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| 3. |
- Andersson, I. M., et al.
(författare)
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Effects of feed composition, protein denaturation and storage of milk serum protein/lactose powders on rehydration properties
- 2020
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Ingår i: International Dairy Journal. - : Elsevier BV. - 0958-6946. ; 110
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Tidskriftsartikel (refereegranskat)abstract
- Whey powder rehydration is expected to be closely linked to both denaturation and lactosylation of the proteins. This study investigated the relation between the forced imbibition rate of spray-dried milk serum protein/lactose powders and the particle morphology and how it is related to the insoluble and lactosylated protein fraction, respectively. Despite extensive variation in protein denaturation, aggregation and lactosylation, only comparably small effects on the forced imbibition rate of the powders and the particle morphology could be observed. A possible explanation for this rather limited effect on the rehydration properties and particle morphology might be that the surface composition of the powder particles is rather similar and dominated by native proteins. These insights have relevance for the formulation of whey powders with improved rehydration properties.
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| 4. |
- Andersson, I. M., et al.
(författare)
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Impact of protein surface coverage and layer thickness on rehydration characteristics of milk serum protein/lactose powder particles
- 2019
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Ingår i: Colloids and Surfaces A. - : Elsevier BV. - 0927-7757 .- 1873-4359. ; 561, s. 395-404
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Tidskriftsartikel (refereegranskat)abstract
- Spray-dried powders were produced from milk serum protein concentrate and lactose in varying ratios, and the rehydration characteristics of the powders were evaluated. The dissolution rate was estimated with a flow-cell based technique, and the external and internal distribution of the powder components were evaluated with X-ray photoelectron spectroscopy and confocal Raman microscopy, respectively. The surface of the powder particles is more or less covered by a thin protein layer. A phase segregation between protein and lactose is observed in the interior of the particle resulting in a protein rich layer in the vicinity of the surface. However, the protein layer in the vicinity of the particle surface tends to become thinner as the bulk protein concentration increases in the powders (from 10 to 60% w/w). The time for the spontaneous imbibition to occur show a linear correlation with the protein surface coverage. The dissolution rate of powders containing 0.1% w/w protein is around 60 times faster than for a powder containing 1% w/w protein but the dissolution rate of powders containing 1% and 100% w/w differ only by a factor of 2. Thus, it is suggested that the outer protein layer becomes denser at the interface as the protein content increases in the powders, thereby causing poorer rehydration characteristics of the powders (especially for low protein concentrations 0.1–1% w/w). This insight has relevance for the formulation of whey protein powders with improved rehydration characteristics. © 2018 Elsevier B.V.
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| 5. |
- Andersson, I. M., et al.
(författare)
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Impact of surface properties on morphology of spray-dried milk serum protein/lactose systems
- 2018
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Ingår i: International Dairy Journal. - : Elsevier BV. - 0958-6946 .- 1879-0143. ; 85, s. 86-95
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Tidskriftsartikel (refereegranskat)abstract
- This study investigated milk serum protein concentrate/lactose systems with varying ratios and how the morphology of the spray-dried particles of these systems could be described by the surface properties of the feed as well as the protein surface coverage of the particles. An extrapolation of the surface pressure of the feed to 0.3 s, the approximate time for molecular diffusion in an atomised droplet in the spray-dryer, showed a relationship with the particle morphology. At low protein concentrations (<1%), the particles were almost totally smooth. At higher protein concentrations (≥1%), the particles became dented and ridged, and these tended to become deeper and thicker as the protein concentration increased. It is suggested that the surface pressure of the feed at low protein concentrations is the most prominent surface property, whereas the modulus of elasticity seems to be the most prominent surface property for particle surface deformation at higher protein concentrations.
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| 6. |
- Andersson, I. M., et al.
(författare)
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Particle morphology and rehydration properties of spray-dried microgels and fractal aggregates with varying fractions of native milk serum proteins
- 2021
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Ingår i: International Dairy Journal. - : Elsevier Ltd. - 0958-6946 .- 1879-0143. ; 112
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Tidskriftsartikel (refereegranskat)abstract
- To keep their functional properties, it is crucial that protein aggregates maintain their structure after spray drying and that the powders can be fully rehydrated. In this study, microgels and fractal aggregates were prepared by heating a mixture of milk serum protein concentrate and lactose (40/60; %, w/w) at 85 °C for 15 min by varying the pH. Various fractions of native proteins were added to the systems prior to spray drying. This study showed that microgels and fractal aggregates kept their structure after spray drying and reconstitution. The particle morphology could be correlated to the stiffness of the interface of the feed droplet. The forced imbibition rate showed a negative correlation with increasing amount of aggregated proteins in the powders that seems to be a result of denatured/aggregated proteins present at the surface. These findings are of importance for the formulation of spray-dried powders with improved rehydration characteristics. © 2020 The Author(s)
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| 7. |
- Duchemin, Sandrine, et al.
(författare)
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Genetic parameters for noncoagulating milk, milk coagulation properties, and detailed milk composition in Swedish Red Dairy Cattle
- 2020
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Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 103:9, s. 8330-8342
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Tidskriftsartikel (refereegranskat)abstract
- The rennet-induced coagulation ability of milk is important in cheese production. For Swedish Red Dairy Cattle (RDC), this ability is reduced because of a high prevalence of noncoagulating (NC) milk. In this study, we simultaneously combined genetic parameters for NC milk, milk coagulation properties, milk composition, physical traits, and milk protein composition. Our aim was to estimate heritability and genetic and phenotypic correlations for NC milk and 24 traits (milk coagulation properties, milk composition, physical traits, and milk protein composition). Phenotypes and ~7,000 SNP genotypes were available for all 600 Swedish RDC. The genotypes were imputed from ~7,000 SNP to 50,000 SNP. Variance components and genetic parameters were estimated with an animal model. In Swedish RDC, a moderate heritability estimate of 0.28 was found for NC milk. For the other 24 traits, heritability estimates ranged from 0.12 to 0.77 (standard errors from 0.08 to 0.18). A total of 300 phenotypic and genetic correlations were estimated. For phenotypic and genetic correlations, 172 and 95 were significant, respectively. In general, most traits showing significant genetic correlations also showed significant phenotypic correlations. In this study, phenotypic and genetic correlations with NC milk suggest that many correlations between traits exist, making it difficult to predict the real consequences on the composition of milk, if selective breeding is applied on NC milk. We speculate that some of these consequences may lead to changes in the composition of milk, most likely affecting its physical and organoleptic properties. However, our results suggest that κ-casein could be used as an indicator trait to predict the occurrence of NC milk at the herd level.
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| 8. |
- Nilsson, K., et al.
(författare)
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Effects of milk proteins and posttranslational modifications on noncoagulating milk from Swedish Red dairy cattle
- 2020
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Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 103:8, s. 6858-6868
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Tidskriftsartikel (refereegranskat)abstract
- Milk that does not coagulate after rennet addition, also called noncoagulating (NC) milk, is unwanted in cheese production due to prolonged processing time. Amounts of whey and casein proteins, genetic variants, as well as posttranslational modifications (PTM) of proteins are all contributing factors in rennet-induced coagulation of milk. In this study, we conducted a wide-ranging investigation of milk proteins in milk samples from 616 Swedish Red dairy cattle using liquid chromatography-high resolution mass spectrometry. Relative concentration of proteins, genetic variants, and PTM were compared between NC milk and coagulating milk. The PTM investigated were phosphorylation of caseins and glycosylation of κ-casein. Several genetic variants and PTM were found, including rare phosphorylation variants of the αS-caseins. Genetic variants were found to effect the expressed amount of different proteins. Further, the effect of protein amounts and PTM on a binary NC milk trait was modeled using a generalized linear model. The model showed that NC milk significantly correlated with higher relative concentrations of α-lactalbumin and β-casein and lower relative concentrations of β-lactoglobulin and κ-casein. Regarding PTM of caseins, an effect on NC milk from a lower relative concentration of αS1-casein with 8 phosphate groups were found, even though an effect from total relative concentration of αS1-casein was not found. This study has provided insights into protein variants and PTM important for NC milk to improve this undesirable property.
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| 9. |
- Edén, J., et al.
(författare)
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Native milk fat globule size and its influence on whipping properties
- 2016
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Ingår i: International Dairy Journal. - : Elsevier BV. - 0958-6946. ; 61, s. 176-181
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this study was to investigate the influence of native milk fat globule size on the aeration of high fat dairy products with regard to maximum firmness time, gas inclusion and foam stability. The results showed that whipping time to maximum firmness was inversely proportional to mean fat globule size for both unhomogenised and slightly homogenised (2 MPa) creams. Additionally, increasing native mean fat globule size of the creams resulted in increased overrun. No significant differences in serum drainage were found between creams with different native milk fat globule size. Furthermore, when creams with native large mean fat globules were homogenised, the results showed that the maximum firmness time was in accordance with the mean fat globule size of non-aggregated creams. In the present study, cream fractionation was achieved by creaming or in a cost effective and fast manner using a modified centrifugal separator.
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