共查询到20条相似文献,搜索用时 15 毫秒
1.
《Bioscience, biotechnology, and biochemistry》2013,77(11):1791-1795
The effects of lecithin addition in oil or water phase on the stability of oil-in-water emulsions made with 0.1 wt% whey protein and 10 wt% n-tetradecane at neutral and acidic pH were studied by monitoring the gravitational creaming and phase separation. The effects of lecithin addition on the interfacial behavior of β-lactoglobulin were also studied to compare with the results of emulsion stability. At neutral pH, crude phosphatidylcholine (PC) from egg yolk or soybean increased the stability of the emulsion made with protein and lowered the interfacial tension of protein films more effectively than pure egg PC. A more remarkable effect on both the emulsion stability and the interfacial tension was found when crude PC was added in the oil phase rather than in the water phase. The purity of lecithins and the way to add them are suggested to be very important to make a stable emulsion with protein. On acidic pH (4.5 or 3.0), the increased creaming or phase separation in a whey protein-stabilized emulsion, but the lowered interfacial tension of β-lactoglobulin films, were found upon the addition of pure or crude PC in oil or water phase. These results suggest that in acidic pH, densely packed films may be formed on a planar oil–water interface, but not on adsorbed layers around oil droplets in an emulsion. 相似文献
2.
The study of the stability of concentrated oil-in-water emulsions is imperative to provide a scientific approach for an important problem in the beverage industry, contributing to abolish the empiricism still present nowadays. The use of these emulsions would directly imply a reduction of transportation costs between production and the sales points, where dilution takes place. The goal of this research was to evaluate the influence of the main components of a lemon emulsion on its stability, aiming to maximize the concentration of oil in the beverage and to correlate its physicochemical characteristics to product stability, allowing an increase of shelf life of the final product. For this purpose, analyses of surface and interface tension, electrokinetic potential, particle size and rheological properties of the emulsions were conducted. A 24-1 fractional factorial design was performed with the following variables: lemon oil/water ratio (30% to 50%), starch and Arabic gum concentrations (0% to 30%) and dioctyl sodium sulfosuccinate (0 mg/L to 100 mg/L), including an evaluation of the responses at the central conditions of each variable. Sequentially, a full design was prepared to evaluate the two most influential variables obtained in the first plan, in which concentration of starch and gum ranged from 0% to 20%, while concentration of lemon oil/water ratio was fixed at 50%, without dioctyl sodium sulfosuccinate. Concentrated emulsions with stability superior to 15 days were obtained with either starch or Arabic gum and 50% lemon oil. The most stable formulations presented viscosity over 100 cP and ratio between the surface tension of the emulsion and the mucilage of over 1. These two answers were selected, since they better represent the behavior of emulsions in terms of stability and could be used as tools for an initial selection of the most promising formulations. 相似文献
3.
Michiko Watanabe Ryohei F. Tsuji Noriko Hirao Soichi Arai 《Bioscience, biotechnology, and biochemistry》2013,77(11):3291-3299
An enzymatically modified gelatin with covalently attached leucine dodecyl ester, referred to as EMG-12, was used as a surfactant to prepare emulsions with different properties by changing the surfactant concentration, oil volume fraction, and pH in the water phase. The emulsions generally resisted the freezing of their constituent bulk water at approximately ?10°C, but similar emulsions produced with soy protein isolate, casein, or Tween-80 as control agents were less resistant. The freezing (or unfreezing) of the bulk water in these emulsions depended on the kind of agent used, not on the emulsion properties such as average area of the oil/water interface, stability against coalescence, and stability against creaming. The emulsion produced with EMG-12, like that produced with polyglycerol stearate, tended to maintain its unfrozen state even in the presence of silver iodide crystals added as heterogeneous ice-nuclei. The significance of producing such an antifreeze emulsion is discussed from the standpoint of cryopreservation of cold-sensitive food and biological systems. 相似文献
4.
In our previous study, we developed very stable formulations of submicron oil-in-water emulsions from Adenanthera pavonina L. (family Leguminosae, subfamily Mimosoideae) seed oil, stabilised with soybean lecithin (SPC). Continuing our research,
we introduced an additional co-emulsifier, Tween 80, to those formulations in order to decrease the size of the emulsion particles
and improve their stability. Formulations with a mean particle size ranging from 43.6 to 306.5 nm and a negative surface charge
from −45.3 to −28.5 mV were obtained. Our stability experiments also revealed that most of the tested formulations had a very
good degree of stability over a 3-month storage period, both at 4°C and at room temperature.
Since many intravenous injectable drugs exhibit lytic activity against erythrocytes, we examined this activity for the emulsion
form of cardol, a natural compound with already proven hemolytic properties. The incorporation of this agent into the emulsion
caused an evident decrease in hemolytic activity (97–99%). This highly protective effect, observed against sheep erythrocytes,
was independent of both the composition and the particle size of the emulsions used. Our studies suggest that nonionic surfactant/phospholipid-based
emulsions containing this edible oil of A. pavonina L. may be useful as an alternative formulation matrix for pharmaceutical, nutritional or cosmetic applications of otherwise
membrane-acting components. 相似文献
5.
Sodium caseinate is a commonly used emulsifier in foods, as it adsorbs on the surface of oil droplets and stabilizes them
via electrostatic and steric stabilization, forming a polyelectrolyte layer at the interface. Since the protein interface
is affected by varying environmental conditions such as pH, ionic strength, concentration of unadsorbed polymers, these emulsions
are prone to a variety of destabilization mechanisms. The objective of the present work was to observe the destabilization
of sodium caseinate stabilized oil in water emulsions using electroacoustic spectroscopy. This technique can be utilized for
the characterization of concentrated colloidal systems in situ, without dilution. The electroacoustic and ultrasonic properties
of soy oil in water emulsions were determined for sodium caseinate stabilized emulsions under conditions known to cause destabilization.
Ultrasonic attenuation and electrophoretic mobility (ζ-potential) could clearly follow the changes occurring in the emulsion
droplets, under minimal sample disruption. This is critical for these systems in a very fragile, metastable state. The emulsions
were stable to the addition of high methoxyl pectin (HMP) up to 0.1% HMP. Addition of free sodium caseinate induced depletion
flocculation, causing a decrease in the attenuation and electrophoretic mobility measured. The presence of HMP limited depletion
interactions. Acidification of the emulsion droplets resulted in a clear sol–gel transition, as shown by a steep increase
in the particle size and a decrease in attenuation. Again, destabilization was limited by HMP addition. It was concluded that
ultrasonics and electroacoustics are suitable techniques to understand the details of the destabilization processes occurring
to food emulsions, measured in situ. 相似文献
6.
PhaP or phasin is an amphiphilic protein located on surfaces of microbial storage polyhydroxyalkanoates granules. This study
aimed to explore amphiphilic properties of PhaP for possible application as a protein surfactant. Following agents were used
to conduct this study as controls including bovine serum albumin, sodium dodecyl sulfate (SDS), Tween 20, sodium oleate, a
commercial liquefied detergent together with the same amount of PhaP. Among all these tested control surfactants, PhaP showed
the strongest effect to form emulsions with lubricating oil, diesel, and soybean oil, respectively. PhaP emulsion stability
study compared with SDS revealed that PhaP had a stronger capability to maintain a very stable emulsion layer after 30 days
while SDS lost half and two-thirds of its capacity after 2 and 30 days, respectively. When PhaP was more than 200 μg/ml in
the water, all liquids started to exhibit stable emulsion layers. Similar to SDS, PhaP significantly reduced the water contact
angles of water on a hydrophobic film of biaxially oriented polypropylene. PhaP was thermally very stable, it showed ability
to form emulsion and to bind to the surface of polyhydroxybutyrate nanoparticles after a 60- min heating process at 95 °C.
It is therefore concluded that PhaP is a protein with thermally stable property for application as natural and environmentally
friendly surfactant for food, cosmetic, and pharmaceutical usages. 相似文献
7.
The purpose of this research was to develop an emulsion formulation of indomethacin (IND) suitable for nasal delivery. IND
was incorporated into the oil phases of oil in water (O/W) and water in oil (W/O) emulsions. For this purpose, different emulsifying
agents (Tween 80, Span 80 and Brij 58) were used in two emulsion formulations. When the effects of several synthetic membranes
(nylon, cellulose, cellulose nitrate) were compared with the sheep nasal mucosa, the cellulose membrane and sheep nasal mucosa
showed similar permeation properties for O/W emulsion (P > 0.05). To examine the absorption characteristics of IND, the anti-inflammatory properties of intravenous solution of IND,
intranasal O/W emulsions of IND (with or without enhancers) and intranasal solution of IND (IND-Sol) were investigated in
rats with carrageenan-induced paw edema. When citric acid was added to the nasal emulsion, the anti-inflammatory activity
was similar to that of intravenous solution (P > 0.05). Finally, it was concluded that, intranasal administration of IND emulsion with citric acid may be considered as
an alternative to intravenous and per oral administrations of IND to overcome their adverse effects. 相似文献
8.
Beatrix Markus Kopriwa 《Histochemistry and cell biology》1977,54(2):109-121
Summary The intensity of radioautographic reactions in Ilford L4, Sakura NR-H2 and Kodak NTE emulsions was compared after exposure in either dry air or dry helium gas at 4°C to test the stability of latent images in the presence or absence of oxygen. A light proof container is described in which slides bearing radioactive sections coated with the three emulsions were exposed in dry helium at a constant pressure of approximately 0.5 atm. The comparison of air and helium atmospheres during exposure of radioautographs was estimated qualitatively for 125I-labeled thyroid sections stored for several years and, in addition, quantitative data was derived from 3H-labeled methacrylate sections stored from 21 days to 1 year.With the three emulsions under study, the background fog remains low under both exposure conditions at 4°C for as long as several years duration. Using L4 emulsion, similar high grain densities are obtained in air and helium and, therefore, the latent images in L4 emulsion remain stable in the presence of oxygen. In the case of NTE and NR-H2 emulsions, as the exposure time increases, substantially lower reaction intensities are observed in air than in helium. This difference in reaction intensity is evident by 3 weeks with NTE and after 4 weeks with NR-H2. Hence, there is fading of the latent images in the latter emulsions in the presence of oxygen.It is concluded that reliable results may be obtained with the L4 emulsion by exposure of radioautographs in dry air, whereas with the NR-H2 and NTE emulsions, exposure should be in an oxygen-free medium, such as is provided by a dry helium atmosphere. 相似文献
9.
10.
《Bioscience, biotechnology, and biochemistry》2013,77(4):667-672
An emulsification method using a gel-like phase of a saccharide and protein mixture has been developed. In the method, which is called a gel emulsification method, an oil is added to the highly concentrated saccharide solution containing protein to form a clear gel-like phase, which followed by dilution with water to form a fine oil-in-water emulsion. This emulsion was investigated as to its emulsifying activity and emulsion stability as compared with that obtained by high-shear equipment, which was called a homomixer method. The emulsifying activity of the emulsions prepared by the gel emulsification method was much higher than that of the emulsions prepared by the homomixer method.The emulsions prepared by both methods were highly stable in terms of the stability against coalescence. On the other hand, the stability against creaming of the emulsions prepared by the gel emulsification method was much higher than that of the emulsions prepared by the homomixer method.The surface hydrophobicity of the protein and the unfreezable water content in the highly concentrated saccharide solution containing protein were not correlated to the emulsifying properties of the emulsions prepared by the gel emulsification method, which appeared to be dependent on the viscosity of the highly concentrated saccharide solution containing protein. 相似文献
11.
Theo Ralla Hanna Salminen Matthias Edelmann Corinna Dawid Thomas Hofmann Jochen Weiss 《Food biophysics》2017,12(3):269-278
This study describes the influence of environmental stresses on the stability of emulsions prepared by a natural sugar beet extract (Beta vulgaris L.). The emulsion stabilizing performance was compared to that of Quillaja extract, which is widely used within the food and beverage industry as natural surfactant. We investigated the influence of pH, ionic strength, heating and freeze-thawing on the mean particle size, ζ-potential and microstructure of oil-in-water emulsions (10% w/w oil, 0.75% w/w emulsifier). The emulsions stabilized by the anionic sugar beet extract were stable at pH 5–8 and against thermal treatments up to 60 °C. However, the prepared emulsions were unstable at acidic (pH 2–4) and basic pH conditions (pH 9), at high temperature (>60 °C), and at salt additions (> 0.1 M NaCl / CaCl2). Moreover, they also phase separated upon freeze-thawing. Our results show that sugar beet extract is capable of stabilizing emulsions and may therefore be suitable as natural emulsifier for selected applications in the food and beverage industry. 相似文献
12.
Enhancement of the antimicrobial properties of bacteriophage‐K via stabilization using oil‐in‐water nano‐emulsions
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Patricia Perez Esteban Diana R. Alves Mark C. Enright Jessica E. Bean Alison Gaudion A.T.A. Jenkins Amber E.R. Young Tom C. Arnot 《Biotechnology progress》2014,30(4):932-944
Bacteriophage therapy is a promising new treatment that may help overcome the threat posed by antibiotic‐resistant pathogenic bacteria, which are increasingly identified in hospitalized patients. The development of biocompatible and sustainable vehicles for incorporation of viable bacterial viruses into a wound dressing is a promising alternative. This article evaluates the antimicrobial efficacy of Bacteriophage K against Staphylococcus aureus over time, when stabilized and delivered via an oil‐in‐water nano‐emulsion. Nano‐emulsions were formulated via thermal phase inversion emulsification, and then bacterial growth was challenged with either native emulsion, or emulsion combined with Bacteriophage K. Bacteriophage infectivity, and the influence of storage time of the preparation, were assessed by turbidity measurements of bacterial samples. Newly prepared Bacteriophage K/nano‐emulsion formulations have greater antimicrobial activity than freely suspended bacteriophage. The phage‐loaded emulsions caused rapid and complete bacterial death of three different strains of S. aureus. The same effect was observed for preparations that were either stored at room temperature (18–20°C), or chilled at 4°C, for up to 10 days of storage. A response surface design of experiments was used to gain insight on the relative effects of the emulsion formulation on bacterial growth and phage lytic activity. More diluted emulsions had a less significant effect on bacterial growth, and diluted bacteriophage‐emulsion preparations yielded greater antibacterial activity. The enhancement of bacteriophage activity when delivered via nano‐emulsions is yet to be reported. This prompts further investigation into the use of these formulations for the development of novel anti‐microbial wound management strategies. © 2014 American Institute of Chemical Engineers Biotechnol. Prog., 30:932–944, 2014 相似文献
13.
Lagenidium giganteum is an effective biological control agent for mosquitoes with limited use due to poor survival and contamination during storage.
Invert (water-in-oil) emulsions using crop oils were investigated for formulating L. giganteum mycelium for improved shelf life and delivery. Cells formulated in a water-in-oil (W/O) emulsion were just as effective against
larvae as those formulated in aqueous suspension. Cells formulated in the W/O emulsion and cell suspension settled during
storage and formed clumps, which significantly reduced the efficacy of formulations. Hydrophobic silica nanoparticles were
added to the W/O emulsion formulation for oil thickening. The addition of silica significantly reduced cell sedimentation
and improved storage; thickened W/O emulsions with an initial cell density of 3900 CFU/mg applied at 0.5 mg/cm2 were greater than 95% effective at infecting mosquitoes after 12 weeks of storage at room temperature. Cell density reduction
during storage was represented using first-order kinetics. Surface treatment of silica nanoparticles and oil refinement both
had a significant effect on the first-order rate constant; as the hydrophobicity of the silica increased and level of oil
refinement decreased, the rate constant increased. The percentage of water in the W/O emulsion and type of refined crop oil
had no significant effect on the first-order rate constant. Cells formulated in the thickened W/O emulsion were less likely
to settle when applied to water compared to cells in aqueous suspension, suggesting better cell distribution in an aqueous
environment could be achieved when cells are applied in a W/O emulsion. 相似文献
14.
Coffee beverage known as espresso, must be topped by a velvety thick, reddish-brown foam called crema, to be considered properly prepared and to be appreciated by connoisseurs. In spite of the relevant role played by crema as a quality marker, espresso coffee foam has not yet been the subject of detailed investigations. Only recently, some aspects
of the Physics and Chemistry behind the espresso coffee foam have attracted the attention of scientists. In addition to sharing
several characteristics with other food foams like beer foam, for instance, the espresso coffee foam may contain solid particles
(minute coffee cell-wall fragments), it is subjected to a remarkable temperature gradient and its continuous phase is an oil
in water emulsion rendering it a very complex system to be studied. Moreover, in the typical regular espresso coffee cup volume
(serving) of 25–30 mL, crema represents at least 10% of the total volume, and this is a limitation in obtaining experimental data by conventional instruments.
The present work is aimed at reviewing the literature on espresso coffee foam. The traditional espresso brewing method will
be briefly described with emphasis on the steps particularly relevant to foam formation and stabilization. In addition to
present up-dated experimental data on surface properties at solid/beverage and air/beverage interface, recent advances on
the espresso foam formation mechanism, as well as on foam stability, will be critically examined. The key role played by carbon
dioxide generated by roasting and the effects of low and high-molecular-weight coffee compounds in promoting/inhibiting the
espresso coffee foam will be discussed and emphasized. 相似文献
15.
In this work, purification of lactoferrin from whey was performed with high recovery rate. Lactoferrin was then exploited
in the preparation of food emulsions. Two tertiary emulsions, formed by olive oil, lecithin, chitosan, and lactoferrin, were
compared: both the emulsions showed similar turbidity and stability. In the secondary emulsion formed by oil/lecithin/chitosan,
the pH was increased to 9 before addition of lactoferrin. Then, lactoferrin was added, and the pH was stabilized above pH 9.
Lactoferrin was found in amounts of 1 to 2.5 mg/ml in the multiple experiments. A fraction of the added lactoferrin was also
present in a milky layer above the emulsion layer. This was, to our knowledge, the first study of emulsions made exploiting
the interactions between lactoferrin and chitosan. It was noted that chitosan droplets remained soluble, although the hydrocolloid
solubility occurs at pH lower than 5.9. These results showed the feasibility of manufacturing lactoferrin-based emulsions
as functional foods. 相似文献
16.
《Bioscience, biotechnology, and biochemistry》2013,77(9):1688-1693
The effects of carnauba wax addition on the physical state of palm kernel oil-in-water emulsions were investigated. The oil-in-water emulsion (40 wt% oil + 60 wt% aqueous phase) kept the liquid state at 25°C irrespective of the presence or absence of carnauba wax in the oil phase. The emulsion containing the wax transformed from the liquid state to the solid state by shearing after storage for 20 h at 4°C, although the liquid-solid transition was not observed for the emulsion not containing the wax upon the same treatment. The viscoelasticity of the solid emulsions was demonstrated by small-deformation mechanical testing. Analysis of flow behavior of the emulsions showed that the change in physical properties of the emulsion containing the wax at 4°C was caused by the shearing at a low shear rate, around 50 s?1–100 s?1. According to the transition from the liquid state to the solid state of the emulsion containing the wax, the aggregation of oil droplets was found to occur to a large extent. The results of differential scanning calorimetry and surface pressure–surface area isotherms suggested that triglyceride molecules of palm kernel oil were more oriented at the oil–water interfaces in the emulsions after the wax addition. Based on these results, it is thought that carnauba wax is important in destabilization of palm kernel oil-in-water emulsions by modifying the physical state of the oil triglyceride molecules at the interfaces. 相似文献
17.
S. Tamilvanan B. Ajith Kumar S. R. Senthilkumar Raj Baskar T. Raja Sekharan 《AAPS PharmSciTech》2010,11(2):904-909
The objectives of the present work were to prepare castor oil-based nano-sized emulsion containing cationic droplets stabilized
by poloxamer–chitosan emulgator film and to assess the kinetic stability of the prepared cationic emulsion after subjecting
it to thermal processing and freeze–thaw cycling. Presence of cryoprotectants (5%, w/w, sucrose +5%, w/w, sorbitol) improved the stability of emulsions to droplet aggregation during freeze–thaw cycling. After storing the emulsion
at 4°C, 25°C, and 37°C over a period of up to 6 months, no significant change was noted in mean diameter of the dispersed
oil droplets. However, the emulsion stored at the highest temperature did show a progressive decrease in the pH and zeta potential
values, whereas the emulsion kept at the lowest temperatures did not. This indicates that at 37°C, free fatty acids were formed
from the castor oil, and consequently, the liberated free fatty acids were responsible for the reduction in the emulsion pH
and zeta potential values. Thus, the injectable castor oil-based nano-sized emulsion could be useful for incorporating various
active pharmaceutical ingredients that are in size from small molecular drugs to large macromolecules such as oligonucleotides. 相似文献
18.
Natdanai Fafaungwithayakul Pranithi Hongsprabhas Parichat Hongsprabhas 《Food biophysics》2011,6(3):407-415
This study investigated physicochemical properties of soy soluble polysaccharide (SSP) and pectinase-hydrolysed soy soluble
polysaccharide (PH-SSP) from okara, the residue from soy milk production, and their influences when used as a fibre source
in oil-in-water (o/w) emulsions. Although pectinase hydrolysed only the carbohydrate fraction in SSP, it resulted in the self-association
of PH-SSP to the large-size aggregates. When PH-SSP was added to liquid emulsion containing 3.33% (w/v) rice bran oil and 3.75% (w/v) heated soy protein, it regulated the contents of protein in serum phase, sediment phase and at oil–water interface. The
types and contents of soy proteins in the serum phase and sediment phase could be manipulated by pre-heating of soy proteins
at 80 °C for 30 min and the addition of PH-SSP. The presence of PH-SSP (0–6% w/v) induced different distribution of proteins to the sediment phase and subsequent in vitro protein digestion in the emulsion.
Overall, this study proposed the means to design the distributions of proteins in different phases of o/w emulsion for different
degrees of oil release, emulsion stability and protein-polysaccharide coacervation during the course of in vitro peptic and
tryptic digestion. 相似文献
19.
This study investigated the potential effect of porcine plasma protein hydrolysates (PPPH) coupled with Tween 20 on the physical and oxidative stability of canola oil-in-water emulsions (10% wt. lipid, pH 7.0). The PPPH obtained via limited alcalase-hydrolysis (60 min) possessed the highest emulsifying activity index and emulsion stability index (P?<?0.05). Emulsions stabilized with PPPH alone were less stable than those prepared with PPPH and Tween 20. However, a lower concentration of PPPH (2.5 mg/mL) combined with Tween 20 formed the most stable emulsions, which is mainly due to competitive adsorption present at the interface. Additionally, compared with PPPH-free emulsions, the addition of PPPH was able to retard lipid oxidation, showing up to an 8.51% decrease in the formation of conjugated dienes and a 22.08% decrease in thiobarbituric acid-reactive substances after 10 days of storage (P?<?0.05). This is mainly attributed to distinct antioxidant amino acid profiles and the distribution of peptides at the interface. Therefore, our results indicate that PPPH derived from limited hydrolysis could be used as both co-emulsifiers and antioxidative compounds in food emulsions. 相似文献
20.
This work evaluated the anionic polysaccharides to improve the functional properties and antioxidant activities, and compared the effects on covalently-linked the soy protein isolate (SPI)- (–)-epigallocatechin-3-gallat (EGCG) binary complexes. The increasing molecular weight via covalent insertion of (–)-epigallocatechin-3-gallat (EGCG) into the soy protein isolate (SPI) was verified by SDS-PAGE. The addition of polysaccharides had no obvious effects on the molecular weight, indicating noncovalent insertion by adsorption. Fourier transform infrared spectroscopy (FT-IR) analysis suggested that SPI-EGCG complexes mixed with polysaccharides changed the secondary structures of SPI with a decrease in α-helix and an increase in β-turn. The emulsions exhibited better stability index (ESI) by adding polysaccharides than the binary complexes emulsion, with decreased particle sizes and increased absolute ζ-potential values, while the value of ESI for the pectin mixed increased more. The 1,1-diphenyl-2-picrylhydrazyl radical (DPPH•) scavenging capacity of SPI-EGCG complexes with the addition of polysaccharides were both greater than 70 %. These findings indicated that anionic polysaccharides could be potentially used as a natural and safe alternative for regulating covalently-linked SPI-EGCG emulsion stability and improving emulsion oxidation resistance. 相似文献