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Holt C, Carver JA. Invited review: Modeling milk stability. J Dairy Sci 2024; 107:5259-5279. [PMID: 38522835 DOI: 10.3168/jds.2024-24779] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Accepted: 02/15/2024] [Indexed: 03/26/2024]
Abstract
Novel insights into the stability of milk and milk products during storage and processing result from describing caseins near neutral pH as hydrophilic, intrinsically disordered, proteins. Casein solubility is strongly influenced by pH and multivalent ion binding. Solubility is high at a neutral pH or above, but decreases as the casein net charge approaches zero, allowing a condensed casein phase or gel to form, then increases at lower pH. Of particular importance for casein micelle stability near neutral pH is the proportion of free caseins in the micelle (i.e., caseins not bound directly to nanoclusters of calcium phosphate). Free caseins are more soluble and better able to act as molecular chaperones (to prevent casein and whey protein aggregation) than bound caseins. Some free caseins are highly phosphorylated and can also act as mineral chaperones to inhibit the growth of calcium phosphate phases and prevent mineralized deposits from forming on membranes or heat exchangers. Thus, casein micelle stability is reduced when free caseins bind to amyloid fibrils, destabilized whey proteins or calcium phosphate. The multivalent-binding model of the casein micelle quantitatively describes these and other factors affecting the stability of milk and milk protein products during manufacture and storage.
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Affiliation(s)
- C Holt
- School of Biomolecular Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom.
| | - J A Carver
- Research School of Chemistry, The Australian National University, Acton, ACT 2601, Australia
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Liu N, Liu Z, Wang K, Zhao J, Fang J, Liu G, Yao H, Pan J. Comparison analysis of microbial agent and different compost material on microbial community and nitrogen transformation genes dynamic changes during pig manure compost. BIORESOURCE TECHNOLOGY 2024; 395:130359. [PMID: 38272144 DOI: 10.1016/j.biortech.2024.130359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 01/17/2024] [Accepted: 01/18/2024] [Indexed: 01/27/2024]
Abstract
This study aimed to assess the impact of microbial agent and different compost material, on physicochemical parameters dynamic change, nitrogen-transfer gene/bacterial community interaction network during the pig manure composting. Incorporating a microbial agent into rice straw-mushroom compost reduced the NH3 and total ammonia emissions by 25.52 % and 14.41 %, respectively. Notably, rice straw-mushroom with a microbial agent reduced the total ammonia emissions by 37.67 %. NH4+-N and pH emerged as primary factors of phylum-level and genus-level microorganisms. Microbial agent increased the expression of narG, nirK, and nosZ genes. Rice straw-mushroom elevated the content of amoA, nirK, nirS, and nosZ genes. Alcanivorax, Luteimonas, Pusillimonas, Lactobacillus, Aequorivita, Clostridium, Moheibacter and Truepera were identified as eight core microbial genera during the nitrogen conversion process. This study provides a strategy for reducing ammonia emissions and analyzes the potential mechanisms underlying compost processes.
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Affiliation(s)
- Naiyuan Liu
- College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, Hunan 410128, China; Hunan Engineering Laboratory for Pollution Control and Waste Utilization in Swine Production, Changsha 410128, China
| | - Zhuangzhuang Liu
- College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, Hunan 410128, China; Hunan Engineering Laboratory for Pollution Control and Waste Utilization in Swine Production, Changsha 410128, China
| | - Keyu Wang
- College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, Hunan 410128, China; Hunan Engineering Laboratory for Pollution Control and Waste Utilization in Swine Production, Changsha 410128, China
| | - Jinfeng Zhao
- College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, Hunan 410128, China; Hunan Engineering Laboratory for Pollution Control and Waste Utilization in Swine Production, Changsha 410128, China
| | - Jun Fang
- College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, Hunan 410128, China; Hunan Engineering Laboratory for Pollution Control and Waste Utilization in Swine Production, Changsha 410128, China.
| | - Gang Liu
- College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, Hunan 410128, China; Hunan Engineering Laboratory for Pollution Control and Waste Utilization in Swine Production, Changsha 410128, China
| | - Hao Yao
- Changsha IMADEK Intelligent Technology Co., LTD, China
| | - Junting Pan
- State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China
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Bauland J, Famelart MH, Faiveley M, Croguennec T. Rheological properties of enzymatic milk gel: Effect of ion partitioning in casein micelles. Food Hydrocoll 2022. [DOI: 10.1016/j.foodhyd.2022.107739] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Wang Q, Ma Y. Characterization of calcium phosphate nanoparticles sequestered by phosphopeptides in response to heat treatment. Lebensm Wiss Technol 2022. [DOI: 10.1016/j.lwt.2022.113816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Anema SG. Heat-induced changes in caseins and casein micelles, including interactions with denatured whey proteins. Int Dairy J 2021. [DOI: 10.1016/j.idairyj.2021.105136] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Barone G, Yazdi SR, Lillevang SK, Ahrné L. Calcium: A comprehensive review on quantification, interaction with milk proteins and implications for processing of dairy products. Compr Rev Food Sci Food Saf 2021; 20:5616-5640. [PMID: 34622552 DOI: 10.1111/1541-4337.12844] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 09/01/2021] [Accepted: 09/02/2021] [Indexed: 12/22/2022]
Abstract
Calcium (Ca) is a key micronutrient of high relevance for human nutrition that also influences the texture and taste of dairy products and their processability. In bovine milk, Ca is presented in several speciation forms, such as complexed with other milk components or free as ionic calcium while being distributed between colloidal and serum phases of milk. Partitioning of Ca between these phases is highly dynamic and influenced by factors, such as temperature, ionic strength, pH, and milk composition. Processing steps used during the manufacture of dairy products, such as preconditioning, concentration, acidification, salting, cooling, and heating, all contribute to modify Ca speciation and partition, thereby influencing product functionality, product yield, and fouling of equipment. This review aims to provide a comprehensive understanding of the influence of Ca partition on dairy products properties to support the development of kinetics models to reduce product losses and develop added-value products with improved functionality. To achieve this objective, approaches to separate milk phases, analytical approaches to determine Ca partition and speciation, the role of Ca on protein-protein interactions, and their influence on processing of dairy products are discussed.
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Affiliation(s)
- Giovanni Barone
- Department of Food Science, Ingredients and Dairy Technology, University of Copenhagen, Frederiksberg, Denmark
| | | | | | - Lilia Ahrné
- Department of Food Science, Ingredients and Dairy Technology, University of Copenhagen, Frederiksberg, Denmark
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Structural Biology of Calcium Phosphate Nanoclusters Sequestered by Phosphoproteins. CRYSTALS 2020. [DOI: 10.3390/cryst10090755] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Biofluids that contain stable calcium phosphate nanoclusters sequestered by phosphopeptides make it possible for soft and hard tissues to co-exist in the same organism with relative ease. The stability diagram of a solution of nanocluster complexes shows how the minimum concentration of phosphopeptide needed for stability increases with pH. In the stable region, amorphous calcium phosphate cannot precipitate. Nevertheless, if the solution is brought into contact with hydroxyapatite, the crystalline phase will grow at the expense of the nanocluster complexes. The physico-chemical principles governing the formation, composition, size, structure, and stability of the complexes are described. Examples are given of complexes formed by casein, osteopontin, and recombinant phosphopeptides. Application of these principles and properties to blood serum, milk, urine, and resting saliva is described to show that under physiological conditions they are in the stable region of their stability diagram and so cannot cause soft tissue calcification. Stimulated saliva, however, is in the metastable region, consistent with its role in tooth remineralization. Destabilization of biofluids, with consequential ill-effects, can occur when there is a failure of homeostasis, such as an increase in pH without a balancing increase in the concentration of sequestering phosphopeptides.
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