scholarly journals Studies of Casein V. The Action of Rennin on Casein

1959 ◽  
Vol 12 (4) ◽  
pp. 479 ◽  
Author(s):  
RG Wake
Keyword(s):  
Trichloroacetic Acid ◽  
Milk Protein ◽  
Protein Fractions ◽  
Protein Nitrogen ◽  
Cent Nitrogen

The liberation of non-protein nitrogen, soluble in 12 per cent. Trichloroacetic acid, from various milk protein fractions by rennin (0,1 fLg rennin NJml) at pH 6�7 and 25�C is examined. 1� 0 per cent. nitrogen is rapidly released from whole casein, 3� 4 per cent. from second-cycle casein-fraction S, and 6� 7 per cent. from K-casein. None is split from other milk protein fractions under the same conditions.

Separation and quantification of water buffalo milk protein fractions and genetic variants by RP-HPLC

2013 ◽  
Vol 136 (2) ◽  
pp. 364-367 ◽  
Author(s):  
Valentina Bonfatti ◽  
Mery Giantin ◽  
Roberta Rostellato ◽  
Mauro Dacasto ◽  
Paolo Carnier
Keyword(s):  
Genetic Variants ◽  
Milk Protein ◽  
Water Buffalo ◽  
Buffalo Milk ◽  
Protein Fractions ◽  
Rp Hplc

Angiotensin I-converting enzyme inhibitory activity of enzymatic hydrolysates of goat milk protein fractions

2013 ◽  
Vol 32 (2) ◽  
pp. 175-183 ◽  
Author(s):  
F. Javier Espejo-Carpio ◽  
Cristian De Gobba ◽  
Antonio Guadix ◽  
Emilia M. Guadix ◽  
Jeanette Otte
Keyword(s):  
Inhibitory Activity ◽  
Milk Protein ◽  
Goat Milk ◽  
Protein Fractions ◽  
Converting Enzyme ◽  
Angiotensin I ◽  
Enzymatic Hydrolysates ◽  
Angiotensin I Converting Enzyme

Determination of total antioxidant capacity of milk by CUPRAC and ABTS methods with separate characterisation of milk protein fractions

2015 ◽  
Vol 82 (2) ◽  
pp. 177-184 ◽  
Author(s):  
Sema Demirci Çekiç ◽  
Aslı Demir ◽  
Kevser Sözgen Başkan ◽  
Esma Tütem ◽  
Reşat Apak
Keyword(s):  
Antioxidant Capacity ◽  
Total Antioxidant Capacity ◽  
Milk Protein ◽  
Skim Milk ◽  
Protein Fractions ◽  
Relative Standard Error ◽  
Antioxidant Power ◽  
Antioxidant Capacities ◽  
Relative Standard ◽  
Total Antioxidant

Most milk-applied antioxidant assays in literature are based on the isolation and quantification of individual antioxidative compounds, whereas total antioxidant capacity (TAC) gives a more holistic picture due to cooperative action of antioxidants. Recently, the cupric reducing antioxidant capacity (CUPRAC) method has been modified to measure the antioxidant capacities of thiol-containing proteins, where the classical ammonium acetate buffer – that may otherwise precipitate proteins– was replaced with concentrated urea buffer (able to expose embedded thiol groups of proteins to oxidative attack) adjusted to pH 7.0. Thus, antioxidant capacity of milk was investigated with two competing TAC assays, namely CUPRAC and ABTS (2,2′-azinobis(3-ethylbenzothiazoline-6-sulphonic acid))/persulphate, because only these assays were capable of evaluating protein contribution to the observed TAC value. As milk fat caused turbidity, experiments were carried out with skim milk or defatted milk samples. To determine TAC, modified CUPRAC method was applied to whole milk, separated and redissolved protein fractions, and the remaining liquid phase after necessary operations. Both TAC methods were investigated for their dilution sensitivity and antioxidant power assessment of separate milk fractions such as casein and whey. Proteins like β-lactoglobulin and casein (but not simple thiols) exhibited enhanced CUPRAC reactivity with surfactant (SDS) addition. Addition of milk protein fractions to whole skim milk produced significant ‘negative-biased’ deviations (up to −26% relative standard error) from TAC absorbance additivity in the application of the ABTS method, as opposed to that of the CUPRAC method less affected by chemical deviations from Beer's law thereby producing much smaller deviations from additivity (i.e. the property of additivity is valid when the measured TAC of a mixture is equal to the sum of individual antioxidant capacities of its constituents).

Serum Albumin and Other Serum Protein Fractions in Stable Patients on Peritoneal Dialysis

2000 ◽  
Vol 20 (6) ◽  
pp. 703-707 ◽  
Author(s):  
Francisco Caravaca ◽  
Manuel Arrobas ◽  
Carmen Dominguez
Keyword(s):  
Peritoneal Dialysis ◽  
Serum Albumin ◽  
Serum Protein ◽  
Serum Proteins ◽  
Electrophoretic Pattern ◽  
Residual Renal Function ◽  
Protein Fractions ◽  
Protein Loss ◽  
Protein Nitrogen ◽  
Baseline Values

Background Hypoalbuminemia is common in peritoneal dialysis (PD) patients; but the reduction in serum albumin levels (SAlb) that should be expected in stable PD patients is less clear. Objectives To determine prospectively, in a group of stable PD patients without comorbid conditions, the changes in SAlb concentration and in the concentrations of the other serum protein fractions. To investigate the best determinants of a significant decrease in SAlb levels. Design Prospective observational study. Methods Seventeen PD patients in stable clinical condition, with no signs of systemic inflammatory response, were included in the study. SAlb and the electrophoretic pattern of serum proteins were determined immediately before PD start, and after 6, 9, 12, 15, 18, 21, and 24 months on PD. In each study period, clinical characteristics, adequacy parameters, protein catabolic rate (PNPNA: protein equivalent of non protein nitrogen appearance), and protein losses were determined. Patients were divided into two subgroups according to whether SAlb decreased less than 10%, or 10% or more, from baseline values after 24 months on PD. The main differences between the subgroups were investigated. Results Mean SAlb did not decrease significantly after 24 months on PD (from baseline 3.99 ± 0.46 g/dL to 3.80 ± 0.54 g/dL), though percentage SAlb values did (58.36% ± 5.58% vs 55.15% ± 5.42%, p < 0.01). A weak increase in α2-globulin was observed after 18 months on PD (from 10.62% ± 2.53% to 12.96% ± 2.51%, p = 0.001). α1-Globulin showed a sustained increase from a mean baseline value of 3.51% ± 1.09% to 6.83% ± 2.13% after 24 months ( p < 0.0001). Seven patients had a reduction in SAlb greater than 10% after 24 months on PD. Kt/V urea and residual renal function tended to be lower in patients whose SAlb decreased. Mean PNPNA was significantly lower in patients who had a reduction in SAlb (0.76 ± 0.12 g/kg/day vs 0.96 ± 0.12 g/kg/day, p < 0.0001). However, total protein loss was even greater in patients who had no SAlb reduction. Conclusions After 24 months on PD, a mean reduction in SAlb of 10% – 15% from baseline values should be expected only in those stable patients whose PNPNA is low.

An evaluation of ammonium sulphate as a potential NPN source for ruminants

1976 ◽  
Vol 16 (83) ◽  
pp. 838 ◽  
Author(s):  
CA Graham ◽  
RB Warner ◽  
SL Jenkins
Keyword(s):  
Single Dose ◽  
Nitrogen Source ◽  
Ammonium Sulphate ◽  
Blood Ammonia ◽  
Protein Nitrogen ◽  
Sulphur Source ◽  
Comparative Toxicity ◽  
Sulphide Toxicity ◽  
Low Nitrogen ◽  
Cent Nitrogen

Experiments were undertaken to examine the comparative toxicity to sheep of ammonium sulphate and urea given as single doses and the value of ammonium sulphate fed alone or in combination with urea as a supplement to low nitrogen roughages. Ammonium sulphate dosing produced significantly lower mean blood ammonia levels than urea dosing. Fifteen grams of nitrogen as ammonium sulphate were tolerated as a single dose but the equivalent level of urea was toxic. lnappetance and ruminal stasis was noted when sheep fed a low nitrogen roughage (0.5 per cent nitrogen) received ammonium sulphate supplement as the sole non-protein nitrogen source. Ruminal stasis and inappetance may have been due to sulphide toxicity. Ammonium sulphate when used at lower levels in varying combinations with urea was well utilized as a nitrogen and sulphur source even when supplying 50 per cent of the supplemented nitrogen.

scholarly journals Milk nutrition and childhood epilepsy: An ex vivo study on cytokines and oxidative stress in response to milk protein fractions

2018 ◽  
Vol 101 (6) ◽  
pp. 4842-4852 ◽  
Author(s):  
M. Albenzio ◽  
A. Santillo ◽  
M.G. Ciliberti ◽  
L. Figliola ◽  
M. Caroprese ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Milk Protein ◽  
Ex Vivo ◽  
Protein Fractions ◽  
Childhood Epilepsy ◽  
Ex Vivo Study ◽  
And Oxidative Stress

The effects of methionine supplementation upon milk composition and production of forage-fed dairy cows

1999 ◽  
Vol 79 (2) ◽  
pp. 235-241 ◽  
Author(s):  
D. Pacheco-Rios ◽  
W. C. McNabb ◽  
J. P. Hill ◽  
T. N. Barry ◽  
D. D. S. Mackenzie
Keyword(s):  
Dairy Cows ◽  
Milk Fat ◽  
Milk Protein ◽  
Whey Proteins ◽  
Protein Composition ◽  
Milk Composition ◽  
Metabolizable Energy ◽  
Protein Nitrogen ◽  
Methionine Supplementation ◽  
And Control

Two experiments (mid- and late lactation) were conducted to test whether methionine (Met) limited milk production in Friesian cows fed sole diets of fresh perennial ryegrass–white clover pasture. In mid-lactation (exp. 1), 26 cows were assigned to one of three treatments: ruminally protected oral DL-Met (15 g d−1), continuous intrajugular infusion of L-Met (15 g d–1) and control. Twelve animals from exp. 1 were used during late lactation (exp. 2) and distributed in two experimental groups: ruminally protected oral DL-Met (15 g d−1) and control. Dry matter, metabolizable energy, crude protein and Met intakes, milk yield and composition and blood Met, cysteine and urea were measured. Oral and intravenous Met supplementation increased blood Met concentration by 50–90% compared with controls. Met supplementation did not alter the concentration of milk fat, protein or lactose in either experiment. Met supplementation had no significant effects on yields of fat, lactose, casein, whey proteins or non-protein nitrogen during mid-lactation. In late lactation, Met supplementation did not affect milk protein composition or yield of milk components, with exception of a decrease (P < 0.05) in the yield of β -casein. Intravenous Met supplementation increased (P < 0.05) the efficiency of conversion of pasture N to milk protein in mid-lactation. Key words: Dairy cows, methionine, ruminally protected methionine, milk protein, casein, fresh pasture diets

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