Protein Stability in Sterilised Milk and Milk Products

Deeth, Hilton C.; Lewis, Mary

doi:10.1007/978-1-4939-2800-2_10

Cited by 30 publications

(33 citation statements)

References 167 publications

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“…In contrast, at 37 • C, pH values decreased linearly by 0.5 units during storage from weeks 0 to 52. Our results for changes in pH corresponded with a study by Al-Saadi and Deeth [45], who stored UHT milk for 12 weeks at 5, 20, and 37 • C, and found the pH decreased from 6.6 to 6.5 when stored at 37 • C. Small changes by 0.1 pH have been reported to result in large changes in heat stability [2,40,41]. The Maillard reaction, including the development of formic acid, proceeds faster at a higher storage temperature, explaining the differences in pH between storage temperatures [45], as well as the rapid decrease in HCT during storage at elevated temperatures.…”

Section: Effect Of Storage Temperature and Storage Timesupporting

confidence: 90%

Effect of calcium, citrate and urea on the stability of ultra-high temperature treated milk: A full factorial designed study

Karlsson¹

2018

J Food Process Technol

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The composition of raw milk is important for the stability of dairy products with a long shelf-life. Based on known historical changes in raw milk composition, the aim of this study was to get a better understanding of how possible future variations in milk composition may affect the stability of dairy products. The effects of elevated calcium, citrate, and urea levels on the stability of ultra-high temperature (UHT) treated milk stored for 52 weeks at 4, 20, 30, and 37 • C were investigated by a two-level full factorial designed study with fat separation, fat adhesion, sedimentation, color, pH, ethanol stability, and heat coagulation time as response variables. The results showed that elevated level of calcium lowered the pH, resulting in sedimentation and significantly decreased stability. Elevated level of citrate was associated with color, but the stability was not improved compared to the reference UHT milk. Elevated levels of urea or interaction terms had little effect on the stability of UHT milk. Storage conditions significantly affected the stability. In conclusion, to continue produce dairy products with high stability, the dairy industry should make sure the calcium content of raw milk is not too high and that storage of the final product is appropriate.

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Section: Effect Of Storage Temperature and Storage Timesupporting

confidence: 90%

Effect of calcium, citrate and urea on the stability of ultra-high temperature treated milk: A full factorial designed study

Karlsson¹

2018

J Food Process Technol

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“…The continuum of protein dissociation and association that occurs during the storage of milk that has been treated at lower heating temperatures (i.e., at pasteurization temperature) is not fully understood, however the studies on UHT milk suggest that the continuous dissociation of caseins from the micelle and their release into the serum phase enhances the involvement of caseins in the aggregate formation (Datta & Deeth, ; Deeth & Lewis, ; Grewal et al., ). One major defect in UHT milk resulting from the casein and whey protein interactions and aggregate formation is the rise in viscosity (> 10 mPa⋅s at 20 °C) that occurs upon storage, and the formation of a three‐dimensional protein network gel, which combine to cause a loss of fluidity in UHT milk.…”

Section: Resultsmentioning

confidence: 99%

“…. the continuous dissociation of caseins from the micelle and their release into the serum phase enhances the involvement of caseins in the aggregate formation (Datta & Deeth, 2001;Deeth & Lewis, 2016;. One major defect in UHT milk resulting from the casein and whey protein interactions and aggregate formation is the rise in viscosity (> 10 mPas at 20°C) that occurs upon storage, and the formation of a three-dimensional protein network gel, which combine to cause a loss of fluidity in UHT milk.…”

Section: Food Chemistrymentioning

confidence: 99%

Changes in Milk Protein Interactions and Associated Molecular Modification Resulting from Thermal Treatments and Storage

Liu¹,

Grosvenor

et al. 2019

Journal of Food Science

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We investigated protein modifications that occur during short‐ and long‐term storage of raw, pasteurized, and ultra‐high‐temperature processed (UHT) milks using RE‐HPLC and redox proteomics. The RE‐HPLC results show that casein dissociation and whey protein/κ‐casein association occurred in both pasteurized and UHT milk. The extent of protein interactions was more pronounced in UHT milk after storage. The redox proteomics analyses show that primary structural level protein modifications were not correlated to processing type on the of day processing but did occur and increase during storage. Methionine oxidation was the most significant type of oxidative modification in all samples, particularly in the caseins. Methionine oxidation increased in the UHT‐treated milk samples with longer storage times, especially in the micelle‐phase proteins, likely due to the increasing exposure of these proteins as they migrated to the serum phase. Glycated and lactosylated early‐stage Maillard reaction products were also found after heat treatment, particularly in UHT‐treated milk, with the levels of these products maintained and generally increased with increasing storage time. Practical Application Understanding changes in protein modification during heat processing and storage of liquid milk products may help develop a model to predict the quality and shelf‐life stability of heat treated milk products.

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“…However, microbiological stability is not a guarantee that the milk will be acceptable throughout its shelf life. Storage for long periods can result in many chemical and physical changes to the milk, and some of these can results in unacceptable characteristics, or, in severe cases, abruptly end shelf life (Datta & Deeth, ; Deeth & Lewis, , ; Machado et al., ; Nieuwenhuijse & van Boekel, ; Stoeckel et al., ; Stoeckel et al., ).…”

Section: Introductionmentioning

confidence: 99%

Age Gelation, Sedimentation, and Creaming in UHT Milk: A Review

Anema

2018

Comp Rev Food Sci Food Safe

100

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Demand for ultra‐high‐temperature (UHT) milk and milk protein‐based beverages is growing. UHT milk is microbiologically stable. However, on storage, a number of chemical and physical changes occur and these can reduce the quality of the milk. These changes can be sufficiently undesirable so as to limit acceptance or shelf life of the milk. The most severe changes in UHT milk during storage are age gelation, with an irreversible three‐dimensional protein network forming throughout, excessive sedimentation with a compact layer of protein‐enriched material forming rapidly at the bottom of the pack, and creaming with excessive fat accumulating at the top. For age gelation, it is known that at least two mechanisms can lead to gelation during storage. One mechanism involves proteolytic degradation of the proteins through heat‐stable indigenous or exogenous enzymes, destabilizing milk and ultimately forming a gel. The other mechanism is referred to as a physico‐chemical mechanism. Several factors are known to affect the physico‐chemical age gelation, such as milk/protein concentration, heat load during processing (direct compared with indirect UHT processes), and milk composition. Similar factors to age gelation are known to affect sedimentation. There are relatively few studies on the creaming of UHT milk during storage, suggesting that this defect is less common or less detrimental compared with gelation and sedimentation. This review focuses on the current state of knowledge of age gelation, sedimentation, and creaming of UHT milks during storage, providing a critical evaluation of the available literature and, based on this, mechanisms for age gelation and sedimentation are proposed.

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Protein Stability in Sterilised Milk and Milk Products

Cited by 30 publications

References 167 publications

Effect of calcium, citrate and urea on the stability of ultra-high temperature treated milk: A full factorial designed study

Effect of calcium, citrate and urea on the stability of ultra-high temperature treated milk: A full factorial designed study

Changes in Milk Protein Interactions and Associated Molecular Modification Resulting from Thermal Treatments and Storage

Age Gelation, Sedimentation, and Creaming in UHT Milk: A Review

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