Effect Of Homogenization Conditions Research Articles

A comparative study on the effect of homogenization conditions on the properties of the film-forming emulsions and the resultant films

Emulsions based on licorice essential oil (LEO) were prepared under different homogenization conditions (ultra-homogenization (U1) or U1 together with sonication (U2)). The obtained emulsions were incorporated into the carboxymethyl cellulose (CMC) film. The results showed that U2 caused significant changes in the size and the surface charge of the emulsions. Remarkable differences in the microstructure were observed between the U1 and the U2 emulsion-based films as revealed by SEM and AFM. Both emulsions reduced the rigidity and increased the flexibility of the films. The film made from the CMC alone had a water vapor permeability (WVP) of 2.66 × 10−9 g m−1 s−1 Pa−1, while the CMC film made from U2 emulsion had a WVP of 1.87 × 10−9 g m−1 s−1 Pa−1. Also, the film containing 0.0125% U1-LEO exhibited antibacterial activity on gram-positive bacteria only while the film containing 0.0125% U2-LEO demonstrated antibacterial activity on both gram-positive and gram-negative bacteria.

Optimization of microencapsulation conditions of transglutaminase by freeze drying.

Transglutaminase (TG), which is an important enzyme for food processing, can enhance the firmness, viscosity and water binding capacity of food products by catalyzing the cross-linking reaction of proteins. Since preservation of the enzyme activity is essential, the production of microencapsulated powder form of TG can be a great challenge to maintain its initial activity. In this study, TG was microencapsulated using a freeze drying technique and the effects of homogenization conditions and coating material ratios on the enzyme activity were investigated using D-optimal combined design. Mannitol, gum arabic and casein were chosen as coating materials and different homogenization times (1-5min) and homogenization rates (11,200-20,000rpm) were applied. The optimum conditions which ensure the maximum enzyme activity have been determined as 11,200 rpm of homogenization rate, 1.27min of homogenization time, and in addition a mixture of mannitol, gum arabic and casein with ratios 38.2, 40.2, and 21.6%, respectively. Most of the activity loss occurred in the homogenization stage and the coating materials preserved enzyme activity during freeze drying. At the optimum point, the remaining activity of the microencapsulated TG was 93% while that of the crude (without coating materials) TG was 64% at the same drying conditions. Moreover, the effects of the microencapsulation conditions on the physical properties of powder such as moisture content, color, particle, bulk and tapped densities, porosity and flowability were determined.

Physical and chemical stability of sweet walnut oil emulsion: Influence of homogenization conditions and stabilizer ratio

AbstractIn the present study, the effect of homogenization conditions (homogenization rate: 10,000–17,500 rpm; homogenization time: 5–10 min) and stabilizer (polyglycerol polyricinoleate [PGPR]: 1–3% oil content) ratio on the physical and chemical stability of walnut oil in water emulsions was investigated based on CCRD experimental design. Results showed that the incorporation of PGPR led to a decrease in the yield stress, viscosity, centrifuge, and kinetic stabilities up to center point (~2% oil content) and increased after that. The increase in homogenization rate and time, on the other side, brought about an increase in parameters as mentioned above. The induction time of refined walnut oil was 5.46 ± 0.37 hr, while the induction time of prepared emulsions ranged between 6.45 ± 0.29 and 8.29 ± 0.05 hr, which implicitly demonstrated that emulsification led to an outstanding increase in oxidative stability of the emulsion. General acceptance in terms of homogenization rate and time, increased up to center point (~13,750 rpm/7.5 min).Practical applicationsWalnut oil is valuable by‐product of the food industry. It is also a functional food ingredient with its minor bioactive components including tocopherols and phytosterols. However, walnut oil is a rich source of polyunsaturated fatty acids, as well. In this sense, extreme care needs to be taken in order to prevent walnut oil oxidation. In order to meet this challenge, walnut oil was incorporated into o/w emulsion formulation within the present study to retard lipid oxidation and prolong the shelf life of walnut oil by increasing its overall stability. Therefore, the effect of the independent variables selected as homogenization rate, time and stabilizer (PGPR) ratio on physical and chemical properties of the emulsion were investigated.

Development of omega-3-rich Camelina sativa seed oil emulsions.

Camelina sativa seed is an underutilized oil source rich in omega‐3 fatty acids; however, camelina oil is not fully explored for food applications. Its high omega‐3 content makes it susceptible to oxidation, which may limit food applications. Therefore, the main objective of this study was to investigate the potential of camelina seed oil to form physically and oxidatively stable emulsions as a potential delivery system for omega‐3 fatty acids. Effects of homogenization conditions, namely, pressure (15 MPa‐30 MPa), number of passes (1,3,5, and 7), and type of homogenizers (high pressure and high shear) on the structural properties and stability of camelina seed oil emulsions stabilized with whey protein isolate were studied. High homogenization pressure (30 MPa) and number of passes (>3) reduced the particle size (278 nm) and formed more physically and oxidatively stable emulsions compared to high shear homogenization; high shear homogenization generated bigger oil particles (~2,517 nm). Apparent viscosity and consistency index (k) decreased with increasing pressure, number of passes, and shear rate. Emulsions prepared with high pressure homogenization at both 15 and 30 MPa with 3 and more passes did not exhibit any peroxide formation over 28 days. Results indicated that camelina seed oil is a promising alternative oil source to form stable omega‐3‐rich emulsions for food applications.

Effects of Homogenization Conditions on the Microstructures of Twin-Roll Cast Foil Stock of AA8021 Aluminum Alloy

AA8021 aluminum alloy twin-roll cast strips with 7mm gauge were rolled to 3.8mm gauge sheets and given homogenization, further rolled into 0.55mm gauge foil stocks with intermediate annealing. This paper investigated the influence of homogenization conditions on microstructures of foil stocks in detail. The results show that, for the foil stock made from the sheet without homogenization, the grain structure is partially recrystallized. While the grain structure of foil stock made from the sheet with medium temperature homogenization is fully recrystallized, but it is coarse near sheet surface. However, foil stock made from the sheet with high temperature homogenization has fine and uniform recrystallized grain structures. The differences of grain structures among these three kinds of foil stocks can be understood by the variation in solid solution content of Fe, Si, Mn and distribution of intermetallic compounds. The optimized homogenization condition was adopted by our plant to produce foil stock, and its grain structure was fine and uniform. The surface quality of final aluminum foil rolled from the foil stock could meet high grade requirements of customers.

The Effect of Homogenization Conditions on Extrusion Texture and Microstructure Evolution in AA3003

Two different conditions were used to study the effect of homogenization on extrusion texture and microstructure evolution in AA3003. The first condition considered homogenization for 8 h at 500°C to obtain a high density of dispersoids and the other condition was homogenized for 24 h at 600°C to produce a sample with a very low density of dispersoids. After uniaxial extrusion at 400°C with a speed of 32 mm/s and an extrusion ratio of 70:1, the material with a high density of dispersoids formed <001> and <111> double fibre texture in the centre of extrusion rod and a smeared texture from <011> to <111> near the surface. For the material without dispersoids, only <001> texture fibre is observed in the centre of extrusion rod and a strong <011> fibre is observed near the surface.

Effect of homogenization conditions on physicochemical properties of chitosan-based film-forming dispersions and films

Film-forming dispersions (FFD) based on high molecular weight chitosan (CH) alone or in combination with oleic acid (OA) were prepared under different homogenization conditions (rotor-stator or rotor stator together with microfluidization at different pressures). Film-forming dispersions (FFD) were characterized in terms of particle size distribution, rheological properties, distribution and ζ-potential. In order to study the impact of the properties of the FFD on the casted films, the water vapour permeability, mechanical properties and microstructure of the dry films were evaluated. Results showed that microfluidization promoted significant changes in the size and surface charge of the FFD particles, which in turn had an impact on the rheological properties of the FFD. The changes were more marked with the increase in microfluidization pressure. As regards film properties, the higher the microfluidization pressure in the FFD, the lower the water vapour permeability values and the stiffer the CH-OA composite films. These results were explained by film microstructure, which was observed by SEM.

Miniemulsification of Monomer-Resin Hybrid Systems

Miniemulsion polymerization is particularly well suited to synthesize hybrid nanocomposites. The first stage in this process is to prepare hybrid monomer−resin nanodroplets by miniemulsification. In this work, the efficiencies of several homogenization equipment (rotor−stator, sonicator, and high-pressure homogenizer) were compared. For the most efficient one, the effect of homogenization conditions, type of resin, emulsifier concentration, and viscosity of the organic phase on the size of the composite droplets was investigated. The results agreed well with a two-step mechanism in series involving droplet breakup and coalescence.

クロムを含むＡｌ‐Ｚｎ‐Ｍｇ‐Ｃｕ合金の再結晶組織に及ぼす均質化条件の影響

The effect of homogenization conditions on the recrystallization during solution-treatment has been studied on hot-rolled Al-5.6%Zn-2.5%Mg-1.6%Cu- (0.12-0.27) %Cr alloys. The condition of obtaining a marked inhibition of recrystallization was not always consistent with that of obtaining the fine and dense distribution of E phases inside the dendritic cell. It was suggested that the absence of PFZ in the area adjacent to the cell boundaries, together with the fine and dense distribution of E phase, was of great importance for suppression of recrystallization during solution-treatment. Recrystallization was most suppressed, when the ingot was held at 200-300°C for a prolonged time in the course of heating to the homogenization temperature.

Effect of mixing on the laws of combustion of charge mixtures

The authors study the effect of homogenization conditions for multicomponent charges on the laws, conditions, and maximum temperature of combustion. Charges with the following components were studied: I) Ti, C, B, Me-bonding agent; II) Ti, Cr, C, Me - bonding agent. The charges were prepared from PTM titanium powder, PKh-1S chromium powder, PNE-1 nickel powder, PM-15TS soot, and amorphous brown boron powder. It is shown that the liberation of gas in the high-temperature reaction occurs mainly in the combustion wave, while the film of melted titanium prevents gases from escaping through the starting part of the sample. At combustion temperatures close to the melting temperature of the final product, the lamella formed can be scorched and surface defects can be healed.

Effect of homogenization conditions on the physicochemical properties of emulsion bases.

The effects of the first pressure and/or number of passes through the homogenizer, and preagitation by an agitator, on the physical properties of emulsion bases were investigated. The first pressure of the homogenizer was varied in the range of 130 to 490kg/cm2, and the second pressure was kept constant at 60kg/cm2. Emulsifiers used were commercial grade Tween 80 and Span 20. Oil and water phases were liquid paraffin and distilled water, respectively. Emulsion stability was evaluated in terms of the following three physicochemical parameters : (1) particle diameter, (2) separation rate of water phase, (3) rheological properties of emulsion products. The following results were obtained. (1) With increases in agitation time and in intensity of agitation, the particle diameter of the emulsion became smaller. (2) The viscosity of emulsion prepared in the homogenizer increased remarkably with increase in the number of passes through the homogenizer. (3) The particle diameter of the emulsion was greatly decreased by the homogenizer only at the first pass. (4) Pre-agitation with an agitator is very useful for the preparation of emulsion products by means of a homogenizer.

The effect of homogenization conditions on sub-cellular distribution in brain

The effect of homogenization conditions on sub-cellular distribution in brain