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Recently, spinel structures (AB2O4) Nanoparticles (NPs) having binary and ternary mixtures of metal oxides have been established as promising redox catalysts. Due to the presence of two mixed valence metal cations, transport of electrons takes place easily between multiple transition-metal cations with relatively low energy of activation. Among these, spinel cobaltite (MCo2O4) is very attractive due to its low cost, non-toxicity, higher stability, higher electronic conductivity and electrochemical property. To date, MCo2O4 has been used in the fabrication of supercapacitors, electrodes for oxygen evolution reaction, and electrochemical sensors for glucose. A variety of MCo2O4materials have been synthesized, characterized, and utilized in the fabrication of super capacitors, electrodes for oxygen evolution reaction, and electrochemical sensors for glucose. The progress in the field of the spinel MCo2O4 materials opens the door to novel and efficient applications in the nanoscience and nanotechnology, and elctrochemistry.

Herein, we report the synthesis of a self-assembled flower-like CuCo2O4 material by the oxalate decomposition method. The crystalline structure and morphology of the material have been analyzed by powder X-ray diffraction, Raman spectroscopy, field-emission scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray measurement techniques. The self-assembled flower-like CuCo2O4 material showed remarkable catalytic activity in the direct aerobic oxidative azo coupling of anilines under oxidant and other additive-free reaction conditions. The mechanistic insight of CuCo2O4 in the oxidative azo coupling reaction has been established by density functional theory calculations, which disclosed that the absorption and dissociation of areal oxygen preferentially take place at the Cu site and dissociation of aniline takes place at the Co site. Thus, the Cu and Co sites of CuCo2O4 exert a cooperative effect on the direct oxidative azo coupling reactions through the selective activation of anilines and aerobic oxygen. The CuCo2O4 material was recovered from the reaction mixture and reused for at least eight runs without appreciable loss of catalytic activity.

Driven by the need for trans and saturated fat replacement strategies, the field of fat mimetics has made tremendous advances over the past decade. Fat mimetics include polymeric networks of ethylcellulose, emulsion-templated networks of proteins and polysaccharides, colloidal and self-assembled fibrillar networks of polar lipid crystals, as well as solid o/w emulsions of oil trapped within crystallized lamellar mesophases. Extensive research has gone into formulating various food products with fat mimetics. These include, bakery products (cakes and laminated pastries), chocolate, dairy products (cream cheese), margarines and spreads, and meat products. The clean-label nature of the ingredients used to produce fat mimetics and their demonstrated functionality makes them a promising alternative to solid fats in food products.

Here, we have demonstrated the visible LED light-promoted synthesis of poly functionalized imidazole derivatives by a four component condensation of 1,2-diphenyl 1,2-diketone aromatic aldehydes and ammonium acetate and/or amines in excellent yields. The solvent- and catalyst-free reaction conditions, excellent isolated yields of the products, shorter reaction times, and simple isolation and purification of the products make the present protocol efficient and a green alternative to existing protocols.

Here, we have demonstrated visible light-emitting diode light-driven selective and efficient aerobic oxidation of primary/secondary alcohols to aldehydes/ketones and oxidative azo-coupling of anilines using biomass rice husk-derived chemically activated carbon sheet-supported copper-iron bimetallic hybrid nanomaterials (Cu x Fe1-x @RCAC) under oxidant and additive-free conditions. The catalytic activity of the Cu x Fe1-x @RCAC materials has been investigated for the oxidation of alcohols and anilines, and Cu0.9Fe0.1@RCAC was established as the best catalyst. Moreover, a tandem one-pot protocol has been developed for the sequential oxidation of alcohols followed by condensation to functionalized imidazole and imine derivatives in high isolated yields. The hybrid materials were highly robust and stable under the reaction conditions and were recovered simply by filtration and recycled up to 12th run without considerable loss in catalytic activity.

This study aims to explore the impact caused by change in viscosity and the roughness of a bearing surface on a ferrofluid lubrication of Shliomis model for short bearing. Based on this model and the Tipei (1962) model, a new resultant Reynolds equation has been found that shows thermal variation. The Christensen and Tonder models have been taken to derive the transverse roughness stochastically. An assumed mean has been taken for the probability density function with a non-zero value. This value is assigned to a random variable that measures the bearing’s surface roughness. This creates a more realistic situation that can have a lot of field applications. The model defines the problem mathematically while defining boundary conditions. It also uses the Simpson’s method to derive a conclusion. The results thus obtained are discussed in terms of pressure distribution and load bearing capacity. The graphical results obtained suggest that in the presence of magnetization, there is a significant enhance in the load bearing capacity. This positive effect can easily nullify the negative impact of the thermal effect. The short bearing approximation shown here is an example of the probable applications. Ferrofluids in the presence of magnetic fields significantly enhance the performance of a short bearing.

Background: Recently, organic synthesis using ionic liquids (ILs) via green approach has attracted considerable attention to address the problem associated with environmental pollution. Magnetization of ILs provides added advantages of separation by external magnet. This can be accomplished by incorporation of high-spin iron(III) in the form of tetrachloro or tetrabromoferrate( III). Thus, synthesis of novel magnetically separable ILs for organic transformations is highly desirable. Results: [AcMIm]FeCl4 ionic liquid showed excellent catalytic activity in the one pot threecomponent synthesis tetrahydrobenzo[b]pyran derivatives at room temperature in excellent yields (94-98 %) within short reaction time (15-20 min.). The ILs were recovered and reused for at least six times with the minimum loss of catalytic activity. Methods: Here, we have demonstrated the excellent catalytic activity of acid functionalized magnetic Ils, [AcMIm]FeCl4 in one-pot multicomponent reactions for the synthesis of biologically important tetrahydrobenzo[b]pyran derivatives. Conclusion: A facile and convenient methodology has been developed for the synthesis of bio-active tetrahydrobenzo[b]pyran derivatives using [AcMIm]FeCl4 ionic liquid as an sufficient and reusable catalyst under environment-benign conditions.

The study focuses on analyzing the effect of slip velocity in the case of a Ferrofluid squeeze film when the surface of truncated cone-shaped plates has a longitudinal roughness. Each oblique to the bottom plate was utilized by the external magnetic field. The bearing surface has a roughness that is designed with the help of a random stochastic variable having a nonzero mean, skewness and variance. The load carrying ability of a bearing system’s surface is determined by calculating the dispersal of pressure in the system, which is calculated by using the associated stochastically average Reynolds’ equation. The graphs obtained from the study shows that there is a correlation between the longitudinal surface roughness and the bearing system performance. The magnetic fluid lubrication has a positive impact on a system’s bearing capacity. However, the load bearing capacity declines as a result of the effect of slip. A high negative skewness of the surface roughness also has a positive impact on a bearing’s load carrying capacity. One interesting finding shows that contrasting to the results of transverse roughness, standard deviation positively impacts the load bearing capacity. This investigation suggests despite the im-portance of aspect ratio and semi vertical angle is significant for performance enhancement, it is also essential to maintain the slip at the lowest level.

In this study, whey protein isolate (WPI)-low methoxyl pectin (LMP) electrostatic complexes were used to encapsulate quercetin (Q) in a model fat-free beverage system. The effect of the pH and WPI : LMP ratio was first studied to form soluble complexes with optimal physical properties, in terms of the hydrodynamic diameter, surface charge, and yield. Based on the results, pH 5.0 and a 2 : 1 (w/w) ratio of WPI : LMP were selected for encapsulation of Q. The stoichiometry of the binding (n) and the binding constant (Kb) of WPI:Q were evaluated at pH values of 5.0 and 7.0 at room temperature. The Q-loaded WPI:LMP nanocomplexes were produced by mixing WPI with Q at two loading concentrations corresponding to 5 : 1 and 1 : 1 WPI : Q molar mixing ratios, followed by the addition of LMP and pH adjustment to 5.0. The microstructure of Q-loaded WPI:LMP complexes was investigated by cryo-SEM imaging. Q was efficiently entrapped at two loading concentrations with an efficiency of about 97%. Q-loaded WPI:LMP complexes showed physical stability during storage and high temperature processing, as well as in the presence of challenging formulation conditions such as a high sugar concentration or salt addition (at a limited concentration). The stability of encapsulated Q against UV irradiation was approximately 4 times better than that of free Q. Moreover, Q-loaded WPI:LMP complexes were also lyophilized into dry powder, which can be useful for practical application in food products.

Enhancement of an individual's security and protection is the major concern in the current era. Biometric security becomes a positive solution, adopted for many identification problems in various sectors, including Aviation. As the avionics business keeps growing worldwide, air terminals face the difficulties of increasingly more passenger volumes; with that, travelers' desire for a secure and consistent pass through the airport terminals is just expanding. COVID-19 has managed a hit in all parts of our lives. Maintaining social distance and wearing masks are very important in maintaining a person's health in this pandemic situation. In this scenario, facial recognition for passenger identification is difficult and tends to false acceptance of passengers with identical faces. To address this issue, contactless biometric traits like iris and fingerprints are considered for security growth. The paper deals with the fusion of iris and fingerprint to identify passengers without removing the masks and promotes safe travel. The iris and fingerprint features are extracted using Gray Level Co-occurrence Matrix(GLCM) and cross number technique. Maintaining these templates requires more space for storage. To make this simple, Sparse autoencoder, an unsupervised deep learning technique is incorporated on the fused template for attaining the dimensionality reduction. A minimum cost matcher(MCM) is employed to increase the multimodal biometric system's accuracy and performance. Thus, the proposed system honors passenger security builds confidence in air travel, and also strives for economic growth.

Today, in the era of Internet, biometric authentication plays many important roles. And for biometric authentication image, enhancement plays a vital role because the recognition of an image is extremely depend on it. The image quality can be improved using image enhancement phase after removing noise, joining damaged ridges and constructing smooth images. Various filtering techniques for image enhancement like min filter, max filter, median filter, mean filter, Gabor filter, O’Gorman filter as well as segmentation techniques like Sobel edge detection are used. In the proposed research work, above all mentioned filters are applied and compared the result for enhancing the fingerprint images. The comparison of all filters is done based on MSE, PSNR and computational time to measure the performance of the proposed research work. The implementation of the proposed research work was done using Java and used custom database of 100 images of 25 users.

Here, we have reported, nano-NiFe2O4–catalyzed direct synthesis of imines/benzothiazoles/benzoxazoles via cascade hydrogenation of nitroarenes followed by condensation of aromatic aldehydes under microwave (MW) irradiation conditions. The NiFe2O4 NPs were very effective in selective reduction of nitro-aromatic compounds to amines. The reactions under MW irradiation conditions added advantages of faster reaction rate (15 ​min), high yields of the products (87–95%). Further, one-pot procedure, use of reusable and robust nano-NiFe2O4 as catalyst are the major advantages of the present protocol.

The use of polysaccharides for developing novel functional colloids has grown extensively in recent years due to their availability, low cost, and biocompatibility and biodegradability. In addition, polysaccharides can be easily modified to enhance their physiochemical properties. This book chapter attempts to enlist major sources of polysaccharides, including plant, marine, and microbial used in food sector, followed by an overview of its basic properties including structure, solubility, gelation, emulsification, and rheological properties. Furthermore, interactions of polysaccharides with other food polymers such as proteins are also revisited. The mixture of polysaccharides and protein may induce intermolecular interactions that modify or impart functional properties more desirable than those derived from polysaccharides or proteins alone. Therefore polysaccharide and protein interactions can be used to create different types of colloidal systems with unique properties. The coverage on these colloidal systems for instance micro- or nanoparticles, emulsions, foams, gels, and films is also included.

This paper is focused on the topic of the use of biometrics framework and strategy for secure access identity management of cloud computing services. This paper present’s a description of cloud computing security issues and explored a review of previous works that represented various ideas for a cloud access framework. This paper discusses threats like a malicious insider, data breaches, and describes ways to protect them. It describes an innovative way portrayed a framework that fingerprint access-based authentication to protect Cloud services from unauthorized access and DOS, DDoS attacks. This biometrics-based framework as an extra layer of protection, added then it can be robust to prevent unauthorized access to cloud services.

When it comes to innovation in the food sector, oleocolloids (or oil-continuous soft matter systems) have unfortunately not received the same level of attention as water-continuous systems. Recently however, a combination of factors including ban on trans-fats from food products by leading health authorities, the rising concern among consumers about the negative health effects of saturated fat consumption, the negative image of palm oil linked to the ecological damage, and, more recently, the industrial drive toward “back-to-natural” products, have together provided renewed impetus for formulating oil-continuous systems. In this chapter, a range of novel oleocolloids such as oleogels, oil-continuous complex emulsions, and oleofilms are discussed with the help of illustrative examples. The chapter concludes with a concise overview of the field and the possible future trends.

A range of dairy products are consumed on a regular basis as sources of macronutrients (fats and proteins) and micronutrients such as minerals and fat-soluble vitamins. Among these, there are products such as butter and cheese that form a part of daily diets and then there are others such as whipped cream and ice-creams that are usually considered as indulgence products. From colloid science point of view, these products could be broadly classified as structured emulsions (butter and butter spreads), coagulated gels (various cheese types) and foamed emulsions (ice-creams and whipped creams). These products have different microstructures (Fig. 13.1), all of them containing a significant proportion of milk fat distributed either in the bulk or dispersed phases. Milk fat is composed primarily of triglycerides (TAGs) with a significantly high proportion of saturated fatty acids (Table 13.1). Palmitic acid, the main fatty acid in milk fat, is known to increase the risk of cardiovascular disease (CVD) (Wang et al., 2017). And it has been consistently suggested by health agencies that replacing dairy fats with vegetable oils rich in polyunsaturated fatty acids reduces the risk of CVD (Chen et al., 2016; Nettleton, Brouwer, Geleijnse, & Hornstra, 2017). However, the high melting fraction of milk fat (composed of TAGs rich in long-chain fatty acids) is responsible for providing the underlying colloidal network of crystalline particles, which in turn governs the macrostructure and organoleptic properties of dairy fat products. Such properties include spreadability of butter and cheese spreads, plasticity of baking butter, hardness of cooking butter, voluminous body of whipped cream, texture of cheese, creaminess of ice-cream and melt-in-mouth effect of most dairy fat products. In addition, the stabilizing effect provided by bulk crystallization of milk fat in butter and interfacial stabilization of partially coalesced fat globules in whipped cream and ice cream is also dependent on the high melting TAGs in milk fat. Due to this broad range of functionality provided by milk fat, it is a challenging prospect to replace high melting milk fat with liquid vegetable oils rich in polyunsaturated fatty acids without compromising on the product attributes of reformulated dairy fat products.

The enhancement in fingerprint image remains as a vital step to recognize or verify the identity of person. The noise is influenced during the acquisition of fingerprint image. The poor quality images are captured and leads to inaccurate levels of discrepancy in values of gray level beside the ridges and furrows because of non-uniformity of ink and contact of finger on scanner. This poor quality images are affect to the minutiae extraction algorithm which may extract incorrect minutiae and affect to the fingerprint matching during post-processing. Normalization is the pre-processing step for increase the quality of images by removing the noise and alters the range of pixel intensity values. The mean and variance are used in process to reduce variants in gray-level values along ridges and valleys. In this paper show the result of applied famous global normalization and prove by empirical analysis of an image that normalization is remain good for enhancement process and make the noise free image which is useful for next step of fingerprint recognition.

The reasons for the increased world-wide incidence of obesity, type-2 diabetes, and cardiovascular disease include sedentary lifestyles and poor food choices. Regulatory agencies in several countries now require companies to add unattractive front of package labels to their products where salt, sugar and fat (or saturated fat) levels are prominently displayed. After the demise of partially hydrogenated fats, saturated fat has become the new target. Consumption of saturated fat over polyunsaturated oil has been clearly shown to increase cholesterol levels in humans. However, saturated fats provide the functionality required in many food products. To complicate matters, concerns over sustainability, veganism, genetically modified organisms, animal welfare, as well as religious beliefs, severely limit our sources of saturated fat. In this review we will discuss recent advances in our understanding of the nano and mesoscale structure of fats, responsible for their physical functionality and contrast it to that of fat mimetics. Fat mimetics include polymeric networks of ethylcellulose, emulsion-templated networks of proteins and polysaccharides, colloidal and self-assembled fibrillar networks of polar lipid crystals, as well as solid o/w emulsions of oil trapped within crystallized lamellar mesophases. Clean label and economic considerations will also be touched upon.

This paper studies the changes on a Ferrofluid (FF)-based longitudinally rough porous plane slider bearing (PSB) caused by the slip velocity (SV). The impact of magnetic fluid (MF) lubrication has been analyzed by using the Neuringer and Rosensweig model. The changes exerted by longitudinal roughness have been studied using the stochastic averaging model of Christensen and Tonder. The effects of SV are calculated by using the slip model of Beavers–Joseph. The pressure distribution (PD) expression has been calculated by solving the related nondimensional Reynolds’ type equation. These calculations have been used to calculate the load carrying capacity (LCC). According to the results, LCC increases due to MF lubricant. The surface roughness, on the other hand, has a negative impact on the performance. The same goes for the SV. However, it has been found that these adversities caused by surface roughness, SV, and porosity can be partially neutralized by the positive impact of magnetization, though it can be said that SV in general decreases the bearing performance.

VANET services aim at elevation in reliability and decrease in delay for information dissemination to all automobiles in a specific geographical area. High latency for individual packets, low delay in transmission and minimal likelihood of packet collision are advisory. Automobiles’ cell and segment should have guaranteed reception of message for safety purposes, reliably and effectively. To address the dynamic mobility of nodes in VANET our work aims at selection of best path for vehicles, whether longer than the existing one, for their detour. Our Contention Window (CW) based design mechanism; Hybrid Partitioning Approach for Data Dissemination (HPADD) selects the window of suitable size based on vehicular density, creates segments, selects the relay node and then sends the message to that relay node in the appropriate segment. This approach augments throughput rate and curtails latency. End-to-end delay is minimized and for a transport highway, it works competently. Using NS2 simulator, the performance of the network link by relying on the choice of window sizes has been revealed. The issues of transmissions by hidden node problem and packet collision are also considered.

In data processing, the foremost common and effective technique is to spot frequent pattern victimization association rule mining. There are such a large amount of algorithms that provides simple and effective method of association rule mining, however still some analysis is required which might improve potency of association rule mining. As we have a tendency to operate with immense historical information (homogeneous or heterogeneous), it is important to spot frequent patterns quickly and accurately. Here during this analytical paper, we have been tried to incorporate survey of analysis systematically towards association rule mining from last many years to till date from totally different researchers. It’s true that one paper isn't enough for complete analysis of all smart researches, however it'll facilitate in future to urge right direction towards association rule mining analysis for fascinating, effective and correct analysis.

Water insoluble bioactive molecules with very high melting temperature and low solubility in water are difficult to formulate in food products. We demonstrate the synthesis of nanoscale particles from steroid glycosides using a facile liquid antisolvent precipitation method in the presence of various food grade stabilizers. Colloidal particles with sizes well below 200 nm are prepared from steroid glycosides containing extracts, as well as mixtures with phytosterol. In the mixtures, the formation of the typical for the phytosterol rod-like particles is suppressed. Particle size and structure are investigated by electron microscopy and dynamic light scattering. Due to the presence of surface charge and steric stabilization, colloidal particles do not display aggregation and are stable for a period of longer than one year. The results of this study are important for the formulation and delivery of steroid glycoside and phytosterol bioactive molecules in the fields of food, nutraceuticals, and medical applications.

We report, for the first time, the fabrication of oleofilms (containing more than 97 wt% edible liquid oil) using high internal phase emulsions (with oil volume fraction φoil = 0.82) as templates. Advanced microscopy studies revealed an interesting microstructure of these films where jammed oil droplets were embedded in a dried matrix of biopolymeric complexes.

In order to modify the self-assembly of sucrose esters (SEs) in sunflower oil, we added sunflower lecithin (SFL) as co-surfactant. It is hypothesized that SFL modifies the self-assembly of SEs by interrupting the extensive hydrogen bonding between SEs monomers. The addition of SFL into SEs induced gelation of the mixed surfactant system oleogels at all studied ratios. The 7:3 SEs:SFL combination showed enhanced rheological properties compared to the other studied ratios, which suggests better molecular ordering induced by SFL. The modifications might have been caused by interference in the hydrogen bonding, connecting the polar heads of SEs molecules in the presence of SFL. This effect was confirmed by thermal behavior and small angle X-ray diffraction (SAXD) analysis. From the crystallization and melting analyses, it was shown that the peak temperature, shape and enthalpy decreased as the SFL ratio increases. Meanwhile, the bi-component oleogels exhibited new peaks in the SAXD profile, which imply a self-assembly modification. The microscopic study through polarized and electrons revealed a change in the structure. Therefore, it can be concluded that a synergistic effect between SEs and SFL, more particularly at 7:3 ratio, towards sunflower oil structuring could be obtained. These findings shed light for greater applications of SEs as structuring and carrier agent in foods and pharmaceutical.

Monoglycerides (MGs) and phytosterols (PS) are known to form firm oleogels with liquid oil. However, the oleogels are prone to undergo polymorphic transition over time that lead to crystals' aggregation thus, compromises physical properties. Thus, we combined MGs with PS to control the crystallization and modify the morphology of the combination oleogels, as both components are reported to interact together. The oleogels were prepared at different ratio combinations and characterized in their rheological, thermal, morphology, and diffraction properties. The results showed that the 8:2 MGP:PS exhibited higher storage modulus (G') than the MGP mono-component. The combination oleogels exhibited effects on the crystallization and polymorphic transition. Consequently, the effects led to change in the morphology of the combination oleogels which was visualized using optical and electron microscope. The resultant effect on the morphology is associated with crystal defect. Due to observable crystals of MGP and PS, it is speculated that the combination oleogels formed a mixed crystal system. This was confirmed with diffraction analysis in which the corresponding peaks from MGP and PS were observed in the combination oleogels. However, the 8:2 oleogel exhibited additional peak at 35.41Å. Ultimately, the 8:2 was the optimum combination observed in our study. Interestingly, this combination is inspired by nature as sterols (phytosterols) are natural component of lipid membrane whilst MGP has properties similar to phospholipids. Hence, the results of our study not only beneficial for oil structuring, but also for the fields of biophysical and pharmaceutical.

Polymethoxyflavones (PMF) are a group of flavonoids isolated from citrus peels that show crystallization properties. The purpose of this study was to investigate the impact of PMF crystallization on the microstructure, stability and bioaccessibility of PMF-loaded high internal phase emulsions (HIPE) stabilized using protein and polysaccharide complexes. To improve the loading capacity of PMF, a HIPE stabilized using biopolymeric complexes was developed as a container for PMF at concentrations ranging from 1 to 4%. At supersaturation, low-density crystals remained dispersed throughout the HIPE while high-density crystals formed a three-dimensional network that disrupted the oil-in-water interface. Based on the microstructure and the rheological studies, the density of the crystals affected the stability properties. The storage temperature significantly influenced the stability of the PMF-containing HIPE system. The simulated lipolysis study showed that the bioaccessibility of crystalline PMF in a HIPE stabilized using protein-polysaccharide complexes was lower than that of solubilized PMF, indicating that the dissolution of PMF could significantly affect their bioaccessibility with simulated digestion conditions. To conclude, crystal formation in a lipid-rich delivery system affected the stability during storage, as well as the dissolution with simulated digestion condition.

Thinning is the important steps in pre-processing phase of fingerprint recognition. It explains the visual quality of skeleton with 1-pixel unit width. This paper presents the implementation work of famous thinning algorithms and enhances the Zhang-Suen algorithm in the facet of removal of pixel criteria for preserving the connectivity of pattern, remove noisy points, and for sensitivity of the binary image. The performances of the implemented algorithms are evaluated using Mean Square Error, Peak Signal Noise Ratio, and computational time measurement standard. The implementation is done on fingerprint databases FVC2000 and FingerDos using java platform.

A facile approach is described in this work to prepare spherical microcapsules of Palm stearine which are coated with hydrated layers of a food polymer-methylcellulose. These microcapsules were then used as structuring units to create unique hybrid oleogels where both crystalline fat particles and the hydrophilic polymer sheets contributed to the microstructure development. This approach could open-up new possibilities of utilizing a range of hydrophilic food polymers to improve the oil structuring properties of commonly used fat hard stocks.

The field of oleogelation have shown a tremendous progress in the last decade both in terms of fundamental exploration as well as practical applications. However, one of the main bottleneck that still limits the full-scale commercial exploitation of oleogelation techniques is identification of ideal oleogelator(s) with desired properties. Most, if not all oleogelators that are currently been explored in the field, have been identified serendipitously. A rational understanding of the structuring mechanisms and the consequent gel properties of existing systems could serve as a catalyst to accelerate our efforts in finding the ideal oil gelling agents. The purpose of this opinion paper is to look at oleogelation from a colloidal gel perspective in order to have new insights into the gelling properties of different categories of oleogelators forming mono and multicomponent gels.

In this research, we report on the use of unmodified proteins and protein:polysaccharide complexes to prepare oleogels through an emulsion-templated approach. The approach consists of the production of highly concentrated oil-in-water emulsions (ϕ oil = 0.6), followed by the evaporation of the water phase which results in the trapping of the oil in a physical network of biopolymers (protein or protein:polysaccharide complexes). As a model system, soy protein isolate (SPI) was chosen as protein and κ-carrageenan (κ-CG) as charged polysaccharide. The characterization of the colloidal aspects of the complex formation revealed that factors such as protein:polysaccharide ratio, pH and the ionic strength strongly influenced the ζ-potential, microscopic appearance and stability of the complexes. Complexes formed at an optimized SPI:κ-CG ratio (15:1) were used for stabilizing concentrated emulsions (ϕ oil = 0.6) and resulted in a better long-term stability of emulsions compared to un-complexed SPI as confirmed from light scattering and microstructure studies. Rheological studies, protein load measurements and cryo-SEM imaging further revealed that the enhanced stability was due to interfacial accumulation of the complexes rather than the increase in the bulk viscosity. On removal of water from these emulsions, a solid-like matrix of dried oil was obtained which could be further sheared into oleogels. The rheological properties of the oleogels determined through oscillatory measurements revealed a good gel strength (G' > 40 000 Pa) and unique microstructural properties (liquid oil structured with a network of water-soluble protein). Interestingly, contrary to emulsion stability, uncomplexed SPI resulted in firmer oleogels compared to SPI:κ-CG complexes. This research proves hydrophilic proteins can be used as structuring agents for hydrophobic liquids, such as liquid oil.

We report the fabrication of homogenous aqueous gels formed by a heat-cool step of whey protein isolate (WPI) and low methoxyl pectin (LMP) mixtures at low pH (2.0). The low pH suppresses the electrostatic repulsion between LMP molecules, leading to stronger intermolecular interactions between WPI and LMP molecules. Response surface methodology was applied to optimize and to investigate the effects of WPI and LMP concentrations on the gelation temperature (Tsol-gel), melting temperature (Tgel-sol), storage modulus (G′), critical stress (σ*), and dynamic yield stress (σy) of the gels. The obtained results revealed that most of the characteristics evaluated were affected by the process variables, while there was also a significant interaction effect of WPI and LMP concentrations on the gel storage modulus as the main indicator of gel formation. A higher concentration of WPI and LMP resulted in a gel with lower porosity and almost frequency independent moduli. The gel microstructure showed the role of WPI to stabilize and develop the pectin network as crosslinking agent. The WPI-LMP gels showed pH-responsive behavior at higher pH values and stability over a wide range of pH values depending on the total biopolymer concentrations studied, respectively, which can make them very attractive for applications in bio-related fields.

Water insoluble bioactive molecules with limited solubility in common triglyceride are difficult to formulate in colloidal form. We demonstrate the fabrication and characterization of nanoscale diacylglycerol oil-in-water emulsions containing high levels (20 wt%) of steroid glycosides stabilized by food grade emulsifiers. The emulsions were produced using ultra high pressure (120 MPa) homogenization with average droplet sizes as small as 80 nm. The nanoscale emulsions were stabilized using food grade surfactants, surface active biopolymers and proteins. Due to amphiphilic nature of steroid glycosides molecule and higher polarity of the diacylglycerol rich oils used as solvents, it was possible to prepare stable emulsifier-free emulsions. The emulsions displayed very good stability against Ostwald ripening, creaming and coalescence. The emulsions were followed in time and were found stable for more than one year. In the presence of some sugars, the emulsions can be freeze-dried and form readily water dispersible powders without significant coalescence.

Surfactant-free oil-in-water-in-oil (O/W/O) emulsions were successfully prepared through a facile approach using natural ingredients (biopolymers and crystalline fat particles) as stabilizers. Microstructure (PLM, cryo-SEM and confocal microscopy) and diffusive NMR studies revealed that emulsions with ultra-high loading of internal oil droplet phase with high storage stability could be easily prepared in absence of low-molecular weight synthetic surfactants. The internal oil droplets were stabilized by the presence of interfacial layers of gelled biopolymers while the encased water droplets were stabilized by a combination of interfacial crystal accumulation (Pickering stabilization) and network stabilization created by bulk crystallization of fat particles. Small (oscillatory shear rheology) and large (force-displacement measurements) deformation studies were used to gain important insights into the ‘structure-properties’ links. Furthermore, on monitoring the stability of these emulsions in terms of droplet size changes and diffusion of the internal oil phase (over a period of 3 months), they showed exceptional stability with absence of any droplet coalescence and minimal oil diffusion to the external phase. Such complex colloids stabilized by natural ingredients could find important industrial applications in development of novel products in bio-related fields of pharmaceuticals, cosmetics and foods.