Buffalo Milk Protein Research Articles

EFFECT OF HEAT TREATMENTS AND SEASONS OF THE YEAR ON THE PROTECTIVE PROTEINS IN MILK OF DIFFERENT ANIMALS

The aim of the present work was to study the effect of heat treatments and seasons of year on immunoglobulin, lactoferrin and lysozyme contents in camel's, cow's and buffalo's milk. The milk samples were heat treated at 63, 72, and 95°C for 30 min., 15 sec. and 15 min. respectively. Camel's milk contained significantly higher amounts of immunoglobulin (IG), lactoferrin (LF) and lysozyme (LZ) than cow's and buffalo's milk. Heating milk at 63°C /30 min. had significant effect on lysozyme and lactoferrin. While the immunoglobulin was more affected in the three kinds of milk. The amounts of immunoglobulin of cow's and buffalo's milk were observed at 72°C /15 sec. compared with camel's immunoglobulin. The amounts of lactoferrin were lost at 95°C /15 min. in all kinds of milk. However, at this level of heat treatment, the losses of lysozyme at 95°C /15 min. were 0.12 ± 0.18, 0.06 ± 0.17 and 0.02 ± 0.14 ug/ml for camel's, cow's and buffalo's milk, respectively. When milk was heated at 95°C /15 min. camel's milk protective proteins were relatively more heat resistant than cow's and buffalo's milk proteins. It was found that the heat resistance for lysozyme > lactoferrin > immunoglobulin. The amounts of milk protective proteins were higher in winter for all kinds of milk, compared with summer milk.

Angiotensin I-converting enzyme inhibitory activity and antioxidant capacity of bioactive peptides derived from enzymatic hydrolysis of buffalo milk proteins

Buffaloes' milk, which is consumed in many parts of the world, is a little-explored source of bioactive peptides. The angiotensin converting enzyme (ACE)-inhibitory activity and the antioxidant capacity of peptides from buffaloes' milk were examined. A retentate from buffaloes' skimmed milk was hydrolysed using papain, pepsin or trypsin. The papain hydrolysate showed the highest ACE-inhibitory activity and radical scavenging capacity and was fractionated by size exclusion chromatography (SEC) and characterized by LC-MS analysis. A SEC-fraction with intermediate peptide size showed very high ACE-inhibitory activity, while two fractions with small peptides exhibited the strongest antioxidant activity. Peptide identification by ultra-performance liquid-chromatography-tandem mass spectrometry showed that these active fractions contained known bioactive sequences, in addition to novel peptides with supposed ACE-inhibitory (FPGPIPK, IPPK, IVPN, and QPPQ) and antioxidant (YPSG, HPFA and KFQ) activities. The results obtained showed the potential of buffaloes' milk proteins to release ACE-inhibitory and antioxidant peptides.

Transglutaminase cross-linking of milk proteins for improved functionality of cow and buffalo milk

Modification of proteins by enzymes such as Transglutaminase (TG) has recently become of great interest to food scientists. TG induced cross-linking has strong effects on the functionality of milk proteins. Effect of TG on heat stability, antioxidant activity, surface hydrophobicity, rennet coagulation time, emulsifying and foaming properties of cow and buffalo milk proteins was studied. TG treatment improves heat stability from 18 min to 38 min in cow milk and 14.5 min to 25.5 min in buffalo milk, surface hydrophobicity from 237.28 to 292.23 in cow milk and 252.8 to 332.7 in buffalo milk. Cross-linked cow and buffalo casein shows better emulsifying and foaming properties. It does not affect the antioxidant activity of milk proteins. Whereas cross-linked milk proteins are highly resistant to rennet coagulation. TG treatment completely prevents rennet coagulation of cow milk, whereas in buffalo milk rennet coagulation time gets elongated.

Transglutaminase cross-linking of milk proteins for improved functionality of cow and buffalo milk

Modification of proteins by enzymes such as Transglutaminase (TG) has recently become of great interest to food scientists. TG induced cross-linking has strong effects on the functionality of milk proteins. Effect of TG on heat stability, antioxidant activity, surface hydrophobicity, rennet coagulation time, emulsifying and foaming properties of cow and buffalo milk proteins was studied. TG treatment improves heat stability from 18 min to 38 min in cow milk and 14.5 min to 25.5 min in buffalo milk, surface hydrophobicity from 237.28 to 292.23 in cow milk and 252.8 to 332.7 in buffalo milk. Cross-linked cow and buffalo casein shows better emulsifying and foaming properties. It does not affect the antioxidant activity of milk proteins. Whereas cross-linked milk proteins are highly resistant to rennet coagulation. TG treatment completely prevents rennet coagulation of cow milk, whereas in buffalo milk rennet coagulation time gets elongated.

Comparative evaluation of allergic sensitization to milk proteins of cow, buffalo and goat

Milk hypersensitivity due to adverse reactions to milk proteins is among the major public concern of food allergies. In present investigation, comparative assessment of humoral and cell mediated immune responses in mice associated with allergenicity of major milk proteins (casein and β-lactoglobulin) of cow, buffalo and goat were carried out. Caseins of all three species of dairy animals appeared to be less immunogenic and allergenic than their corresponding β-lactoglobulins. Cow milk proteins (caseins and β-lactoglobulin) were observed to increase protein specific IgE sensitization as well as lymphocyte proliferation index significantly (P<0.01) as compared to buffalo and goat milk proteins. On the other hand, buffalo and goat milk proteins similar to cow's proteins raised remarkably higher (P<0.01) immunogenic response in terms of IgG levels than the negative control group. The results obtained were correlated with B and T cell epitopes of milk proteins cited in literature after multiple alignment in silico. Thus present study suggests cow milk proteins (β-lactoglobulin and casein) are highly allergenic among the milk proteins of three species of dairy animals.

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

A RP-HPLC method, developed for the separation and quantification of the most common genetic variants of bovine milk proteins, was successfully applied to the analysis of water buffalo milk. All the most common buffalo casein and whey proteins fractions, as well as their genetic variants, were detected and separated simultaneously in 40min. Purified buffalo proteins were used as calibration standards and a total of 536 individual milk samples were analysed for protein composition. αS1-, αS2-, βγ-, and κ-casein were 32.2%, 15.8%, 36.5%, and 15.5%, respectively, of total casein content, whereas content of β-Lactoglobulin was approximately 1.3 times as high as that of α-Lactalbumin. The existence of a polymorphism of κ-casein was demonstrated in Mediterranean water buffalo and αS1- and κ-casein genetic variants were successfully detected by RP-HPLC.

Effect of parity, days in milk, and milk yield on detailed milk protein composition in Mediterranean water buffalo

The effects of some nongenetic factors on milk protein fraction contents and relative proportions were estimated in 606 individual milk samples of Mediterranean water buffalo. Content of αS1-casein (CN), αS2-CN, β-CN, γ-CN, κκ-CN, glycosylated κ-CN (glyco-κ-CN), α-lactalbumin, and β-lactoglobulin was measured by reversed-phase HPLC. Relative contents of αS1-CN%, αS2-CN%, β-CN%, and κ-CN% were, respectively, 32.1, 17.1, 34.5, and 15.7%, whereas γ-CN% accounted for 0.6% of total casein content. Increasing total casein content in milk would result in a greater proportion of β-CN% at the expense of all of the other major casein fractions, especially of κ-CN%. Values of αS2-CN%, β-CN%, and γ-CN% tended to decrease with parity, although their variations were not significant, whereas αS1-CN% and glyco-κ-CN% showed the opposite trend. Contents of most protein fractions showed the typical trends observed for milk components as lactation progressed, with high contents in early lactation, a minimum in midlactation, followed by a gradual increase toward the latter part of lactation. Values of αS1-CN% increased during lactation, whereas αS2-CN% decreased. The proportion of β-CN% had its maximum value between 60 and 160d of lactation, followed by a decrease, whereas κ-CN% had its minimum value in early lactation (<60d) and remained relatively constant in the period of mid and late lactation. Glyco-κ-CN% and β-lactoglobulin% decreased in the first part of lactation, to reach their minimum values in midlactation, followed by an increase. Milk of top-producing buffaloes, compared with that of low-producing ones, had a significantly greater value of β-CN% and glyco-κ-CN%, and lower proportion of αS1-CN%. The possible effect exerted by protein genetic variants in affecting variation of milk protein fraction contents and relative proportions should be further considered to better get insight into buffalo milk protein composition.

A comprehensive review on the composition and properties of buffalo milk

The aim of this review is to update the knowledge regarding the composition and properties of buffalo milk (BM). Buffalo milk has higher levels of fat, lactose, protein, ash and Ca, and vitamins A and C and lower levels of vitamin E riboflavin and cholesterol; an absence of carotene; and the presence of the blue-green pigment (biliverdin) as well as a bioactive pentasaccharide and gangliosides not present in cow milk (CM). The fat globules of BM are larger but are less stable and contained less membrane materials than that of CM. Buffalo milk fat has slightly higher levels of saturated fatty acids and has quantitative differences in the distribution of triglycerides and physical properties in comparison to CM. The casein micelles of BM are larger and richer in minerals and can be disrupted by alkali at higher pH values than that of CM. The primary structures of all BM proteins have been established. High homologies have been found between the proteins of BM and CM, but BM αs1-casein and αs2-casein have lower levels of phosphorylation. The activities of several enzymes in BM are presented and discussed. The viscosity and curd tension of BM are higher; rennet coagulation is faster, and heat stability is lower than that of CM. The available published data gives a better understanding of BM, but more studies are required on some aspects to give a clearer picture on the detailed composition and properties of BM.

Effect of chemical phosphorylation on solubility of buffalo milk proteins

Abstract Buffalo milk proteins (casein, co-precipitate or whey protein concentrate) were phosphorylated with phosphorus oxychloride (POCl 3 ) at three different pH values (5.0, 7.0 and 9.0). The solubilities of phosphorylated milk proteins were examined over the pH range 3.0–9.0 in water and ionic (0.1 m NaCl or 10–70 m m Ca 2+ ) systems. The solubilities of buffalo milk proteins decreased at pH 3.0, while there was an increase in the solubilities of casein and co-precipitate near their isoelectric points upon phosphorylation. Solubilities of these phosphorylated milk proteins were pH dependent in 0.1 m NaCl but there was a decrease in their solubilities with increase in calcium ion concentration. This alteration could be due to the shifting of isoionic points of phosphorylated buffalo milk proteins towards acidic pH.

Effect of heat treatment on camel milk proteins with respect to antimicrobial factors: a comparison with cows' and buffalo milk proteins

Camel, cow and buffalo skim milk samples were heated at 65, 75, 85 and 100°C for 10, 20 and 30 min. Presence and identity of whey proteins (WPs) were monitored using SDS-PAGE technique. Changes in activities of antimicrobial factors were measured. Heat-induced changes of WPs increased with increasing temperature and time of heating; they were more pronounced in buffalo and cow milk than in camel milk. Camel WPs were markedly more heat resistant than their counterparts in cow and buffalo milk. Among the WPs, the order of heat resistance found was: α-lactalbumin > β-lactoglobulin > serum albumin. Camel milk contained significantly ( P⩽0.01) higher concentrations of lysozyme (LZ), lactoferrin (LF) and immunoglobulin G (IgG) than cow and buffalo milk. Heating milk at 65°C/30 min had no significant effect on LZs and LFs, however, loss of activity of IgGs was significantly ( P⩽0.01) affected in the three kinds of milk. The whole activity of IgG in cow and buffalo milk was lost at 75°C/30 min versus 68.7% in loss activity of camel IgG. The entire activity of LFs was lost at 85°C/30 min in all kinds of milk, however, at this level of temperature, the activity losses of LZs were 56, 74 and 81.7% for camel, cow and buffalo milk, respectively. Camel milk antimicrobial factors were significantly ( P⩽0.01) more heat resistant than cow and buffalo milk proteins. Among the antimicrobial factors, the order of heat resistance found was LZ > LF > IgG.

REDUCTION OF ALLERGENICITY AND INCREASING THE BIOLOGICAL VALUE OF BUFFALO'S MILK PROTEINS BY ENZYMATIC MODIFICATION

Buffalo milk proteins were covalently enriched with methionine (Met) during the enzymatic peptide modification (EPM) process. The maximal Met-enrichment occurred when the α-chymotryptic hydrolysate of buffalo's milk proteins was treated with methionine ethyl ester in the presence of α-chymotrypsin during the EPM. Methionine content of this product was more than three times (5.4%) higher than that of the original buffalo milk protein (1.5%). The electrophoretic patterns of the modified proteins showed that the enzymatic reaction was mainly characterized by transpeptidation. Molecular masses of the modified protein fractions were influenced by the concentration of L-methionine ethyl esters in the reaction mixture during the EPM. EPM products from the buffalo milk protein hydrolysates with α-chymotrypsin and trypsin or with pepsin and trypsin showed low allergenic activities compared with those when buffalo milk proteins were hydrolyzed with α-chymotrypsin or with pepsin alone.

Effect of hydrogen peroxide on buffalo milk proteins.

Effect of hydrogen peroxide on buffalo milk proteins.