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1.
Stability of emulsions formulated with 10 wt.% oil (concentrated fish oil, CFO, sunflower oil, SFO, or olive oil, OO), sodium caseinate concentrations varying from 0.5 to 5 wt.%, giving oil-to-protein ratios of 20–2, and 0, 20, 30 or 40 wt.% aqueous trehalose solution was studied by Turbiscan. Particle size distribution, microstructure, and small angle X-ray scattering (SAXS) patterns were also obtained. The main mechanism of destabilization in a given formulation strongly depended on oil-to-protein ratio. As evidenced by the BS-profile changes with time, emulsions formulated with 0.5 and 1 wt.% NaCas destabilized mainly by creaming while for the 2 wt.% NaCas concentration, both creaming and flocculation mechanisms, were involved. The main destabilization mechanism for the 3, 4 or 5 wt.% NaCas emulsions was flocculation. Stability of emulsions was also affected by the content of trehalose in the aqueous phase. Trehalose diminished the volume-weighted mean diameter (D4,3) and greatly improved stability.  相似文献   

2.
For milk-based emulsion products such as canned coffee or tea, the addition of bacteriostatic emulsifiers is necessary to inhibiting the growth of heat-resistant sporeformers. Since bacteriostatic emulsifiers often cause the destabilization of emulsions, other type of emulsifiers, such as stability-enhancing ones, are necessary for the long-term stability of emulsions. Four milk-based emulsions were prepared from powdered milk combined with several types of emulsifiers. The long-term stability of emulsions, which was detected by the occurrence of a creaming layer after 3 months of storage, differed according to the composition of emulsifiers. To understand the reason for the differences in the stability of emulsions, particle size, distribution, ζ-potential, and the amount of proteins and phospholipids present in the cream layer (separated oil droplets) in the emulsions were measured. Only the amount of proteins adsorbed onto oil droplets was found to be closely related to the difference in emulsion stability, that is, the more proteins adsorbed, the higher the emulsion stability. SDS–PAGE analyses revealed that κ-casein and β-lactoglobulin play an important role in emulsion stability by adsorbing onto the oil droplet surface.  相似文献   

3.
Delphinidin-3-rutinoside, a high-value of anthocyanin, was isolated and purified by ionic liquid (IL)-modified countercurrent chromatography (CCC) from waste peel of eggplant (Solanum melongena), one of the most common vegetables consumed all around the world. Different conventional CCC and IL-CCC solvent systems were evaluated in respect of partition coefficient (K), separation factor (α), and stationary phase retention factor (Sf) to separate polar target and other components. Basic solvent system, kind of ILs, and amount of ILs were systematically optimized by totally K-targeted strategy, which drastically reduced the experimental effort. Finally, a novel CCC two-phase solvent system (methyl tert-butyl ether–butanol–acetonitrile–1% trifluoroacetic acid water–1-butyl-3-methylimidazolium hexafluorophosphate ([C4MIM][PF6]) [2:4:1:5:0.2; v/v/v/v/v]) was successfully established and applied. The baseline separation of target fraction was obtained in one cycle process. The purity of delphinidin-3-rutinoside was over 99%. Moreover, the distribution behavior of different kinds of ILs in biphasic solvent system and the removal method of ILs were explored. The results showed that hydrophobic IL significantly improved the partition of polar anthocyanin in organic solvent system, thereby the separation resolution and stationary phase retention through introducing intermolecular forces. This IL-modified CCC strategy may be applied for the separation of other anthocyanins from variety of natural food resources and waste.  相似文献   

4.
Aqueous extraction is an emerging alternative to hexane-based oilseed extraction since it eliminates the dangers associated with processing, and allows the simultaneous recovery of high-quality protein products and vegetable oils. Five different successive non-enzymatic and enzymatic aqueous extraction processes (AEPs/EAEPs) were developed for dehulled yellow mustard flour with the aim of producing food-grade protein and yellow mustard oil for industrial applications. The oil released in these processes was tied up in oil-in-water emulsions that must be destabilized to recover free oil prior to industrial utilization. This study endeavored to ascertain the extraction parameters that increase oil and protein extraction yields and reduce emulsion stability during successive AEPs/EAEPs for dehulled yellow mustard flour. The remarkable stability of the emulsions was due to the presence of protein emulsifiers of high molecular weight along with the mixed phospholipid–oleosin layer. pH adjustment for emulsion destabilization was relatively inefficient; therefore, enzymatic demulsification treatments with different proteases and phospholipases were evaluated for their ability to release free oil by hydrolyzing the targeted emulsifiers. Although protease treatments with Protex 6 L at a concentration of 2.5 wt.% were effective in recovering over 91% of the oil in the emulsions, phospholipase treatments did not modify the free oil recovery from the emulsions. The results indicated that the enzymatic aqueous extraction of dehulled yellow mustard flour did not offer sufficient improvement in usable protein recovery to warrant the extra effort and cost.  相似文献   

5.
Bagasse, a by-product from raw sugar factories, is conventionally burned for energy production. In this study, bagasse extracts from hydrothermal liquefaction (HTL) treatment (160 °C, 1 MPa and 30 min) with a carbohydrate content of 510.3 mg g−1 and 0.5 mg g−1 of total phenols were applied as emulsifiers in oil-in-water (O/W) emulsions. Bagasse extracts from HTL (0.5–4 wt%) lowered the interfacial tension between oil–water interphase from 19.8 to 14.0 mN m−1, owing possibly to the surface-active hydrophilic carbohydrate-hydrophobic lignin complexes in the extracts (lignin content: 7.1% w/w). Emulsions stabilised by bagasse extracts from HTL with average droplet size, dav of 0.79 μm were comparable with gum arabic (GA), dav of 2.24 μm after 11 days at 25 °C. Bagasse extracts containing biopolymers have the potential for industrial applications involving emulsion systems; therefore, HTL treatment of bagasse without any solvents can be regarded as an effective tool for producing natural emulsifiers.  相似文献   

6.
In this study, the effect of high-intensity ultrasound (HIUS) (200 and 400 W for 0, 5, 10 and 15 min respectively) on conformational changes, physicochemical, rheological and emulsifying properties of scallop (Patinopecten yessoensis) myofibrillar protein (SMP) was investigated. HIUS-treated SMP had lower α-helix content and higher β-sheet content compared with the native SMP. HIUS treatment induced the unfolding of SMP and increased the surface hydrophobicity. The particle size of SMP decreased and the absolute zeta-potential increased after ultrasonication, which in turn increased the solubility of SMP. The conformational changes and the improvement of physicochemical properties of SMP increased the ability for SMP to lower the interfacial tension at the oil–water interface and increased the percentage of adsorbed protein. As a result, the emulsifying properties, rheological properties of SMP and storage stability of emulsions were also improved. In conclusion, HIUS treatment has future potential for improving the emulsifying properties of SMP.  相似文献   

7.
Water-in-oil-in-water (W1/O/W2) double emulsions (DEs) containing gelatin and sodium chloride (NaCl) in the inner aqueous phase were developed for controlled release applications. Emulsions were prepared with water and canola oil, as well as with polyglycerol polyricinoleate and polysorbate 80 as emulsifiers for the primary water-in-oil (W1/O) emulsion and secondary W1/O/W2 emulsions, respectively. All DEs containing both NaCl and gelatin were stable against sedimentation for the month-long study whereas control emulsions (with either no NaCl or gelatin) showed visual phase separation. The average oil globule size in freshly-prepared DEs grew from ∼45 to 70 μm with an increase in salt load from 2 to 8% (w/w), and changed little after 1 month. Besides its role in stabilization, NaCl was also used as a marker to evaluate DE release behaviour. The salt diffusion coefficient obtained using Fujita’s model rose from 4.7 to 6.0 × 10−11 cm2/s with increasing NaCl concentration in the DEs from 2 to 8% (w/w). All stable DEs showed a high salt retention in the inner aqueous phase (>94%) after 1 month of storage at 4 °C. These results demonstrated the synergistic action of a gelling agent and electrolyte in stabilizing and modulating the release behaviour of NaCl from W1/O/W2 DEs.  相似文献   

8.
王春玲  孟祥晨 《食品工业科技》2012,33(7):329-332,400
采用单因素实验设计,通过机械搅拌方法制备O/W乳状液。通过乳状液的离心稳定性、粘度和乳状液的显微结构,研究不同HLB值的复合乳化剂及含量、脱脂乳粉溶液的浓度以及油和水比例对乳状液性质的影响,最终确定较佳的乳状液成分。实验结果表明:当以Span-80和Tween-80为复合乳化剂,其HLB值为9.6、复合乳化剂含量为16%(w/w)、脱脂乳粉溶液浓度为25%(w/v)、油与水比为1∶1(w/w)时,可以获得状态较好的乳状液,此时乳状液的离心稳定性最高,可以达到97.5%。  相似文献   

9.
The aim of this work was to enhance emulsification properties of canola proteins through enzymatic proteolysis and pH variaton. Canola protein isolate (CPI) and hydrolysates (CPHs) were used to form emulsions at pH 4.0, 7.0 and 9.0 followed by storage at 4 or 25 °C for 7 days. Controlled enzymatic hydrolysis led to increased peptide bond cleavage with time (0.23 g/100 g in CPI to 7.18 g/100 g after 24‐h Alcalase hydrolysis). Generally, oil droplet sizes were smaller for emulsions made at pH 9.0, which suggest better quality than those made at pH 4.0 and 7.0. Trypsin hydrolysate emulsions were the most physically stable at pH 7.0 and 9.0; in contrast, the pepsin hydrolysate emulsions were unstable at all conditions. The results suggest that selective enzymatic hydrolysis could play an important role in enhancing successful incorporation of canola proteins and peptides into food systems as protein emulsifiers.  相似文献   

10.
Emulsion-filled gels are widely used in cosmetic, food, and pharmaceutical industry. As rheological properties of these systems are strongly dependent on the properties of the gelled polymer network, rheological characteristics of gels containing high and low acyl gellan gum were analyzed. Under the processing conditions low acyl emulsions were unstable, thus in the present work the influence of oil and hydrocolloid concentrations on the viscoelastic behavior of emulsion-filled gels containing high acyl gellan gum was studied. Increasing gellan concentration (from 0.1 g/100 g to 0.5 g/100 g) produced stronger gels, while oil fraction (10 g/100 g–30 g/100 g) slightly affected the elastic behavior of the emulsions reinforcing the structure and the elastic characteristics of the gellan matrix. Sauter diameter (d32) was measured for all emulsions and an average value of 12 μm was obtained. Rheological data (oscillatory and creep–recovery tests) were successfully modeled to interpret the structural characteristics of the gelled emulsions. The broadened Baumgaertel–Schausberger–Winter spectrum was used to represent the linear viscoelastic behavior of the continuous phase and the emulsified system, showing that the rheological behavior of the systems was controlled by the highly structured continuous phase rather than the contribution of filler lipid droplet in the emulsion. Relaxation spectra were validated using creep–recovery experiments. Regardless of hydrocolloid concentration, creep compliance of the gel emulsions decreased compared with their respective gels, showing that the inclusion of oil droplets produced a reinforcement of the structure and the gel strength of the matrix.  相似文献   

11.
The objective of this study was to investigate the protective effect of five different emulsifiers on iron‐mediated lipid oxidation in 70% fish oil‐in‐water emulsions. The emulsifiers were either based on protein (whey protein isolate and sodium caseinate) or based on phospholipid (soy lecithin and two milk phospholipids with different phospholipid contents, MPL20 and MPL75). Lipid oxidation was studied at pH 4.5 and 7.0, and results were compared to lipid oxidation in neat fish oil. Results showed that all emulsions oxidised more than neat oil. Furthermore, emulsions prepared with proteins oxidised more at low pH than at high pH, and casein emulsions oxidised the least (Peroxide value (PV) at day 7 was 0.5–0.7 meq kg?1). Among emulsions prepared with phospholipids, emulsions with MPL75 were the most oxidised followed by emulsions prepared with lecithin and MPL20. Thus, PV in MPL75 emulsions was 5.0–5.5 meq kg?1 at day 7 compared with 0.9–1.9 meq kg?1 in MPL20 emulsions.  相似文献   

12.
Changes induced by addition of calcium chloride in particle size distribution and electrokinetic potential were determined in sodium caseinate/sodium alginate mixtures dissolved in water or acetate buffer at ambient temperature. Rheological properties of aqueous mixtures and respective oil-in-water emulsions (30% oil w/w) were evaluated using a low-stress rheometer. Stability and particle diameter of emulsions were measured. Caseinate and alginate solutions were negatively charged and showed negative electrokinetic potential; however values of mixtures were between those of the values for the individual hydrocolloids. When calcium ions were added the electrokinetic potential diminished while the negative charge was preserved. Aqueous mixtures of caseinate and alginate showed average particles size between of those of caseinate or alginate samples. We observed low viscosity values and Newtonian behavior for both caseinate (1 and 2%) and alginate (0.1%). Addition of 5 mM CaCl2 to alginate solutions induced shear-thinning behavior as well as the development of viscoelasticity. Both the viscosity and the elastic modulus of these polysaccharide solutions were attenuated by the presence of protein or dispersed oil in mixtures or emulsions, respectively. High average particle diameter of emulsions prepared was obtained (close to 10 μm), however, stability of emulsions was possible only with the addition of CaCl2 to the mixtures, in both water and acetate buffer. In these cases elastic behavior predominated to viscosity in the formation of emulsions, confirming the prevalence of aqueous phase rheology on emulsions.  相似文献   

13.
In this study, the chemical composition and emulsifying properties of camellia lecithin recovered from crude camellia oil by both acid and enzymatic degumming were investigated. Camellia lecithin recovered from acid degumming (CLAD) mainly comprised phospholipids (PS, PI, PE and PA), whereas camellia lecithin recovered from enzymatic degumming (CLED) contained more lysophospholipids (LPI, LPE, LPA). The saturated fatty acids made up a large portion of total fatty acids in CLED compared to CLAD. CLED-stabilised emulsions tended to be more stable than CLAD-stabilised emulsions. Meanwhile, emulsions stabilised by CLED exhibited smaller particle size in agreement with their microstructures. Moreover, both CLED and CLAD-stabilised emulsions were sensitive to pH and ionic strength changes and provided smaller particle size and higher stability at pH = 7 and 1 mm NaCl concentration. These findings provide valuable information for potential applications of camellia lecithin with characteristic phospholipid composition as alternative o/w emulsifiers in food industry.  相似文献   

14.
Thixotropic behavior of mixed 8% starch/gelatin gels and gel-emulsions (8% of the sunflower oil dispersed in the starch/gelatin gel), prepared with the addition of different emulsifiers, by means of the rotational viscometer with coaxial cylinders, has been investigated. Different emulsifiers (Na-dodecyl sulfate, cetyl alcohol, mono- and diglycerides of fatty acids and alkyl polyglycolethers) were applied before (at 40°C) and after (at 96°C) gelatinization of the starch. Thixotropic properties, i.e. the coefficients of thixotropy of gels and emulsions were determined by the thixotropic loop method. Samples were taken in different time intervals (up to 72 h), in order to investigate the ageing effects. Very stable gels and gel emulsions (containing carbohydrate, protein and fatty component), with high aging stability can be obtained.  相似文献   

15.
Modification of milk fat composition might be desirable to alter manufacturing characteristics or produce low saturated fat dairy products that more closely meet consumer dietary preferences. The aim of this research was to evaluate functional properties of butter oil obtained from milks with fat composition modified by altering the profile of long-chain fatty acids (FA) absorbed from the small intestine of cows. A control and 5 mixtures of long-chain free FA were infused into the abomasum of lactating dairy cows in a 6 × 6 Latin square design with 21-d periods. Treatments were 1) control (no FA infused), 2) mostly saturated FA (C16:C18 = 0.72), 3) low-linoleic palm FA (C16:C18 = 0.85), 4) palm FA (C16:C18 = 0.72), 5) soy FA (C16:C18 = 0.10), and 6) high-palmitic soy FA (C16:C18 = 0.68). All treatments included meat solubles and Tween 80 as emulsifiers. Solid fat content (from 0 to 40°C), melting point, and force at fracture were determined in butter oil. Milk fat from cows infused with palm FA (treatment 4) exhibited functionality equal to or better than control butter oil. Infusion with palm FA increased amounts of triglyceride (TG) fractions with 48, 52, and 54 carbon numbers but decreased TG with 32, 34, 36, and 42 carbon numbers. Infusion with soy FA increased TG with 26, 38, 40, 52, and 54 carbon numbers but decreased TG with 34, 42, and 46 carbons. Infusion of the mostly saturated FA increased TG with 38, 50, 52, and 54 carbon numbers but decreased TG with 32, 34, and 42 carbon numbers. These TG groups were consistently correlated with functional properties of butter oils from different treatments. The content of palmitic acid is important for maintaining functionality in the presence of increased polyunsaturated FA. The composition of milk fat may be able to be optimized through nutritional manipulation of diets for dairy cows if the optimal composition of FA and TG is defined for a particular dairy product.  相似文献   

16.
This study aimed to develop vitamin D3 fortified ice cream by incorporating vitamin D3 in an emulsified form using milk protein as emulsifier. Physicochemical stability of vitamin D3 emulsions using different milk protein emulsifiers including nonfat dry milk, sodium caseinate (Na-Cas), and whey protein isolate was investigated. Emulsion using Na-Cas had the smallest oil droplet size and the lowest creaming index throughout the storage time (P < 0.05) and was selected to fortify in full-fat, reduced-fat, and low-fat ice creams at 250 IU per serving. Vitamin D3 retention in each ice cream was determined after 0, 7, 14, 28 and 56 d of storage at −20 °C. The results indicated that the emulsified form of vitamin D3 remarkably improved vitamin D3 stability in all ice cream formulations.  相似文献   

17.
《Food Hydrocolloids》2007,21(5-6):943-952
The subject of the present paper was to investigate the possibility of stabilising water-in-oil-in-water emulsions (W/O/W) by using sodium caseinate (SC)–dextran (Dex) conjugates in order to influence the release of vitamin B12 from the inner water phase (W1) to the outer aqueous phase (W2).To prepare the conjugate the SC was combined with Dex (Mr 250,000 or 500,000 g/mol) and incubated at 60 °C and a humidity of 79% for 8 h.The double emulsions, with encapsulated vitamin B12, were prepared using a two-step emulsification technique. Whereas different amounts of polyglycerin polyricinoleate (PGPR, E476) were the hydrophobic emulsifier, the conjugate and the SC alone were used as the hydrophilic emulsifiers. The investigations comprised the determination of the particle size distribution of the W/O/W emulsion and measurement of the amount of vitamin B12 migration from W1- to the W2-phase during the second stage of emulsion preparation and after heating or pH changing of emulsion.The water-containing oil droplets of the W/O/W emulsions were smaller and distributed more narrowly using SC–Dex conjugate as emulsifier instead of pure protein. Under acidic conditions, the conjugate-containing emulsions were more coalescence stable than the emulsions with SC, and the vitamin B12 release from the inner W1-phase was significantly decreased.  相似文献   

18.
This work investigates the fundamental properties of emulsifiers that may contribute to the fat-associated sensory attributes of emulsions. Model oil-in-water emulsions were prepared with 0, 12, 24, 36 and 48% oil and emulsified with seven different emulsifiers; two proteins; sodium caseinate and whey protein, and five different sucrose esters. Emulsions were rated for perceived ‘fat content’, ‘creaminess’ and ‘thickness’ on nine-point category scales. Instrumental measurements of particle size, viscosity, thin film drainage, surface dilational modulus and interfacial tension were made. The sensory results indicate significant main and interactive effects of fat level and emulsifier type. At higher fat levels, emulsions prepared with sodium caseinate and whey protein emulsifiers had higher viscosities and higher sensory scores than those prepared with the sucrose esters. Results indicate that emulsifier type has a significant effect on the sensory properties of oil-in-water emulsions, and relationships between instrumental and sensory measures suggest that this may be due to the interfacial properties of emulsifiers at the oil–water interface. © 1998 SCI.  相似文献   

19.
Emulsion-filled hydrogels are a promising approach to encapsulate lipophilic bioactive compounds and protect them throughout storage. This study aimed to investigate the chemical stability of a vitamin complex (β-carotene, cholecalciferol, α-tocopherol, and ascorbic acid) in lentil protein emulsion-filled pectin hydrogel produced using high-intensity ultrasound (HIUS) as homogenization technique. The impacts of HIUS nominal power, the addition of xylooligosaccharides (XOS) and ascorbic acid on the viscoelastic properties, chemical stability, microstructure, color, lipid oxidation and antioxidant activity of the formed emulsion-filled hydrogels were evaluated. Overall, the hydrogels showed shear-thinning behavior. The addition of ascorbic acid had no significant effect on the rheological properties. The samples processed at 900 W for β-carotene and ascorbic acid contents and 600 W for cholecalciferol and α-tocopherol contents after 21 days of storage had maximum retention capacity. The presence of ascorbic acid contributed to the improved antioxidant activity, thus reducing the lipid oxidation in the samples. The FT-IR spectra showed no conformational difference before and after HIUS processing, indicating no degradation of the vitamin structures and XOS used. The emulsion-filled hydrogels were then dried to form aerogels using supercritical carbon dioxide (SC-CO2) technology. The concentration of pectin used influenced the drying of aerogels. Emulsion-filled hydrogels and aerogels with improved stability of the complex vitamins were produced.  相似文献   

20.
The potential of high-pressure homogenization (HPH) to allow the production of a fermented potato protein isolate-based yogurt alternative with low and high oil concentration was investigated. The yogurt alternatives containing different oil concentrations (1.5%, 3%, and 10%) were obtained by inoculating the homogenized (0.1 MPa, 30 MPa, and 200 MPa) emulsions. HPH reduced emulsion particle size (all oil levels) compared to the non-homogenized samples (0.1 MPa). The overall emulsion whiteness index increased after HPH treatment while the highest value was obtained for 200 MPa 10% oil, 76.01 ± 0.50, compared to 65.33 ± 2.05 obtained for 0.1 MPa 10% oil. The creaming velocity was decreased by HPH, e.g., for 3% oil from 10.70 ± 0.11 (0.1 MPa) to 0.59 ± 0.04 after 200 MPa. Microscopic images of gels from HPH treated emulsions revealed smaller oil droplets and narrower component distribution. This study further highlights the possibility of HPH technology to produce plant-protein-based yogurt alternatives with different oil concentrations.Industrial relevanceIn recent years, the food industry has changed rapidly and has faced new consumer demands and global food trends. Consumers pay attention to food and its effect on their health, and the popularity of dairy alternatives with reduced-oil and, on the other hand, Greek-style yogurt analogs has grown. (Ultra) high-pressure homogenization ((U)HPH) is a continuously emerging technology that can potentially provide simultaneous homogenization and microbial inactivation and induce changes in solution physicochemical properties such as emulsion stabilization mainly by significantly reducing oil droplet size and improving interactions between emulsifiers and oil phase. By utilizing HPH, plant-based yogurt alternatives can be formed with a wide range of oil concentrations and similar texture profiles and water holding capacity, free of additional stabilizers and artificial emulsifiers. The results of this bottom-up approach study could be of great importance for considering the potential for scaling-up and future implementation of (U)HPH in the food industry to produce plant-based milk and yogurt alternatives with low and high oil content, having a clean label.  相似文献   

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