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Esther H.-J. Kim - One of the best experts on this subject based on the ideXlab platform.
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Surface composition of industrial spray-Dried Milk powders. 2. Effects of spray drying conditions on the surface composition.
Journal of Food Engineering, 2009Co-Authors: Esther H.-J. Kim, Xiao Dong Chen, David L. PearceAbstract:The effects of various spray drying conditions (feed solids content, drying temperature, degree of homogenization and initial droplet size) on the surface composition of industrial spray-Dried Milk powders (skim Milk powder and whole Milk powder) were investigated. Experiments were performed in a laboratory-scale spray drier and the surface compositions of the powders were measured using electron spectroscopy for chemical analysis (ESCA). For whole Milk powder, the amount of surface free-fat was also measured as a complement to the surface composition estimated using ESCA. For both skim Milk powder and whole Milk powder, the surface composition of the powders was found to be determined to a large extent by the spray drying conditions employed. At higher feed solids content or drying temperature, less fat and protein appeared on the surface of the powders. Less redistribution of components seemed to occur within the drying droplet because of high viscosity and rapid crust formation. Increasing the number of homogenization passes reduced the fat globule size and consequently the amount of fat present on the powder surface. The initial droplet size did not have a significant effect on the range of particle sizes studied in this work. Strong interaction effects between the spray drying conditions were also found. The results suggest that a combination of spray drying conditions is necessary to control the surface composition of Milk powders. Possible mechanisms behind the formation of the surface composition of industrial spray-Dried Milk powders were proposed based on the findings in this work and theoretical considerations.
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Surface composition of industrial spray-Dried Milk powders. 3. Changes in the surface composition during long-term storage
Journal of Food Engineering, 2009Co-Authors: Esther H.-J. Kim, David PearceAbstract:The changes in the surface composition of industrial spray-Dried Milk powders (skim Milk powder, whole Milk powder and cream powder) during long-term storage were investigated. The powders were stored in the conditions, which are more likely for commercial circumstances, for 6 months and the surface composition of the powders was analyzed before and after storage using electron spectroscopy for chemical analysis (ESCA). For the fat-containing powders (whole Milk powder and cream powder), the various Milk fat fractions (surface free-fat, inner free-fat and encapsulated fat) were also extracted before and after storage, and analyzed for their fatty acid and triglyceride compositions to evaluate whether there was a release of fat onto the powder surface during storage and if this causes changes in the melting characteristics of the fat present on the powder surface. The structure of the powders and the physical state of the lactose present in the powder were studied before and after storage by scanning electron microscopy (SEM) and X-ray diffractometer (XRD), respectively. The results showed that the lactose present in the powders remained in the amorphous state over the storage, and therefore no significant changes in structure and surface composition of the powders occurred. However, a release of encapsulated low-melting triglycerides towards the surface of powder during storage was observed in the fat-containing powders, thereby the melting points of the surface free-fat and the inner free-fat were lowered. This phenomenon was observed in both whole Milk powder and cream powder, but more significant changes were observed in CP.
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Surface composition of industrial spray-Dried Milk powders. 1. Development of surface composition during manufacture
Journal of Food Engineering, 2009Co-Authors: Esther H.-J. Kim, David PearceAbstract:Development of the surface composition of Milk powders during manufacture was investigated in three industrial spray-Dried Milk powders (skim Milk powder, whole Milk powder and instant whole Milk powder). Samples were obtained from commercial production plants and were collected at different manufacturing stages. As the powder properties of Milk powder are defined in spray-drying and the subsequent manufacturing processes, the powder samples were collected at the exit of the spray drying chamber and the exit(s) of the fluidized bed(s), and the surface compositions of the powder samples collected were studied using electron spectroscopy for chemical analysis (ESCA). For all three industrial spray-Dried Milk powders, no significant differences in surface composition were observed between the samples collected at different manufacturing stages, except for a slight increase (3%) in the surface fat coverage for whole Milk powder after the fluidized bed drying process. These results indicate that the surface composition of Milk powders is determined to a large extent during the spray drying process and that the subsequent fluidized bed drying and handling processes have no or little effect on the surface composition of Milk powders, even though these processes affect the final powder quality (e.g. moisture content, particle size). For whole Milk powder and instant whole Milk powder, no fat appeared to leak out on to the powder surface during the fluidized bed drying process; however, the fat present on the powder surface after the spray-drying process appeared to flow over the particle surfaces, resulting in a slight increase in the surface fat coverage. After lecithin treatment (instantization), because a mixture of lecithin and anhydrous Milk fat was sprayed on the powder, a slight increase in the thickness of the surface fat layer was observed.
David Pearce - One of the best experts on this subject based on the ideXlab platform.
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Surface composition of industrial spray-Dried Milk powders. 3. Changes in the surface composition during long-term storage
Journal of Food Engineering, 2009Co-Authors: Esther H.-J. Kim, David PearceAbstract:The changes in the surface composition of industrial spray-Dried Milk powders (skim Milk powder, whole Milk powder and cream powder) during long-term storage were investigated. The powders were stored in the conditions, which are more likely for commercial circumstances, for 6 months and the surface composition of the powders was analyzed before and after storage using electron spectroscopy for chemical analysis (ESCA). For the fat-containing powders (whole Milk powder and cream powder), the various Milk fat fractions (surface free-fat, inner free-fat and encapsulated fat) were also extracted before and after storage, and analyzed for their fatty acid and triglyceride compositions to evaluate whether there was a release of fat onto the powder surface during storage and if this causes changes in the melting characteristics of the fat present on the powder surface. The structure of the powders and the physical state of the lactose present in the powder were studied before and after storage by scanning electron microscopy (SEM) and X-ray diffractometer (XRD), respectively. The results showed that the lactose present in the powders remained in the amorphous state over the storage, and therefore no significant changes in structure and surface composition of the powders occurred. However, a release of encapsulated low-melting triglycerides towards the surface of powder during storage was observed in the fat-containing powders, thereby the melting points of the surface free-fat and the inner free-fat were lowered. This phenomenon was observed in both whole Milk powder and cream powder, but more significant changes were observed in CP.
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Surface composition of industrial spray-Dried Milk powders. 1. Development of surface composition during manufacture
Journal of Food Engineering, 2009Co-Authors: Esther H.-J. Kim, David PearceAbstract:Development of the surface composition of Milk powders during manufacture was investigated in three industrial spray-Dried Milk powders (skim Milk powder, whole Milk powder and instant whole Milk powder). Samples were obtained from commercial production plants and were collected at different manufacturing stages. As the powder properties of Milk powder are defined in spray-drying and the subsequent manufacturing processes, the powder samples were collected at the exit of the spray drying chamber and the exit(s) of the fluidized bed(s), and the surface compositions of the powder samples collected were studied using electron spectroscopy for chemical analysis (ESCA). For all three industrial spray-Dried Milk powders, no significant differences in surface composition were observed between the samples collected at different manufacturing stages, except for a slight increase (3%) in the surface fat coverage for whole Milk powder after the fluidized bed drying process. These results indicate that the surface composition of Milk powders is determined to a large extent during the spray drying process and that the subsequent fluidized bed drying and handling processes have no or little effect on the surface composition of Milk powders, even though these processes affect the final powder quality (e.g. moisture content, particle size). For whole Milk powder and instant whole Milk powder, no fat appeared to leak out on to the powder surface during the fluidized bed drying process; however, the fat present on the powder surface after the spray-drying process appeared to flow over the particle surfaces, resulting in a slight increase in the surface fat coverage. After lecithin treatment (instantization), because a mixture of lecithin and anhydrous Milk fat was sprayed on the powder, a slight increase in the thickness of the surface fat layer was observed.
Björn Bergenståhl - One of the best experts on this subject based on the ideXlab platform.
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impact of surface properties on morphology of spray Dried Milk serum protein lactose systems
International Dairy Journal, 2018Co-Authors: I M Andersson, Anna Millqvistfureby, Maria Glantz, M Alexander, Marie Paulsson, Björn BergenståhlAbstract: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. (Less)
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surface composition of spray Dried Milk protein stabilised emulsions in relation to pre heat treatment of proteins
Colloids and Surfaces B: Biointerfaces, 2001Co-Authors: Anna Millqvistfureby, Ulla M Elofsson, Björn BergenståhlAbstract:Abstract Several important technical properties of spray-Dried food powders depend on particle–liquid interactions (e.g. wettability, dispersability) and particle–particle interactions (e.g. flowability). It can be assumed that the chemical composition of the surface layer of the particles to a large extent determine these properties. The present study has been aimed to investigate the relation between the surface composition of spray-Dried Milk protein-stabilised emulsions and pre-heat treatment of the proteins. Solutions of WPC were heat-treated at low (60–90°C) and high (140°C) temperature and the degree of denaturation was determined, prior to the preparation of emulsions with rapeseed oil. The surface composition of the dry powders were established by using ESCA (electron spectroscopy of chemical analysis). The emulsions were characterised by droplet size distribution before spray drying and after dissolution of the powders. Also free fat extractions and estimations of wettability (dissolution rates) were performed. The powder surface coverage of protein decreased with increasing degree of protein denaturation before the emulsification, whereas the emulsion droplet size increased both before spray drying and after reconstitution of powders. The free fat extraction as well as the dissolution rate, whereof the latter decreased with increasing surface fat coverage, correlated well with the fat coverage of the powder surface.
Cordelia Selomulya - One of the best experts on this subject based on the ideXlab platform.
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reduction of surface fat formation on spray Dried Milk powders through emulsion stabilization with λ carrageenan
Food Hydrocolloids, 2017Co-Authors: Martin Foerster, Thomas R Gengenbach, Meng Wai Woo, Chang Liu, Cordelia SelomulyaAbstract:The appearance of surface fat during the atomization process in spray drying of Milk particles often impairs the functional powder properties. To investigate a possible approach that could minimise the surface fat formation, the interaction between a whole Milk model emulsion and λ-carrageenan at various concentrations was studied, as well as how it influences the atomization behaviour and the resulting particle characteristics. Carrageenan can stabilize emulsions in the presence of Milk protein by adsorption on the Milk fat globule membranes. If too little or too much of the polysaccharide was added, bridging flocculation or depletion flocculation, respectively, occurred inside the emulsions. The best stability and minimal fat globule size were obtained for a carrageenan content of 0.3% w/w. Rheological investigation indicated that the extensional viscosity can be an important factor influencing the emulsion disintegration behaviour during atomization. The λ-carrageenan stabilized emulsions featured a significantly increased extensional viscosity and a better fat encapsulation in the corresponding spray-Dried particles, promoting solubility and oxidative stability. Surface fat extraction showed that the most stable emulsion lead to particles with the least amount of surface fat. Though the surface of these particles was still covered by fat according to spectroscopic analysis, this surface fat layer was very thin in comparison to carrageenan-free powder as observed by confocal microscopy. Yet, the addition of carrageenan was also found to have one adverse effect on the intended powder properties, as the strengthened emulsion network translated into denser particles and thus a deterioration of the powder's reconstitution behaviour.
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the impact of atomization on the surface composition of spray Dried Milk droplets
Colloids and Surfaces B: Biointerfaces, 2016Co-Authors: Martin Foerster, Thomas R Gengenbach, Meng Wai Woo, Cordelia SelomulyaAbstract:The dominant presence of fat at the surface of spray-Dried Milk powders has been widely reported in the literature and described as resulting in unfavourable powder properties. The mechanism(s) causing this phenomenon are yet to be clearly identified. A systematic investigation of the component distribution in atomized droplets and spray-Dried particles consisting of model Milk systems with different fat contents demonstrated that atomization strongly influences the final surface composition. Cryogenic flash-freezing of uniform droplets from a microfluidic jet nozzle directly after atomization helped to distinguish the influence of the atomization stage from the drying stage. It was confirmed that the overrepresentation of fat on the surface is independent of the atomization technique, including a pressure-swirl single-fluid spray nozzle and a pilot-scale rotary disk spray dryer commonly used in industry. It is proposed that during the atomization stage a disintegration mechanism along the oil-water interface of the fat globules causes the surface predominance of fat. X-ray photoelectron spectroscopic measurements detected the outermost fat layer and some adjacent protein present on both atomized droplets and spray-Dried particles. Confocal laser scanning microscopy gave a qualitative insight into the protein and fat distribution throughout the cross-sections, and confirmed the presence of a fat film along the particle surface. The film remained on the surface in the subsequent drying stage, while protein accumulated underneath, driven by diffusion. The results demonstrated that atomization induces component segregation and fat-rich surfaces in spray-Dried Milk powders, and thus these cannot be prevented by adjusting the spray drying conditions.
Germano Mucchetti - One of the best experts on this subject based on the ideXlab platform.
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Physical characterization of whole and skim Dried Milk powders
Journal of Food Science and Technology-mysore, 2017Co-Authors: Alessandro Pugliese, Emma Chiavaro, Maria Paciulli, Eleonora Carini, Giovanni Cabassi, Germano MucchettiAbstract:The lack of updated knowledge about the physical properties of Milk powders aimed us to evaluate selected physical properties (water activity, particle size, density, flowability, solubility and colour) of eleven skim and whole Milk powders produced in Europe. These physical properties are crucial both for the management of Milk powder during the final steps of the drying process, and for their use as food ingredients. In general, except for the values of water activity, the physical properties of skim and whole Milk powders are very different. Particle sizes of the spray-Dried skim Milk powders, measured as volume and surface mean diameter were significantly lower than that of the whole Milk powders, while the roller Dried sample showed the largest particle size. For all the samples the size distribution was quite narrow, with a span value less than 2. The loose density of skim Milk powders was significantly higher than whole Milk powders (541.36 vs 449.75 kg/m3). Flowability, measured by Hausner ratio and Carr’s index indicators, ranged from passable to poor when evaluated according to pharmaceutical criteria. The insolubility index of the spray-Dried skim and whole Milk powders, measured as weight of the sediment (from 0.5 to 34.8 mg), allowed a good discrimination of the samples. Colour analysis underlined the relevant contribution of fat content and particle size, resulted in higher lightness (L*) for skim Milk powder than whole Milk powder, which, on the other hand, showed higher yellowness (b*) and lower greenness (−a*). In conclusion a detailed knowledge of functional properties of Milk powders may allow the dairy to tailor the products to the user and help the food processor to perform a targeted choice according to the intended use.
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characterization of commercial Dried Milk and some of its derivatives by differential scanning calorimetry
Journal of Thermal Analysis and Calorimetry, 2016Co-Authors: Alessandro Pugliese, Emma Chiavaro, Maria Paciulli, Germano MucchettiAbstract:The comprehension of the thermal phenomena of Milk powders is still object of investigation, being the result of complex interactions among their components as affected by composition, storage conditions and manufacturing. For a better understanding of the above-mentioned phenomena, the effect of the single Milk component (proteins, casein, whey proteins and lactose) on the thermal behavior of whole and skim Milk powders was investigated by means of DSC during heating. Whole Milk powders exhibited two endothermic transitions related to the fat crystal melting at temperatures between 276 and 325 K. Glass transitions of lactose (309 K) and caseins (347–358 K) with their enthalpy relaxation phenomena were observed in the Milk derivatives, being instead highly influenced from a w and composition in the Dried Milk. At higher temperature (353–473 K), different exothermic events, such as lactose crystallization, Maillard reaction and/or decomposition of carbohydrates and proteins, were recognized in the curves of Milk and protein derivatives powders. A good explanation of the thermal properties of the Milk powders was obtained from the comparison with the heating curves of the single components. Lactose resulted the key component of many thermal events, being the molecule more influenced by the environmental conditions. These results can lead to a better comprehension of the physical properties of the Milk powders, fundamental for their functional and commercial quality.
