat3. Over the 12 h postprandial period, the patterns of duodenal digesta flow and secretion of pancreatic fluid did not differ markedly between the four diets. The abomasal outflow of both nitrogen and lipid in a 12 h postprandial period was related to their intakes from the ‘penultimate’(5th and 11th) meals for diets SKF and SK but to their intakes at the ‘experimental meals’ for diets ASKF and BSKF. Secretion of pancreatic enzyme activity was highest during the 1st hour after feeding but the main outflow from the abomasum of total N and lipid occurred 5–10 h after feeding4. The time required for all the whey marker (PEG) to pass through the duodenum was similar for diets SKF and SK, but only 53 and 42% respectively of the ingested protein marker passed through the duodenum in the 12 h after feeding. More acid appeared to be secreted by the abomasum when diet SK was given; also less undigested protein passed out of the abomasum after giving this diet. It is concluded that the physical absence of fat globules in the abomasal clot increases the degree of proteolysis5. The secretions of pancreatic fluid and pancreatic enzyme activity were all markedly lower for diet SK than for diet SKF6. With diets containing non-milk proteins (ASKF and BSKF), abomasal proteolysis was less efficient and the ingested protein passed out of the abomasum more rapidly than for diet SKF. There was no difference in the rate of abomasal outflow of the whey fluids between diets SKF, ASKF and BSKF7. In comparison with diet SKF, diets ASKF and BSKF tended to induce less pancreatic enzyme secretion over a 12 h postprandial period, with the exception of lipase8. There appeared to be no direct relationship between the quantities of any of the pancreatic enzymes secreted during a postprandial period and either the concurrent flow of duodenal digesta or the total quantities of dietary constituents passing through the duodenum.

scholarly journals 263BINDING OF STALLION SPERM TO EQUINE AND BOVINE ZONAE PELLUCIDAE: EFFECT OF MILK, MILK PROTEINS AND GLUCOSE

2004 ◽  
Vol 16 (2) ◽  
pp. 252 ◽  
Author(s):  
M.A. Coutinho da Silva ◽  
G.E. Seidel ◽  
E.L. Squires ◽  
Y.H. Choi ◽  
E.M. Carnevale
Keyword(s):  
Milk Powder ◽  
Skim Milk ◽  
Milk Proteins ◽  
Skim Milk Powder ◽  
Binding Assays ◽  
Hoechst 33342 ◽  
Animal Reproduction ◽  
Sperm Binding ◽  
High Concentrations ◽  
Bovine Oocytes

The ability of sperm to bind to zonae pellucidae (ZP) has been correlated with fertilizing capacity of sperm in several species. Limited numbers of equine oocytes are available to perform such assays. Therefore, use of heterologous ZP to perform gamete binding tests with stallion sperm would be useful. We have found that addition of 10% of skim milk-based extender with glucose [EZ-Mixin®, Animal Reproduction Systems, Chino, USA;; (EZ)] to TALP significantly increased the number of stallion sperm bound to bovine ZP. Objectives of the present experiments were to determine: (1) if stallion sperm bind in similar numbers to equine and bovine ZP, and (2) the effects of skim milk, milk proteins and glucose on sperm binding to ZP. Denuded bovine (immature) and equine (mature) oocytes were stored at 5°C in salt solution (1.5M MgCl2, 40mM HEPES, 0.1% PVP). In Experiment I, 4 ejaculates from 2 stallions were centrifuged at 300g for 6min, and sperm pellets were resuspended in 1mL of TALP or EZ. Sperm were stained with Hoechst 33342, centrifuged, and resuspended to 2×106 sperm mL−1. Oocytes were placed into droplets of 45μL of TALP (7 to 10 oocytes/trt/ejac). Extended sperm (5μL) were added to oocytes, resulting in 2times105 sperm mL−1, and the mixutre was incubated for 2h at 38.5°C. Oocytes then were pipetted in TALP to remove loosely attached sperm and observed with fluorescence microscopy;; mean numbers of sperm bound to bovine and equine ZP for TALP were 29±1.9 and 36±2.6 (P>0.1) and for EZ, 149±5 and 152±6.3 (P>0.1), respectively. More sperm bound to ZP with EZ than to ZP with TALP (P<0.001). Experiment II used 4 ejaculates from 4 stallions. After initial centrifugation, sperm were resuspended in 1mL of each of six extenders: TALP, EZ, TALP containing 89.5mM glucose (TG), TALP containing 163.5mM glucose (THG), TALP containing 2.4mgmL−1 of skim-milk powder (TSM), and INRA 96® (IMV Technologies, L’Aigle, France) that contains 27mgmL−1 of native phosphocaseinate. Hoechst 33342-stained sperm and bovine oocytes were processed as described for Experiment I. Treatments containing milk proteins resulted in more sperm binding (P<0.01) than those without milk proteins (Table 1). In conclusion, use of bovine oocytes led to similar results for equine and bovine oocytes;; therefore, bovine oocytes can be used for binding assays with stallion sperm. High concentrations of glucose increased numbers of sperm bound to ZP;; however, presence of milk or milk proteins was more effective in enhancing binding of sperm to ZP. INRA96 contains relatively low glucose (67mM) and one milk protein. Therefore, we hypothesize that native phosphocaseinate may cause increased sperm binding to ZP. Table 1 Mean sperm bound per ZP±SEM (n=38–40/group)

Improved heat stability of recombined evaporated milk emulsions by wet heat pretreatment of skim milk powder dispersions

2021 ◽  
pp. 106757
Author(s):  
Jianfeng Wu ◽  
Simin Chen ◽  
Teng Wang ◽  
Hao Li ◽  
Ali Sedaghat Doost ◽  
...  
Keyword(s):  
Milk Powder ◽  
Skim Milk ◽  
Heat Stability ◽  
Skim Milk Powder ◽  
Heat Pretreatment ◽  
Wet Heat

Anti-obesity effects of Lactobacillus rhamnosus 4B15, and its synergy with hydrolysed lactose skim milk powder

2021 ◽  
pp. 104997
Author(s):  
Sejeong Kim ◽  
Jae Yeon Joung ◽  
Daekyoung Kang ◽  
Nam Su Oh ◽  
Yohan Yoon
Keyword(s):  
Milk Powder ◽  
Lactobacillus Rhamnosus ◽  
Skim Milk ◽  
Skim Milk Powder

A note on the performance and management of calves reared on cold acidified milk replacer fed ad libitum

1983 ◽  
Vol 36 (1) ◽  
pp. 147-150 ◽  
Author(s):  
W. S. Thickett ◽  
N. H. Cuthbert ◽  
T. D. A. Brigstocke ◽  
M. A. Lindeman ◽  
P. N. Wilson
Keyword(s):  
Milk Powder ◽  
Skim Milk ◽  
Live Weight ◽  
Skim Milk Powder ◽  
Barley Straw ◽  
Milk Replacer ◽  
Bull Calves ◽  
The Mean ◽  
Ad Libitum ◽  
Dry Food

ABSTRACTResults are presented from six trials dealing with aspects of management on the cold ad libitum system of calf rearing using an acidified milk replacer containing over 600 g skim milk powder per kg.Thirty-six calves were housed in pens of six for each trial and were fed through a teat and pipeline from a storage barrel. Acidified milk replacer, pH 5·6, was mixed cold at 125 g/1 and made available ad libitum to 3 weeks. A rationed allowance was given daily, on a reducing scale, over the following 2 weeks with weaning completed at 35 days. A pelleted dry food containing 180 g crude protein per kg, together with water in buckets and barley straw in racks, was available ad libitum throughout. Each trial lasted 8 weeks. Results for the mean of the six cold ad libitum trials involving 216 calves were compared with the mean results of 10 conventional bucket-fed trials carried out separately at the same unit, involving 912 calves. All calves were purchased British Friesian male (bull) calves.Calves on the ad libitum system showed improved live-weight gains of 9·4 kg at 3 weeks, 8·8 kg at 5 weeks and 7·5 kg at 8 weeks, compared with the conventional system. The consumption of milk replacer powder was higher in ad libitum trials at 29·4 kg cf. 12·5 kg by bucket but intake of pelleted dry feed was lower on the ad libitum system at 50·7 kg cf. 71·3 kg to 8 weeks. Calf appearance scores were significantly improved on the ad libitum system which gave the main improvement in performance in the first 3 weeks.

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