Production of fat-based emulsion powder by prilling process using twin-fluid atomizer for controlled release of iron

Encapsulation of iron is necessary to supply bioavailable iron to large number of population possess iron deficiency. In the present study, we dispersed the iron solution in a fat matrix of palm stearin, and prepared the simple emulsion (water-in-oil) at 60 ◦C, where fat was a continuous phase. Using that emulsion, we produced fat based emulsion particles through prilling (spray + chilling) process using twin fluid atomizers (internal mixing). We characterized the particle in terms of size and size distribution, and investigated the internal structure of the fatparticles by cryogenic scanning electron microscopy (cryo-SEM) for observing the distribution or homogeneity of dispersed phase. Present study includes mainly the iron release kinetics through the fat matrix of the emulsion particle in an in-vitro gastric system (pH ≈ 2.0 ) as a function of (a) particle size of prills, (b) thickener concentration (polyethylene glycol, PEG) in dispersed phase, (c) droplet size of dispersed phase, (d) mixing properties (Reynolds number, Re), and (e) shelf-life of particles. The release kinetics was explained by the second order kinetics, where we estimated the release kinetic constant, and co-related with the viscosity ratio of dispersed phase to continuous phase, mean particle size of emulsion, and shelf-life of particles. The result showed that the control of the release properties can be obtained by choosing particle size and thickener concentration

Modification of the CAB Model for Air-Assist Atomization of Food Sprays

The Cascade Atomization and Drop Breakup (CAB) model has been originally developed for pressure atomizers. In this study, the CAB model is modified to accommodate the atomization of low-pressure, air-assist atomizers. The modifications include the first breakup which is modeled by estimating theWeber number due to the increased liquid-gas relative velocity caused by the air flow. This breakup depends on whether the Weber number is in the catastrophic, stripping or bag breakup regime. The second modification includes a change in the product drop distributions, namely, instead of a uniform distribution, as used in the original CAB model, a X-squared distribution with the same average drop size is assumed. The model changes are validated with experimental data obtained by means of two different air-assist atomizers using an oil-in-water emulsion. The simulations are performed with a modified version of the KIVA-3 CFD code; they show good agreement with the experiments

Easy flowing emulsion (o/w) based spray-dried powder produced using dietary fiber as a wall material

The production of emulsion (o/w) based microstructured food powder through spray drying is a common practice in the food industry due to better shelf-life and easy transportation of the structured material. In general, the emulsion based powder flow behavior is poor due to lipid phase diffusion into the surface. The microstructure transform during spray-drying and the reconstitution of the emulsion powder are also a challenge by preserving the desired physiochemical properties such as emulsion size, stability, the control release kinetics of actives etc. The main objective of this study is to encapsulate the lipid phase using a wall material composed of protein (whey protein) and apple fiber. The stable submicron emulsions (o/w) were prepared using a rotor-stator at room temperature. Different fiber concentrations and different spray drying conditions were tested by varying the air to liquid mass ratio (ALR). The easy flowing of the emulsion powder was achieved when a relatively small amount (max. 5%) of fiber was used; however, the flowing performance declines with higher fiber content. The excellent reconstitution of the emulsion was also found by dissolving the particles at room temperature

Comparative study on the rice bran stabilization processes: A review

Rice bran is an undervalued/underutilized by-product of rice milling, rich in protein, lipids, dietary fibers, vitamins, and minerals. It is an inexpensive source of high-quality protein, fiber and lipids to be incorporated into value-added food products. The issue with rice bran is its susceptibility to rancidity and therefore measures must be taken to stabilize the bran in order for it to be fully utilized. Due to this susceptibility to rancidity, historically the bran has either been disposed and wasted or used as low-grade animal feed. As the nutritional value of the bran has been recognized, along with its potential to add value to food products, research has been increasing in volume in order to determine the most effective methods for stabilizing the bran and extracting the valuable nutrients from it. It’s been reported that a free fatty acid content of over 5% is considered to render the bran unfit for human consumption (Tao, Rao & Liuzzo, 1993). Therefore, controlling this level of rancidity is imperative to being able to store and use rice bran over extended periods of time. In order to achieve control, stabilization procedures can be carried out on the rice bran to slow down the lipase activity within the bran and preserve the nutritional qualities that rice bran possesses. Stabilization of rice bran is particularly important for use over winter months in developing countries, where there may be no crops to harvest and therefore a supply of non- rancid rice bran could be extremely beneficial. This length of storage for stabilized rice bran could be up to a period of 6 months, where it can become important for value-added product development (Bagchi, Adak & Chattopadhyay, 2014). The present review will provide an overview of the traditional and innovation rice bran stabilization techniques, those have been a common interest in the research community, and the suitability of the process in terms of the energy consumption

Electrosprayed particles derived from nano-emulsions as carriers of fish oil

Fish oil encapsulated submicron particles were produced by electrospraying emulsions. Emulsions were homogenized by various pressures (1000 and 2000 bar) and passes (1,2, 4, and 8). The physical properties of the emulsions were evaluated, namely droplet size, stability, microstructure, and rheology. Various physicochemical characterizations of the prepared particles were carried out, including the morphology and size of the electrosprayed particles, and the encapsulation efficiency of the fish oil. In optimised conditions, nano-emulsions were produced (d50 < 100 nm). It was found that the homogenization parameters of the emulsions affect the structure of the particles. Low emulsion viscosity combined with low oil droplet size and high stability yielded particles with the smallest diameters. The proposed emulsion electrospraying technology could be promising for the production of powdered ingredients enriched with omega-3

Influence of flowing fluid property through an elastic tube on various deformations along the tube length

The study of fluid flow characteristics in collapsible elastic tubes is useful to understand biofluid mechanics encountered in the human body. The research work presented here is aimed at thoroughly investigating the influence of both Newtonian and/or non-Newtonian fluids (low and high shear thinning) during steady flow through an elastic tube on various tube deformations, which enables understanding of the interaction between wall motion, fluid flow, and intestinal transmembrane mass transfer as a crucial contribution to a mechanistic understanding of bioaccessibility/bioavailability. It is observed that for a given steady volume flow rate, the tube is buckled from an elliptical shape to a line or area contacted two lobes as the critical external pressure is increased. The downstream transmural pressure is found to get more negative than that at the upstream as the outlet pressure decreased due to stronger tube collapse resulting in a reduced cross-sectional area. The experimental results depict that the tube cross-sectional area decreased by only about a factor of one for PEG (polyethylene glycol) and about a factor of six for both CMC (carboxymethyl cellulose) and PAA (polyacrylamide) from the undeformed one under an applied external pressure of 105 mbar. The corresponding maximum velocity increased by a factor of two during steady flow of shear-thinning fluids. The shear-thinning behavior of both CMC and PAA solutions is clearly observed at a constant flow rate of 17 ml/s as the tube cross-sectional area decreased due to an increase in compressive transmural pressure. In addition, the viscosity of PAA is drastically decreased due to its high shear-thinning behavior than that of the CMC under the same applied external pressure

Enhanced biohydrogen production from citrus wastewater using anaerobic sludge pretreated by an electroporation technique

In the present study, the applicability of electroporation (EP) has been investigated as a pretreatment method for enriching hydrogen producers and eliminating hydrogen consumers in anaerobic sludge (AS). Citrus wastewater was used as a feed source for biohydrogen production. Different treatment intensities (TI) of EP for 0.5 min (TI = 30 kWh/m3), 1 min (TI = 60 kWh/m3), and 2 min (TI = 120 kWh/m3) were employed to observe the effects of EP on the microbial community of AS. Furthermore, sonication with a probe, sonication in a bath, and heat-shock pretreatments were also conducted to compare the hydrogen yield with EP. The cell inactivation was evaluated and visualized using colony-forming units (CFU) and field emission scanning electron microscopy (FESEM), respectively. Among the different TIs, the TI of 60 kWh/m3 achieved higher methanogen inactivation with maximum hydrogen (896 mL) production compared to other EP pretreatments after 180 h of dark fermentation. In comparison with other pretreatments, the highest hydrogen production of 896 mL was achieved with EP treatment, followed by sonication with a probe (678 mL) and sonication in a bath (563 mL). The heat-shock pretreatment exhibited the lowest ultimate hydrogen production of 545 mL among the four different methods applied in this study. The outcome of this study suggests that EP is a promising technique for pretreating mixed cultures for the enhanced production of biohydrogen

Extracellular Electron Transport in Microbial Electrochemical Cells

Microbial electrochemical cells (MxCs) are engineered biological systems that use microbial metabolism of anode-respiring bacteria (ARB) to catalyze electron transfer from a soluble electron donor to the anode via extracellular electron transfer (EET). Although several EET mechanisms (via direct contact, mediators, and conduction) have been proposed, understanding of EET in biofilm anodes generating high current density is limited. Recent findings suggested that electrical conduction would be a key EET pathway in MxCs producing high current density, in which biofilm conductivity (Kbio) would mainly regulate EET kinetics. However, there is no clear understanding of the influence of various environmental factors, such as anode potential, local pH, and substrate limitation in biofilm anodes on EET kinetics and Kbio. In addition, scalable, economical designs of MxCs producing high current density still need improvement for deployment of MxCs in field, such as multi-anode MxCs. Hence, the goals of this study were to systematically characterize the effects of (a) anode potential (Eanode), (b) local pH in biofilm anodes and (c) substrate limitations on EET kinetics and Kbio for a key fundamental aspect of MxCs, and develop scalable, economical MxCs using multi-anode configurations in an engineering aspect of MxCs. A biofilm anode enriched with Geobacter spp. showed high Kbio (0.96-1.24 mS/cm) to Eanode change from -0.2 V to +0.2 V vs. standard hydrogen electrode (SHE), while the steady-state current density varied significantly in the MxC. Change of Eanode shifted population of Geobacter genus in the biofilm anode, influencing intracellular electron transfer (IET) kinetics. However, high Kbio was consistently kept in the biofilm at Eanode change. This result suggests that EET kinetics would be relatively insensitive to Eanode dynamics. A step-wise decrease in phosphate buffer concentration from 100 to 2.5 mM caused pH gradient of ~0.5 pH unit between the outmost and inmost layers of a biofilm anode, showing a pH of 6.5-6.7 near the anode in a thick (>100 m) biofilm. This pH gradient substantially dropped current density from 2.38 to 0.64 A/m2 in an MxC, and Kbio decreased by 69% for the 2.5 mM phosphate buffer. These results imply that the metabolic activity of ARB inhibited by acidic pH is closely associated with conductive nature of biofilm anodes and EET kinetics. In a steady-state MxC, Kbio dynamically decreased from 0.53 mS/cm to 0.14 mS/cm during the long starvation (4-5 days) lacking exogenous electron donor. However, the poor Kbio was recovered to 0.55 mS/cm after acetate spiking, indicating that ARB’s activity profoundly influences Kbio and EET kinetics. A multi-anode MxC equipped with three anode modules showed a non-linear increase of current density to the number of anodes. The anode closest to a reference electrode (i.e., low ohmic energy loss) contributed to 65% of the overall current density of 9.15 A/m2 from the multi-anode MxC, where Geobacter species were dominant at 87% and half saturation potential (-0.251 to -0.242 V vs. SHE) was lowest among all anode electrodes. In comparison, the current density from the other two anodes distant from the reference electrode was as small as 1.4-1.7 A/m2, along with negligible population of Geobacter species. These results suggest that Eanode changed by ohmic energy losses in individual anodes can shift microbial communities, and lead to different electron transfer kinetics and current density on each anode