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Björn Bergenståhl - One of the best experts on this subject based on the ideXlab platform.
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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.
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changes in surface composition of spray Dried Food powders due to lactose crystallization
Lwt - Food Science and Technology, 1996Co-Authors: Pia Fäldt, Björn BergenståhlAbstract:Abstract The surface composition of spray-Dried lactose-containing powders was estimated by electron spectroscopy for chemical analysis (ESCA), and particle structure was studied by scanning electron microscopy before and after storage in a humid atmosphere. The surface composition of dry powders made from lactose/sodium caseinate solutions was nearly identical to that of powders stored at 75% relative humidity for 4 d. Protein started to dominate the powder surface even when it was present at only low solution concentrations. The particle structure after storage in a humid atmosphere was completely changed even though the surface composition remained relatively unchanged. When soybean oil emulsions with sodium caseinate and lactose were spray-Dried, protein was over-represented on the powder surface. If the protein concentration was sufficiently high, the fat was almost completely encapsulated. In the case of the powders with high lactose content almost total release of encapsulated fat on the powder surface was observed after storage in a humid atmosphere. When the lactose concentration was lower, release of fat on the powder surface was less pronounced. The structure of fat-containing powders was studied by scanning electron microscopy. Before storage in a humid atmosphere, particles were discrete with smooth surfaces. As the fat was released onto the powder surface, the powder became highly agglomerated and attained a smooth structure.
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Fat encapsulation in spray-Dried Food powders
Journal of the American Oil Chemists’ Society, 1995Co-Authors: Pia Fäldt, Björn BergenståhlAbstract:The surface composition of spray-Dried sodium caseinate/lactose emulsions having different oil phases were estimated using electron spectroscopy for chemical analysis (ESCA), and the particle structure was studied using scanning electron microscopy (SEM) both before and after storage under humid conditions. After spray-drying, powders in which the oil phases consisting of fats with intermediate melting points, such as hardened coconut oil and butter fat, had the highest surface coverage of fat, approximately 34%. The powder with soybean oil as the oil phase had a surface coverage of fat of approximately 15%. The high-melting hardened rapeseed oil was almost completely encapsulated after spray-drying. After storage in a humid atmosphere, fat was released onto all the powder surfaces (surface fat after storage, between 50–65%) except for those with hardened rapeseed oil in which the fat remained encapsulated. These observations are consistent with the powder structure observed by SEM. The surface composition estimated by ESCA for spray-Dried sodium caseinate/lactose-containing emulsions with different amounts of soybean oil and a constant lactose/sodium caseinate ratio showed an almost completely encapsulated oil-phase after drying. Storage of these powders in a humid atmosphere leads to a release of fat onto the powder surface even if the soybean oil content is low (1% of the dry weight). Powders made from soybean oil emulsions with sodium caseinate alone exhibit a much lower degree of encapsulation than in the system where lactose is present.
Li Vun Chong - One of the best experts on this subject based on the ideXlab platform.
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A mathematical model of the self-heating of spray-Dried Food powders containing fat, protein, sugar and moisture
Chemical Engineering Science, 1999Co-Authors: Li Vun ChongAbstract:Spray drying is a primary process for particulate forming in the Food industry. Powders that contain fat, protein and sugar are potentially explosive. The self-heating of milk powders (as typical examples) can become a source for a fire or even dust explosion in dairy powder plants. In order to predict the heating behaviour in milk powder deposits, a mathematical model describing self-heating in low moisture solids has been developed and a numerical simulation program has been written. The program solves the mass and energy balances in the model simultaneously for the dairy powder samples. The model can be shown to be capable of adequately simulating the change in temperature as influenced by evaporation in the samples. Results of the simulation have been compared with measured data. There is good agreement between the predicted and experimental results. It is envisaged that the model will also be useful for other exothermically reactive solids.
Pia Fäldt - One of the best experts on this subject based on the ideXlab platform.
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changes in surface composition of spray Dried Food powders due to lactose crystallization
Lwt - Food Science and Technology, 1996Co-Authors: Pia Fäldt, Björn BergenståhlAbstract:Abstract The surface composition of spray-Dried lactose-containing powders was estimated by electron spectroscopy for chemical analysis (ESCA), and particle structure was studied by scanning electron microscopy before and after storage in a humid atmosphere. The surface composition of dry powders made from lactose/sodium caseinate solutions was nearly identical to that of powders stored at 75% relative humidity for 4 d. Protein started to dominate the powder surface even when it was present at only low solution concentrations. The particle structure after storage in a humid atmosphere was completely changed even though the surface composition remained relatively unchanged. When soybean oil emulsions with sodium caseinate and lactose were spray-Dried, protein was over-represented on the powder surface. If the protein concentration was sufficiently high, the fat was almost completely encapsulated. In the case of the powders with high lactose content almost total release of encapsulated fat on the powder surface was observed after storage in a humid atmosphere. When the lactose concentration was lower, release of fat on the powder surface was less pronounced. The structure of fat-containing powders was studied by scanning electron microscopy. Before storage in a humid atmosphere, particles were discrete with smooth surfaces. As the fat was released onto the powder surface, the powder became highly agglomerated and attained a smooth structure.
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Fat encapsulation in spray-Dried Food powders
Journal of the American Oil Chemists’ Society, 1995Co-Authors: Pia Fäldt, Björn BergenståhlAbstract:The surface composition of spray-Dried sodium caseinate/lactose emulsions having different oil phases were estimated using electron spectroscopy for chemical analysis (ESCA), and the particle structure was studied using scanning electron microscopy (SEM) both before and after storage under humid conditions. After spray-drying, powders in which the oil phases consisting of fats with intermediate melting points, such as hardened coconut oil and butter fat, had the highest surface coverage of fat, approximately 34%. The powder with soybean oil as the oil phase had a surface coverage of fat of approximately 15%. The high-melting hardened rapeseed oil was almost completely encapsulated after spray-drying. After storage in a humid atmosphere, fat was released onto all the powder surfaces (surface fat after storage, between 50–65%) except for those with hardened rapeseed oil in which the fat remained encapsulated. These observations are consistent with the powder structure observed by SEM. The surface composition estimated by ESCA for spray-Dried sodium caseinate/lactose-containing emulsions with different amounts of soybean oil and a constant lactose/sodium caseinate ratio showed an almost completely encapsulated oil-phase after drying. Storage of these powders in a humid atmosphere leads to a release of fat onto the powder surface even if the soybean oil content is low (1% of the dry weight). Powders made from soybean oil emulsions with sodium caseinate alone exhibit a much lower degree of encapsulation than in the system where lactose is present.
Yrjo H Roos - One of the best experts on this subject based on the ideXlab platform.
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comparison of nonenzymatic browning kinetics in spray Dried and freeze Dried carbohydrate based Food model systems
Journal of Food Science, 2006Co-Authors: Song Miao, Yrjo H RoosAbstract:ABSTRACT: Nonenzymatic browning (NEB) rates of amorphous, carbohydrate-based, freeze-Dried and spray-Dried Food model systems containing L-lysine and D-xylose as reactants (5% w/w) were investigated at different temperatures (40 °C, 50 °C, 60 °C, 70 °C, 80 °C, 90 °C). Samples were exposed to various relative vapor pressure levels (11%, 23%, and 33%) to adjust water contents. Water sorption was determined gravimetrically, and data were modeled using the Brunauer-Emmett-Teller and Guggenheim-Anderson-deBoer equations. Glass transition, Tg, was observed by differential scanning calorimetry. NEB was followed spectrophotometrically. The surface structures of freeze-Dried and spray-Dried models were observed by scanning electron microscopy. The freeze-Dried samples and the spray-Dried samples showed different surface structures and slight differences in thermal behavior. Crystallization of component sugars in the freeze-Dried samples was slightly more delayed than in spray-Dried samples. The glass transition temperatures in spray-Dried samples were higher than those of the freeze-Dried samples at the same water activity. The temperature dependence of NEB rate in both systems followed the Arrhenius kinetics, but the activation energies were different. Williams-Landel-Ferry equation could be used to model the NEB kinetics in the freeze-Dried system, but for the spray-Dried system, negative constant values were not within the allowable range.
Joanna Kroehnke - One of the best experts on this subject based on the ideXlab platform.
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Food drying enhancement by ultrasound a review
Trends in Food Science and Technology, 2016Co-Authors: Grzegorz Musielak, Dominik Mierzwa, Joanna KroehnkeAbstract:Abstract Background Drying is one of the most popular methods of preserving a wide variety of Food and agricultural products. Unfortunately, this unit operation may negatively influence product quality. Moreover, due to the high heat capacity of water, drying is usually a long-lasting and energy-intensive process, thus new drying techniques are continuously being sought. Scope and approach This review presents the current state of art in ultrasonic-assisted drying. Despite immense knowledge on the principles of ultrasound generation and action, this technology has found no practical application in industrial drying yet. In this paper we tried to find the reasons for this state of affairs. Up-to-date designs of dryers using ultrasound to enhance the drying process and the various possible mechanisms of accelerating the drying process with the application of ultrasonic waves are discussed. The influence of ultrasound on the product's quality (Dried Food) is judged and described. Key findings and conclusions The analysis of the results presented by the researchers here allows to state that applying ultrasound to drying caused a shortening of the drying time and could reduce total energy consumption. Moreover, due to the small “temperature effect”, the quality of the obtained products was noticeably better as compared to the control processes (without ultrasound enhancement). The lack of an effective technology for generating power ultrasound in air was distinguished as the primary constraint for industrial application of this technology. The necessity of conducting detailed studies on ultrasound application in drying was emphasized.
