| 1. |
- Börjesson, Erik, et al.
(författare)
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The dissolution behavior of individual powder particles
- 2013
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Ingår i: Dairy Science & Technology. - : Springer Science and Business Media LLC. - 1958-5586 .- 1958-5594. ; 93:4-5, s. 357-371
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Tidskriftsartikel (refereegranskat)abstract
- The formation of lumps is a common problem during powder reconstitution in food industry. If more knowledge regarding the phenomena controlling the process could be obtained, the process of industrial powder recombination could be optimized. This demands investigation of the process at three different levels: the scale of individual powder particles, the scale of powder beds, and the scale of industrial recombination. If knowledge from all three scales could be combined, a model of the entire process could be constructed. In this study, we present a new flow-cell-based method for investigating the dissolution rate of individual powder particles in controlled liquid flow. The flow cell allows for alteration of the flow velocity and only subjects the investigated powder particles to mild stress before the analysis. The dissolution process in the cell is recorded, and data are obtained by image analysis. Sodium caseinate has been used as a model substance in these experiments. The results show that the particle dissolution rate is a function of the flow velocity of the liquid, and the results correspond to earlier established methods. The investigation of individual particles shows a variation in dissolution rate between particles resulting from the diverse particle morphology from an industrial batch of powder. The results indicate that the dissolution interface concentration of dissolving sodium caseinate particles corresponds well to the overlap concentration of the specie.
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| 2. |
- Hunt, Karen, et al.
(författare)
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Classical enterotoxins of coagulase-positive Staphylococcus aureus isolates from raw milk and products for raw milk cheese production in Ireland
- 2012
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Ingår i: Dairy Science & Technology. - : Springer Science and Business Media LLC. - 1958-5586 .- 1958-5594. ; 92:5, s. 487-499
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Tidskriftsartikel (refereegranskat)abstract
- Toxin-producing Staphylococcus aureus can be present in raw milk and therefore in cheese made from raw milk. To determine the number and type of toxin producers in raw milk used for raw milk cheese production in Ireland, 117 samples of raw milk and related products from five raw milk suppliers, to four raw milk cheesemakers in the South of Ireland, were analysed for coagulase positive S. aureus. Enumeration, using ISO 688-2 and plating on Baird Parker Rabbit Plasma Fibrinogen selective agar showed samples were within limits set by EC regulations. Isolates (151 from 81 positive samples) were characterised for production of staphylococcal enterotoxins (SEs) SEA, SEB, SEC and SED by reverse passive latex agglutination (SET-RPLA) and by multiplex polymerase chain reaction for the sea, seb, sec, sed and see genes. The results showed 83.2% of the isolates did not contain the se genes or the toxin producing capability tested for. From only one supplier, 26 isolates contained the sec gene and produced SEC. Within these 26 isolates, there were only two PFGE types. One SEC-producing isolate showed no toxin production when grown in sterile 10% reconstituted skim milk at 10 degrees C and 12 degrees C for 96 and 74 h, respectively. Low concentrations of SEC were produced at 14 degrees C and 16 degrees C after 74 and 55 h, respectively. The results of this survey indicate that milk used for raw milk cheese production in Ireland poses a limited risk to public health, although further studies on occurrence of toxin producing S. aureus should be undertaken.
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| 3. |
- Lenton, Samuel, et al.
(författare)
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A review of the biology of calcium phosphate sequestration with special reference to milk.
- 2015
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Ingår i: Dairy Science & Technology. - : Springer Science and Business Media LLC. - 1958-5586 .- 1958-5594. ; 95:1, s. 3-14
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Forskningsöversikt (refereegranskat)abstract
- In milk, a stable fluid is formed in which sequestered nanoclusters of calcium phosphate are substructures in casein micelles. As a result, calcium and phosphate concentrations in milk can be far in excess of their solubility. Variations of calcium, phosphate and casein concentrations in milks, both within and among species, are mainly due to the formation of the nanocluster complexes. Caseins evolved from tooth and bone proteins well before the evolution of lactation. It has therefore been suggested that the role of caseins in milk is an adaptation of an antecedent function in the control of some aspect of biomineralisation. There is new evidence that nanocluster-type complexes are also present in blood serum and, by implication, in many other closely related biofluids. Because such fluids are stable but nevertheless supersaturated with respect to the bone and tooth mineral hydroxyapatite, they allow soft and mineralised tissues to co-exist in the same organism with relative ease. An appreciable concentration of nanocluster complexes exists in fresh saliva. Such saliva may stabilise tooth mineral and help to repair demineralised lesions. In the extracellular matrix of bone, nanocluster complexes may be involved in directing the amorphous calcium phosphate to intrafibrillar spaces in collagen where they can mature into oriented apatite crystals. Thus, evidence is accumulating that calcium phosphate sequestration by phosphopeptides to form equilibrium complexes, first observed in milk, is more generally important in the control of physiological calcification.
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| 4. |
- Wedholm, Anna, et al.
(författare)
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Different proteomic profiles of sweet whey and rennet casein obtained after preparation from raw versus heat-treated skimmed milk
- 2010
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Ingår i: Dairy Science and Technology. - : Springer Science and Business Media LLC. - 1958-5586 .- 1958-5594. ; 90, s. 641-656
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Tidskriftsartikel (refereegranskat)abstract
- Proteomic profiles of sweet whey and rennet casein fractions prepared from raw or pasteurised (72 degrees C for 15 s), skimmed milk were studied by proteomics coupled with the detection of protein spots by MALDI TOF mass spectrometry Proteins were analysed by a modification of the traditional two-dimensional gel electrophoresis (2-DGE) method under non-reducing running conditions, which potentially permits the visualisation of disulphide-linked potent complexes formed in response to pasteurisation Separated proteins were stained with Coomassie blue The relative spot volumes obtained after 2-DGE of fractions from raw or pasteurised milk were compared A number of different spots in the rennet casein and sweet whey fractions were found to vary in response to pasteurisation Some of these represented higher molecular mass complexes that increased in the chymosin-precipitated casein fraction, and they were identified by mass spectrometry to contain alpha(si)-casein Certain fragments of asi-casein probably generated as a result of chymosin cleavage, increased in the whey after pasteurisation The whey content of proteose peptone component 3 (PP3) or lactophorin decreased after pasteurisation which could indicate increased association of PP3 with for example the milk fat globule membrane after pasteurisation This shows that gel-based proteome analysis can be used in the characterisation of subtle variations in protein composition of milk fractions that occur as a consequence of pasteurisation
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