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Zhang T, Liu Y, Cao J, Jiang L, Lin K, Wang P, Ren F, Yi H. Milk serum peptidomics revealed the age gelation of direct UHT milk. Food Chem 2024; 456:140012. [PMID: 38876066 DOI: 10.1016/j.foodchem.2024.140012] [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: 02/16/2024] [Revised: 06/01/2024] [Accepted: 06/06/2024] [Indexed: 06/16/2024]
Abstract
Age gelation is undesirable for direct UHT (dUHT) milk, which is closely related to protein hydrolysis. However, little information is available for the role of serum peptides during the age gelation. In this study, the composition and protein morphology of serum phase were characterized by RP-HPLC, ICP-MS and TEM. The results showed significant increases in soluble proteins, free amino acids, calcium, and phosphorus from casein micelles, indicating protein hydrolysis and peptide release into the serum phase. 23,466 peptides derived from caseins and other proteins were identified in serum phase by peptidomics. The serum peptide profiles of age gelation milk changed dramatically. Peptide fingerprinting revealed that plasmin and cathepsin contributed to the protein hydrolysis during age gelation, with a significant increase in their activity observed. 23 characteristic peptides were ultimately selected as potential indicators for age gelation. These findings provide new insights into the age gelation of UHT milk.
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Affiliation(s)
- Tai Zhang
- College of Food Science and Engineering, Ocean University of China, Qingdao 266003, Shandong Province, China; Food Laboratory of Zhongyuan, Luohe 462300, Henan, China
| | - Yisuo Liu
- College of Food Science and Engineering, Ocean University of China, Qingdao 266003, Shandong Province, China; Food Laboratory of Zhongyuan, Luohe 462300, Henan, China
| | - Jiayuan Cao
- College of Food Science and Engineering, Ocean University of China, Qingdao 266003, Shandong Province, China
| | - Lu Jiang
- College of Food Science and Engineering, Ocean University of China, Qingdao 266003, Shandong Province, China
| | - Kai Lin
- College of Food Science and Engineering, Ocean University of China, Qingdao 266003, Shandong Province, China
| | - Pengjie Wang
- Key Laboratory of Functional Dairy, Department of Nutrition and Health, China Agricultural University, Beijing, China; Food Laboratory of Zhongyuan, Luohe 462300, Henan, China
| | - Fazheng Ren
- Key Laboratory of Functional Dairy, Department of Nutrition and Health, China Agricultural University, Beijing, China; Food Laboratory of Zhongyuan, Luohe 462300, Henan, China.
| | - Huaxi Yi
- College of Food Science and Engineering, Ocean University of China, Qingdao 266003, Shandong Province, China; Food Laboratory of Zhongyuan, Luohe 462300, Henan, China.
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2
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Wang Y, Guo M, Wu P, Fan K, Zhang W, Chen C, Ren F, Wang P, Luo J, Yu J. New insights into the destabilization of fat globules in ultra-instantaneous UHT milk induced by added plasmin: Molecular mechanisms and the effect of membrane structure on plasmin action. Colloids Surf B Biointerfaces 2024; 240:113987. [PMID: 38795586 DOI: 10.1016/j.colsurfb.2024.113987] [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: 03/15/2024] [Revised: 04/29/2024] [Accepted: 05/22/2024] [Indexed: 05/28/2024]
Abstract
Residual plasmin activity in whole ultra-instantaneous UHT (UI-UHT) milk causes rapid fat rise during storage, seriously affecting consumers' purchase intentions. In this work, the molecular mechanisms underlying fat destabilization in whole UI-UHT milk by added plasmin were investigated based on the hydrolysis behavior of interfacial proteins. By using SDS-PAGE and peptidomic analysis, we found that the hydrolysis of interfacial proteins by plasmin led to a decrease in the amount and coverage of interfacial proteins and an increase in zeta-potential value, causing the flocculation and coalescence of fat globules. Moreover, the hydrolysis pattern varied in different categories of interfacial proteins by plasmin. In total, 125 peptides in all samples were identified. Plasmin tended to hydrolyze most major milk fat globule membrane (MFGM) proteins into protein fragments (>10 kDa) rather than peptides (<10 kDa). In contrast, peptides derived from caseins were more preferentially identified within a relatively short incubation time. It was the co-hydrolysis of caseins and some major MFGM proteins as anchors that destroyed the stability of MFGM. Furthermore, studies on the effect of trilayer membrane structure remaining at the interface on the hydrolysis rate of major MFGM proteins by plasmin revealed that ADPH and BTN were very sensitive to plasmin action, while PAS 7 was very resistant to plasmin action. Overall, membrane structure reduced the susceptibility of some major MFGM proteins to plasmin and provided protective effects. Therefore, this study provided important insights into the hydrolysis behavior of interfacial proteins in whole UI-UHT milk induced by plasmin.
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Affiliation(s)
- Yi Wang
- College of Food Science and Engineering, Tianjin University of Science & Technology, Tianjin 300457, China; Department of Nutrition and Health, China Agricultural University, Beijing 100083, China
| | - Mengyuan Guo
- Department of Nutrition and Health, China Agricultural University, Beijing 100083, China; Key Laboratory of Functional Dairy, Co-constructed by Ministry of Education and Beijing Government, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China
| | - PeiPei Wu
- Department of Nutrition and Health, China Agricultural University, Beijing 100083, China; College of Food Science and Technology, Hunan Agricultural University, Changsha 410114, China
| | - Ke Fan
- College of Food Science and Technology, Hunan Agricultural University, Changsha 410114, China
| | - Weibo Zhang
- Department of Nutrition and Health, China Agricultural University, Beijing 100083, China
| | - Chong Chen
- Department of Nutrition and Health, China Agricultural University, Beijing 100083, China
| | - Fazheng Ren
- Department of Nutrition and Health, China Agricultural University, Beijing 100083, China; Key Laboratory of Functional Dairy, Co-constructed by Ministry of Education and Beijing Government, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China
| | - Pengjie Wang
- Department of Nutrition and Health, China Agricultural University, Beijing 100083, China
| | - Jie Luo
- Key Laboratory of Functional Dairy, Co-constructed by Ministry of Education and Beijing Government, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China; College of Food Science and Technology, Hunan Agricultural University, Changsha 410114, China.
| | - Jinghua Yu
- College of Food Science and Engineering, Tianjin University of Science & Technology, Tianjin 300457, China.
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3
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Fan K, Wu P, Guo M, Wang Y, Cao Y, Wang P, Ren F, Luo J. Destabilization of ultra-instantaneous ultra-high-temperature sterilized milk stored at different temperatures. J Dairy Sci 2024; 107:5460-5472. [PMID: 38554824 DOI: 10.3168/jds.2024-24705] [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: 01/23/2024] [Accepted: 02/25/2024] [Indexed: 04/02/2024]
Abstract
Ultra-instantaneous UHT (UI-UHT, >155°C, <0.1 s) treated milk exhibits higher retention of active protein than regular UHT milk. However, UI-UHT products demonstrate increased susceptibility to destabilization during storage. This study aimed at monitoring the destabilizing process of UI-UHT milk across different storage temperatures and uncovering its potential mechanisms. Compared with regular UHT treatment, ultra-instantaneous treatment markedly accelerated the milk's destabilization process. Aged gel formation occurred after 45 d of storage at 25°C, whereas creaming and sedimentation were observed after 15 d at 37°C. To elucidate the instability mechanism, measurements of plasmin activity, protein hydrolysis levels, and proteomics of the aged gel were conducted. In UI-UHT milk, plasmin activity, and protein hydrolysis levels significantly increased during storage. Excessive protein hydrolysis at 37°C resulted in sedimentation, whereas moderate hydrolysis and an increase in protein particle size at 25°C resulted in aged gel formation. Proteomics analysis results indicated that the aged gel from UI-UHT milk contained intact caseins, major whey proteins, and their derived peptides. Furthermore, specific whey proteins including albumin, lactotransferrin, enterotoxin-binding glycoprotein PP20K, and MFGM proteins were identified in the gel. Additionally, MFGM proteins in UI-UHT milk experienced considerable hydrolysis during storage, contributing to fat instability. This study lays a theoretical foundation for optimizing UI-UHT milk storage conditions to enhance the quality of liquid milk products.
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Affiliation(s)
- Ke Fan
- College of Food Science and Technology, Hunan Agricultural University, Changsha, 410114, China
| | - Peipei Wu
- College of Food Science and Technology, Hunan Agricultural University, Changsha, 410114, China
| | - Mengyuan Guo
- Key Laboratory of Functional Dairy, Co-constructed by Ministry of Education and Beijing Government, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China
| | - Yi Wang
- Key Laboratory of Functional Dairy, Co-constructed by Ministry of Education and Beijing Government, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China
| | - Ye Cao
- College of Food Science and Technology, Hunan Agricultural University, Changsha, 410114, China
| | - Pengjie Wang
- Key Laboratory of Functional Dairy, Co-constructed by Ministry of Education and Beijing Government, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China
| | - Fazheng Ren
- College of Food Science and Technology, Hunan Agricultural University, Changsha, 410114, China.
| | - Jie Luo
- College of Food Science and Technology, Hunan Agricultural University, Changsha, 410114, China; Key Laboratory of Functional Dairy, Co-constructed by Ministry of Education and Beijing Government, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China.
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4
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Zhang T, Liu Y, Cao J, Liu Y, Hao L, Lin K, Yi H. Exploration of Novel Plasmin Inhibitor from β-Lactoglobulin for Enhancing the Storage Stability of UHT Milk. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:17041-17050. [PMID: 39024493 DOI: 10.1021/acs.jafc.4c04986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/20/2024]
Abstract
Plasmin-induced protein hydrolysis significantly compromises the stability of ultrahigh-temperature (UHT) milk. β-Lactoglobulin (β-Lg) was observed to inhibit plasmin activity, suggesting that there were active sites as plasmin inhibitors in β-Lg. Herein, plasmin inhibitory peptides were explored from β-Lg using experimental and computational techniques. The results revealed that increased denaturation of β-Lg enhanced its affinity for plasmin, leading to a stronger inhibition of plasmin activity. Molecular dynamics simulations indicated that electrostatic and van der Waals forces were the primary binding forces in the β-Lg/plasmin complex. Denatured β-Lg increased hydrogen bonding and reduced the binding energy with plasmin. The sites of plasmin bound to β-Lg were His624, Asp667, and Ser762. Four plasmin inhibitory peptides, QTMKGLDI, EKTKIPAV, TDYKKYLL, and CLVRTPEV, were identified from β-Lg based on binding sites. These peptides effectively inhibited plasmin activity and enhanced the UHT milk stability. This study provided new insights into the development of novel plasmin inhibitors to improve the stability of UHT milk.
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Affiliation(s)
- Tai Zhang
- State Key Laboratory of Marine Food Processing & Safety Control, College of Food Science and Engineering, Ocean University of China, Qingdao, Shandong Province 266003, China
- Food Laboratory of Zhongyuan, Luohe, Henan Province 462300, China
| | - Yisuo Liu
- State Key Laboratory of Marine Food Processing & Safety Control, College of Food Science and Engineering, Ocean University of China, Qingdao, Shandong Province 266003, China
- Food Laboratory of Zhongyuan, Luohe, Henan Province 462300, China
| | - Jiayuan Cao
- State Key Laboratory of Marine Food Processing & Safety Control, College of Food Science and Engineering, Ocean University of China, Qingdao, Shandong Province 266003, China
| | - Yinxue Liu
- State Key Laboratory of Marine Food Processing & Safety Control, College of Food Science and Engineering, Ocean University of China, Qingdao, Shandong Province 266003, China
| | - Linlin Hao
- State Key Laboratory of Marine Food Processing & Safety Control, College of Food Science and Engineering, Ocean University of China, Qingdao, Shandong Province 266003, China
| | - Kai Lin
- State Key Laboratory of Marine Food Processing & Safety Control, College of Food Science and Engineering, Ocean University of China, Qingdao, Shandong Province 266003, China
| | - Huaxi Yi
- State Key Laboratory of Marine Food Processing & Safety Control, College of Food Science and Engineering, Ocean University of China, Qingdao, Shandong Province 266003, China
- Food Laboratory of Zhongyuan, Luohe, Henan Province 462300, China
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5
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Miller AL, Renye JA, Oest AM, Liang C, Garcia RA, Plumier BM, Tomasula PM. Bacteriocin production by lactic acid bacteria using ice cream co-product as the fermentation substrate. J Dairy Sci 2024; 107:3468-3477. [PMID: 38246535 DOI: 10.3168/jds.2023-24249] [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: 09/27/2023] [Accepted: 12/15/2023] [Indexed: 01/23/2024]
Abstract
Ice cream manufacture commonly results in the accumulation of wasted product that contains valuable food-grade quality components, including fat, carbohydrates, and protein. Methods have been developed for recovering the fat from this waste stream, but this results in the generation of a co-product rich in fermentable carbohydrates. This study aimed to investigate the potential for using this co-product as a fermentation substrate for production of antimicrobial peptides, called bacteriocins, by dairy starter cultures. Results showed that Streptococcus thermophilus B59671 and Lactococcus lactis 11454 produced the broad-spectrum bacteriocins thermophilin 110 and nisin, respectively, when the fermentation substrate was melted ice cream, or a co-product generated by a modified butter churning technique. Bacteriocin production varied depending on the brand and variety of vanilla ice cream used in this study. When an alternate enzyme-assisted fat extraction technique was used, S. thermophilus metabolism was impaired within the resulting co-product, and thermophilin 110 production was not observed. Lactococcus lactis was still able to grow in this co-product, but antimicrobial activity was not observed. Results from this study suggest the co-product generated when using the churning technique is a better choice to use as a base medium for future studies to optimize bacteriocin production.
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Affiliation(s)
- Amanda L Miller
- Dairy and Functional Foods Research Unit, Agricultural Research Service, USDA, Wyndmoor, PA 19038.
| | - John A Renye
- Dairy and Functional Foods Research Unit, Agricultural Research Service, USDA, Wyndmoor, PA 19038
| | - Adam M Oest
- Dairy and Functional Foods Research Unit, Agricultural Research Service, USDA, Wyndmoor, PA 19038
| | - Chen Liang
- Department of Viticulture & Enology, University of California, Davis, Davis, CA 95616
| | - Rafael A Garcia
- Dairy and Functional Foods Research Unit, Agricultural Research Service, USDA, Wyndmoor, PA 19038
| | - Benjamin M Plumier
- Dairy and Functional Foods Research Unit, Agricultural Research Service, USDA, Wyndmoor, PA 19038
| | - Peggy M Tomasula
- Dairy and Functional Foods Research Unit, Agricultural Research Service, USDA, Wyndmoor, PA 19038
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Qin X, Cheng J, Qi X, Guan N, Chen Q, Pei X, Jiang Y, Yang X, Man C. Effect of Thermostable Enzymes Produced by Psychrotrophic Bacteria in Raw Milk on the Quality of Ultra-High Temperature Sterilized Milk. Foods 2023; 12:3752. [PMID: 37893644 PMCID: PMC10606520 DOI: 10.3390/foods12203752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 10/06/2023] [Accepted: 10/10/2023] [Indexed: 10/29/2023] Open
Abstract
Ultra-high temperature sterilized milk (UHT) is a popular dairy product known for its long shelf life and convenience. However, protein gel aging and fat quality defects like creaming and flavor deterioration may arise during storage. These problems are primarily caused by thermostable enzymes produced by psychrotrophic bacteria. In this study, four representative psychrotrophic bacteria strains which can produce thermostable enzymes were selected to contaminate UHT milk artificially. After 11, 11, 13, and 17 weeks of storage, the milk samples, which were contaminated with Pseudomonas fluorescens, Chryseobacterium carnipullorum, Lactococcus raffinolactis and Acinetobacter guillouiae, respectively, demonstrated notable whey separation. The investigation included analyzing the protein and fat content in the upper and bottom layers of the milk, as well as examining the particle size, Zeta potential, and pH in four sample groups, indicating that the stability of UHT milk decreases over time. Moreover, the spoiled milk samples exhibited a bitter taste, with the dominant odor being attributed to ketones and acids. The metabolomics analysis revealed that three key metabolic pathways, namely ABC transporters, butanoate metabolism, and alanine, aspartate, and glutamate metabolism, were found to be involved in the production of thermostable enzymes by psychrotrophic bacteria. These enzymes greatly impact the taste and nutrient content of UHT milk. This finding provides a theoretical basis for further investigation into the mechanism of spoilage.
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Affiliation(s)
- Xue Qin
- Key Laboratory of Dairy Science, Ministry of Education, College of Food Science and Engineering, Northeast Agricultural University, Harbin 150030, China; (X.Q.); (J.C.); (X.Q.); (Q.C.); (Y.J.); (X.Y.)
| | - Jingqi Cheng
- Key Laboratory of Dairy Science, Ministry of Education, College of Food Science and Engineering, Northeast Agricultural University, Harbin 150030, China; (X.Q.); (J.C.); (X.Q.); (Q.C.); (Y.J.); (X.Y.)
| | - Xuehe Qi
- Key Laboratory of Dairy Science, Ministry of Education, College of Food Science and Engineering, Northeast Agricultural University, Harbin 150030, China; (X.Q.); (J.C.); (X.Q.); (Q.C.); (Y.J.); (X.Y.)
| | - Ning Guan
- Center for Dairy Safety and Quality, National Center of Technology Innovation for Dairy, No. 1 Jinshan Road, Jinshan Development Zone, Hohhot 010110, China;
| | - Qing Chen
- Key Laboratory of Dairy Science, Ministry of Education, College of Food Science and Engineering, Northeast Agricultural University, Harbin 150030, China; (X.Q.); (J.C.); (X.Q.); (Q.C.); (Y.J.); (X.Y.)
| | - Xiaoyan Pei
- Risk Assessment Department, Inner Mongolia Yili Industrial Group Co., Ltd., No. 1 Jinshan Road, Jinshan Development Zone, Hohhot 010110, China;
| | - Yujun Jiang
- Key Laboratory of Dairy Science, Ministry of Education, College of Food Science and Engineering, Northeast Agricultural University, Harbin 150030, China; (X.Q.); (J.C.); (X.Q.); (Q.C.); (Y.J.); (X.Y.)
| | - Xinyan Yang
- Key Laboratory of Dairy Science, Ministry of Education, College of Food Science and Engineering, Northeast Agricultural University, Harbin 150030, China; (X.Q.); (J.C.); (X.Q.); (Q.C.); (Y.J.); (X.Y.)
| | - Chaoxin Man
- Key Laboratory of Dairy Science, Ministry of Education, College of Food Science and Engineering, Northeast Agricultural University, Harbin 150030, China; (X.Q.); (J.C.); (X.Q.); (Q.C.); (Y.J.); (X.Y.)
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Dacres H, Weihs F, Wang J, Anderson A, Trowell SC. Bioluminescence resonance energy transfer biosensor for measuring activity of a protease secreted by Pseudomonas fluorescens growing in milk. Anal Chim Acta 2023; 1270:341401. [PMID: 37311608 DOI: 10.1016/j.aca.2023.341401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 05/18/2023] [Accepted: 05/20/2023] [Indexed: 06/15/2023]
Abstract
Bacterial proteases are sporadic contributors to milk spoilage, reducing the quality of ultra-heat treated (UHT) milk and other dairy products. Current methods for measuring bacterial protease activity in milk are insensitive and too slow to be used in routine testing in dairy processing plants. We have designed a novel bioluminescence resonance energy transfer (BRET)-based biosensor to measure the activity of proteases secreted by bacteria in milk. The BRET-based biosensor is highly selective for bacterial protease activity compared with other proteases tested, notably including plasmin, which is abundant in milk. It incorporates a novel peptide linker that is selectively cleaved by P. fluorescens AprX proteases. The peptide linker is flanked by green fluorescent protein (GFP2) at the N-terminus and a variant Renilla luciferase (RLuc2) at the C-terminus. Complete cleavage of the linker by bacterial proteases from Pseudomonas fluorescens strain 65, leads to a 95% decrease in the BRET ratio. We applied an azocasein-based calibration method to the AprX biosensor using standard international enzyme activity units. In a 10-min assay, the detection limit for AprX protease activity in buffer was equivalent to 40 pg/mL (≈0.8 pM, 22 μU/mL) and 100 pg/mL (≈2pM, 54 μU/mL) in 50% (v/v) full fat milk. The EC50 values were 1.1 ± 0.3 ng/mL (87 μU/mL) and 6.8 ± 0.2 ng/mL (540 μU/mL), respectively. The biosensor was approximately 800x more sensitive than the established FITC-Casein method in a 2-h assay, the shortest feasible time for the latter method. The protease biosensor is sensitive and fast enough to be used in production settings. It is suitable for measuring bacterial protease activity in raw and processed milk, to inform efforts to mitigate the effects of heat-stable bacterial proteases and maximise the shelf-life of dairy products.
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Affiliation(s)
- H Dacres
- CSIRO Health & Biosecurity, Food Innovation Centre, 671 Sneydes Road, Werribee, VIC, 3030, Australia
| | - F Weihs
- PPB Technology Pty Ltd, PO Box 265, Erindale Centre, ACT, 2903, Australia; CSIRO Health & Biosecurity, Canberra, ACT, 2601, Australia.
| | - J Wang
- CSIRO Health & Biosecurity, Canberra, ACT, 2601, Australia
| | - A Anderson
- CSIRO Health & Biosecurity, Canberra, ACT, 2601, Australia
| | - S C Trowell
- PPB Technology Pty Ltd, PO Box 265, Erindale Centre, ACT, 2903, Australia; CSIRO Health & Biosecurity, Canberra, ACT, 2601, Australia
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Effect of ultra-high pressure homogenization on structural and techno-functional properties of egg yolk granule proteins. Lebensm Wiss Technol 2023. [DOI: 10.1016/j.lwt.2023.114624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
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9
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Markers and Mechanisms of Deterioration Reactions in Dairy Products. FOOD ENGINEERING REVIEWS 2023. [DOI: 10.1007/s12393-023-09331-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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10
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Zhang S, Hu L, Xue Y, Zhang D, Zhang Y, Wang S. Development of a real-time loop-mediated isothermal amplification method for monitoring Pseudomonas lurida in raw milk throughout the year of pasture. Front Microbiol 2023; 14:1133077. [PMID: 37125188 PMCID: PMC10130427 DOI: 10.3389/fmicb.2023.1133077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Accepted: 03/20/2023] [Indexed: 05/02/2023] Open
Abstract
Introduction The psychrophilic bacterium Pseudomonas lurida (P. lurida) and its thermostable alkaline proteases can seriously damage raw milk quality. Methods In this study, specific primers were designed for P. lurida's gyrB and aprX genes, and a real-time loop-mediated isothermal amplification (RealAmp) rapid detection method was developed for the early monitoring of P. lurida and its proteases in raw milk. A phylogenetic tree of the gyrB and aprX genes of P. lurida was constructed to analyze the homology of the design sequence of the RealAmp primer. The DNA of 2 strains of P. lurida and 44 strains of non-P. lurida were detected via RealAmp to analyze the specificity of the primer. Results It was found that aprX-positive proteases were produced by P. lurida-positive strains only when Pseudomonas fluorescens was negative. The dissociation temperatures of gyrB and aprX in the RealAmp-amplified products were approximately 85.0°C and 90.0°C, respectively. Moreover, DNA was detected through a 10-fold dilution of P. lurida in a pure bacterial solution and artificially contaminated skimmed milk. The limit of detection of P. lurida DNA copy number in the pure bacterial solution was 8.6 copies/μL and that in the 10% skimmed milk was 5.5 copies/μL. Further, 144 raw milk samples throughout the year from three farms in Hebei province were analyzed using RealAmp. The highest detection rate of P. lurida was 56% in the first and third quarters, and that of proteases was 36% in the second quarter. The detection rates of P. lurida and its proteases were the highest in samples collected from pasture 2 (52 and 46%, respectively), and the ability of P. lurida to produce proteases reached 88%. Discussion In conclusion, RealAmp established an early and rapid method for the detection of P. lurida and its proteases in raw milk samples, allowing the identification and control of contamination sources in a timely manner to ensure the quality of milk and dairy products.
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Affiliation(s)
- Shufei Zhang
- College of Food Science and Biology, Hebei University of Science and Technology, Shijiazhuang, Hebei, China
| | - Lianxia Hu
- College of Chemical Engineering, Shijiazhuang University, Shijiazhuang, Hebei, China
| | - Yuling Xue
- Junlebao Dairy Group Co., Ltd., Shijiazhuang, Hebei, China
| | - Dong Zhang
- Junlebao Dairy Group Co., Ltd., Shijiazhuang, Hebei, China
| | - Yaoguang Zhang
- Junlebao Dairy Group Co., Ltd., Shijiazhuang, Hebei, China
| | - Shijie Wang
- College of Food Science and Biology, Hebei University of Science and Technology, Shijiazhuang, Hebei, China
- Junlebao Dairy Group Co., Ltd., Shijiazhuang, Hebei, China
- *Correspondence: Shijie Wang,
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11
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Yang R, Lin W, Liu J, Liu H, Fu X, Liu H, Han Z, Wang L, Wang Y, Ba G. Formation mechanism and solution of Pu-erh tea cream based on non-targeted metabonomics. Lebensm Wiss Technol 2022. [DOI: 10.1016/j.lwt.2022.114331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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12
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Guo R, Ju N, Wang Y, Gou M, Li P, Luo Y. Metagenomic reveals succession in the bacterial community and predicts changes in raw milk during refrigeration. J Food Saf 2022. [DOI: 10.1111/jfs.13028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Rong Guo
- College of Food and Wine Ningxia University Yinchuan P.R. China
| | - Ning Ju
- College of Food and Wine Ningxia University Yinchuan P.R. China
| | - Yuanyuan Wang
- College of Food and Wine Ningxia University Yinchuan P.R. China
| | - Meng Gou
- College of Food and Wine Ningxia University Yinchuan P.R. China
| | - Puyu Li
- College of Food and Wine Ningxia University Yinchuan P.R. China
| | - Yulong Luo
- College of Food and Wine Ningxia University Yinchuan P.R. China
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13
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14
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Meng F, Uniacke-Lowe T, Kelly AL. Factors affecting the creaming of raw bovine milk: A comparison of natural and accelerated methods. Lebensm Wiss Technol 2022. [DOI: 10.1016/j.lwt.2022.113288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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15
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Heat-induced changes in milk fat and milk fat globules and its derived effects on acid dairy gelation – A review. Int Dairy J 2022. [DOI: 10.1016/j.idairyj.2021.105213] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Bu Y, Qiao W, Zhai Z, Liu T, Gong P, Zhang L, Hao Y, Yi H. Establishment and Evaluation of a Loop-Mediated Isothermal Amplification Assay for Rapid Detection of Pseudomonas fluorescens in Raw Milk. Front Microbiol 2022; 12:810511. [PMID: 35069513 PMCID: PMC8770903 DOI: 10.3389/fmicb.2021.810511] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Accepted: 11/22/2021] [Indexed: 01/22/2023] Open
Abstract
Raw milk is susceptible to microbial contamination during transportation and storage. Pseudomonas fluorescens producing heat-resistant enzymes have become the most common and harmful psychrophilic microorganisms in the cold chain logistics of raw milk. To rapidly detect P. fluorescens in raw milk, the protease gene aprX was selected as a detection target to construct a set of primers with strong specificity, and a loop-mediated isothermal amplification (LAMP) assay was established. The detection thresholds of the LAMP assay for pure cultured P. fluorescens and pasteurized milk were 2.57 × 102 and 3 × 102 CFU/mL, respectively. It had the advantages over conventional method of low detection threshold, strong specificity, rapid detection, and simple operation. This LAMP assay can be used for online monitoring and on-site detection of P. fluorescens in raw milk to guarantee the quality and safety of dairy products.
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Affiliation(s)
- Yushan Bu
- College of Food Science and Engineering, Ocean University of China, Qingdao, China
| | - Wenjun Qiao
- College of Food Science and Engineering, Ocean University of China, Qingdao, China
| | - Zhengyuan Zhai
- Key Laboratory of Functional Dairy, Co-constructed by Ministry of Education and Beijing Municipality, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
| | - Tongjie Liu
- College of Food Science and Engineering, Ocean University of China, Qingdao, China
| | - Pimin Gong
- College of Food Science and Engineering, Ocean University of China, Qingdao, China
| | - Lanwei Zhang
- College of Food Science and Engineering, Ocean University of China, Qingdao, China
| | - Yanling Hao
- Key Laboratory of Functional Dairy, Co-constructed by Ministry of Education and Beijing Municipality, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China.,College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
| | - Huaxi Yi
- College of Food Science and Engineering, Ocean University of China, Qingdao, China
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17
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Rodrigues RDS, Machado SG, Carvalho AFD, Nero LA. Pseudomonas sp. as the causative agent of anomalous blue discoloration in Brazilian fresh soft cheese (Minas Frescal). Int Dairy J 2021. [DOI: 10.1016/j.idairyj.2021.105020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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18
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Yang X, Wang Z, Zhang C, Wang L, Pang L, Zhang D, Man C, Jiang Y. Assessment of the production of Bacillus cereus protease and its effect on the quality of ultra-high temperature-sterilized whole milk. J Dairy Sci 2021; 104:6577-6587. [PMID: 33741157 DOI: 10.3168/jds.2020-19818] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 01/30/2021] [Indexed: 01/09/2023]
Abstract
Bacillus cereus is one of the most important spoilage microorganisms in milk. The heat-resistant protease produced is the main factor that causes rotten, bitter off-flavors and age gelation during the shelf-life of milk. In this study, 55 strains of B. cereus were evaluated, of which 25 strains with protease production ability were used to investigate proteolytic activity and protease heat resistance. The results showed that B. cereus C58 had strong protease activity, and its protease also had the highest thermal stability after heat treatment of 70°C (30 min) and 100°C (10 min). The protease was identified as protease HhoA, with a molecular mass of 43.907 kDa. The protease activity of B. cereus C58 in UHT-sterilized whole milk (UHT milk) showed an increase with the growth of bacteria, especially during the logarithmic growth phase. In addition, the UHT milk incubated with protease from B. cereus C58 at 28°C (24 h) and 10°C (6 d) were used to evaluate the effects of protease on the quality of UHT milk, including protein hydrolysis and physical stability. The results showed that the hydrolysis of casein was κ-CN, β-CN, and αS-CN successively, whereas whey protein was not hydrolyzed. The degree of protein hydrolysis, viscosity, and particle size of the UHT milk increased. The changes in protein and fat contents indicated that fat globules floated at 28°C and settled at 10°C, respectively. Meanwhile, confocal laser scanning microscopy images revealed that the protease caused the stability of UHT milk to decrease, thus forming age gelation.
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Affiliation(s)
- Xinyan Yang
- Key Laboratory of Dairy Science, Ministry of Education, Department of Food Science, Northeast Agricultural University, Harbin, 150030, China
| | - Zhenghui Wang
- Key Laboratory of Dairy Science, Ministry of Education, Department of Food Science, Northeast Agricultural University, Harbin, 150030, China
| | - Chenxi Zhang
- Key Laboratory of Dairy Science, Ministry of Education, Department of Food Science, Northeast Agricultural University, Harbin, 150030, China
| | - Lihan Wang
- Key Laboratory of Dairy Science, Ministry of Education, Department of Food Science, Northeast Agricultural University, Harbin, 150030, China
| | - Lidong Pang
- Key Laboratory of Dairy Science, Ministry of Education, Department of Food Science, Northeast Agricultural University, Harbin, 150030, China
| | - Dongyan Zhang
- Key Laboratory of Dairy Science, Ministry of Education, Department of Food Science, Northeast Agricultural University, Harbin, 150030, China
| | - Chaoxin Man
- Key Laboratory of Dairy Science, Ministry of Education, Department of Food Science, Northeast Agricultural University, Harbin, 150030, China.
| | - Yujun Jiang
- Key Laboratory of Dairy Science, Ministry of Education, Department of Food Science, Northeast Agricultural University, Harbin, 150030, China.
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19
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İnce CoŞkun AE. Phase separation behavior of whey protein isolate particle dispersions in the presence of xanthan. Turk J Chem 2021; 44:1314-1326. [PMID: 33488232 PMCID: PMC7751911 DOI: 10.3906/kim-2004-57] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 07/14/2020] [Indexed: 11/03/2022] Open
Abstract
In this study, phase separation of colloidal whey protein isolate (WPI) particle dispersions was studied using a rod-like polysaccharide xanthan. Effects of different xanthan concentration, particle volume fraction, and temperature were analyzed by visual observations, turbidity measurements, and particle mobility tracking method. Particle mobility was determined using a diffusing wave spectroscopy (DWS) set up. Xanthan concentration was kept low in order not to increase the viscosity of dispersions, so that the phase separation could be observed easily. Visual observations showed that there was a minimum concentration of xanthan to induce phase separation at a constant particle volume fraction, and xanthan concentration was found to have an important effect on the degree of phase separation. The temperature was also found to have an effect on depletion mechanism. Phase separation was mainly a result of different sizes of WPI particles, and xanthan induced the depletion interaction between WPI particles, as supported by the data obtained from DWS. The results of this study explained both the mechanism and the stability range of particle dispersions in the presence of xanthan, which is important for the design of stable systems, including colloidal particles.
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Bottiroli R, Zhang C, Aprea E, Fogliano V, Hettinga K, Gasperi F. Short communication: Short-time freezing does not alter the sensory properties or the physical stability of ultra-high-temperature hydrolyzed-lactose milk. J Dairy Sci 2020; 103:8822-8828. [PMID: 32773317 DOI: 10.3168/jds.2020-18415] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 05/18/2020] [Indexed: 11/19/2022]
Abstract
In this study, the effect of milk freezing was studied, focusing on the changes in 1% and 3% fat UHT hydrolyzed-lactose milk after slow- (-20°C) and fast-rate freezing (-80°C) for 72 h. Changes on the sensory properties were first assessed by discriminant analysis (triangle test), and then by volatile organic compounds and color analysis. The milk emulsion stability was characterized by optical centrifugation, particle size analysis, and confocal microscopy. The sensory panel was not able to distinguish the milk subjected to freezing from the control (72 h at 20°C). The volatile organic compounds and color analysis demonstrated that both freezing rates did not cause any significant changes in the milk aroma or color characteristics. The results of physical properties confirmed that short-time freezing did not lead to a distinct destabilization, except for a slight increase in the mean particle diameter at -80°C. Taking all the results together, UHT hydrolyzed-lactose milk was not significantly altered during the operation of freezing and thawing and, therefore, short-time freezing at both -20°C and -80°C can be used for milk storage without altering the product.
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Affiliation(s)
- R Bottiroli
- Department of Food Quality and Nutrition, Research and Innovation Centre, Fondazione Edmund Mach (FEM), via E. Mach 1, 38010 San Michele all'Adige, TN, Italy; Department of Agriculture and Food Science, University of Naples, Federico II, 80055 Portici, NA, Italy
| | - C Zhang
- Dairy Science and Technology Group, Wageningen University, PO Box 8129, 6700 EV Wageningen, the Netherlands
| | - E Aprea
- Department of Food Quality and Nutrition, Research and Innovation Centre, Fondazione Edmund Mach (FEM), via E. Mach 1, 38010 San Michele all'Adige, TN, Italy; Center Agriculture Food Environment, University of Trento/Fondazione Edmund Mach, via E. Mach 1, 38010 San Michele all'Adige, TN, Italy.
| | - V Fogliano
- Food Quality and Design Group, Wageningen University, PO Box 8129, 6700 EV Wageningen, the Netherlands
| | - K Hettinga
- Dairy Science and Technology Group, Wageningen University, PO Box 8129, 6700 EV Wageningen, the Netherlands
| | - F Gasperi
- Department of Food Quality and Nutrition, Research and Innovation Centre, Fondazione Edmund Mach (FEM), via E. Mach 1, 38010 San Michele all'Adige, TN, Italy; Center Agriculture Food Environment, University of Trento/Fondazione Edmund Mach, via E. Mach 1, 38010 San Michele all'Adige, TN, Italy
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