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Effect of Commercially Utilized Thermal Treatments on Interactions Between Casein and β-lactoglobulin and Their Digestion in Simulated Gastrointestinal Environment. FOOD BIOPHYS 2023. [DOI: 10.1007/s11483-023-09776-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
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2
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Renzone G, Arena S, Scaloni A. Cross-linking reactions in food proteins and proteomic approaches for their detection. MASS SPECTROMETRY REVIEWS 2022; 41:861-898. [PMID: 34250627 DOI: 10.1002/mas.21717] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 06/29/2021] [Accepted: 06/29/2021] [Indexed: 06/13/2023]
Abstract
Various protein cross-linking reactions leading to molecular polymerization and covalent aggregates have been described in processed foods. They are an undesired side effect of processes designed to reduce bacterial load, extend shelf life, and modify technological properties, as well as being an expected result of treatments designed to modify raw material texture and function. Although the formation of these products is known to affect the sensory and technological properties of foods, the corresponding cross-linking reactions and resulting protein polymers have not yet undergone detailed molecular characterization. This is essential for describing how their generation can be related to food processing conditions and quality parameters. Due to the complex structure of cross-linked species, bottom-up proteomic procedures developed to characterize various amino acid modifications associated with food processing conditions currently offer a limited molecular description of bridged peptide structures. Recent progress in cross-linking mass spectrometry for the topological characterization of protein complexes has facilitated the development of various proteomic methods and bioinformatic tools for unveiling bridged species, which can now also be used for the detailed molecular characterization of polymeric cross-linked products in processed foods. We here examine their benefits and limitations in terms of evaluating cross-linked food proteins and propose future scenarios for application in foodomics. They offer potential for understanding the protein cross-linking formation mechanisms in processed foods, and how the inherent beneficial properties of treated foodstuffs can be preserved or enhanced.
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Affiliation(s)
- Giovanni Renzone
- Proteomics and Mass Spectrometry Laboratory, ISPAAM, National Research Council, Naples, Italy
| | - Simona Arena
- Proteomics and Mass Spectrometry Laboratory, ISPAAM, National Research Council, Naples, Italy
| | - Andrea Scaloni
- Proteomics and Mass Spectrometry Laboratory, ISPAAM, National Research Council, Naples, Italy
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Koutsoumanis K, Alvarez‐Ordóñez A, Bolton D, Bover‐Cid S, Chemaly M, Davies R, De Cesare A, Herman L, Hilbert F, Lindqvist R, Nauta M, Peixe L, Ru G, Simmons M, Skandamis P, Suffredini E, Castle L, Crotta M, Grob K, Milana MR, Petersen A, Roig Sagués AX, Vinagre Silva F, Barthélémy E, Christodoulidou A, Messens W, Allende A. The efficacy and safety of high-pressure processing of food. EFSA J 2022; 20:e07128. [PMID: 35281651 PMCID: PMC8902661 DOI: 10.2903/j.efsa.2022.7128] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
High-pressure processing (HPP) is a non-thermal treatment in which, for microbial inactivation, foods are subjected to isostatic pressures (P) of 400-600 MPa with common holding times (t) from 1.5 to 6 min. The main factors that influence the efficacy (log10 reduction of vegetative microorganisms) of HPP when applied to foodstuffs are intrinsic (e.g. water activity and pH), extrinsic (P and t) and microorganism-related (type, taxonomic unit, strain and physiological state). It was concluded that HPP of food will not present any additional microbial or chemical food safety concerns when compared to other routinely applied treatments (e.g. pasteurisation). Pathogen reductions in milk/colostrum caused by the current HPP conditions applied by the industry are lower than those achieved by the legal requirements for thermal pasteurisation. However, HPP minimum requirements (P/t combinations) could be identified to achieve specific log10 reductions of relevant hazards based on performance criteria (PC) proposed by international standard agencies (5-8 log10 reductions). The most stringent HPP conditions used industrially (600 MPa, 6 min) would achieve the above-mentioned PC, except for Staphylococcus aureus. Alkaline phosphatase (ALP), the endogenous milk enzyme that is widely used to verify adequate thermal pasteurisation of cows' milk, is relatively pressure resistant and its use would be limited to that of an overprocessing indicator. Current data are not robust enough to support the proposal of an appropriate indicator to verify the efficacy of HPP under the current HPP conditions applied by the industry. Minimum HPP requirements to reduce Listeria monocytogenes levels by specific log10 reductions could be identified when HPP is applied to ready-to-eat (RTE) cooked meat products, but not for other types of RTE foods. These identified minimum requirements would result in the inactivation of other relevant pathogens (Salmonella and Escherichia coli) in these RTE foods to a similar or higher extent.
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Zouari A, Briard-Bion V, Schuck P, Gaucheron F, Delaplace G, Attia H, Ayadi MA. Changes in physical and biochemical properties of spray dried camel and bovine milk powders. Lebensm Wiss Technol 2020. [DOI: 10.1016/j.lwt.2020.109437] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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5
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Liu Y, Zhang W, Han B, Zhang L, Zhou P. Changes in bioactive milk serum proteins during milk powder processing. Food Chem 2020; 314:126177. [DOI: 10.1016/j.foodchem.2020.126177] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 01/04/2020] [Accepted: 01/07/2020] [Indexed: 12/14/2022]
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6
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Arena S, Renzone G, D'Ambrosio C, Salzano AM, Scaloni A. Dairy products and the Maillard reaction: A promising future for extensive food characterization by integrated proteomics studies. Food Chem 2016; 219:477-489. [PMID: 27765254 DOI: 10.1016/j.foodchem.2016.09.165] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 09/23/2016] [Accepted: 09/27/2016] [Indexed: 10/20/2022]
Abstract
Heating of milk and dairy products is done using various technological processes with the aim of preserving microbiological safety and extending shelf-life. These treatments result in chemical modifications in milk proteins, mainly generated as a result of the Maillard reaction. Recently, different bottom-up proteomic methods have been applied to characterize the nature of these structural changes and the modified amino acids in model protein systems and/or isolated components from thermally-treated milk samples. On the other hand, different gel-based and shotgun proteomic methods have been utilized to assign glycation, oxidation and glycoxidation protein targets in diverse heated milks. These data are essential to rationalize eventual, different nutritional, antimicrobial, cell stimulative and antigenic properties of milk products, because humans ingest large quantities of corresponding thermally modified proteins on a daily basis and these molecules also occur in pharmaceuticals and cosmetics. This review provides an updated picture of the procedures developed for the proteomic characterization of variably-heated milk products, highlighting their limits as result of concomitant factors, such as the multiplicity and the different concentration of the compounds to be detected.
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Affiliation(s)
- Simona Arena
- Proteomics & Mass Spectrometry Laboratory, ISPAAM, National Research Council, Naples, Italy
| | - Giovanni Renzone
- Proteomics & Mass Spectrometry Laboratory, ISPAAM, National Research Council, Naples, Italy
| | - Chiara D'Ambrosio
- Proteomics & Mass Spectrometry Laboratory, ISPAAM, National Research Council, Naples, Italy
| | - Anna Maria Salzano
- Proteomics & Mass Spectrometry Laboratory, ISPAAM, National Research Council, Naples, Italy
| | - Andrea Scaloni
- Proteomics & Mass Spectrometry Laboratory, ISPAAM, National Research Council, Naples, Italy.
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7
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Proteomic study on the stability of proteins in bovine, camel, and caprine milk sera after processing. Food Res Int 2016. [DOI: 10.1016/j.foodres.2016.01.023] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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8
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Devi AF, Buckow R, Singh T, Hemar Y, Kasapis S. Colour change and proteolysis of skim milk during high pressure thermal–processing. J FOOD ENG 2015. [DOI: 10.1016/j.jfoodeng.2014.09.017] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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9
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Cilla A, Alegría A, de Ancos B, Sánchez-Moreno C, Cano MP, Plaza L, Clemente G, Lagarda MJ, Barberá R. Bioaccessibility of tocopherols, carotenoids, and ascorbic acid from milk- and soy-based fruit beverages: influence of food matrix and processing. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2012; 60:7282-7290. [PMID: 22738607 DOI: 10.1021/jf301165r] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
A study was made of the effect of high-pressure processing (HPP) and thermal treatment (TT) on plant bioactive compounds (tocopherols, carotenoids, and ascorbic acid) in 12 fruit juice-milk beverages and of how the food matrix [whole milk (JW), skimmed milk (JS), and soy milk (JSy)] modulates their bioaccessibility (%). HPP (400 MPa/40 °C/5 min) produced a significant decrease in carotenoid and ascorbic acid bioaccessibility in all three beverages and maintained the bioaccessibility of tocopherols in JW and JS while decreasing it in JSy. TT (90 °C/30 s) produced a significant decrease in tocopherol and carotenoid bioaccessibility in all three beverages and increased the bioaccessibility of ascorbic acid. With regard to the food matrix, α-tocopherol and ascorbic acid bioaccessibility was greatest in JW beverages and lowest in JSy beverages, whereas no significant differences were found among the three beverages in terms of carotenoid bioaccessibility. HPP-treated samples showed higher tocopherol and carotenoid bioaccessibility than TT-treated samples, thus indicating that HPP combined with a milk matrix positively modulates the bioaccessibility of certain types of bioactive components of food, mainly those of a lipophilic nature.
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Affiliation(s)
- Antonio Cilla
- Nutrition and Food Chemistry, Faculty of Pharmacy, University of Valencia, Avenida Vicente Andrés Estellés s/n, 46100 Burjassot, Valencia, Spain.
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Le Maréchal C, Thiéry R, Vautor E, Le Loir Y. Mastitis impact on technological properties of milk and quality of milk products—a review. ACTA ACUST UNITED AC 2011. [DOI: 10.1007/s13594-011-0009-6] [Citation(s) in RCA: 109] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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11
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Rousseau-Ralliard D, Goirand F, Tardivel S, Lucas A, Algaron F, Mollé D, Robert V, Auchère D, Boudier JF, Gaillard JL, Monnet V, Tauzin J, Grynberg A. Inhibitory effect of αS1- and αS2-casein hydrolysates on angiotensin I-converting enzyme in human endothelial cells in vitro, rat aortic tissue ex vivo, and renovascular hypertensive rats in vivo. J Dairy Sci 2010; 93:2906-21. [PMID: 20630208 DOI: 10.3168/jds.2010-3060] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2010] [Accepted: 03/17/2010] [Indexed: 01/10/2023]
Abstract
A great number of milk-derived peptides have been shown to exhibit angiotensin converting enzyme (ACE) inhibitory properties and thus potential utility in the regulation of blood pressure. The present work aimed to investigate the effects of 2 milk trypsin hydrolysates from alpha(S1)- and alpha(S2)-casein (CH1 and CH2, respectively) on ACE activity evaluated in human umbilical vein endothelial cells (HUVEC) in vitro, rat aortic tissues ex vivo, and renovascular hypertensive rat in vivo. Incubation of HUVEC and rat aortic tissues with CH1 or CH2 induced a concentration-dependent inhibition of hydrolysis of the ACE substrate hippuryl-histidyl-leucine (HHL), the hydrolysates being much less potent than perindopril (an ACE inhibitor). However, in contrast to perindopril, CH1 and CH2 failed to modify angiotensin I-induced aortic ring vasoconstriction. The HPLC profiles of rat plasma after intragastric administration were variable among individuals but none of the observed peaks corresponded to peptides comprising CH1 or CH2 or to fragments of these peptides. During 4 wk of cardiovascular monitoring, in hydrolysate-fed renovascular hypertensive rats, systolic blood pressure weakly decreased compared with the control group. However, the CH1-fed hypertensive rats exhibited a decrease of heart rate during the nocturnal period of activity. To conclude, our results show that CH1 and CH2 inhibited ACE activity in HUVEC and rat aortic tissue but failed to antagonize the aortic-constricting effects of the natural agonist angiotensin I. Moreover, we demonstrated that CH1, to a greater extent than CH2, can slightly affect cardiovascular parameters although the ingested bioactive peptides could not be detected in the blood.
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Affiliation(s)
- D Rousseau-Ralliard
- INRA, Unité Mixte de Recherche 1154 INRA-Université Paris-Sud 11, Laboratoire Lipides membranaires et régulations fonctionnelles du coeur et des vaisseaux, Châtenay-Malabry, F-92296 France.
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12
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Scheidegger D, Pecora R, Radici P, Kivatinitz S. Protein oxidative changes in whole and skim milk after ultraviolet or fluorescent light exposure. J Dairy Sci 2010; 93:5101-9. [DOI: 10.3168/jds.2010-3513] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2010] [Accepted: 07/25/2010] [Indexed: 11/19/2022]
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13
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Rodiles-López JO, Arroyo-Maya IJ, Jaramillo-Flores ME, Gutiérrez-López GF, Hernández-Arana A, Barbosa-Cánovas GV, Niranjan K, Hernández-Sánchez H. Effects of high hydrostatic pressure on the structure of bovine alpha-lactalbumin. J Dairy Sci 2010; 93:1420-8. [PMID: 20338419 DOI: 10.3168/jds.2009-2786] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2009] [Accepted: 12/24/2009] [Indexed: 11/19/2022]
Abstract
The effects of high hydrostatic pressure (HHP) processing (at 200 to 600 MPa, 25 to 55 degrees C, and from 5 to 15 min) on some structural properties of alpha-lactalbumin was studied in a pH range of 3.0 to 9.0. The range of HHP processes produced a variety of molten globules with differences in their surface hydrophobicity and secondary and tertiary structures. At pH values of 3 and 5, there was a decrease in the alpha-helix content concomitant with an increase in beta-strand content as the pressure increased. No changes in molecular size due to HHP-induced aggregation were detected by sodium dodecyl sulfate-PAGE. All samples showed higher thermostability as the severity of the treatment increased, indicating the formation of a less labile structure related to the HHP treatment.
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Affiliation(s)
- J O Rodiles-López
- Departamento de Graduados e Investigación en Alimentos, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Carpio y Plan de Ayala, CP. 11340 México, DF, México
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14
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Smith K, Mendonca A, Jung S. Impact of high-pressure processing on microbial shelf-life and protein stability of refrigerated soymilk. Food Microbiol 2009; 26:794-800. [DOI: 10.1016/j.fm.2009.05.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2009] [Revised: 05/01/2009] [Accepted: 05/04/2009] [Indexed: 10/20/2022]
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15
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Inoue K, Gotou T, Kitajima H, Mizuno S, Nakazawa T, Yamamoto N. Release of antihypertensive peptides in miso paste during its fermentation, by the addition of casein. J Biosci Bioeng 2009; 108:111-5. [PMID: 19619856 DOI: 10.1016/j.jbiosc.2009.03.007] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2009] [Revised: 02/22/2009] [Accepted: 03/12/2009] [Indexed: 11/21/2022]
Abstract
Casein hydrolysate by Aspergillus oryzae protease has been developed to obtain two kinds of antihypertensive peptides, Val-Pro-Pro and Ile-Pro-Pro. In this study, casein miso paste was prepared by adding casein at various concentrations during miso paste fermentation in order to release angiotensin-I converting enzyme (ACE) inhibitory peptides. Increase of peptide concentration and ACE inhibitory activity in casein miso paste was observed and corresponded to the degradation of casein and soy bean proteins during fermentation for 7 days. ACE inhibitory activity of the casein miso paste was higher than that of the general (casein-free) miso paste after fermentation for 7 days. The levels of ACE inhibitory peptides, Val-Pro-Pro and Ile-Pro-Pro, were increased in the casein miso paste during the fermentation. Significant antihypertensive effects of casein miso paste compared to water and the general miso paste (P<0.05 and P<0.05) were confirmed in spontaneously hypertensive rats at a dosage of 1.8 g of the casein miso paste/kg of BW. Taken into account of minimum effective dosages of Val-Pro-Pro and Ile-Pro-Pro in previous clinical studies, these results suggest that casein miso paste might have the potential to control blood pressure in humans.
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Affiliation(s)
- Kaori Inoue
- Functional Food and Drink Development Laboratory, Calpis Co., Ltd., 11-10 5-Chome, Fuchinobe, Sagamihara-shi, Kanagawa 229-0006, Japan
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Chevalier F, Hirtz C, Sommerer N, Kelly AL. Use of reducing/nonreducing two-dimensional electrophoresis for the study of disulfide-mediated interactions between proteins in raw and heated bovine milk. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2009; 57:5948-5955. [PMID: 19526987 DOI: 10.1021/jf900518n] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The composition and interactions of proteins in bovine milk, and modifications resulting from milk storage and processing, are complex and incompletely understood. Analysis of the milk proteome can elucidate milk protein expression, structure, interaction, and modifications. Raw milk was analyzed by two-dimensional electrophoresis (isolelectric focusing followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis) under reducing and nonreducing, or combined, conditions, followed by mass spectrometry of separated protein spots; a small number of high-abundance proteins, that is, caseins (alpha(S1)-, alpha(S2)-, beta-, kappa-, and gamma-), beta-lactoglobulin, alpha-lactalbumin, and serum albumin, represented the vast majority of protein spots on the two-dimensional electrophoretograms of raw milk samples, but some cross-linked protein complexes (mainly homopolymers of kappa-casein and alpha(S2)-casein but also some heteropolymeric complexes) were resolved under native/unheated conditions. When skim milk was heated to 90 degrees C for up to 10 min, the level of native whey proteins decreased in parallel with an increase in disulfide-linked complexes, including very complex heteropolymers, for example, casein/whey protein polymers containing multiple species. The analysis strategy used in this study reveals numerous disulfide-mediated interactions and can be proposed to analyze reduction/oxidation of milk and dairy product proteins following processing treatments applied for processing and storage.
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Affiliation(s)
- François Chevalier
- Department of Food and Nutritional Sciences, University College Cork, Cork, Ireland.
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Rodiles-López JO, Jaramillo-Flores ME, Gutiérrez-López GF, Hernández-Arana A, Fosado-Quiroz RE, Barbosa-Cánovas GV, Hernández-Sánchez H. Effect of high hydrostatic pressure on bovine α-lactalbumin functional properties. J FOOD ENG 2008. [DOI: 10.1016/j.jfoodeng.2007.12.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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18
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Identification of peptides in milk as a result of proteolysis at different levels of somatic cell counts using LC MALDI MS/MS detection. J DAIRY RES 2008; 75:76-83. [DOI: 10.1017/s0022029907002968] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The somatic cell count (SCC) in milk is associated with increasing proteolytic degradation of caseins and it has been suggested that enzymes derived from somatic cells contribute to a lower yield and poorer quality of cheese. It is essential to increase the knowledge on naturally occurring milk proteinase activities to better understand how to improve the technological quality of milk. The aim of this work was to identify peptides actually present in milk as a result of proteolysis at different levels of SCC and to assign these peptides to potential responsible proteases where possible. Peptide fractions were prepared from acid whey by ultrafiltration at a molecular cut-off value of 10 000 Da. The peptides were separated using capillary reversed phase high performance liquid chromatography (RP-HPLC) and identified by matrix-assisted laser desorption/ionization-time of flight tandem mass spectrometry (MALDI-TOF MS/MS). Peptides identified ranged in mass from 1023 to 2000 Da, and originated from αS1-, αS2- or β-casein. Possible responsible proteases that could be suggested when examining the peptide cleavage sites included plasmin, cathepsin B, D and leukocyte elastase. The results indicated that plasmin was primarily responsible for the observed proteolysis in milk at low cell count, whereas the cathepsins and elastase became implicated at elevated cell count. Specificity and activity of cathepsins and elastase has earlier mainly been studied in model systems, whereas less is known about their activities in milk itself. This is also the first indication of involvement of elastase in milk proteolysis through the unequivocal determination of cleavage sites.
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Belloque J, Chicón R, López-Fandiño R. Unfolding and refolding of beta-lactoglobulin subjected to high hydrostatic pressure at different pH values and temperatures and its influence on proteolysis. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2007; 55:5282-8. [PMID: 17542606 DOI: 10.1021/jf070170w] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The unfolding of beta-lactoglobulin during high-pressure treatment and its refolding after decompression were studied by 1H NMR and 2H/1H exchange at pH 6.8 and 2.5 and at 37 and 25 degrees C. The extent of unfolding increased with the pressure level. The structure of beta-lactoglobulin required higher pressures to unfold at pH 2.5 than at pH 6.8. More flexibility was achieved at 37 degrees C than at 25 degrees C. Results indicated that the structural region formed by strands F, G, and H was more resistant to unfold under acidic and neutral conditions. The exposure of Trp19 at an earlier time, as compared to other protein regions, supports the formation of a swollen structural state at pH 2.5. Refolding was achieved faster when beta-lactoglobulin was subjected to 200 MPa than to 400 MPa, to 37 degrees C than to 25 degrees C, and to acidic than to neutral pH. After treatment at 400 MPa for 20 min at neutral pH, the protein native structure was not recovered. All samples at acidic pH showed that the protein quickly regained its structure. Hydrolysis of beta-lactoglobulin by pepsin and chymotrypsin could be related to pressure-induced changes in the structure of the protein. Compared to the behavior of the protein at atmospheric pressure, no increased proteolysis was found in samples with no increased flexibility (100 MPa, 37 degrees C, pH 2.5). Slightly flexible structures were associated with significantly increased proteolysis (100 MPa, 37 degrees C, pH 6.8; 200 MPa, 37 degrees C, pH 2.5). Highly flexible structures were associated with very fast proteolysis (>or=200 MPa, 37 degrees C, pH 6.8; >or=300 MPa, 37 degrees C, pH 2.5). Proteolysis of prepressurized samples improved only when the protein was significantly changed after the pressure treatment (400 MPa, 25 degrees C, 20 min, pH 6.8).
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Brisson G, Britten M, Pouliot Y. Heat-induced aggregation of bovine lactoferrin at neutral pH: Effect of iron saturation. Int Dairy J 2007. [DOI: 10.1016/j.idairyj.2006.09.002] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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21
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Brisson G, Britten M, Pouliot Y. Effect of Iron Saturation on the Recovery of Lactoferrin in Rennet Whey Coming from Heat-Treated Skim Milk. J Dairy Sci 2007; 90:2655-64. [PMID: 17517705 DOI: 10.3168/jds.2006-725] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
This study aimed to determine the effect of thermal treatments on the recovery of lactoferrin in whey coming from rennet-coagulated skim milk. The impact of lactoferrin iron saturation was also assessed using skim milk spiked with different lactoferrin iron forms. The recovery of lactoferrin in the rennet whey fraction was determined by reverse-phase HPLC. One- and 2-dimensional sodium dodecyl sulfate PAGE analyses were performed on rennet curds to characterize the protein interactions involving lactoferrin in heated milk. The extent of lactoferrin recovered in the whey fraction was found to reduce as the heating temperature increased. The binding of iron by lactoferrin improved its thermal stability and its recovery in the whey fraction. Poly-acrylamide gel electrophoresis results showed that the association of lactoferrin in the unheated milk rennet curd involved noncovalent interactions, whereas upon heating, lactoferrin also interacted via an intermolecular disulfide link. Depending on the severity of the heat treatment, lactoferrin aggregates with Cys-containing proteins (beta-lactoglobulin, alpha-lactalbumin, alpha(s2)-casein, and kappa-casein) occurred by intermolecular thiol/disulfide exchange reactions. These noncovalent and covalent interactions explained the lower recovery of lactoferrin in heated milk.
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Affiliation(s)
- G Brisson
- Groupe de Recherche STELA, Institut sur les Nutraceutiques et Aliments Fonctionnels, Pavillon Paul-Comtois, Université Laval, Québec, Québec, Canada G1K 7P4
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Effects of heat and β-lactoglobulin on distribution of fluorescently labeled tissue- and urokinase-type plasminogen activators in a model milk system. Int Dairy J 2007. [DOI: 10.1016/j.idairyj.2006.06.025] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Kleber N, Maier S, Hinrichs J. Antigenic response of bovine β-lactoglobulin influenced by ultra-high pressure treatment and temperature. INNOV FOOD SCI EMERG 2007. [DOI: 10.1016/j.ifset.2006.05.001] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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24
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López-Fandiño R. High pressure-induced changes in milk proteins and possible applications in dairy technology. Int Dairy J 2006. [DOI: 10.1016/j.idairyj.2005.11.007] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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25
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Firth MA, Shewen PE, Hodgins DC. Passive and active components of neonatal innate immune defenses. Anim Health Res Rev 2006; 6:143-58. [PMID: 16583779 DOI: 10.1079/ahr2005107] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Innate immune defenses are crucial for survival in the first days and weeks of life. At birth, newborns are confronted with a vast array of potentially pathogenic microorganisms that were not encountered in utero. At this age, cellular components of the adaptive immune system are in a naive state and are slow to respond. Antibodies received from the dam are essential for defense, but represent a finite and dwindling resource. Innate components of the immune system detect pathogen-associated molecular patterns (PAMPs) on microorganisms (and their products) by means of pattern-recognition receptors (PRRs). Soluble mediators of the innate system such as complement proteins, pentraxins, collectins, ficolins, defensins, lactoferrin, lysozyme etc. can bind to structures on pathogens, leading to agglutination, interference with receptor binding, opsonization, neutralization, direct membrane damage and recruitment of additional soluble and cellular elements through inflammation. Cell-associated receptors such as the Toll-like receptors (TLRs) can activate cells and coordinate responses (both innate and adaptive). In this paper, accumulated knowledge of the receptors, soluble and cellular elements that contribute to innate defenses of young animals is reviewed. Research interest in this area has been intermittent, and the literature varies in quantity and quality. It is hoped that documentation of the limitations of our knowledge base will lead to more extensive and enlightening studies.
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Affiliation(s)
- Matthew A Firth
- Department of Pathobiology, University of Guelph, Guelph, ON, Canada NIG 2W1
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Wang L, Hayes KD, Mauer LJ. Fluorescent Labeling Study of Plasminogen Concentration and Location in Simulated Bovine Milk Systems. J Dairy Sci 2006; 89:58-70. [PMID: 16357268 DOI: 10.3168/jds.s0022-0302(06)72069-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A fluorescent labeling method was developed to study plasminogen (PG) concentration and location in simulated bovine milk. Activity and stability of PG labeled with Alexa Fluor 594 (PG-594) were comparable to those of native PG. The fluorescent signal of PG-594 exhibited pH, temperature, and storage stability, and remained stable throughout typical sample treatments (stirring, heating, and ultracentrifugation). These characteristics indicate broad applicability of the fluorescent labeling technique for milk protease characterization. In an example application, PG-594 was added to simulated milk samples to study effects of heat and beta-lactoglobulin (beta-LG) on the distribution of PG. Before heating, about one-third of the PG-594 remained soluble in the whey fraction (supernatant) whereas the rest became associated with the casein micelle. Addition of beta-LG to the system slightly shifted PG-594 distribution toward the whey fraction. Heat-induced PG-594 binding to micelles in whey-protein-free systems was evidenced by a decrease of PG-594 from 31 to 15% in the whey fraction accompanied by an increase of PG-594 from 69 to 85% in casein micelle fractions. When beta-LG was present during heating, more than 95% of PG-594 became associated with the micelle. A comparison with the distribution pattern of PG-derived activities revealed that heat-induced PG binding to micelles accompanies heat-induced PG inactivation in the micelle fraction. Incubation of the casein micelles with the reducing agent beta-mercaptoethanol revealed that disulfide bonds formed between PG and casein or between PG and casein-bound beta-LG are the mechanisms for heat-induced PG binding to casein micelles. Western blotting and zymography results correlated well with fluorescent labeling studies and activity studies, respectively. Theoretically important findings are: 1) when heated, serum PG is capable of covalently binding to micellar casein or complexing with beta-LG in whey and then coadhering to micelles, and 2) PG that associated with micellar casein through lysine binding sites before heating is capable of developing heat-induced disulfide bonds with casein. The overall results are PG covalently binding to micelles and inactivation thereafter. Our results suggest that, instead of thermal denaturation through irreversible unfolding, covalent bond formation between PG and other milk proteins is the mechanism of PG inhibition during thermal processing.
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Affiliation(s)
- L Wang
- Department of Food Science, Purdue University, West Lafayette, IN 47907, USA
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