Supratim Ghosh

University of Saskatchewan | U of S · Department of Food and Bioproduct Sciences

The overall goal of this research was to develop plant protein-based lipid composite films by examining the effect of shear (mechanical shear; MS vs. high pressure shear; HPS) and type of legume protein isolates (pea, lentil, soy, and faba bean). Compared to MS, HPS emulsions had smaller droplet size, and HPS emulsions from pea and lentil were more...

The food industry has long been searching for an efficient replacement for saturated-fatty-acid-rich fats for baking applications. Although oleogels have been considered a potential alternative for saturated and trans fats, their success in food application has been poor. The present study explored the use of oleofoams obtained by whipping the puls...

Lentil protein isolate (LPI)-κ-carrageenan (κ-C) and -ι-carrageenan (ι-C) based microcapsules were prepared through spray-drying and freeze-drying to encapsulate flaxseed oil in order to reach final oil levels of 20% and 30%. Characteristics of the corresponding emulsions and their dried microcapsules were determined. For emulsion properties, all L...

The stability and viscoelasticity of an oil-in-water emulsion formed with canola proteins could be significantly improved by heat-induced protein thermal denaturation followed by aggregation at the oil droplet surface. This phenomenon was used to develop emulsion-templated oleogels with improved rheology and used in cake baking. Canola oil (50 wt%)...

Background and objectives The use of plant protein ingredients within the food industry is increasing rapidly due to their lower cost, greater environmental sustainability, perceived safety concerns related to consuming animal products, and consumer dietary preferences. Lentil protein, as an emerging non-soy, gluten-free, plant-based protein could...

Lentil protein isolate (LPI) was conjugated with plant polyphenols (quercetin, rutin, ellagic acid), and the structural and functional characteristics of the conjugates were determined in comparison with the proteins and pure polyphenols. The interaction between polyphenols and protein was achieved by a grafting method at pH 9.0 in the presence of...

An analytical photo-centrifuge was used to develop novel experimental methods to predict the shelf-life, rheology, and inter-droplet interactions in 40 wt% canola oil-in-water nanoemulsions stabilized by 3 and 5 wt% citric acid esters of monoglyceride (Citrem). The combined influence of micellar concentration and oil droplet size on the rheology, c...

Use of oleogels prepared from hydrocolloids has recently gained considerable attention as an alternative for trans and saturated fats. Lately, pulse proteins such as faba bean protein and pea protein have been successfully used to prepare oleogels using a foam‐templated approach. Although the pulse proteins are healthy oleogelators, high oil loss a...

Salt-extracted canola protein isolate (CPI) from a cold-pressed meal was used (1–4 wt%) to develop concentrated 50% canola oil-in-water emulsions (pH 7) using a high-pressure homogenizer and the effect of various environmental factors on emulsion stability and rheology was investigated. As CPI concentration increased, droplet size decreased from 16...

Conventional polymerase chain reaction (PCR) performed in a continuous aqueous phase often shows an inability to detect ultra-low DNA concentration. Droplet digital PCR, where DNA polymerization happens in isolated water droplets of water-in-oil (W/O) emulsions, could significantly improve the detection limit. However, water droplet breakups under...

Structuring liquid oil into a self-standing semisolid material without trans and saturated fat has become a challenge for the food industry after the recent ban of trans fat by the US Food and Drug Administration and Health Canada. Lately, the use of hydrocolloids such as animal proteins and modified cellulose for oleogel preparation has gained mor...

The present study examines the foaming behavior of pea and faba bean protein concentrates and isolates and explores the impact of pH and protein-polysaccharide complexation on overrun and foam stability. Foams were prepared with 5 wt% proteins with and without 0.25 wt% xanthan gum (XG) at pH 3, 5, 7 and 9. Most foams were unstable without XG. With...

Rheology of sodium caseinate (SC) and whey protein isolate (WPI)-stabilized nanoemulsions (NEs) was investigated as a function of protein (1–5 wt%) and oil (30 and 40 wt%) concentration and storage time. For SC NEs, gel strength increased with an increase in protein and oil concentration and a decrease in droplet size and below a critical size tran...

This research aimed to investigate the possibility of forming gelled nanoemulsions (NEs) by inducing attractive interactions among the nanodroplets. The effect of salt concentration and changes in pH on the stability and gelation behavior of 2, 4, and 5% sodium caseinate (SC) and whey protein isolate (WPI)-stabilized 40% canola oil-in-water NEs wer...

Protein nanoparticles have recently found a lot of interests due to their unique physicochemical properties and structure-functionality compared to the conventional proteins. The aim of this research was to synthesize pea protein nanoparticles (PPN) using ethanol-induced desolvation, to determine the changes in secondary structures and the particle...

This research investigated the effect of pH on forming electrostatic complexes between lentil protein isolate (LPI) and a range of anionic polysaccharides [carboxymethyl cellulose (CMC), gum Arabic (GA), alginate (AL), and ι-carrageenan (CAR)] at 4:1 LPI-polysaccharide mixing ratio, and their resulting emulsifying abilities. Maximum optical densiti...

The aim of this work was to test the applicability of the Mason-Scheffold model, developed for monodispersed systems, on predicting the storage modulus of sodium dodecyl sulfate-stabilized polydisperse canola oil nanoemulsion gels as a function of oil volume fraction (ϕ) and average droplet size. The storage moduli increased with ϕ but at a constan...

The interfacial adsorption and interfacial shear viscoelasticity of lentil protein isolate (LPI) and fenugreek gum (FG) complexes against canola oil were determined at pH 2 and 7 to understand their effectiveness as emulsifiers. The interfacial elastic moduli of LPI-FG complexes were stronger at pH 2 compared to pH 7. In contrast, the biopolymer in...

Gelling properties of three galactomannan dispersions (fenugreek (FG), guar (GG) and locust bean gum (LBG)) were compared by strain and frequency sweep viscoelasticity, and temperature cycle at a constant strain and frequency in the concentration range 1 to 2 wt%. For FG and GG dispersions, tan δ remain <1 in the linear viscoelastic region during s...

Fenugreek gum (FG), guar gum (GG), and locust bean gum (LBG) dispersions were studied for their flow behaviour, intrinsic viscosity, viscoelasticity and the effect of environmental stress on their physicochemical properties. Shear thinning behaviour was observed in all three gum dispersions prepared at concentrations > 0.25 wt%. The impact of the c...

The goals of this research were to develop oil‐in‐water nanoemulsions (NE) encapsulating curcumin by partially replacing sodium caseinate (SC) with pea protein isolate (1:1) and to investigate the lipid digestibility and bioaccessibility of curcumin using in vitro digestion. Structural changes in oil droplets during digestion were also examined usi...

Oxidative deterioration is a major issue limiting the utilization of flaxseed oil (FSO). Present study explored the effects of hydrophilic (tannic acid), hydrophobic (alpha-tocopherol), and intermediate polarity (ascorbyl palmitate) natural antioxidants, which displayed highest DPPH radical scavenging and iron chelating abilities among several othe...

Liquid nanoemulsions are shown to transform into viscoelastic gels by reducing droplet size, increasing interfacial repulsive barrier between the nanodroplets and therefore increasing the effective oil volume fraction. The repulsive gelation in nanoemulsions can be achieved at a significantly lower oil volume fraction compared to conventional emuls...

In this research, the stability of sodium dodecyl sulfate (SDS)-stabilized canola oil nanoemulsion gels was investigated as a function of repeated rotational shear, oscillatory strain and storage time. Nanoemulsion gels, termed nanogels, were formed from oil-in-water nanoemulsions, prepared with various concentrations of SDS to get a range of dropl...

In this research, we studied the composition of aquafaba from two kabuli chickpea cultivars (Leader and Orion), and we compared its foaming properties with commercial egg whites.

Fenugreek (FG), locust bean (LBG) and guar gum (GG) are naturally derived hydrocolloids with a structural similarity that falls under the category of galactomannans with a difference in the ratios of galactose and mannose subunits. Although galactomannans, such as LBG and GG have been widely used in food formulations as thickener and stabilizer, ap...

Proteins from pulses such as lentil are seen as an important plant-based alternative to animal proteins in the food and beverage industry. In this research physically modified (homogenized at 5000 psi and 15,000 psi) lentil protein isolate (LPI) solutions (1–2 wt%) were examined as an emulsifier in stabilizing 5 wt% oil-in-water nanoemulsions. High...

The formation, stability and rheology of 5 wt% oil-in-water nanoemulsions as a function of lentil protein isolate concentration (0.5 to 5 wt%) at pH 3.0 was investigated for 28 days. All nanoemulsions, except 1wt% protein, showed bimodal droplet size distribution where the larger diameter peak was ascribed to protein aggregates and entrapped oil dr...

Model water-in-oil emulsions were shear-crystallized to produce crystal spheroid-encapsulated droplets. The bulk oil phase was composed of canola oil (CO), fully-hydrogenated canola oil (FHCO), and different emulsifiers: glycerol monostearate (GMS), glycerol monopalmitate (GMP), glycerol monooleate (GMO), sorbitan monostearate (SMS), or polyglycero...

Oil-in-water (5 wt%) nanoemulsions were prepared with different concentration (2.5–10 wt%) of sodium caseinate as a sole emulsifier and their long-term storage stability was investigated for 6 months. Previous studies associated with sodium caseinate looked only into nanoemulsion formation; hence the challenges with long-term stability were not add...

Nanoemulsions are emulsions with an average droplet radius less than 100 nm. So far applications of nanoemulsions in food have been limited to liquid-based products. However, by reducing droplet size and modifying interdroplet interactions liquid nanoemulsions can be transformed into solid-like matrices, called nanogel, at a much lower oil volume f...

In this research, pea protein isolate (PPI) was used to partially replace sodium caseinate (SC) in the formation and long-term stabilization of 5 wt% oil-in-water nanoemulsions. Both SC and PPI alone and their 1:1 mixture, at various total protein concentrations, were used to prepare the nanoemulsions using a high-pressure homogenizer. The presence...

Flaxseed gum (FG) was prepared from six Canadian flaxseed (Linum usitatissimum L.) cultivars. Yield, neutral sugar content, acidic sugar content and protein content varied significantly among cultivar FG extracts. Zeta potential (−16.4 to −27.4 mV) and rheological properties of solution were cultivar dependent. Solutions prepared with CDC Glas FG h...

The impact of cooling rate and mixing on the long-term kinetic stability of wax-stabilized water-in-oil emulsions was investigated. Four cooling/mixing protocols were investigated: cooling from 45°C to either 25°C or 4°C with/without stirring and two cooling rates - slow (1°C/min) and fast (5°C/min). The sedimentation behaviour of the emulsions was...

The inter-relationships between the physicochemical, interfacial and emulsifying properties for pea, soy, lentil and canola protein isolates as a function of pHs (3.0, 5.0, and 7.0) were investigated. Surface charge, hydrophobicity, solubility, interfacial tension, rheology, droplet size and emulsion stability were all studied. Conditions that favo...

The aim of this paper is to understand how the change in droplet size and ionic emulsifier concentration influence cage-driven repulsive jamming and bond driven attractive gelation in nanoemulsions. It was hypothesized that in repulsive regime decrease in droplet size would increase the influence of counterion shell layer around the nanodroplets th...

Confined gap shear-cooling was used to structure a model solid fat/liquid oil system consisting of fully hydrogenated canola oil (FHCO) and canola oil (CO). Samples were cooled at various cooling rates (0.2–5.0 °C/min) and shear rates (0, 500, 1000, and 2000 s–1) and characterized via polarized light microscopy and rheology. In the absence of shear...

Nanoemulsion gels are a new class of soft materials that manifest stronger elasticity even at lower dispersed phase volume fraction. In this work gelation in 40 wt% canola oil-in-water nanoemulsions was investigated as a function of emulsifier type (anionic sodium dodecyl sulfate (SDS) or nonionic Tween 20) and concentration. It was observed that t...

Fat crystal-stabilized water-in-oil emulsions were developed as a controlled release matrix for the delivery of salt. Glycerol monostearate (GMS), glycerol monooleate (GMO) and polyglycerol polyricinoleate (PGPR) were used as emulsifiers and hydrogenated canola oil (HCO) was added as a solid fat. Salt release towards an external aqueous phase was m...

The impact of continuous phase wax solidification on the isothermal rheological properties of water-in-oil (W/O) emulsions at different water cuts (10-50wt%) was investigated. Rotational viscometry, oscillatory rheology and creep compliance and recovery were performed on emulsions aged up to 28days. Higher water cuts yielded emulsions with a higher...

We demonstrate the collective roles of surfactant–triacylglycerol interactions and confined gap shear crystallization on the creation of novel microstructured water-in-oil emulsions containing solid lipid-encapsulated water droplets. The emulsions studied consisted of 20 wt % water dispersed in a mixture of canola oil, a stabilizing fat [hydrogenat...

Products such as cosmetics, pharmaceuticals, and crude oil often exist as water-in-oil (W/O) emulsions during their processing or in final form. In many cases, their dispersed aqueous phase is encased in a crystal network and/or by interfacially-adsorbed (‘Pickering’) particles [paraffins, triacylglycerols, polymers, etc.] that promote emulsion kin...

Raman spectroscopy was used to characterize the polymorphs and liquid state of cocoa butter, with emphasis placed on the evolution of the ester carbonyl stretching region (1800–1700 cm⁻¹), along with complementary analysis and comparison of the Raman-active CC (1200–1000 cm⁻¹), CC (1660 cm⁻¹), CH (3000–2700 cm⁻¹) and CH2 (1500–1250 cm⁻¹) vibrationa...

We compared the efficacy of Pickering crystals, a continuous phase crystal network, and a combination thereof against sedimentation and dispersed phase coalescence in water-in-oil (W/O) emulsions. Using 20 wt % water-in-canola oil emulsions as our model, glycerol monostearate (GMS) permitted Pickering-type stabilization, whereas simultaneous usage...

This chapter focuses on the effect of emulsion breakdown on food quality. The mechanisms of emulsion destabilization are described and ways to control them discussed. The factors (composition, heating, freezing and processing conditions) that influence emulsion destabilization are described, and a brief section on the methods used to characterize e...

The nature of intermolecular interactions during complexation between pea protein isolate (PPI) and gum arabic (GA) was investigated as a function of pH (4.30-2.40) by turbidimetric analysis and confocal scanning microscopy in the presence of destabilizing agents (100 mM NaCl or 100 mM urea) and at different temperatures (6-60 degrees C). Complex f...

Factors influencing water-in-oil emulsion stability during freeze/thaw-cycling, namely interfacial crystallization vs. network crystallization and the sequence of crystallization events (i.e., dispersed vs. continuous phase or vice versa), are assessed. We show that destabilization is most apparent with a liquid-state emulsifier and a continuous oi...

Temperature-induced destabilization of the dispersed phase in butter and margarine was compared by following changes in droplet size (d(3,3)), solid fat content (SFC), and fat crystal spatial organization in the 28-34 degrees C range. At 28 degrees C, both butter and margarine were stable, with similar d(3,3) values (approximately 6 microm) and dro...

The release kinetics of four model aroma compounds from coarse (d 32 = 1.0μm) and fine (d 32 = 0.25μm) eicosane and hydrogenated palm stearin (HPS) emulsions prepared with either solid or liquid lipid droplets were measured using a model mouth instrument. For both lipids, the release of aroma compounds from emulsions with solid droplets was higher...

Previous work in rats has demonstrated that an Intermittent (Monday, Wednesday, Friday) schedule of access promotes binge-type consumption of 100% vegetable shortening during a 1-h period of availability. The present study used novel shortening-derived stable solid emulsions of various fat concentrations. These emulsions were the consistency of pud...

Many food emulsions are frozen to provide long-term stability to the product or as a necessary part of the food itself (e.g., ice cream), but very often the thawed emulsion is significantly destabilized and sometimes completely broken down into an oily and an aqueous phase. The phase behaviour of the frozen emulsion and hence the potential stresses...

Aroma compounds partition between the different phases of a food emulsion and the headspace but only those in the headspace are perceived. Phase transitions in the lipid droplets profoundly affect the position of the partitioning equilibria and hence headspace aroma concentration. The release of four volatile aroma compounds (ethyl butanoate, penta...

* Introduction * Thermodynamics of flavour interactions * Kinetics of flavour release * Experimental systems to validate models * Conclusions * References.

Aroma compounds partition between the dispersed and the continuous phases in emulsions, and phase transitions in the lipid droplets profoundly affect the position of the equilibrium. In the present study, the release of ethyl butyrate, ethyl pentanoate, ethyl heptanoate, and ethyl octanoate from a series of sodium caseinate-stabilized, n-eicosane e...

The freeze-thaw induced coalescence of sodium caseinate stabilized n-hexadecane emulsions was investigated as a function of added protein (0–2wt.%), fat (0–40wt.%) and aqueous sugar (0–2wt.% sucrose, maltose, glucose, corn syrup solids) contents. For all variables there was a critical dependence on aqueous phase composition. Emulsions were stable t...

Oil in water emulsions (40wt%) were prepared from a homologous series of n-alkanes (C10–C18). The samples were temperature cycled in a differential scanning calorimeter (two cycles of 40 °C to −50 °C to 40 °C at 5 °C min−1) and in bulk (to −20 °C). The emulsions destabilized and phase-separated after freeze–thaw if the droplets were solid at the sa...