Molecular modification associated with the heat treatment of bovine milk

Gathercole, Jessica; Reis, Marlon M.; Agnew, Michael; Humphrey, Rex; Harris, Patricia M.; Clerens, Stefan; Haigh, Brendan; Dyer, Jolon M.

doi:10.1016/j.idairyj.2017.05.008

Cited by 28 publications

(24 citation statements)

References 41 publications

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“…Proteins were extracted from this solution and the serum phase (100 µL) by shaking in 7 M urea, 2 M thiourea, 50 mM dithiothreitol, and 50 mM Tris for 18 hr at 25 °C. The proteins in the supernatant were precipitated using methanol and chloroform, resuspended in 0.1 M ammonium bicarbonate and reduced and alkylated as previously described (Gathercole et al., ).…”

Section: Methodsmentioning

confidence: 99%

“…Digestion was performed overnight at 37 °C with the addition of 5 µg of sequencing‐grade trypsin (Promega). To fractionate and remove unwanted reagents, the peptides were bound to C18 Empore disks with the first fraction eluted in 10 mM ammonium formate in 10% (v/v) acetonitrile and a second fraction eluted in 10 mM ammonium formate in 50% (v/v) acetonitrile (Gathercole et al., ). Both fractions were combined and the sample was dried.…”

Section: Methodsmentioning

confidence: 99%

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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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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

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

Self Cite

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“…Milk contains numerous lipids, such as triacylglycerols, diacylglycerides, saturated/polyunsaturated fatty acids, and phospholipids. Heat treatment, as an important step in the milk process, can induce lipid oxidation and produce free fatty acids, methyl ketones, and oxidized fatty acids, which are directly correlated with milk flavor [9,10]. In heated (at or above 72 °C) milks, some lactones, methyl ketones, and aldehydes are formed from milk fat.…”

Section: Introductionmentioning

confidence: 99%

“…Some carbonyl compounds that have also been identified in heated milk may be derived from milk fat [11]. Notably, Gathercole et al pointed out that in the presence of lipids, the concentrations of free fatty acids, methyl ketones, and oxidized fatty acids were directly related to the heat treatment temperature [9]. In addition, compared with ultra-pasteurized (UP)-treated (about 138 °C, 2 s) skim milk, UP-treated 2% fat milk had better sensory properties (overall aroma, sweetly aromatic, etc.)…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, the interaction of these milk matrices due to thermal treatment can lead to the changes in taste and aroma of milk [10,15]. This may be attributed to the fact that the lysine residues of proteins can react with the milk’s reducing carbohydrates, resulting in the so-called non-enzymatic browning or Maillard reaction during heat treatment and inducing both protein and lipid modification [9,16]. Taken together, these reactions affect the sensory properties (aroma, flavor, and appearance) of milk by heat treatment in the presence of fat.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Preheating Treatment before Defatting on the Flavor Quality of Skim Milk

Tong

Wang

et al. 2019

Molecules

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Skim milk has a poor flavor due to the lack of fat. Finding ways to improve the flavor quality of skim milk has attracted the attention of more and more researchers. The purpose of this study was to create a skim milk product with good flavor by processing. Briefly, raw milk was treated by preheating at pasteurization (85 °C, 15 s) and ultra-high temperature (UHT) instantaneous sterilization (137–141 °C, 4 s). Subsequently, the sample was centrifuged to remove fat and obtain two kinds of skim milk, namely, PSM (skim milk obtained by preheating at 85 °C, 15 s) and USM (skim milk obtained by preheating at 137–141 °C, 4 s). The results showed that the intensity of the main sensory attributes (overall liking, milk aroma, etc.) and the concentrations of the key flavor compounds (2-heptanone, 2-nonanone, decanal, hexanoic acid, etc.) were significantly higher in the USM (p < 0.05) than that of the PSM and RSM (skim milk without preheating). Principal component analysis (PCA) with E-Nose (electronic nose) showed that the RSM had significant differences in the milk aroma compared with the PSM and USM. Furthermore, it was found that there were good relationships between volatile compounds and sensory attributes by partial least squares regression (PLSR) analysis. These findings provided insights into improving the flavor quality of skim milk by preheating treatment instead of any flavor additives.

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Investigating changes of proteome in the bovine milk serum after retort processing using proteomics techniques

Wei

Kang

Liao

et al. 2021

Food Science & Nutrition

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The objective of this study was to investigate the changes of the proteins in bovine milk serum after retort processing by label‐free quantification proteomics techniques. A total of 96 and 106 proteins were quantified in control group (CG) and retort group (RG), respectively. Hierarchical clustering analysis of the identified milk serum proteins showed a decrease in the abundance of most proteins, such as serum albumin, lactoperoxidase, lactotransferrin, and complement C3, and an increase in the abundance of other proteins such as κ‐casein, lipocalin 2, and Perilipin. Student's t‐test showed 21 proteins significantly differential abundance between CG and RG (p < .05), of which intensity‐based absolute quantification (iBAQ) of five proteins decreased and iBAQ of 16 proteins increased. Bioinformatics analysis demonstrated that retort processing increased the digestibility of proteins, but this improvement was offset by a decrease in the digestibility of proteins caused by protein modification. Our results provide insight into the proteome of retort sterilized milk for the first time. Given the extremely high security of retort sterilized milk, the proteome of bovine milk serum changes after retort sterilization exposed in this study will contribute to the formula design of retort sterilized milk products.

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Molecular modification associated with the heat treatment of bovine milk

Cited by 28 publications

References 41 publications

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

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

Effect of Preheating Treatment before Defatting on the Flavor Quality of Skim Milk

Investigating changes of proteome in the bovine milk serum after retort processing using proteomics techniques

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