scholarly journals The Effect of High-Pressure Treatment and Skimming on Caprine Milk Proteins

2021 ◽  
Vol 11 (13) ◽  
pp. 5982
Author(s):  
Katarzyna Kiełczewska ◽  
Aneta Dąbrowska ◽  
Agnieszka Jankowska ◽  
Maria Wachowska ◽  
Jarosław Kowalik
Keyword(s):  
Protein Solubility ◽  
Whey Proteins ◽  
Color Space ◽  
Skim Milk ◽  
Milk Proteins ◽  
Protein Composition ◽  
Color Difference ◽  
Nitrogen Compounds ◽  
Caprine Milk ◽  
Kjeldahl Method

Background: Proteins are susceptible to HP-treatment and there is a need to determine the applicability of HP-treatment in dairy production. The aim of this study was to determine the effect of HP-treatment at 200–500 MPa (tconst. = 10 min; Tconst. = 20 °C) and skimming of HP-treated milk on the content of nitrogen compounds and protein composition of caprine milk. Methods: The content of nitrogen (total, non-casein, non-protein) was determined using the Kjeldahl method. Casein fractions and whey proteins were separated using SDS-PAGE electrophoresis. Color parameters were measured in the CIELAB color space. Results: HP-treatment decreased (p < 0.05) the content of non-casein nitrogen and soluble whey proteins. Skimming decreased the content of nitrogen compounds, and the noted decrease was more pronounced in HP-treated milk. Pressure and skimming had no influence on the proportions of α-, β-, κ-casein, β-lactoglobulin and α-lactalbumin. Total color difference (ΔE) increased with a rise in pressure, particularly in skim milk. Conclusion: HP-treatment led to a loss of protein solubility at pH 4.6 in caprine milk. In HP-treated milk, skimming did not induce changes in protein composition, despite a decrease in the content of nitrogen compounds after the separation of the cream layer. Higher values of ΔE in skim milk than in whole milk point to changes in colloidal phase components.

Hydrolysis of Milk Proteins by Microbial Enzymes

1980 ◽  
Vol 43 (9) ◽  
pp. 709-712 ◽  
Author(s):  
A. GEBRE-EGZIABHER ◽  
E. S. HUMBERT ◽  
G. BLANKENAGEL
Keyword(s):  
Room Temperature ◽  
Polyacrylamide Gel Electrophoresis ◽  
Whey Proteins ◽  
Skim Milk ◽  
Milk Proteins ◽  
Raw Milk ◽  
Incubation Periods ◽  
Pure Cultures ◽  
Sterilized Milk ◽  
Hydrolysis Of

Raw skim milk was incubated at 7 C for 15 days after inoculation with six psychrotrophic bacterial cultures previously isolated from raw milk. Effects of the microbial activities on proteins of milk were evaluated by polyacrylamide gel electrophoresis. Results showed that all psychrotrophs hydrolyzed milk proteins. The K- and β-caseins were most susceptible to proteolysis while the a-casein was less affected. Most of the isolates required extended incubation periods for hydrolysis of the whey proteins. Commercially sterilized milk samples inoculated with pure cultures developed bitterness after 4 days of storage at 7 C when the psychrotrophic count was 2.5 × 106/ml. The addition of 9.8 enzyme units to UHT milk caused a bitter flavor within 28 days at 7 C and in less than 3 days at room temperature. The presence of only 2 units resulted in bitterness in less than 7 days at room temperature.

Effects of atropine on the concentration and composition of milk protein in dairy cows

2000 ◽  
Vol 25 ◽  
pp. 169-173
Author(s):  
M.J. Auldist ◽  
C.M. Menzies ◽  
R.J. Hooper ◽  
C.G. Prosser
Keyword(s):  
Milk Protein ◽  
Low Dose ◽  
Whey Proteins ◽  
Latin Square ◽  
Milk Proteins ◽  
Protein Composition ◽  
Amino Acid Profile ◽  
Post Treatment ◽  
Circulating Levels ◽  
Medium Dose

AbstractThe objective of this study was to measure the effects of varying doses of atropine on the concentration and composition of milk protein and on blood α-amino N levels. Four treatments were administered to each of 12 cows over 12 days in a replicated Latin square experiment. There were at least 2 days between each of 4 treatment days. Treatments were: control (C; saline); low dose (L; 30mg atropine/kg LWT); medium dose (M; 40mg atropine/kg LWT); and 2 x low dose (2L). All treatments were administered via subcutaneous injection immediately after the morning milking; the second dose of the 2L treatment was given two hours later. Milk was sampled from each cow at the morning milking (time 0 h). Cows were then milked again 2, 6 and 10 h after treatment, and milk samples again collected. Blood samples were drawn from the coccygeal vein of each cow after each milking. Atropine decreased milk secretion at 6 h for the 2L treatment and 10 h for all treatments. Atropine reduced concentrations of milk protein and casein at 2 h and 6 h, but not at 10 h. Concentrations of whey proteins and of α-casein were depressed by atropine only at 6 h post-treatment, while a reduction in α-lactalbumin due to atropine was observed at 6 and 10 h post-treatment. In contrast, atropine increased concentrations of IgG and BSA at 6 h and 10 h post-treatment. Atropine also increased the ratio of casein:total protein at 6 h after injection. There was no difference between the effects of the low and medium doses of atropine, but the double low dose induced effects which were greater than for the single doses. Effects of a single dose of atropine were greatest for most milk proteins at 6 h post treatment; thus this would be the most useful milk sampling time for future experiments. Atropine did not significantly affect α-amino N concentrations in whole blood, although there was a trend for a reduction for all treatments at 2 h after treatment. Atropine may be useful for reducing milk protein concentrations and circulating levels of certain blood amino acids to base levels, during studies designed to elucidate the effects of perturbations in the blood amino acid profile on milk protein composition.

scholarly journals Effect of Heat Treatment on the Property, Structure, and Aggregation of Skim Milk Proteins

2021 ◽  
Vol 8 ◽  
Author(s):  
Hongbo Li ◽  
Tingting Zhao ◽  
Hongjuan Li ◽  
Jinghua Yu
Keyword(s):  
Secondary Structure ◽  
Disulfide Bonds ◽  
Polyacrylamide Gel Electrophoresis ◽  
Whey Proteins ◽  
Skim Milk ◽  
Milk Proteins ◽  
Surface Hydrophobicity ◽  
Random Coil ◽  
Heat Treated ◽  
Different Temperatures

To study the mechanism of heat-induced protein aggregates, skim milk was heated at 55, 65, 75, 85, and 95°C for 30 s. Then, the sulfhydryl content, surface hydrophobicity, and secondary structure of heat-treated skim milk were studied. Treating skim milk at different temperatures induced a decrease in sulfhydryl content (75.9% at 95°C) and an increase in surface hydrophobicity (44% at 95°C) with a disrupted secondary structure containing random coil, β-sheet, and β-turn of skim milk proteins. The change in these properties facilitated aggregate formation through disulfide bonds and hydrophobicity interaction. Microstructural observation also showed a higher degree of aggregation when skim milk was heated at 85 and 95°C. The result of two-dimensional polyacrylamide gel electrophoresis demonstrated that the aggregates consisted of a high proportion of κ-casein, β-lactoglobulin, and other whey proteins.

Proteins of human milk. I. Identification of major components.

1982 ◽  
Vol 28 (4) ◽  
pp. 1045-1055 ◽  
Author(s):  
N G Anderson ◽  
M T Powers ◽  
S L Tollaksen
Keyword(s):  
Human Milk ◽  
Whey Proteins ◽  
Bovine Milk ◽  
Skim Milk ◽  
Milk Proteins ◽  
Relative Molecular Mass ◽  
Isoelectric Points ◽  
Beta Casein ◽  
Dimensional Electrophoresis ◽  
New Protein

Abstract Traditionally, human milk proteins are identified largely by reference to bovine milk. Hence, to identify the major proteins in human milk, we subjected human and bovine milk, in parallel, to high-resolution two-dimensional electrophoresis. Isoelectric precipitation at pH 4.6 was our criterion for distinguishing whey proteins from those of the casein complex. The alpha- and beta-caseins were identified on the basis of relative abundance, relative molecular mass, and relative isoelectric points. Kappa casein was identified as a series of four spots, which disappear from bovine skim milk treated with rennin (chymosin; EC 3.4.23.4) during the clotting process. Para kappa-casein does not appear on the standard ISO-DALT pattern after treatment of bovine milk with rennin, but does appear in BASO-DALT pattern, indicating its high isoelectric point. No protein disappeared from ISO-DALT patterns of human milk after rennin treatment, and no new protein comparable to bovine para kappa-casein appeared in the BASO-DALT patterns; this suggests that kappa-casein is absent from human milk. The proteins identified in human milk patterns include the alpha and beta casein families, lactalbumin, albumin, transferrin, IgA, and lactoferrin. Numerous additional proteins seen in patterns for human milk remain to be identified.

scholarly journals Study on milk composition and milk protein distribution in Romanian Holstein cattle

2020 ◽  
Vol 23 (1) ◽  
pp. 13-21
Author(s):  
Rodica Ştefania Pelmuş ◽  
Cristina Lazăr ◽  
M. L. Palade ◽  
Mariana Stancu ◽  
C. M. Rotar ◽  
...  
Keyword(s):  
Milk Protein ◽  
Whey Proteins ◽  
Milk Proteins ◽  
Protein Composition ◽  
Holstein Cattle ◽  
Protein Distribution ◽  
Quality Indices ◽  
Milk Samples ◽  
Sds Page ◽  
Β Lactoglobulin

AbstractThe aim of this study was to determine milk quality indices as well as the milk protein composition in Romanian Holstein cattle raised under the conditions of experimental farm of INCDBNA-IBNA. The study was carried out on 22 milk samples. The types of different milk proteins were identified by SDS-PAGE technique. Sampling day and milk chemical composition were performed during the milking period of studied cattle. The quality indices were breed-specific for protein (3.38%) and higher for fat (4.39%).Milk proteins analysis of Romanian Holstein cattle separated by SDS-PAGE electrophoresis showed the presence of four major caseins (αs1-, αs2-, β- and k-casein) and two whey proteins (β-lactoglobulin, α-lactalbumin). The caseins accounted 77.28% of the total milk proteins, while the major proteins (β-lactoglobulin, α-lactalbumin) from the whey represented 22.72% of the total proteins. αs1-casein + αs2-casein had a higher expression (36.01%) followed by β-casein (31.45%), β-lactoglobulin (18.16%), k-casein (9.82%) and α-lactalbumin (4.56%). The most of milk samples was characterized by a medium expression level of both caseins and whey proteins

scholarly journals A Study of Automatic Judgment of Food Color and Cooking Conditions with Artificial Intelligence Technology

Processes ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 1128
Author(s):  
Chern-Sheng Lin ◽  
Yu-Ching Pan ◽  
Yu-Xin Kuo ◽  
Ching-Kun Chen ◽  
Chuen-Lin Tien
Keyword(s):  
Artificial Intelligence ◽  
Image Processing ◽  
Color Space ◽  
Color Difference ◽  
Color Space Conversion ◽  
Before And After ◽  
Artificial Intelligence Technology ◽  
Artificial Intelligence Algorithm ◽  
Time Image ◽  
Cooking Conditions

In this study, the machine vision and artificial intelligence algorithms were used to rapidly check the degree of cooking of foods and avoid the over-cooking of foods. Using a smart induction cooker for heating, the image processing program automatically recognizes the color of the food before and after cooking. The new cooking parameters were used to identify the cooking conditions of the food when it is undercooked, cooked, and overcooked. In the research, the camera was used in combination with the software for development, and the real-time image processing technology was used to obtain the information of the color of the food, and through calculation parameters, the cooking status of the food was monitored. In the second year, using the color space conversion, a novel algorithm, and artificial intelligence, the foreground segmentation was used to separate the vegetables from the background, and the cooking ripeness, cooking unevenness, oil glossiness, and sauce absorption were calculated. The image color difference and the distribution were used to judge the cooking conditions of the food, so that the cooking system can identify whether or not to adopt partial tumbling, or to end a cooking operation. A novel artificial intelligence algorithm is used in the relative field, and the error rate can be reduced to 3%. This work will significantly help researchers working in the advanced cooking devices.

scholarly journals Post translational modifications of milk proteins in geographically diverse goat breeds

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
P. K. Rout ◽  
M. Verma
Keyword(s):  
Protein Function ◽  
Whey Proteins ◽  
Milk Proteins ◽  
Goat Milk ◽  
Peptide Sequence ◽  
Cow Milk ◽  
Post Translational Modification ◽  
Post Translational Modifications ◽  
Functional Roles ◽  
Dpp Iv

AbstractGoat milk is a source of nutrition in difficult areas and has lesser allerginicity than cow milk. It is leading in the area for nutraceutical formulation and drug development using goat mammary gland as a bioreactor. Post translational modifications of a protein regulate protein function, biological activity, stabilization and interactions. The protein variants of goat milk from 10 breeds were studied for the post translational modifications by combining highly sensitive 2DE and Q-Exactive LC-MS/MS. Here we observed high levels of post translational modifications in 201 peptides of 120 goat milk proteins. The phosphosites observed for CSN2, CSN1S1, CSN1S2, CSN3 were 11P, 13P, 17P and 6P, respectively in 105 casein phosphopeptides. Whey proteins BLG and LALBA showed 19 and 4 phosphosites respectively. Post translational modification was observed in 45 low abundant non-casein milk proteins mainly associated with signal transduction, immune system, developmental biology and metabolism pathways. Pasp is reported for the first time in 47 sites. The rare conserved peptide sequence of (SSSEE) was observed in αS1 and αS2 casein. The functional roles of identified phosphopeptides included anti-microbial, DPP-IV inhibitory, anti-inflammatory and ACE inhibitory. This is first report from tropics, investigating post translational modifications in casein and non-casein goat milk proteins and studies their interactions.

scholarly journals Changes in Particle Size, Sedimentation, and Protein Microstructure of Ultra-High-Temperature Skim Milk Considering Plasmin Concentration and Storage Temperature

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2339
Author(s):  
So-Yul Yun ◽  
Jee-Young Imm
Keyword(s):  
Particle Size ◽  
High Temperature ◽  
Storage Temperature ◽  
Whey Proteins ◽  
Skim Milk ◽  
Storage Period ◽  
Sediment Analysis ◽  
Sediment Formation ◽  
And Storage ◽  
Ultra High Temperature

Age gelation is a major quality defect in ultra-high-temperature (UHT) pasteurized milk during extended storage. Changes in plasmin (PL)-induced sedimentation were investigated during storage (23 °C and 37 °C, four weeks) of UHT skim milk treated with PL (2.5, 10, and 15 U/L). The increase in particle size and broadening of the particle size distribution of samples during storage were dependent on the PL concentration, storage period, and storage temperature. Sediment analysis indicated that elevated storage temperature accelerated protein sedimentation. The initial PL concentration was positively correlated with the amount of protein sediment in samples stored at 23 °C for four weeks (r = 0.615; p < 0.01), whereas this correlation was negative in samples stored at 37 °C for the same time (r = −0.358; p < 0.01) due to extensive proteolysis. SDS-PAGE revealed that whey proteins remained soluble over storage at 23 °C for four weeks, but they mostly disappeared from the soluble phase of PL-added samples after two weeks’ storage at 37 °C. Transmission electron micrographs of PL-containing UHT skim milk during storage at different temperatures supported the trend of sediment analysis well. Based on the Fourier transform infrared spectra of UHT skim milk stored at 23 °C for three weeks, PL-induced particle size enlargement was due to protein aggregation and the formation of intermolecular β-sheet structures, which contributed to casein destabilization, leading to sediment formation.

scholarly journals Longitudinal Changes in the Concentration of Major Human Milk Proteins in the First Six Months of Lactation and Their Effects on Infant Growth

Nutrients ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 1476
Author(s):  
Jian Zhang ◽  
Ai Zhao ◽  
Shiyun Lai ◽  
Qingbin Yuan ◽  
Xiaojiang Jia ◽  
...  
Keyword(s):  
Human Milk ◽  
Maternal Education ◽  
Mode Of Delivery ◽  
Milk Proteins ◽  
Protein Composition ◽  
Infant Growth ◽  
Term Infants ◽  
Longitudinal Changes ◽  
Milk Samples ◽  
The Impact

Our knowledge related to human milk proteins is still limited. The present study determined the changes in multiple human milk proteins during the first six months of lactation, investigated the influencing factors of milk proteins, and explored the impact of milk proteins on infant growth. A total of 105 lactating women and their full-term infants from China were prospectively surveyed in this research. Milk samples were collected at 1–5 days, 8–14 days, 1 month, and 6 months postpartum. Concentrations of total protein and α-lactalbumin were measured in all milk samples, and concentrations of lactoferrin, osteopontin, total casein, β-casein, αs−1 casein, and κ-casein were measured in milk from 51 individuals using ultra performance liquid chromatography coupled with mass spectrometry. The concentration of measured proteins in the milk decreased during the first six months of postpartum (p-trend < 0.001). Maternal age, mode of delivery, maternal education, and income impacted the longitudinal changes in milk proteins (p-interaction < 0.05). Concentrations of αs−1 casein in milk were inversely associated with the weight-for-age Z-scores of the infants (1 m: r −0.29, p 0.038; 6 m: r −0.33, p 0.020). In conclusion, the concentration of proteins in milk decreased over the first six months postpartum, potentially influenced by maternal demographic and delivery factors. Milk protein composition may influence infant weights.

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