Influence of Lipid Phase Composition of Excipient Emulsions on Curcumin Solubility,Stability, and Bioaccessibility

The influence of oil type on the ability of excipient emulsions to improve the solubility, stability, and bioaccessibility of curcumin was examined. Oil-in-water emulsions were prepared using coconut, sunflower, corn, flaxseed, or fish oils. These excipient emulsions were then mixed with powdered curcumin and incubated at 30 or 100 °C. For all oils, more curcumin was transferred from powder to excipient emulsion at 100 °C (190–200 μg/mL) than at 30 °C (30–36 μg/mL), which was attributed to increased curcumin solubility with temperature. Oil type influenced the stability and bioaccessibility of curcumin when excipient emulsions were exposed to simulated gastrointestinal tract conditions, which was attributed to differences in the molecular composition and physicochemical properties of the oils. Overall, the use of fish oil led to the highest effective curcumin bioavailability (38 %). This study provides valuable information for optimizing excipient emulsions to increase curcumin bioavailability in food, supplement, or pharmaceutical applications.     

Effects of Lecithin Addition in Oil or Water Phase on the Stability of Emulsions Made with Whey Proteins

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.     

Influence of the Dispersed Particulate in Chocolate on Cocoa Butter Microstructure and Fat Crystal Growth during Storage

The dispersed particulates present in chocolate are shown to influence the microstructural development and fat crystal growth of cocoa butter (CB) during storage. Atomic force microscopy of both chocolate and CB showed that surface crystal growth on both materials was similar during isothermal (25 °C) storage over 4 weeks. However, unique micron-scale amorphous mounds also appeared on the surface of chocolate. With time, these regions increased in number and diameter and eventually solidified into clustered crystalline masses. X-Ray diffraction, solid fat content, and whiteness index measurements substantiated the observed crystal growth, with gradual increases in the proportion of the form VI polymorph, solid fat, and whiteness over time. Overall, these findings suggest that typical chocolate refining and tempering protocols result in a heterogeneously distributed particulate network that has a substantial impact on the morphology and crystallization pathway of the fat phase.     

油相的极性对乳剂稳定性的影响

乳剂是热力学不稳定体系,其不稳定性是由在分散相和分散介质之间形成最小界面区域的趋势造成的.最小界面区域主要由絮凝和Ostwald ripening决定的.絮凝通常被认为是导致乳剂破坏的最主要原因,但是絮凝可以通过选择适宜的稳定剂来避免.而另一方面,只要有弯曲界面的存在,就会发生Ostwald ripening.这种分散相的传递既有胶束传递又有分子传递,而分子传递不仅与乳滴曲率的不同有关,还与乳滴的组成有关.乳滴组成的不同主要是油相的不同,可以通过油相极性的知识来预测,通常来讲,随着油相极性的增大,乳剂的稳定性降低.     

Mapping of Quantitative Trait Loci for Butter Content and Hardness in Cocoa Beans (Theobroma cacao L.)

Cocoa butter is an important raw material for the chocolate, pharmaceutical, and cosmetic industries. The butter content and quality in cocoa beans are genetically controlled characteristics, and affect its commercial value and industrial applicability. In the present work, an F₂ population derived from the cross between the ICS-1 and Scavina-6 cocoa clones was used for molecular mapping. A linkage map was constructed based on amplified fragment length polymorphism, random amplified polymorphic DNA, and simple sequence repeat markers, resulting in a total of 273 markers, distributed in 14 linkage groups (LGs). Phenotyping of butter content was performed after ether extraction and butter hardness was determined by sweeping differential calorimetry. One quantitative trait locus (QTL) associated to butter content was mapped at linkage group 9 (LG9) and two QTLs for butter hardness were identified at linkage groups 9 and 7 (LG9 and LG7). The two QTLs mapped at the LG9 explained 51.0% and 28.8% of the phenotypic variation for butter content and hardness, respectively. These QTLs were concentrated in the same map region, suggesting a close genetic linkage or pleiotropic effect. The QTLs identified may be useful in further marker-assisted selection breeding programs aimed at cocoa butter quality improvement.     

Sugar Crystallization and Glass Transition as Destabilizing Factors of Protein-Stabilized Emulsions

Temperature cycling across the glass transition of the aqueous phase of oil-in-water emulsions stabilized by whey protein isolate was considered as a possible factor affecting stability. Emulsions were formulated with an aqueous phase containing 80% (w/w) fructose, fructose:glucose 1:1 or glucose, in order to prepare a glass forming aqueous phase with sugar concentration corresponding to that of the unfrozen phase of the maximally freeze-concentrated solutions. This allowed thermal cycling across the glass transition in the absence of the formation of ice crystals. Emulsion stability was studied using differential scanning calorimetry, dynamic light scattering and by visual analysis of the morphology of the systems. Emulsified systems undergoing glass transition cycles of the aqueous phase did not show destabilization of the dispersed (crystallized) lipid phase. Sugar crystallization in the aqueous phase, which occurred when glucose systems were stored above the T_g, led to emulsion breakdown. In this study, the formation of a glassy structure in the continuous aqueous phase preserved the interfacial structure of WPI, thus protecting the dispersed lipid phase from destabilization. On the contrary, glucose crystallization caused disruption of the interfacial membrane structure and loss of integrity of the interface which resulted in extensive lipid phase destabilization.     

Influence of Nanoemulsion Addition on the Stability of Conventional Emulsions

Interest in using nanoemulsions as delivery systems for lipophilic food ingredients is growing due to their high optical clarity, good physical stability, and ability to increase bioavailability. Nanoemulsion-based delivery systems may need to be incorporated into food matrices that also contain conventional emulsions. The aim of this work was to evaluate the effect of adding nanoemulsions (d?<?200 nm) to conventional emulsions (d?>?200 nm) on the creaming stability and microstructure of the mixed systems. Droplet flocculation and rapid creaming was observed when the nanoemulsion concentration exceeded a particular level: the critical flocculation concentration (CFC) was 3.75 % and 0.25 % (v/v) for conventional emulsions with average droplet diameters of 350 and 250 nm, respectively. Confocal microscopy indicated that there was appreciable droplet flocculation, and the fraction of individual droplets with diameters?<?100 nm decreased after 14 days storage, which was probably due to Ostwald ripening and/or coalescence. The results of the present study might have important implications for the incorporation of nanoemulsion-based delivery systems into food products containing larger fat droplets, such as dressings, sauces, or beverages.     

脂肪乳剂理化性质和稳定性的影响因素浅析

静脉注射脂肪乳剂是由两种互不相溶的液体(油相和水相)混合而成,是水不溶性药物的良好栽体,可以提高易水解药物的稳定性并且减少各种毒副作用.脂肪乳荆属于热力学不稳定体系,其会表现出各种不稳定的现象如聚集,絮凝,聚结等,最终可能出现相分离.本文就处方、工艺及包装等影响脂肪乳剂理化性质及稳定性的主要因素进行综述.     

Stability of Lycopene in Oil‐in‐Water Emulsions

Lycopene can be dissolved within the oil phase of oil‐in‐water emulsions to increase bioavailability in water‐dispersible systems. It is sensitive to oxidative conditions and easily undergoes isomerization at high temperatures. Degradation kinetics and isomerization of lycopene in oil‐in‐water‐emulsions were investigated as a function of thermal treatment and oxygen content. Lycopene degradation was found to follow a first‐order kinetics and rate constants were determined. Higher temperatures are directly correlated with increasing lycopene losses. Moreover, thermal treatment leads to a significant decrease of the concentrations of all‐trans and 13‐cis isomer, while the concentration of the 9‐cis isomer increased. Oxygen‐free conditions reduce lycopene losses significantly.     

Layered Oxide Cathodes for Sodium‐Ion Batteries: Phase Transition,Air Stability,and Performance

The increasing demand for replacing conventional fossil fuels with clean energy or economical and sustainable energy storage drives better battery research today. Sodium‐ion batteries (SIBs) are considered as a promising alternative for grid‐scale storage applications due to their similar “rocking‐chair” sodium storage mechanism to lithium‐ion batteries, the natural abundance, and the low cost of Na resources. Searching for appropriate electrode materials with acceptable electrochemical performance is the key point for development of SIBs. Layered transition metal oxides represent one of the most fascinating electrode materials owing to their superior specific capacity, environmental benignity, and facile synthesis. However, three major challenges (irreversible phase transition, storage instability, and insufficient battery performance) are known for cathodes in SIBs. Herein, a comprehensive review on the latest advances and progresses in the exploration of layered oxides for SIBs is presented, and a detailed and deep understanding of the relationship of phase transition, air stability, and electrochemical performance in layered oxide cathodes is provided in terms of refining the structure–function–property relationship to design improved battery materials. Layered oxides will be a competitive and attractive choice as cathodes for SIBs in next‐generation energy storage devices.     

Evaluation of the Stability of Concentrated Emulsions for Lemon Beverages Using Sequential Experimental Designs

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 2^4-1 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.     

Impact of Phytic Acid on the Physical and Oxidative Stability of Protein-Stabilized Oil-in-Water Emulsions

The effects of phytic acid on the physical and oxidative stability of flaxseed oil-in-water emulsions containing whey protein-coated lipid droplets were investigated. The surface potential, particle size, microstructure, appearance, and oxidation of these emulsions were monitored when they were stored at pH 3.5 and 7.0 for 25 days in the dark (37 °C). The phytic acid and protein-coated lipid droplets had similar charges (both negative) at pH 7.0, but had opposite charges (negative and positive) at pH 3.5. At pH 7.0, the addition of phytic acid had no impact on the physical stability of the emulsions but significantly improved their oxidative stability, which was attributed to its ability to sequester pro-oxidant transition metals (iron ions). At pH 3.5, extensive droplet aggregation and creaming occurred in the emulsions containing phytic acid, which was ascribed to charge neutralization and ion bridging. The oxidative stability of the acidified emulsions, however, still increased after addition of phytic acid, which was again attributed to its ability to chelate iron ions. Interestingly, the antioxidant activity of phytic acid decreased as its level was increased. Our results suggest that phytic acid may be used as a natural antioxidant to improve the oxidative stability of food emulsions containing polyunsaturated fatty acids, but its level must be carefully controlled.

     

Spontaneous Formation of Flavor Oil Emulsions by Using Sucrose Esters and Emulsion Stability Study

Food Biophysics - This work aimed to prepare natural flavor oil emulsions by spontaneous emulsification by adding organic mixtures consisting of flavor oils, sucrose esters, and with/without...     

相转化水凝胶微针的制备和处方优化

目的:考察分子量为4 k Da的透明质酸,羧甲基纤维素钠对相转化水凝胶微针的影响以及对药物体外释放的影响。方法:制备含有不同浓度透明质酸或羧甲基纤维素钠的微针,利用显微镜观察微针的外观形态,用高效液相色谱法检测药物的体外释放,并用统计分析软件检测体外释放率的差异性。结果:含有透明质酸的微针出现相分离现象,体外释放24 h,释放率为55%左右;羧甲基纤维素钠的微针未出现相分离现象,体外释放24 h,释放率能达到60%左右,两种微针在3 h和24 h时体外释放率无显著性差异,在12 h时有显著性差异(P0.05)。结论:透明质酸与聚乙烯醇混合易出现相分离现象,可应用于微针的浓度范围较窄,羧甲基纤维素钠微针不易出现相分离现象。在12 h体外释放方面,含有羧甲基纤维素钠的微针处方优于含有透明质酸的微针处方,但是哪一种辅料更优还需要进一步的实验验证。     

Phase Transition Temperature and Chilling Sensitivity of Bovine Oocytes

A limiting factor for achieving cryopreservation of oocytes is direct chilling injury (DCI), which occurs during cooling. DCI, or cold shock, is defined as an irreversible damage expressed shortly after exposure to low, but not freezing, temperatures. The primary target of DCI is thought to be the plasma membrane. Recently, an association between DCI in sperm and the thermotropic phase transition of their membrane lipids was demonstrated. In the present study, we examined the phase transition of the membrane lipids of immature andin vitro-matured bovine oocytes during cooling, using Fourier transform infrared spectroscopy (FTIR). The phase transition of the membrane lipids of oocytes at the germinal vesicle (GV) stage occurred between 13 and 20°C, while a very broad phase transition, which centered around 10°C, was observed for mature oocytes (MII) stage. Thermotropic phase transitions were demonstrated to be related to the temperature at which DCI affected the integrity of the oocyte membranes. When immature oocytes were cooled to 13°C, fewer oocytes (40%) retained their membrane integrity than after exposure to 4°C (51%) or holding them at 38°C (78%), (as determined by the Fluorescein Diacetate-FDA test). This finding might suggest that holding immature oocytes at the phase transition temperature is more damaging to their membranes than exposure to lower temperatures. By contrast, no significant differences in membrane integrity were observed whenin vitro-matured oocytes were cooled to the same temperatures. Subsequently, GV oocytes were cooled to 4°C, and 26% underwent maturation and 19% underwent fertilizationin vitro. In vitro-matured oocytes that were cooled to 4°C displayed a slightly decreased rate of fertilization; the overall fertilization was 60% with 24% polyspermy, rather than the 76% fertilization rate with 12% polyspermy obtained with those not subjected to cooling. The high rate of polyspermy indicates that a site(s) other than the plasma membrane is affected during cooling of bovine oocytes. Nucleated bovine GV oocytes were electrofused within vitro-matured and enucleated oocytes, and then cooled to 4°C. Evaluation of the membrane integrity of the fused oocytes showed that these oocytes are chilling resistant, which strongly suggests that alteration of the membrane composition of an oocyte can change the cell's susceptibility to low temperatures. This finding led to an improvement in the survival of oocytes after cryopreservation.     

Microbiological Examination of Cocoa Powder

Total aerobic plate counts of 36 cocoa powders ranged from 100 to 27,000 per g, with 86% having counts of less than 9,300 per g. Bacillus and Micrococcus were the only genera identified.     

Effect of Soy Soluble Polysaccharide on the Stability of Soy-Stabilised Emulsions During In Vitro Protein Digestion

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.