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Objective: This paper investigates the critical role of material thickness in freeze-dried pellets for enhancing the storage stability of encapsulated bacteria. Freeze dried material of varying thicknesses obtained from different annealing durations is quantified using Scanning Electron Microscopy (SEM) and X-ray microtomography (μCT), the material thickness is then correlated to the storage stability of the encapsulated cells.A formulation comprising of sucrose, maltodextrin, and probiotic cells is quenched in liquid nitrogen to form pellets. The pellets undergo different durations of annealing before undergoing freeze-drying. The material thickness is quantified using SEM and μCT. Storage stability in both oxygen-rich and oxygen-poor environments is evaluated by measuring CFU counts and correlated with the pellet structure.The varying annealing protocols produce a range of material thicknesses, with more extensive annealing resulting in thicker materials. Storage stability exhibits a positive correlation with material thickness, indicating improved stability with thicker materials. Non-annealed pellets exhibit structural irregularities and inconsistent storage stability, highlighting the impracticality of avoiding annealing in the freeze-drying process.Extensive annealing not only enhances the storage stability of probiotic products but also provides greater control over the freeze-drying process, ensuring homogeneous and reproducible products. This study underscores the importance of material thickness in freeze-dried pellets for optimizing storage stability for probiotic formulations, and emphasize the necessity of annealing as a critical step in freeze-drying quenched pellets to achieve desired structural and stability outcomes.Methods: This paper investigates the critical role of material thickness in freeze-dried pellets for enhancing the storage stability of encapsulated bacteria. Freeze dried material of varying thicknesses obtained from different annealing durations is quantified using Scanning Electron Microscopy (SEM) and X-ray microtomography (μCT), the material thickness is then correlated to the storage stability of the encapsulated cells.A formulation comprising of sucrose, maltodextrin, and probiotic cells is quenched in liquid nitrogen to form pellets. The pellets undergo different durations of annealing before undergoing freeze-drying. The material thickness is quantified using SEM and μCT. Storage stability in both oxygen-rich and oxygen-poor environments is evaluated by measuring CFU counts and correlated with the pellet structure.The varying annealing protocols produce a range of material thicknesses, with more extensive annealing resulting in thicker materials. Storage stability exhibits a positive correlation with material thickness, indicating improved stability with thicker materials. Non-annealed pellets exhibit structural irregularities and inconsistent storage stability, highlighting the impracticality of avoiding annealing in the freeze-drying process.Extensive annealing not only enhances the storage stability of probiotic products but also provides greater control over the freeze-drying process, ensuring homogeneous and reproducible products. This study underscores the importance of material thickness in freeze-dried pellets for optimizing storage stability for probiotic formulations, and emphasize the necessity of annealing as a critical step in freeze-drying quenched pellets to achieve desired structural and stability outcomes.Results: This paper investigates the critical role of material thickness in freeze-dried pellets for enhancing the storage stability of encapsulated bacteria. Freeze dried material of varying thicknesses obtained from different annealing durations is quantified using Scanning Electron Microscopy (SEM) and X-ray microtomography (μCT), the material thickness is then correlated to the storage stability of the encapsulated cells.A formulation comprising of sucrose, maltodextrin, and probiotic cells is quenched in liquid nitrogen to form pellets. The pellets undergo different durations of annealing before undergoing freeze-drying. The material thickness is quantified using SEM and μCT. Storage stability in both oxygen-rich and oxygen-poor environments is evaluated by measuring CFU counts and correlated with the pellet structure.The varying annealing protocols produce a range of material thicknesses, with more extensive annealing resulting in thicker materials. Storage stability exhibits a positive correlation with material thickness, indicating improved stability with thicker materials. Non-annealed pellets exhibit structural irregularities and inconsistent storage stability, highlighting the impracticality of avoiding annealing in the freeze-drying process.Extensive annealing not only enhances the storage stability of probiotic products but also provides greater control over the freeze-drying process, ensuring homogeneous and reproducible products. This study underscores the importance of material thickness in freeze-dried pellets for optimizing storage stability for probiotic formulations, and emphasize the necessity of annealing as a critical step in freeze-drying quenched pellets to achieve desired structural and stability outcomes.Conclusions: This paper investigates the critical role of material thickness in freeze-dried pellets for enhancing the storage stability of encapsulated bacteria. Freeze dried material of varying thicknesses obtained from different annealing durations is quantified using Scanning Electron Microscopy (SEM) and X-ray microtomography (μCT), the material thickness is then correlated to the storage stability of the encapsulated cells.A formulation comprising of sucrose, maltodextrin, and probiotic cells is quenched in liquid nitrogen to form pellets. The pellets undergo different durations of annealing before undergoing freeze-drying. The material thickness is quantified using SEM and μCT. Storage stability in both oxygen-rich and oxygen-poor environments is evaluated by measuring CFU counts and correlated with the pellet structure.The varying annealing protocols produce a range of material thicknesses, with more extensive annealing resulting in thicker materials. Storage stability exhibits a positive correlation with material thickness, indicating improved stability with thicker materials. Non-annealed pellets exhibit structural irregularities and inconsistent storage stability, highlighting the impracticality of avoiding annealing in the freeze-drying process.Extensive annealing not only enhances the storage stability of probiotic products but also provides greater control over the freeze-drying process, ensuring homogeneous and reproducible products. This study underscores the importance of material thickness in freeze-dried pellets for optimizing storage stability for probiotic formulations, and emphasize the necessity of annealing as a critical step in freeze-drying quenched pellets to achieve desired structural and stability outcomes. [ABSTRACT FROM AUTHOR]

Summary: During whey powder production, the feed is subjected to several heat treatments which can cause lactosylation of proteins. In this study, lactosylation of whey proteins was evaluated in spray‐dried powders before and after storage by varying the native protein fraction as well as the serum protein/lactose ratio in the powders. The lactosylation of native α‐lactalbumin and β‐lactoglobulin in the powders before storage was not affected to a large extent by the protein denaturation or if the feed had been heat treated in a high or low lactose environment. After storage (relative humidity of 23.5%, 30 °C, 25 days), the kinetic of lactosylation tended to increase with increasing native protein fraction and bulk protein content in the powders. An explanation could be that proteins dissolved in the lactose glassy structure might have a lower reactivity, while proteins present in the protein glassy structure with dissolved lactose may display higher lactosylation reactivity. [ABSTRACT FROM AUTHOR]

The structure of a freeze-dried material is essential for its ability to preserve and protect biologics such as proteins, cells and other sensitive structures. The structure of a typical freeze-dried matrix can be described as pores surrounded by thin walls where the walls are the encapsulating material (for e.g. cells). The objective of this investigation is to evaluate X-ray microtomography (µCT) as a characterization method to quantifying the matrix of a freeze dried material, and compare it to scanning electron microscopy (SEM). The material consists of maltodextrin, freeze-dried below or above the glass transition temperature of the maximal freeze concentration ( T g ′) and after applying annealing. The SEM images have high resolution and provide an excellent view of the sample. However, it is challenging to perform any image analysis and to ensure that a representative section is presented. The µCT images provide a rather uniform contrast between material and void, allowing for a simple grey-level thresholding when separating structure from the background. A robust image analysis procedure allows the results extracted from a representative sample volume to be evaluated. Further image analysis has been focused on understanding the thickness of the encapsulating structures by estimations of volume-weighted averages of inscribed spheres within the walls. The results show two types of structures: A large pore structure of around 20–100 µm separated by thin walls around 2–3 µm thick, and a finer structure consisting of smaller pockets of air (< 10 µm) packed in a honeycomb like structure. The structures of the samples dried below and above T g ′ have smaller and thinner structures, while material dried after annealing has larger and thicker structures. The structures display comparably small differences between the different drying protocols despite the quite different drying conditions. [Display omitted] • Wall thickness of freeze dried material can be a relevant factor when large biological bodies needs to be encapsulated. • It is possible to use X-ray µCT for characterizing and quantifying the wall thickness of freeze-dried materials. • The annealing procedure provides a structure with larger chambers and thicker wall material. • The wall thickness can be determined both by the measured wall thickness and re-estimated based on the chamber size. • The thickness of the materials are similar despite the very different drying conditions. [ABSTRACT FROM AUTHOR]

In this paper, we investigate whether dissolution in water under autoclaving conditions (140 °C, 20 min) or in dimethyl sulfoxide, DMSO (100 °C, 1 h), is preferable for characterization of amylose. Two types of amylose, potato and maize, were dissolved either in water using an autoclave or in DMSO. On the aqueous solutions obtained, the extent of molecular dissolution of the sample (referred to as the dissolution yield) was determined by enzymatic analysis as well as the molecular properties, such as molar mass and root-mean-square radius, obtained with asymmetrical flow field-flow fractionation coupled to multi-angle light scattering and differential refractive index detection (AF4-MALS-dRI). The results showed that both dissolution methods are efficient at dissolving amylose. However, AF4-MALS-dRI analysis revealed substantial differences. Amylose aqueous solutions obtained by dissolution in DMSO were relatively stable over time, but the dissolution method in autoclave caused some degradation of the molecules, and their solutions display a high tendency to retrograde. [ABSTRACT FROM AUTHOR]

We have investigated methods of starch dissolution with the aim of finding an optimum method to completely dissolve starch granules to form a molecularly dissolved starch solution without degradation of the polymers. Glycogen was used as a model molecule for amylopectin, to identify the dissolution conditions under which the degradation of the polymers was limited or not present. Dissolution was performed in water with temperatures up to 200 °C, facilitated by the use of heating in an autoclave or a microwave oven, or in dimethyl sulfoxide (DMSO) at 100 °C. Waxy maize starch was chosen due to its high content of amylopectin and very low content of amylose. The degree of starch dissolution under different conditions was determined enzymatically. The effect of different dissolution conditions on the molar mass and root-mean-square radius of the polymers was determined with asymmetrical flow field-flow fractionation coupled to multi-angle light scattering and differential refractive index (AF4-MALS-dRI) detectors under aqueous conditions. The results suggest that reliable and accurate size separation and characterization of amylopectin can be obtained by dissolution of starch granules in an aqueous environment at 140 °C by autoclaving or in DMSO at 100 °C. The results also clearly show an upper limit for heat treatment of starch, above which degradation cannot be avoided. [ABSTRACT FROM AUTHOR]

Abstract: Parsnip (Pastinaca sativa) suspensions, at concentrations corresponding to a dilute and concentrated regime, were subjected to pasteurization, and heat treatments that favored β-elimination reactions and pectin methyl esterase activity. The different heat treatments were combined with homogenization. Physicochemical properties such as content of insoluble/soluble material and insoluble/soluble pectin were measured together with particle and rheological properties. Pectin methyl esterase activity led to a high yield of insoluble material and insoluble pectin, whereas β-elimination led to a high yield of soluble material and solubilized pectin. Homogenization after heat treatment resulted in increased solubilization of the pectin, especially after β-elimination reactions. Parsnip suspensions subjected to pectin methyl esterase activity exhibited the highest elastic modulus most likely due to the cross-linked pectin conferring rigidity to the cell walls. The content of insoluble material and the particle properties such as size and rigidity are important factor for the rheological properties of concentrated parsnip suspensions. [Copyright &y& Elsevier]

Abstract: The dietary fibre composition in parsnip has been determined in the soluble and insoluble fraction, together with the physicochemical properties (morphology of particles, particle size distribution (PSD), volume fraction and rheological properties) of the parsnip suspensions at different paste concentration and degree of homogenization. The content of dietary fibre in parsnip was 30.4% of the dry matter, composed mainly by neutral sugars (18.4%), pectic substances (10.10%) and Klason lignin (1.92%). Homogenization affected the particle size distribution of parsnip suspension (p<0.001), resulting in smaller cell-clusters. By increasing the degree of homogenization, the area based diameter of large particles (d 32L ) and the volume percentage of large particles (vol L %) decreased, whereas the volume percentage of small particles (vol S %) increased. Concentration affected the rheological properties of parsnip suspensions (p<0.001). The volume fraction (ϕ) increased with paste concentration but was reduced with homogenization. By plotting the elastic modulus, G′, as a function of volume fraction, ϕ, we showed the existence of a diluted and concentrated regime with a transition region at approximately ϕ =19% for parsnip suspensions. Above the transition region, concentration of particles played an important role for the rheological properties. Based on the results achieved in this investigation we suggest that the gel network is mainly formed by the large particles, e.g. >100μm, and the smaller are preferably in the voids between the larger ones. [Copyright &y& Elsevier]

Solid-state properties of dried protein formulations are important for stability and functionality of the product. This study investigates how different drying technologies (freeze-drying with and without annealing, spray drying and spray-freeze drying) affect the structure and solid-state properties of a set of matrix formulations composed of trehalose (glass former) and mannitol (scaffolding agent) in five ratios. The dried materials were characterized using differential scanning calorimetry, thermogravimetric analysis, x-ray diffraction and scanning electron microscopy. The morphology of the dried matrix is determined by the drying technology and the composition. In all mixtures, mannitol partially dissolved in the amorphous trehalose, resulting in reduced glass transition temperature. At least 50% mannitol is required to achieve a scaffolding effect through crystallized mannitol. At 25% mannitol poor structural stability is obtained regardless of drying technology. Despite the vast differences in drying kinetics, all drying technologies resulted in similar amorphous content in the dried material. [ABSTRACT FROM AUTHOR]

Amaranthus caudatus is a nutrient-rich Andean pseudocereal with wide genetic variability. Six productive varieties (Oscar Blanco, Pucara, Tomina, Cotahuasi, Barbechos, and Guindo Criollo) were compared by proximate, mineral, and fatty acid composition. The proximal content showed certain singularities in the varieties. Barbechos and Guindo Criollo stood out for their fat content (9.50% and 9.01%, respectively), while Tomina stood out for their carbohydrate content (72.6%), and Pucara and Oscar Blanco for their fiber content (4.59% and 4.48%, respectively). The mineral content presented differences, highlighting the Ca content for Pucara (108 mg/100 g), and Tomina with micro-minerals (Zn, Mn, Fe, and Cu, 4.67, 5.90, 9.13 and 1.03 mg/100 g, respectively). All varieties showed high tricosanic acid (C23:0) content, and Cotahuasi was highlighted for its high linoleic acid (C18:2) content. Multivariate analysis showed negative correlations between proteins and carbohydrates, and between fat and fiber in their proximal content, as well as between Fe and Na for their mineral content, and C18:1 and C18:2 for the fatty acids. Although certain differences were found, the total nutritional composition tended to have minor differences between the investigated varieties. [ABSTRACT FROM AUTHOR]

Abstract: Coconut milk press cake, the spent endosperm left over after the extraction of coconut milk, was utilized to extract additional protein under alkaline conditions. The maximum protein yield was observed at 50°C and pH 11 and corresponded to total endosperm protein yield of 71%, favourably comparable to yields of more complex extractions. The extract was characterized by amino acid analysis and 1D SDS-PAGE, 2D electrophoresis and MS MS spectroscopy. Coconut milk and insoluble milk sediment from the same individual nuts were also analyzed. The alkaline extract reproducibly differed from the other fractions and from those reported by others in amino acid content as seen in Principal Component Analysis, and had in particular higher threonine content The peptide found in the alkaline extract but with no counterpart in coconut milk or its sediment showed IP (≈5) and mass (≈40kDa) and matched partially glutelin from oil palm. [Copyright &y& Elsevier]

Abstract: The rheological behavior of amylopectin–β-lactoglobulin–water system in the region of incompatibility was studied by performing constant shear rate and oscillatory measurements. Phase-segregated samples were prepared at concentrations that laid over the binodal and tie-lines. The results were interpreted in terms of the isostress and isostrain blending laws. For this purpose the bases of Takayanagi model was used and a modified model considering the gradual formation of double emulsions close to the phase-inversion concentration that explain the transition was proposed. Good agreement between observed and calculated values was obtained using the isostress and isostrain models. Phase segregation and the phase-inversion control the rheological properties of the amylopectin–β-lactoglobulin mixture in aqueous media. [Copyright &y& Elsevier]

Abstract: Phase behavior of aqueous amylopectin and β-lactoglobulin system was studied using Fourier transform infrared spectroscopy. Polysaccharide–protein mixtures were prepared at different concentrations and left for equilibration; afterwards their spectra were recorded and correlated using Partial Least Square analysis. Tertiary phase diagrams were built for the system at different equilibration times (2 and 6 weeks); the binodals were asymmetric and displayed toward the protein concentration. In the two-phase region of the phase diagrams the mixtures showed an upper layer rich in β-lactoglobulin and a lower layer rich in retrograded amylopectin, and in some cases an intermediate layer was seen which was a metastable phase. [Copyright &y& Elsevier]

Abstract: In this paper we study the adsorption at cationic emulsion droplets of starch which had been hydrophobically modified with octenyl succinic anhydride (OSA), a modification which also renders the starch anionic. Emulsions were formed with didodecyldimethylammonium bromide (DDAB) after which the OSA-starch was added. The emulsions were separated by centrifugation and the surface load of OSA-starch was determined through serum depletion. The results show the adsorbed amounts can become very high, in some cases reaching approximately 40 mg/m2. The surface load correlates positively with the surface charge density of the starch which depends on the degree of substitution, rms radius and molar mass. Furthermore, the surface load obtained depends on the ratio between polymer surface charge density and the interface charge density which could be varied experimentally by combining various amounts of DDAB and dioleoyl phosphatidylcholine (DOPC) in the formation of the emulsion. The very high surface loads should correspond to very thick adsorbed layers. Thus, OSA-starch should be appropriate for encapsulation applications provided a suitable adhesion substance is employed. [Copyright &y& Elsevier]

The expanding capacity and the stabilizing function of an α-crystalline emulsifier on the bubble surfaces during and after expansion of a sugar foam were examined by volume measurements, confocal laser scanning microscopy (CLSM), freeze-etching and transmission electron microscopy (TEM) and oscillatory rheological measurements. 0.2–10% (w/w) emulsifier, either a polyglycerol ester mixed with monoglycerides (PGE/MG) in α-gel form or sodium oleate in micellar form, was mixed into a 65% sucrose solution in a specially designed vessel at a pressure of 1–5 bar. The foam produced was expanded to ambient pressure before measurements were made.The total volume of the foam was shown to increase proportionally to the expansion with both emulsifiers. With PGE/MG, small bubbles were produced (1–4 μm). With oleate, the bubbles became much larger (5–25 μm) and more coalescence could be observed. The storage modulus of the foam was shown to depend on the bubble sizes, the volume fraction of air and also the emulsifier. The foam stabilized with PGE/MG was stiff at a high concentration of emulsifier, while the micelle forming emulsifier remained more liquid-like. A possible explanation was that the α-crystalline PGE/MG emulsifier formed aggregates and caused an attractive bridging interaction between the bubbles, which resulted in a higher storage modulus. The micellar oleate did not cause any bubble bridging. [Copyright &y& Elsevier]

• In solution, iso-humulone forms stable spherical nanodroplets 20−90 nm. • At hydrophobic surfaces, iso-humulone adsorbs and forms relatively thick layer. • With additional ions, the adsorbed mass becomes very high. • Iso-humulone aggregates are spontaneously formed and grow through Ostwald ripening. Iso-humulone is an essential component for beer derived from hop, which is able to improve foam stability, increase bitterness and prolong shelf life, but its physiochemical properties have not been fully characterised. There is a limited amount of knowledge on how iso-humulone behaves in solution and at interfaces. In this work, the properties of iso-humulone are characterised in solution and at hydrophobic surfaces. The results show that iso-humulone is able to self-associate both in bulk solution and at the interface. The presence of ions typically found in beer (the mixture of Ca2+, K+, Mg2+ and Na+) increases the aggregation and adsorbed mass at the interface. Cryo-TEM confirms the presence of a liquid-like phase with nano-droplets with diameters of 20−90 nm. The results suggest that the droplets are spontaneously formed, have a limited growth through Ostwald ripening and can be dissolved upon dilution. [ABSTRACT FROM AUTHOR]

Oil-based drug delivery systems have been studied in different aspects. The present study proposes a new application for an oil-based delivery system, focusing on controlled release until the drug reaches the later part of the small intestine. Bulk surfactants and interfacial surfactants were added into the oil formulation to provide a better mechanistic understating of the lipolysis. Validation of the modified in vitro method shows the overall conversion from medium-chain triglyceride oil (MCT oil) to free fatty acids (FFA) of 100 ± 4% in five replicates. This fully converted level and high reproducibility are fundamental for the following investigations where any retarding effect can be distinguished from the experimental errors. The results show that viscosity and thermodynamic activity have limited retardation. Furthermore, the former may change the kinetics of lipolysis, while the latter changes the equilibrium level. The gel-forming retarder (ethylcellulose) displayed a strong effect. Whereas the lipolysis was significantly retarded (>50%) when the retarders altered the interfacial composition (poloxamer 407), degradable interfacial surfactants did not have the same effect. However, surface-active, lipolysis-resistant retarders with a high CMC did not show a retarding effect. [ABSTRACT FROM AUTHOR]

It is well known that both protein and iso-humulone, originating from barley malt and hops respectively, play important roles in beer foam stability. In this study, we hypothesize that the interaction of iso-humulone and different beer proteins will give rise to adsorbed layers with different characteristics at hydrophobic surfaces. The properties of these adsorbed layers are likely to play a crucial role for beer foam formation and stability. Beer protein and iso-humulone were extracted based on the brewing process from barley malt and hop respectively. The proteins were fractionated into two fractions (lipid transfer protein (LTP) and a mixed fraction of LTP and protein Z) and their interfacial properties as well as interaction with iso-humulone in solution and at hydrophobic surfaces were investigated by surface rheology and ellipsometry. The results show that the composition and properties of the adsorbed layers depend on how the layer is formed and that iso-humulone plays an important role for the characteristics of the adsorbed protein layers. The interaction between iso-humulone and protein Z is found to have pronounced effects of yielding a coherent and elastic adsorbed layer and, thus, for beer foam stability. Image 1 • Synergistic effects on surface pressure and dilatational moduli from wort proteins. • Iso-humulone and protein Z interaction leads to increased dilatational moduli. • Iso-humulone disrupts lipid transfer protein layers, decreasing dilatational moduli. [ABSTRACT FROM AUTHOR]

A correction to the article "Development and evaluation of methods for starch dissolution using asymmetrical flow field-flow fractionation. Part II: dissolution of amylose" is presented.

There is a scarcity of information on mineral and phytate content in plant‐based foods in Bolivia. This study aimed to analyze iron, zinc, calcium, and phytate content and estimate the mineral bioavailability of foods consumed in Chapare, Bolivia. Minerals and phytate were analyzed, and bioavailability was estimated in 17 food samples. Leafy vegetables and green legumes had the highest mineral content, followed by pseudocereals. Estimated mineral bioavailability was low for cereals, dry legumes, pseudocereals, and flaxseeds foods mainly due to phytate content. But estimated zinc bioavailability for black cornmeal, yellow corn, and dry peas was moderate. Strong correlations (p < 0.01) were found between the three minerals, while phytate correlated negatively to iron, zinc, and calcium. To get an overview of the estimated mineral bioavailability of plant‐based diets, we have included foods, from the same area, analyzed in a previous study where the evaluated diet covers 80% of RNI for iron and zinc, but <40% of calcium. In conclusion, leafy vegetables and green legumes had the highest contents of minerals and the lowest phytate content of the foods analyzed in the study. The usage of processing strategies and dietary diversification to reduce phytate content would significantly improve estimated mineral bioavailability in plant‐based diets. [ABSTRACT FROM AUTHOR]

Abstract Three Andean grains - amaranth (Amaranthus caudatus), quinoa (Chenopodium quinoa), canihua (Chenopodium pallidicaulle) - and two Andean roots starches - achira (Canna indica), maca (Lepidium meyenii) - were studied. Physicochemical properties such as granule size, crystallinity, pasting properties among other as well as structural properties such as root-mean-square radius (r rms), weight-average molar mass (M w) and apparent density (ρ app) were analyzed in order to evaluate the relation between them. Grains were similar in most of their characteristics as roots in their i.e. granule size, shape, type of crystallinity, M w and r rms varied according to botanical source. The starch granules from grains were in a narrow diameter range (0.5 to 2 μm) and displayed A-type X-ray diffraction pattern (XRD). Roots starch had a wide granule diameter range (1 to 100 μm) and displayed a B-type XRD. The amylose content varied between 0 and 48% where amaranth had the lowest value and achira had the highest. Furthermore, quinoa and canihua starches had very low breakdown in pasting properties, indicating high stability during cooking. A model is proposed that relates pasting properties i.e. peak viscosity and final viscosity with ρ app , gelatinization enthalpy, granule size and amylose content. [ABSTRACT FROM AUTHOR]

Yacón root is a natural source of fructans, which has many potential benefits. Convective drying has been applied to increase the shelf life of yacón roots. However, this processing may lead to detrimental effects on the physicochemical functionality. The drying was investigated using different conditions (drying temperatures of 45 °C, 50 °C and 55 °C at a drying air velocity of 2 m/s and 60 °C at a drying air velocity of 2 m/s, 3 m/s and 4 m/s). The dried samples were compared to the original yacón with regard to their physicochemical properties. From all the properties that were studied, the color of the dried material and the elastic modulus of the reconstituted yacón were the most important properties being minimized respectively. The results of this investigation indicate that the best drying conditions, where the physicochemical properties of the samples are kept closest to the original material, are obtained either by using temperatures of 55 °C and 2 m/s or using higher temperatures but increasing the air velocity. [ABSTRACT FROM AUTHOR]

In this study the effect of the dispersed state of soy phosphatidylcholine on emulsification is investigated. The emulsifier is either dispersed in the aqueous phase (coarsely, as small vesicles, as large vesicles), or it is dispersed in the oil phase. Oil-in-water emulsions are prepared with the emulsifier present in the different dispersed states. High-pressure homogenization is used for the emulsification and the impact of pressure, number of passes through the homogenizer and emulsifier concentration is investigated by determination of droplet size and surface loads. Pre-emulsions made using a rotor-stator mixer have a smaller average droplet diameter when the emulsifier is dispersed in the oil phase than in the aqueous phase whereas the smallest droplets are obtained with small vesicles when high-pressure homogenization and repeated passages is used. Moreover, the droplet size can be significantly decreased by increasing the number of passages while an increased pressure has a smaller effect on droplet size. Hence, for a slow adsorbing emulsifier, repeated passages through the homogenizer may be more efficient since successive adsorption can occur. The surface loads, adsorption yields and emulsification efficiencies are observed to depend on the emulsification conditions and dispersed state of the emulsifier. The results from this study illustrates that the dispersion of the emulsifier may have a significant impact on emulsification and, hence, it may be important to consider the dispersed state of the emulsifier in order to achieve desired emulsion properties. [ABSTRACT FROM AUTHOR]

The effects of chocolate shell particle size were investigated by means of its influence on rate of oil migration and fat bloom development. The particle size of the non-fat particles in the chocolate, i.e. sugar and cocoa particles was varied between 15, 22 and 40 μm. A novel set of analytical techniques was used and by combining migration results with surface topology results clear differences could be observed between the samples. At 23 °C storage the samples with a particle size of 15 μm showed higher rate of oil migration and further, the earliest development of fat bloom at the surface. This could be observed both macroscopically and microscopically. Thus, it appears as a larger specific surface area of the non-fat particles facilitates migration of filling oil, possibly due to a more heterogeneous and coarser crystal network with higher permeability. Molecular diffusion cannot explain the level of oil migration observed and, thus, convective flow is assumed to be an important contribution in addition to the molecular diffusion. [ABSTRACT FROM AUTHOR]

The effect of adding soy protein on the texture and colour of garri, a West African cassava food, is evaluated. Garri is mostly pre-gelatinized and agglomerate starch product. The challenge lies in maximizing the protein supplementation without changing the textural characteristics. Three different soybean flours were used for fortification: toasted soy flour (TSF), isolated soy protein (ISP) and defatted soy flour (DSF). The soy flours were dispersed in water, and the pH of the dispersions adjusted to 6.5 and 4.5. Both boiled and unboiled dispersions were used. Fortification of garri with soy flour to a protein content of 15% w/w affected the texture of garri agglomerates. The addition of soy flour suspensions that were not boiled to the shredded cassava roots resulted in increase of hardness of swollen garri particles by a factor greater than 1.7 for ISP and DSF and a factor of 1.2 for TSF. Suitable pretreatment of the soy suspension in term of pH adjustment to 4.5 and boiling, restored the hardness to the level of non-fortified garri with all types of flour. Light microscopy of garri aggregates showed a positive correlation between the size and continuity of protein domains and hardness, where 'hard garri' consist of a system of 'starch in protein' and 'soft garri' consist in a system of 'protein in starch'. The hue turned more yellow and the darkness of fortified garri increased as consequence of the colours of the soy flours added. [ABSTRACT FROM AUTHOR]

Abstract: Direct determination of hydrodynamic radius from retention time is an advantage of the field-flow fractionation techniques. However, this is not always completely straight forward since non-idealities exist and assumptions have been made in deriving the retention equations. In this study we investigate the effect on accuracy from two factors: (1) level of sophistication of the equations used to determine channel height from a calibration experiment and (2) the influence of secondary relaxation on the accuracy of hydrodynamic radius determination. A new improved technique for estimating the channel height from calibration experiments is suggested. It is concluded that severe systematic error can arise if the most common channel height equations are used and an alternative more rigorous approach is described. For secondary relaxation it is concluded that this effect increases with the cross-flow decay rate. The secondary relaxation effect is quantified for different conditions. This is part one of two. In the second part the determination of hydrodynamic radius are evaluated experimentally under similar conditions. [Copyright &y& Elsevier]

Abstract: The Oil Transfer Technique (OTT) was developed by Taisne et al. to measure coalescence during emulsification and has been applied since in several studies. One of the main drawbacks of this technique is that it only gives a qualitative measure of coalescence. This paper proposes a new evaluation method of OTT experimental results for estimating qualitative coalescence rates, e.g. for investigating the scaling of coalescence with emulsification parameters (such as homogenizing pressure, and emulsifier concentration). The method is based on comparison with simulated OTT experiments using bivariate Population Balance Equation models. Simulations have been performed under a wide variety of conditions in order to investigate the influence of assumptions on coalescence and fragmentation kernels. These investigations show that the scaling of coalescence rates could be determined accurately when the scaling of efficient residence time of drops in the active region of homogenization is known. The proposed evaluation method is also exemplified by analyzing OTT data from two previously published studies. [Copyright &y& Elsevier]

Abstract: The molecular and emulsifying properties of gum arabic (GA) and mesquite gum (MG) were characterized using asymmetrical flow field-flow fractionation connected to multi-angle light scattering and refractive index detection. Properties such as molar mass, root-mean-square radius (r rms), hydrodynamic radius (r h), conformation, apparent densities and distribution of proteinaceous matter over the whole molar mass range were determined. GA displayed a low molar mass (3.4×105 g/mol), protein-poor component (population 1) and a high molar mass (1.9×106 g/mol), protein-rich component (population 2). MG displayed one molar mass population with an average molar mass of 1.1×106 g/mol. For both GA and MG, the conformation (r rms/r h) was increasingly spherical with increasing molar mass. However, MG had higher values of r rms/r h for a specific molar mass suggesting differences in structure between GA and MG. The protein content increased with increasing molar mass for both gums, although to a higher extent for GA. Selective adsorption, during emulsification experiments, could be observed of population 2 of GA which may be due to a combination of the higher protein content and a more flexible structure rendering it more surface active than population 1. Comparing GA and MG in terms of emulsion stability, it could be concluded that GA-stabilized emulsions have considerably higher stability against coalescence. [Copyright &y& Elsevier]

To study the composition of wild strawberries grown at high altitude, total antioxidant capacity, total phenolic compounds, total flavonoids, and individual phenolic compounds were measured in wild strawberries (Fragaria vesca) collected between 2,650 and 3,300 m above sea level in Bolivia. Total antioxidant capacity, as assessed by the ferric-reducing antioxidant power and 2,2' -azino-bis(3-ethylbenzotiazoline-6-sulphonic acid) methods, was in the range 16-39 μmol of Trolox equivalents/g fw by both methods. The total phenolic content was 9.7-21 μmol gallic acid equivalents/g fw, and the flavonoid content ranged between 2.8 and 4.9 μmol of catechin equivalents/g fw. The data obtained by the four methods showed several significant linear correlations confirming that flavonoids and other phenolic compounds contributed significantly to the total antioxidant capacity values. Reversed-phase high performance liquid chromatography analysis of extracts subjected to acid hydrolysis showed the presence of seven major fractions, tentatively identified as ellagic acid, cyanidin, pelargonidin, quercetin, kaempferol, gallic acid derivatives, and catechin derivatives. The data indicated that wild strawberries have a somewhat higher total antioxidant capacity content in comparison with that reported for cultivated strawberries. No obvious difference to the composition reported for wild strawberries grown at low altitude could be found. [ABSTRACT FROM AUTHOR]

Abstract: A simulation model for emulsification in high pressure homogenization (HPH), based on a population balance approach, is developed assuming it to be controlled by three simultaneous processes; fragmentation, coalescence and adsorption of a macromolecular emulsifier. The aim is to investigate the implications of adding a set of models together; studying the effects of dynamics, size effects and process interactions. For fragmentation, turbulent inertial and turbulent viscous forces are included using a dynamic model based on the Weber and Capillary number. It was extended to include a deformation time scale. The rate of adsorption and coalescence is assumed to be controlled by the collision rate of macromolecular stabilizer and bare interface, modeled using convective and diffusive transport in turbulent flow. By comparing simulation results to general trends found in the literature, it can be concluded that the models can reproduce the general HPH process well. By dividing the active region of emulsification in the homogenizing valve into discrete steps, the dynamic process could also be examined, indicating the homogenization process being composed of three stages with coalescence predominantly found in the last one. [Copyright &y& Elsevier]

Abstract: The emulsification in a high pressure homogenizer was studied using a dynamic simulation model based on the population balance equation. The model includes fragmentation, recoalescence and adsorption of macromolecular emulsifier and uses a simple flow model in order to link the hydrodynamics in the homogenizer to the three physical processes mentioned above. A computer model offers an interesting opportunity to study the effect of model assumptions on the overall outcome of the process. The computer model is also an interesting complement to experiments in this case since internal measurements in the active region of homogenization are very hard to carry out, due to small scales and high forces, and information on the spatial position of the different processes is of great importance in design. Based on a set of assumptions, mainly that the turbulent jet responsible for break-up can be described by a one dimensional model and that the macromolecular emulsifiers hindrance of recoalescence can be described by a wall like repulsion, it is shown that the active region of homogenization can be divided into two zones; a narrow zone with fast fragmentation and nearly no recoalescence in the most intense part of the region followed by a recoalescence zone as drop–drop interactions starts to dominate with decreasing turbulence intensity. The effect of operating parameters is seen to be close to the ones found from experiment. The results are discussed in relation to a flow field obtained by a simplistic CFD and assumptions made about hydrodynamics and emulsifier behavior. [Copyright &y& Elsevier]

Abstract: Autoxidation of five flavonoids representing range of different hydrophilicities (epicatechin gallate (ECG), (+) catechin((+)C), epicatechin (EC), epigallocatechin gallate (EGCG) and epigallocatechin (EGC)) in three different aqueous solutions: molecular solution, micellar solution (Tween 20) and liposomal dispersion (soybean lecithin) was monitored by HPLC. The rate of oxidaton of the five flavonoids was higher at pH 4.5 than at pH 3.5. Compared with the control, addition of Tween-20 (micellar structure) and lecithin (liposomal structure) significantly decreased the degradation of flavonoids. In the presence of lecithin the autoxidation of all the five flavonoids was slower than in the presence of Tween-20. The effective protection of the colloidal structures was compared the hydrophilicity of the flavonoids estimated from the partitioning between octanol and water. The protection from oxidation in the presence of the colloidal structures (micellar or liposomal) increased with increasing partitioning of a flavonoid towards the hydrophobic environment. The protecting effect of the colloidal structures was more effective at pH 4.5 than at pH 3.5. [Copyright &y& Elsevier]

Abstract: High-pressure homogenization of modified starches is a type of treatment used within the food and pharmaceutical industry for the production of emulsions. Such intense mechanical treatment may, however, influence the size and size distribution of the starch polymer, which may affect the properties of the emulsions. In this work, asymmetrical flow field-flow fractionation (AsFlFFF) connected on-line to a multi-angle light scattering detector (MALS) was used to study the influence of high-pressure homogenization upon molar mass and root-mean-square (r.m.s.) radius of three different octenyl succinate anhydride (OSA) starch samples originating from potato. The homogenization at constant pressure resulted in a significant decrease of both molar mass and r.m.s. radius. The magnitude of the change in molar mass and r.m.s. radius could be correlated to the initial size of the OSA starch and the energy dissipation rate of the homogenization treatment. [Copyright &y& Elsevier]

Optimisation of cultivation conditions in the industrial production of probiotics is crucial to reach a high-quality product with retained probiotic functionality. Flow cytometry-based descriptors of bacterial morphology may be used as markers to estimate physiological fitness during cultivation, and can be applied for online monitoring to avoid suboptimal growth. In the current study, the effects of temperature, initial pH and oxygen levels on cell growth and cell size distributions of Limosilactobacillus reuteri DSM 17938 were measured using multivariate flow cytometry. A pleomorphic behaviour was evident from the measurements of light scatter and pulse width distributions. A pattern of high growth yielding smaller cells and less heterogeneous populations could be observed. Analysis of pulse width distributions revealed significant morphological heterogeneities within the bacterial cell population under non-optimal growth conditions, and pointed towards low temperature, high initial pH, and high oxygen levels all being triggers for changes in morphology towards cell chain formation. However, cell size did not correlate to survivability after freeze-thaw or freeze-drying stress, indicating that it is not a key determinant for physical stress tolerance. The fact that L. reuteri morphology varies depending on cultivation conditions suggests that it can be used as marker for estimating physiological fitness and responses to its environment. [ABSTRACT FROM AUTHOR]

[Display omitted] This paper explores how vacuum foam-drying of a protein is influenced by formulation parameters by investigating the foam structure, physical properties of the foam, and the stability of the protein. Recombinant human bile salt-stimulated lipase was used as a model of a protein drug. The stability of the lipase was evaluated through activity measurements. Two disaccharides (sucrose and trehalose), strongly tending to an amorphous form, were used as matrix formers, and the physical properties were assessed through residual water content, glass transition temperature, and crystalline state. Moreover, some formulations included surfactants with different sizes and structures of the head group. The alkyl chain length was kept constant to only investigate the impact of the surfactant head group, in the presence of the lipase, on the foamability and surface coverage of the lipase. The study demonstrated that the lipase allowed for a dry, solid foam with a foam overrun of up to 2600 %. The wall thickness of the dry, solid foam was estimated to be 20–50 µm. Clear differences between sucrose and trehalose as matrix former were identified. The lipase showed no tendency to lose activity because of the drying and rehydration, despite a proportion of the lipase covering the surfaces of the dry material. [ABSTRACT FROM AUTHOR]

In beer, the main amphiphilic components are protein and iso-humulone. Two major populations of protein are identified as lipid transfer protein (LTP) (9.7 kDa) and protein Z (43 kDa). In this paper, protein and iso-humulone are extracted from barley malt and hop, respectively, based on the brewing process. Mixtures of protein and iso-humulone are mixed at different concentrations and centrifuged. Supernatants are analyzed by asymmetric flow field-flow fractionation (AF4) coupled to UV with multi-angle light scattering (MALS) detection as well as by sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE). The presence of aggregates and their structures are investigated by light microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that protein and iso-humulone can form aggregates from molecular level by AF4-UV-MALS and SDS-PAGE. The interaction is shown as solution depletion which is analyzed by AF4-UV-MALS. With 300 mg/L iso-humulone and 3 g/L protein in bulk, the decrease of protein peak levels off. The peak of protein Z is preferentially decreased as an effect of iso-humulone being present, suggesting that interaction between these populations is favored. The iso-humulone/protein aggregates consist of both undefined irregular aggregates as well as spherical aggregates. The spherical aggregates are observed in light microscopy, SEM and TEM. From SEM, it is clear that there are two types of spherical aggregates: rough and smooth. With TEM it can be observed that the smooth aggregates consist of a thin layer of the aggregated proteins and iso-humulone enclosing a liquid domain. This structure can best be described as an iso-humulone/protein vesicle. The rough vesicles are formed by further precipitation at the surface of the smooth vesicles. Image 1 • Iso-humulone aggregates mainly with protein Z, and less with LTP. • Aggregates are large uncharacteristic floccs, but also vesicules • Vesicular aggregates are spontaneously formed in 1–20 μm. [ABSTRACT FROM AUTHOR]

Background: Quinoa is a pseudocereal with relatively high content of proteins and minerals that also contains mineral inhibitors such as phytate. The aim of the present study was to evaluate lactic acid fermentation and dry roasting on the nutritional quality and sensory attributes of quinoa. Various processes were evaluated, and quinoa grains were dry‐roasted, milled, and fermented, either with or without the addition of wheat phytase or activated quinoa phytase (added as back‐slop starter), for 10 hr. In other processes, raw quinoa flour was fermented for 10 hr or 4 hr and dry‐roasted. Hedonic sensory evaluation was then performed to evaluate the acceptability of the fermented flours prepared as porridges. Results: The combined dry roasting and fermentation processes significantly (p <.05) degraded phytate between 30% and 73% from initial content. The most effective process was fermentation of raw quinoa flour followed by dry roasting, which improved the estimated zinc and iron bioavailability. Particularly, estimated zinc bioavailability improved from low (Phy:Zn 25.4, Phy·Zn:Ca 295) to moderate (Phy:Zn 7.14, Phy·Zn:Ca 81.5). Phytate degradation was mainly attributed to the activation of endogenous phytase during fermentation. Dry roasting was effective in improving the sensory attributes of the fermented quinoa flour. Porridge made with raw quinoa flour fermented for 4 hr and dry‐roasted was more favorable to overall acceptability than that which was fermented for 10 hr and dry‐roasted. Conclusion: Fermentation of quinoa flour for 4 hr followed by dry roasting was successful in improving both nutritional and sensory attributes of the final product. [ABSTRACT FROM AUTHOR]

BACKGROUND: Pseudocereals are nutrient‐rich grains with high mineral content but also phytate content. Phytate is a mineral absorption inhibitor. The study's aim was to evaluate phytate degradation during spontaneous fermentation and during Lactobacillus plantarum 299v® fermentation of quinoa, canihua, and amaranth grains and flours. It also aimed to evaluate the accessibility of iron, zinc, and calcium and to estimate their bioavailability before and after the fermentation of flours with starter culture. Lactic acid, pH, phytate, and mineral content were analyzed during fermentation. RESULTS: Higher phytate degradation was found during the fermentation of flours (64–93%) than during that of grains (12–51%). Results suggest that phytate degradation was mainly due to endogenous phytase activity in different pseudocereals rather than the phytase produced by added microorganisms. The addition of Lactobacillus plantarum 299v® resulted in a higher level of lactic acid (76.8–82.4 g kg−1 DM) during fermentation, and a relatively quicker reduction in pH to 4 than in spontaneous fermentation. Mineral accessibility was increased (1.7–4.6‐fold) and phytate : mineral molar ratios were reduced (1.5–4.2‐fold) in agreement with phytate degradation (1.8–4.2‐fold) in fermented flours. The reduced molar ratios were still above the threshold value for the improved estimated mineral bioavailability of mainly iron. CONCLUSION: Fermentation proved to be effective for degrading phytate in pseudocereal flours, but less so in grains. Fermentation with Lactobacillus plantarum 299v® improved mineral accessibility and estimated bioavailability in flours. © 2019 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Complete wetting is crucial for efficient recombination of powders. On the powder bed scale, wetting is governed solely by capillary forces and the resistance to flow, i.e. spontaneous imbibition. Slow or incomplete imbibition of the powder bed may lead to gelling of the liquid front, which will stop the recombination process and cause the formation of lumps, which is usually undesirable. In this study, the spontaneous imbibition of powder beds consisting of spray-dried dairy powders with diverse morphologies has been investigated. Uniform radial spreading of the imbibition front was seen in all the beds, but a large amount of air was trapped in the inter-particle free space in the imbibed volume. A positive correlation was found between bed porosity and the fraction of air trapped in the bed after imbibition. Since the amount of trapped air was calculated as a fraction of the porosity of the dry bed, this relation was unexpected. The large fraction of air trapped in the bed and the uniform radial spreading of the imbibition front indicate considerable heterogeneity of bed on the microscopic scale, but a homogenous structure on the macroscopic scale. Possible explanations of the large fraction of trapped air are the presence of local dead-end structures in the bed and film flow of the imbibing liquid. [ABSTRACT FROM AUTHOR]

The trend of using protein produced from microorganisms to be a meat substitute or replacing other meat alternative sources such as soy and pea is becoming increasingly popular because of its possibility to produce meat-like food products and other functional properties such as its emulsifying properties. The effective use of mycoprotein for food applications requires liberation of cell protein by destruction of indigestible cell walls. Therefore, with an aim of investigating different treatments for cell wall degradation and mycoprotein extraction along with research of filamentous fungal protein functionalities, it offers a possibility to increase the potential usage of filamentous fungal biomass on food applications. High pressure homogenization (HPH) was found to be the most effective methods on cell wall degradation compared with ultrasonication and enzymatic treatment. A pH-shifting procedure was performed to solubilize and recover the proteins. Combination of HPH and pH-shifting for mycoprotein extraction have achieved an overall protein yield of 71 % of original filamentous fungal biomass, with a protein concentration up to 77 % in dry weight. The emulsifying properties of freeze-dried protein isolate (FDPI) and spray-dried protein isolate (SDPI) did not show significant difference, but they were better than the freeze-dried fungal biomass (FDB). The foaming ability of FDPI and SDPI did not show significant difference, while the foaming stability of FDPI was greater than SDPI. Both FDPI and SDPI have greater foaming properties than FDB. The findings of this study can help for better understanding of the application of mycoprotein and optimizing the protein extraction from filamentous fungi. [Display omitted] [ABSTRACT FROM AUTHOR]

The formation of lumps during industrial recombination of powder is a common problem in many industries. An important step in the recombination process is the wetting of the dry material. Only with an efficient wetting the individual powder particles will disperse and a complete dissolution will occur. In difference, a slow or incomplete wetting will not supply liquid to all portions of the powder, resulting in the formation of lumps. The resistance to wetting can be described by a material's permeability. This parameter is often estimated using the Kozeny-Carman equation, which models the permeability of a porous medium (such as a bed of powder) based on the porosity and specific surface area of the medium. This model has proven valid for a bed of packed spheres, but due to the model assumptions the accuracy of the model when utilized on beds formed from more complex, spray dried powders can be questioned. In this study, the permeability of powder beds consisting of spray-dried diary powders when exposed to an air flux has been characterized, using a method based on air permeametry. The results show that the Kozeny-Carman model is insufficient to estimate the permeability of such beds. Furthermore, the measured porosity of the bed had no influence on the permeability constant. Based on the results of this study a correlation between morphological powder parameters and permeability was developed. This correlation indicates that a small surface weighted average diameter of the particles as well as a narrow width of the particle size distribution have a positive effect on the permeability of a bed. In addition, incorporation of the structural parameter “BedRatio”, defining the basis of the bed to consist of agglomerates or primary particles (fines), indicates that a bed consisting of mainly agglomerates has a slightly larger permeability. [ABSTRACT FROM AUTHOR]

• Wine colloids WC are complex and heterogeneous compounds naturally present in wines. • Wine colloids can interact and aggregate forming haziness and insoluble compounds. • The fining process is intended to remove excessive colloidal material. • Clarifiers of different source remove specific colloidal and macromolecular fractions. • AF4 is a technique that allow us to monitor colloidal changes during clarification. Clarifiers are substances used during the winemaking process to enhance clarity and stability in the wines. The different clarifiers may alter removal capacities differently. In this study, the removal efficiency of seven common fining agents, divided into three groups (mineral clarifiers, synthetic polymeric clarifiers, and vegetable protein clarifiers), was analyzed with Asymmetrical Flow Field-Flow fractionation (AF4). Besides, the relationship between the removal capacity and different molecular and macromolecular properties has been evaluated. The results showed extensive removal of colloidal and macromolecular matter by the bentonites with potential impact on characteristic properties of the wine. The vegetable clarifiers showed a more profiled reduction, potentially preserving characteristics of the wine. The synthetic polymers showed a more limited removal efficiency but with a high affinity to remove colloidal phenols. The use of AF4-UV-MALS-dRI allowed the characterization of the wines after different clarification treatments, showing to be an analytical technique with a potential impact on the wine industry. [ABSTRACT FROM AUTHOR]

The effect of heat treatment on the soluble protein content in oat groats (Kerstin commercial variety) was evaluated using asymmetric flow field-flow fractionation (AF4) in combination with online multiangle light scattering (MALS) and UV detection. The AF4 method was used to separate the monomeric proteins from globulin hexamer and aggregate proteins and β-glucan polysaccharides in the soluble oat protein fraction. The total amount of soluble protein (with respect to total protein) was reduced to 35.7 ± 4.5 wt. % in heat treated oats from 74.6 ± 5.3 wt. % in non-heat treated oats. The ratio of monomeric to globulin hexamer and aggregate proteins was reduced from 1.82 to 1.48 as a result of heat treatment. Sodium-dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis revealed the selective elimination of protein bands associated with the albumin and prolamin protein fractions as a result of heat treatment. These results were supported through amino acid analysis by cation exchange chromatography coupled with UV detection which revealed a reduction in amino acid residues associated with prolamin. The globulin proteins were found to be less sensitive to heat treatment. [ABSTRACT FROM AUTHOR]

Abstract: The formation of lumps during large scale wetting of spray dried powders is a common problem in the industry. The result is a large energy demand if an efficient mixing is to be achieved at the industrial scale. If more knowledge regarding the phenomena governing lump formation is obtained, the unit operation could be optimized and made more efficient. As a part of increasing the understanding of lump formation, the wetting of the porous media that is a powder bed needs to be understood. This wetting relates to the structure and void space (porosity) of the powder bed, which is why a relation between powder bed porosity and readily obtainable powder particle morphology parameters is sought. In this study a thorough investigation of the morphology of five different spray dried milk powders, with arbitrary particle shapes, was performed using manual image analysis of scanning electron microscope (SEM) images as well as automated methods based on light scattering and projected image analysis. The results of the automated methods, when utilized on the complexly shaped samples, were validated by a comparison to the SEM image analysis. This enabled the development of a relation between powder morphology and powder bed porosity based on data from automated methods. The results indicate that automated methods based on light scattering underestimate the particle sizes of arbitrary shaped particles. Methods based on projected image analysis, however, show a better agreement with SEM image analysis. The developed relation between powder bed porosity and powder particle morphology is based on defining the bed as having either an “Agglomerates in fines”, “Bicontinuous” or “Fines in agglomerates” structure. The structure of each powder is determined based on calculation of a “BedRatio” which is a function of the ϕagglomerate and ϕfines both shown to be readily obtainable by automated methods. The calculated porosities of the powders investigated in this study show a good agreement with experimental measurements and are considered to correspond well to earlier literature. It is, however, clear from the experiments that care needs to be taken during bulk density measurement of spray dried powders so that no intra particle void space is taken into consideration in the calculations. [Copyright &y& Elsevier]

Sensory evaluation was performed to investigate how size and concentration of small rye bran particles in a continuous phase with varying viscosity influence the sensory perception of grittiness. The threshold for the sensation of grittiness of rye bran particles in a starch gel, evaluated by triangular sensory tests, was very low. The particles were discerned at a concentration of 0.1-0.3%, despite the fact that they were very small (20-180 μm). The sensory panel was able to detect the increase in particle concentration in a ranking test, but the ability to detect the increase in concentration was not influenced by particle size. The rheological properties of the medium did not influence the detection threshold. Practical Applications Due to health benefits, addition of dietary fiber in food products is popular. Rye bran is a by-product, which is very high in dietary fiber, and for which new applications are requested. Rye bran consists mainly of insoluble dietary fiber and the rye bran particles are hard and irregular in shape. To understand the oral sensitivity of these kinds of particles is important to avoid the negative sensation of grittiness of dietary fiber fortified products. Since it was shown that even the size fraction of 20 μm was perceived as gritty at very low concentrations (0.2-0.3%), the milling technique is probably not the solution to reduce the grittiness. Preferably a way of making the particles softer, with less sharp edges should be sought, at least if the rye bran is going to be added to a smooth food matrix of a starch gel. [ABSTRACT FROM AUTHOR]

The soluble proteins and protein aggregates in Belinda oats were characterized using asymmetric flow field-flow fractionation (AF4) coupled with online UV-vis spectroscopy and multiangle light-scattering detection (MALS). Fractions from the AF4 separation were collected and further characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The AF4 fractogram of the oat extracts revealed three peaks which were determined to be monomeric forms of soluble proteins, globulin aggregates, and β-glucan, respectively. The early eluting monomeric proteins ranged in molar mass (MM) between 5 and 90 kg/mol and in hydrodynamic diameter ( D) from 1.6 to 13 nm. The MM at peak maximum of the globulin aggregate peak was found to be ∼300 kg/mol and the D was measured to be ∼20 nm. SDS-PAGE of the collected fraction across this peak revealed two bands with MM of 37 and 27 kg/mol which correspond to the α and β subunits of globulin indicating the elution of globulin aggregates. A third peak at long retention time was determined to be β-glucan through treatment of the oat extract with β-glucanase and by injection of β-glucan standards. The amount of soluble protein was measured to be 83.1 ± 2.3 wt.%, and the amount of albumin proteins was measured to be 17.6 ± 5.7 wt.% of the total protein in the oats. The results for Belinda oat extracts show that the AF4-MALS/UV platform is capable of characterizing the physicochemical properties such as MM and hydrodynamic size distribution of proteins and protein aggregates within a complicated food matrix environment and without the need to generate protein isolates. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Abstract: The high-pressure homogenizer emulsification modelling framework by Håkansson et al. (2009a, Chemical Engineering Science 64, 2915–2925; 2009b. Food Hydrocolloids 23, 1177–1183), is further developed in this study. The model, including the simultaneous fragmentation of drops, coalescence of drops and kinetic adsorption of macromolecular emulsifiers, is improved with regard to two points. First, the transport of adsorbed emulsifier between drops of different sizes due to the fragmentation and coalescence of drops, is included using bivariate population balances. Second, the coupling of hydrodynamics to the emulsification model is improved using information from recent hydrodynamic investigations. The proposed framework is exemplified using a set of physically reasonable kernels and a production scale high-pressure homogenizer geometry, showing realistic emulsification results. [Copyright &y& Elsevier]

The effect of disperse phase volume fraction on the turbulence in a scale model of a high-pressure homogenizer was studied experimentally. Velocity fields of the continuous phase were measured using particle image velocimetry. Refractive index matching combined with digital filtering enabled measurement with disperse phase present. Geometry and physical properties were carefully scaled in order to ensure turbulent flow and disperse phase modulation comparable to that of a technical high-pressure homogenizer. The results show a widening of the jet downstream of the gap and increased Reynolds stresses in the region of high turbulence intensity. This is consistent with previous experiments under similar conditions. Furthermore, the spectra of turbulent kinetic energy were investigated, indicating that the increase in turbulent kinetic energy is mainly due to an increase in energy of eddies of large length scales. [ABSTRACT FROM PUBLISHER]

The susceptibility to enzymatic hydrolysis of starch extracted from raw roots of Canna indica, Manihot esculenta and Xanthosoma sagittifolium, grown in Bolivia, were studied below the gelatinization temperature. The granule size and amylose content were as followed: C. indica> M. esculenta> X. sagittifolium. The hydrolysis showed a rapid rate at the initial stage, followed by a progressive decrease thereafter. At 30, 40 and 50°C, during the initial stage, the rate of hydrolysis was observed to be influenced by the size of the granules, being the highest for the small sized granules X. sagittifolium, followed by the medium sized granules M. esculenta and the lowest rate was for the large sized granules C. indica starch. During the slow phase, A-type M. esculenta and B-type C. indica showed higher hydrolysis rates than A-type X. sagittifolium. At 60°C, a positive correlation was found between the amylose content and the rate of hydrolysis among the starches. Microscopic observations showed a pattern of attack by the enzyme towards C. indica starch granules, suggesting that high amylose content is concentrated around the hilum. [ABSTRACT FROM AUTHOR]

Abstract: Yacon roots are a promising source of inulin­type fructans (35g/100g dry matter) with a total amount of dietary fiber of about 45g/100g dry matter. The polydispersity of the particle size distribution of yacon aqueous suspension was reduced with increasing the degree of homogenization due to two phenomena: aggregation of particles, and disruption of large particles. Non­homogenized yacon suspensions exhibited large cell clusters that were disrupted into small cell clusters, single cells, and aggregates. The most concentrated suspension exhibited mainly aggregates. The volume fraction of the suspensions decreased significantly with increasing the degree of homogenization. This was attributed to a denser packing of small particles and aggregates in between large particles thus allowing the water within the structure to be released. Yacon suspensions exhibited high elastic modulus (750Pa) at low water insoluble solids content (0.9% WIS). Additional results suggested that inulin­type fructans contributed to the elastic properties of yacon suspensions. The yacon suspensions studied in this work can be considered as semi­concentrated suspensions, i.e. the plot elastic modulus of the suspensions versus concentration exhibited a region immediately after the transition region. Particle interactions seem to be of great importance in this region in the particular case of yacon suspension since the elastic modulus (G′) reached 750Pa at low water insoluble solids content (<1%). [Copyright &y& Elsevier]