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1.
This study aims to examine the microstructure, rheology and lipolysis of water-in-oil (W/O) emulsions (40 wt.%) prepared with or without (Control) the addition of normal (NAM) and high amylose (HAM) maize starch during simulated digestion in a semi-dynamic gastrointestinal tract (GIT) model. Microstructural examinations showed modification in initial W/O emulsion droplets to multiple W1/O/W2 droplets during in vitro digestion. This is in line with the rheological results, where the shear viscosity and moduli in the oral phase were remarkably reduced after entering the intestinal phase. In comparison to control and NAM emulsions, HAM emulsions showed a more compact and continuous network structure and greater viscosity and elastic modulus throughout GIT digestion. These results support lipolysis, where fewer free fatty acids were released in the HAM emulsion (70%) than in the control (86%) and NAM (78%) emulsions. This work has provided an in-depth understanding of the digestion of W/O emulsions as influenced by amylose content, which is meaningful for the development of low-fat products with reduced lipid digestibility.  相似文献   

2.
ABSTRACT: In this study we tried to prepare stable water-in-oil-in-water (W/O/W) emulsions using polyglycerol polyricinoleate (PGPR) as a hydrophobic emulsifier and whey protein isolate (WPI) as a hydrophilic emulsifier. At first, water-in-oil (W/O) emulsions was prepared, and then 40 wt% of this W/O emulsion was homogenized with 60 wt% aqueous solution of different WPI contents (2, 4, and 6 wt% WPI) using a high-pressure homogenizer (14 and 22 MPa) to produce W/O/W emulsions. The mean size of final W/O/W droplets ranged from 3.3 to 9.9 μm in diameter depending on the concentrations of PGPR and WPI. It was shown that most of the W/O/W droplets were small (<5 μm) in size but a small population of large oil droplets (d > 20 μm) was also occasionally observed. W/O/W emulsions prepared at the homogenization pressure of 22 MPa had a larger mean droplet size than that prepared at 14 MPa, and showed a microstructure consisting of mainly approximately 6 to 7-μm droplets. When a water-soluble dye PTSA as a model ingredient was loaded in the inner water phase, all W/O/W emulsions showed a high encapsulation efficiency of the dye (>90%) in the inner water phase. Even after 2 wk of storage, >90% of the encapsulated dye still remained in the inner water phase; however, severe droplet aggregation was observed at relatively high PGPR and WPI concentrations.  相似文献   

3.
Water-in-oil-in-water (W1/O/W2) emulsions provide protective encapsulation to plant bioactive compounds in food matrix and under gastrointestinal conditions. However, the stability of the emulsions during the storage is crucial for their use in the food industry. Hence, the aim of this study was to enhance the stability and bioaccessibility of W1/O/W2 emulsions containing anthocyanins with the use of sodium carboxymethylcellulose (CMCNa). The emulsions were prepared by ultrasound technology, adding polyglycerol polyricinoleate (PGPR) in the inner aqueous phase of emulsions, and lecithin and Tween 20 in the outer aqueous phase. The systems were physicochemical characterized over the time and their behavior under simulated gastrointestinal conditions was investigated. Our results showed high encapsulation efficiencies above 90% and an increase in bioaccessibility with the use of CMCNa. Moreover, the polymer addition slowed down the free fatty acid release and increased the oil digestibility of lecithin-stabilized emulsions. These latter emulsions presented the highest bioaccessibility (31.08?±?1.73%), the more negative values of ζ-potential and no variations on the particle size and the backscattering profile over the time, thus being the most stable emulsions. These results provide useful information for the design of anthocyanin emulsion-based delivery systems to guarantee their functionality in food matrices as well as through the gastrointestinal tract.  相似文献   

4.
Water-in-oil-in-water (W/O/W) emulsions were formulated based on rapeseed oil, olive oil, olein and miglyol. Polyglycerol polyricinoleate and sodium caseinate were used as lipophilic and hydrophilic emulsifiers, respectively. Magnesium was encapsulated in the inner aqueous droplets. Emulsion stability was assayed through particle sizing and magnesium release at two storage temperatures (4 and 25 °C) over 1 month. Irrespective of the oil nature, both the primary W/O and W/O/W emulsions were quite stable regarding the size parameters, with 10-μm fat globules and 1-μm internal water droplets. Magnesium leakage from W/O/W emulsions was influenced by the oil type used in the formulation: the higher leakage values were obtained for the oils characterized by the lower viscosity and the higher proportion of saturated fatty acids. Magnesium release was not due to droplet–globule coalescence but rather to diffusion and/or permeation mechanisms with a characteristic rate that varied over time. In addition, W/O/W emulsions were resistant to various thermal treatments that mimicked that used in pasteurization processes. Finally, when W/O/W emulsions were placed in the presence of pancreatic lipase, the emulsion triglycerides were hydrolysed by the enzyme. These results indicated a possible use of W/O/W emulsions loaded with magnesium ions in food applications.  相似文献   

5.
The aim of this paper was to prepare and characterise multiple emulsions and assess their utility as pork backfat replacers in meat gel/emulsion model systems. In order to improve the fat content (in quantitative and qualitative terms) pork backfat was replaced by a water-in-oil-in-water emulsion (W1/O/W2) prepared with olive oil (as lipid phase), polyglycerol ester of polyricinoleic acid (PGPR) as a lipophilic emulsifier, and sodium caseinate (SC) and whey protein concentrate (WP) as hydrophilic emulsifiers. The emulsion properties (particle size and distribution, stability, microstructure) and meat model system characteristics (composition, texture, fat and water binding properties, and colour) of the W1/O/W2, as affected by reformulation, were evaluated. Multiple emulsions showed a well-defined monomodal distribution. Freshly prepared multiple emulsions showed good thermal stability (better using SC) with no creaming. The meat systems had good water and fat binding properties irrespective of formulation. The effect on texture by replacement of pork backfat by W1/O/W2 emulsions generally depends on the type of double emulsion (associated with the hydrophilic emulsifier used in its formulation) and the fat level in the meat system.  相似文献   

6.
为对比不同米糠蛋白质量浓度下O/W及W/O/W乳液的稳定性,以米糠蛋白作为基料,采用双乳化法制备O/W及W/O/W乳液,考察不同米糠蛋白质量浓度下乳液的微观形态和稳定性并探究其界面稳定机理。结果表明:W/O/W乳液的贮存稳定性显著优于O/W乳液;与相同蛋白含量的O/W乳液相比,W/O/W乳液的黏度显著提高;当米糠蛋白质量浓度为0.4 g/100 mL时,W/O/W乳液的稳定性较O/W乳液提高了1 倍以上;乳液内部包裹更多的W/O液滴,W/O/W乳液的粒径较大;而此时静电斥力也较大,起到稳定乳液的目的。同时,米糠蛋白质量浓度不小于0.4 g/100 mL时,O/W及W/O/W乳液中蛋白质的吸附率较高,达到78%以上。本研究为天然米糠蛋白质在食品级乳液中的开发提供参考,为粮食副产物的综合利用提供了新思路。  相似文献   

7.
The evaluation of functional properties of different chia protein hydrolysates (CPH) and their application in O/W emulsions were studied. Enzymatic treatments with pepsin, pancreatin or the sequential action of pepsin–pancreatin were applied to hydrolyse a chia protein concentrate (CPC). Oil-in-water emulsions stabilised with CPC or these CPHs, with or without chia mucilage, were prepared at pH 7 or 10. Particle size, global stability, ζ-potential and rheological measurement of emulsions were determined. CPH presented higher (P ≤ 0.05) solubility and surface hydrophobicity levels, exhibiting better emulsifying properties than CPC. Emulsions with CPH presented smaller (P ≤ 0.05) droplet sizes than those with CPC. Regarding to physicochemical stability, emulsions at pH 7 were less stable than those at pH 10, showing destabilisation by creaming and coalescence. The addition of chia mucilage increased the apparent viscosity of emulsions and led to modifications in their fluid behaviour, exhibiting an interesting role as a thickening agent.  相似文献   

8.
《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   

9.
研究制备方法和乳化剂对W/O/W型复乳稳定性的影响,优化工艺参数,并研究体系包埋矢车菊素-3-葡萄糖苷(cyanidin-3-glucoside,C-3-G)的效果。得到优化条件:初乳搅拌速率15 500 r/min、复乳搅拌速率7 000 r/min、油相乳化剂聚甘油蓖麻醇酯添加量16%、亲水性乳化剂的亲水亲油平衡值10、亲水性乳化剂添加量10%,优化后离心保留率达到80.25%。利用优化得到的复乳体系包裹C-3-G,发现复乳对C-3-G有良好的包裹能力,复乳对C-3-G的载药量为1 500 mg/L,包封率为98.08%,且C-3-G的包埋提高内水相渗透压和复乳稳定性。  相似文献   

10.
In order to broaden the range of applications for oyster peptides in the food field, the amino acid composition of oyster peptide was analysed, after which the peptide sequence was identified using liquid-mass spectrometry technology. A W1/O/W2 double emulsion was prepared by the two-step shear emulsification method. The W1/O/W2 double emulsion was further freeze-dried after addition of alginate to obtain the final product, and the characteristics of the related product were analysed. The results show that oyster peptides are mainly composed of short peptides with molecular weights between 459.3 Da and 2716.3 Da. Polyglycerol polyrinoleate (PGPR) was selected as the emulsifier and added at 5% of the mass of the oil phase. The mass ratio of the oil phase to the water phase was O:W = 6:4, and optimal stability of the W1/O emulsion was obtained by shearing and emulsifying for 2 min at 12 000 rpm. A superior W1/O/W2 double emulsion can be obtained by secondary emulsification in which the hydrophilic emulsifier Tween 80 was added at 0.8% (w/w) of the mass of the external water phase (W2). The mass ratio of the emulsion to the external water phase was 5:5. The lyophilised product has good re-solubility, with the reconstituted emulsion maintaining the double-emulsion structure. Electronic nose results showed that the peculiar smell of the reconstituted emulsion was significantly lower than that of the oyster peptide solution. The results of this research provide a reference for the development and application of oyster peptides in the field of functional health foods.  相似文献   

11.
The present study was performed to investigate the possibility of using 4-α-glucanotransferase (4αGTase)-treated starch in W/O/W emulsions to increase their encapsulation efficiency (EE) and stability. Emulsions were prepared using soybean oil, polyglycerol polyricinoleate (PGPR), 4αGTase-treated starch and Tween 20. The mean diameter of W/O/W droplets ranged from 4 to 10 μm depending on the sonication time. When the dye was loaded in the internal water phase, the emulsion prepared by sonication for 1 and 2 min showed a high EE of the dye (>90%). The W/O/W emulsion prepared by sonication for 3 min showed an EE of <90%, but this EE was improved by adding 4αGTase-treated starch to the internal water phase. 4αGTase-treated starch was added to the internal water phase of W/O/W emulsions prepared with a low concentration of PGPR, and the PGPR concentration required to maintain an EE >90% was reduced. W/O/W emulsions containing 4αGTase-treated starch also showed better stability against heating and shearing stresses. These results indicated that 4αGTase-treated starch could be used in the preparation of W/O/W emulsions, which would allow the formulation of W/O/W emulsions with a reduced surfactant concentration.  相似文献   

12.
The potential food applications of water-in-oil-in-water (W1/O/W2) double emulsions are great, including the encapsulation of flavours or active ingredients. However, the stability of these emulsions restricts their applications in food systems. Sodium caseinate (NaCN)–maltodextrin (Md40 or Md100) conjugates were investigated for their potential to improve the stability of W1/O/W2 double emulsions compared to NaCN. NaCN–Md40 and NaCN–Md100 conjugates were prepared by a Maillard-type reaction by dry heat treatment of mixtures of NaCN–Md40 or NaCN–Md100 at 60 °C and 79% relative humidity for 4 days. Water-in-oil-in-water (W1/O/W2) double emulsions with NaCN, NaCN–Md40 or NaCN–Md100 as outer aqueous phase containing emulsifier were prepared using a two-step emulsification process. General emulsion stability was characterised by determining the droplet size distribution, viscosity characteristics and by confocal microscopy of the W1/O/W2 double emulsions on formation and after their storage under accelerated shelf life testing conditions at 45 °C for up to 7 days. Inner phase encapsulation and stability were characterised by monitoring the level of entrapped Vitamin B12 in the inner aqueous phase on formation of the double emulsions and after storage at 45 °C for up to 7 days. Conjugate stabilized emulsions were more generally stable than NaCN stabilized emulsions. In comparison to NaCN stabilized emulsions, conjugate stabilized emulsions showed improved Vitamin B12 encapsulation efficiency in the inner aqueous phase on emulsion formation and improved encapsulation stability following storage of the emulsions.  相似文献   

13.
Semi-solid multiple W/O/W emulsions with low concentrations (0.8, 1.6 and 2.4% w/w) of lipophilic polymeric primary emulsifier PEG-30-dipolyhydroxystearate (PDHS) have been formulated. Both emulsions, primary and multiple, were prepared with high content of inner phase (Phi1 = Phi2 = 0.8). All the formulations differ only in the lipophilic emulsifier concentration. Evaluating several parameters such as macroscopic and microscopic aspect, droplet size, accelerated stability under centrifugation and flow and oscillatory rheological behaviour, assessed the multiple systems. It is possible to formulate the semi-solid W/O/W multiple emulsions with low concentrations of PDHS as the primary emulsifier. It appeared that the highest long-term stable multiple emulsion with the lowest droplet size, the highest apparent viscosity and highest elastic characteristic, was the sample with the highest concentration (2.4% w/w) of the primary emulsifier.  相似文献   

14.
Ferrous bisglycinate aqueous solution was entrapped in the inner phase (W1) of water-in-oil-in-water (W1/O/W2) multiple emulsions. The primary ferrous bisglycinate aqueous solution-in-mineral oil (W1/O) emulsion contained 15% (w/w) ferrous bisglycinate, had a dispersed phase mass fraction of 0.5, and was stabilized with a mixture of Grindsted PGPR 90:Panodan SDK (6:4 ratio) with a total emulsifiers concentration of 5% (w/w). This primary emulsion was re-emulsified in order to prepare W1/O/W2 multiple emulsions, with a dispersed mass fraction of 0.2, and stabilized using protein (whey protein concentrate (WPC)):polysaccharide (gum arabic (GA) or mesquite gum (MG) or low methoxyl pectin (LMP)) complexes (2:1 ratio) in the W2 aqueous phase. The W1/O/W2 multiple emulsion stabilized with WPC:MG (5% w/w total biopolymers concentration) provided smaller droplet sizes (2.05 μm), lower rate of droplet coalescence (7.09 × 10−7 s−1), better protection against ferrous bisglycinate oxidation (29.75% Fe3+) and slower rate of ferrous bisglycinate release from W1 to W2 (KH = 0.69 mg mL−1 min−0.5 in the first 24 h and 0.07 mg mL−1 min−0.5 for the next 19 days of storage time). Better encapsulation efficiencies, enhanced protection against oxidation and slower release rates of ferrous bisglycinate were achieved as the molecular weight of the polysaccharide making up protein:polysaccharide complex was higher. Thus, the factor that probably affected most the overall functionality of multiple emulsions was the thickness of the complex adsorbed around the multiple emulsion oil droplets. These thicknesses determined indirectly by measuring the z-average diameter of the complexes, and that of the WPC:MG (529.4 nm) was the largest.  相似文献   

15.
W/O/W多重乳状液的实验研究   总被引:2,自引:0,他引:2  
研究了W/O/W多重乳状液的制备方法及影响其稳定性的因素。通过正交试验选出较佳的工艺参数,获得了较稳定的W/O/W多重乳状液。  相似文献   

16.
Water-in-oil-in-water (W/O/W) double emulsions present a reduced-fat alternative to conventional O/W food emulsions, as part of the dispersed oil phase is replaced with water. In this study, the concept of a reduced-fat whipped topping produced by W/O/W technology was proven. Whipping of a W/O/W emulsion, containing only 20% oil phase and a solid fat content of 78%, produced a superior whipped topping, in terms of firmness and overrun, compared to its whipped O/W emulsion counterparts. The presence of PGPR in the oil phase increased structure formation during whipping, while the additional dispersed-phase volume resulted in a better air inclusion. Two commercial monoacylglycerols (saturated and unsaturated) were investigated to improve the whipping properties of the produced W/O/W double emulsion. Both increased the susceptibility towards partial coalescence, thereby reducing whipping time and overrun, while increasing firmness of the produced whipped topping. Furthermore, the effect was stronger for the unsaturated than for the saturated monoacylglycerol.  相似文献   

17.
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   

18.
介绍了酒精对酪蛋白酸钠溶液及酪蛋白稳定的O/W乳状液性质的影响 .试验表明酒精在一定程度上可以降低酪蛋白酸钠的溶解度 .界面张力的测定则表明酒精的存在在很大程度上可以降低油—水界面和油—酪蛋白溶液界面的界面张力 .含酒精的乳状液体系的粘度会由于酒精的存在而提高 ,在酒精体积分数达 3 0 %时 ,乳状液体系的粘度会突然大幅度升高 .通过O/W乳状液的分层稳定性测定可发现 ,低浓度的酒精可以提高酪蛋白稳定的乳状液的分层稳定性 ,但酒精质体积分数超过 3 2 %时 ,乳状液的分层稳定性会受到破坏 .含酒精的O/W乳状液体系中油相含量的提高在一定范围内可以提高乳状液的稳定性 ,但高分散相浓度的含酒精的乳状液体系中由于连续相中酒精浓度的提高使乳状液体系稳定性下降 .  相似文献   

19.
The effect of heteroaggregation of oppositely charged protein microspheres dispersed within a liquid oil phase on the microstructure and rheological properties of water-in-oil (W/O) emulsions was evaluated. The aqueous phase of the initial W/O emulsions contained either 10% β-lactoglobulin or 10% lactoferrin (pH 7, 100 mM NaCl). At this pH, β-lactoglobulin (BLG) is negatively charged while lactoferrin (LF) is positively charged. The oil phase consisted of a lipophilic non-ionic surfactant (8% polyglycerol polyricinoleate, PGPR) dispersed within soybean oil. Three 40% W/O emulsions were formed containing different types of protein microspheres: (i) BLG: 100% BLG droplets; (ii) LF: 100% LF droplets; and (iii) Mixed: 50% BLG droplets and 50% LF droplets. Prior to heating, the mixed emulsions had a higher shear viscosity, yield stress, and shear modulus than the BLG or LF emulsions, which suggested that electrostatic attraction led to the formation of a three-dimensional network of aggregated droplets. All three W/O emulsions underwent an irreversible fluid-to-solid transition when they were heated above ≈70 °C. This phenomenon was attributed to thermal denaturation of the globular BLG and LF molecules within the aqueous phase promoting aggregation and network formation of the protein microspheres. After heating, the mixed emulsions had a higher shear viscosity, yield stress and shear modulus than the BLG or LF emulsions, suggesting that a stronger droplet network was formed due to electrostatic attraction. Shear rheology measurements of the W/O emulsions showed that the lipid phases formed after heating were non-ideal plastics characterized by a yield stress and shear thinning behavior. These results may facilitate the design of semi-solid or solid foods with reduced saturated- or trans-fat contents suitable for use in commercial products.  相似文献   

20.
以重质碳酸钙作为颗粒稳定剂制备O/W型Pickering乳液,利用球磨法获得不同尺寸的碳酸钙,研究碳酸钙颗粒粒度、颗粒浓度、油相比例对乳液类型、稳定性、微观形貌及流变学特性的影响。结果表明:球磨后不同粒度的碳酸钙均能稳定Pickering乳液,且该乳液具有一定的储存稳定性,固体颗粒粒径对乳液性质有一定的影响,乳液粒径随固体颗粒粒径的增大而增大;随固体颗粒浓度的增大,乳液的乳析指数、乳液粒径以及乳液黏度均减小,但当固体颗粒浓度达到9g/100 mL以上时,增加颗粒浓度对乳液粒径影响不大;增大油相比例会使乳析指数减小、乳液粒径和黏度增大。  相似文献   

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