Methodology and development of a high-protein plant-based cheese alternative.

Animal-based food products, such as meat and dairy, contribute the most to greenhouse gas emissions in the food sector. This, coupled with the demonstrably worsening climate crisis, means that there needs to be a shift to more sustainable alternatives in the form of plant-based foods. In particular, the plant-based cheese alternative industry is relevant, as the products lack critical functionalities and nutrition compared to their dairy-based counterparts. Waxy starch, plant-protein isolate, and coconut oil were combined to create a novel high-protein (18% w/w) plant-based cheese alternative. We determined that when using native waxy starch, we can enhance its existing viscoelastic properties by modulating gelatinization through adding plant protein and fat. Texture profile analysis indicated that the cheese analogues could reach hardness levels of 15-90N, which allowed samples to be tailored to a broader range of dairy products. We determined that plant proteins and fat can behave as particulate fillers, enhance network strength, and create strategic junction points during starch retrogradation. The degree of melt and stretch of the high-protein plant-based analogues were 2-3 times greater than those observed for commercial plant-based cheese alternatives and significantly more similar to dairy cheese. The rheological melting kinetics saw that the high-protein plant-based cheese alternative displayed more viscous properties with increasing temperature. Tan δ (G"/G') at 80 °C was used as an indicator for sample meltability where, values ≥1 indicate better melt and more viscous systems. The high-protein plant-based cheese alternative reached Tan δ values upwards to 0.7, whereas commercial plant-based cheese alternatives only reached tan δ values around 0.1. Ultimately, the novel high-protein plant-based cheese alternative demonstrates the use of simple ingredients to form complex food systems.

Mixed cyclo di-amino acids structured edible oils: a potential hardstock fat mimic.

Pure cyclic diamino acids (CdAA) gel differently than combinations of CdAAs, altering the gelation behavior to highly-branched colloidal protein crystal networks reminiscent of traditional fat crystal networks in canola oil, making it an exciting structuring agent for unsaturated oils.

Lipid crystallinity of oil-in-water emulsions alters in vitro.

10 wt% oil-in-water emulsions with varied palm olein and stearin PO:PS ratios stabilized with 0.8 wt% Tween80 and tempered to obtain partially crystalline (CR) droplets (cooled from 80 to 4 °C and held overnight to induce nucleation/crystallization) or undercooled liquid (UC) droplets (cooled from 80 °C to 37 °C) produced emulsions with constant droplet size and polymorphism. However, zeta-potential decreased in undercooled emulsions due to crystallization/orientation of interfacial Tween, increasing alignment and ultimately a greater dipole moment. Significant differences in overall bioaccessibility between PO and PS present for the CR (PO bioaccessible fraction was 91%, whereas PS was 60%) and UC emulsions (PO and PS bioaccessibility were 96% and 77%).When only the solid fat content differs, and all other physical attributes remain constant, lipid digestibility decreases with increasing solid fat content; these findings, along with others, can be employed during food formulation and design more healthful foods.

Structuration, elastic properties scaling, and mechanical reversibility of candelilla wax oleogels with and without emulsifiers.

The crystal network development, elastic properties scaling behavior, and mechanical reversibility of candelilla wax (CW) oleogels with and without emulsifiers were studied. Saturated monoglycerides (MG) and polyglycerol polyricinoleate (PGPR) were added at 1 or 2 times the critical micelle concentration. Although the micelles of both emulsifiers act as nucleation sites for the mixture of aliphatic acids and alcohols of CW, they did not affect the oleogel's thermodynamic stability. It was established that the crystal network of CW consists of at least two types of crystals, one rich in n-hentriacontane and other rich in aliphatic acids. Both crystals species contributed significantly to the oleogel elasticity. The elastic properties scaling behavior of CW oleogels fitted the fractal model within the weak-link regime. The setting temperature and added emulsifier modified the crystal network fractal dimension. During shearing, oleogels had massive breaking of junction zones, causing the loss of fractality in the crystal network, which in turn decreased the system's elasticity.

Engineering rheological properties of edible oleogels with ethylcellulose and lecithin.

Addition of 1% (w/w) soy lecithin increased the shear moduli 10-fold and gel hardness 20-fold for 10% ethylcellulose (EC) oleogels. Higher lecithin addition levels or addition to gels with a higher EC concentration caused smaller increases. Similar trends were observed in the penetration force of the gels. Gels displayed thermal reversibility and a high temperature plateau at T≈120-130 °C. Large amplitude oscillatory shear rheology demonstrated similar solid-to-fluid transitions indicating that the polymer drives elastic softening and failure of the network. However, EC oleogels differed in their resistance to flow: the addition of unsaturated lecithin promoted a more gradual thickening response compared to gels containing saturated lecithin or only EC (the last two types of gels display strong intra-cycle thickening and thinning, more indicative of brittle failure). The thickening response of EC oleogels containing unsaturated lecithin, resembles more closely that of a model edible fat (lard).

Water immobilization by glass microspheres affects biological activity.

We recently reported that the water holding capacity of myofibrillar protein hydrogels could be increased upon addition of small amounts of microparticles, particularly glass microspheres. Glass microspheres were found to decrease the spin-spin relaxation time (T2) of water protons in the gels, which was interpreted as enhanced water binding by the glass. We were thus interested in determining whether the observed effects on water proton relaxation were a direct consequence of water-glass interactions. Here we show how glass microspheres reduce the mobility of pure water, reflected in large decreases in the T2 of water protons, decreases in the self-diffusion coefficient of water molecules, a lower water activity, and strengthening of O-H bonds. Even though glass is considered an inert material, glass microspheres were shown to inhibit the growth of human embryonic kidney cells, and stimulate or inhibit the growth of leukemia and monocytic lymphoma cells in vitro, depending on dose and time. The germination of alfalfa seeds and the growth of E.coli cells were also inhibited upon exposure to glass microspheres. This work indicates that the properties and behavior of materials, even ones considered inert, can be affected by their size. These observations suggest possible toxicological consequences of exposure to microparticles, but also open us possibilities to affect cellular/organism function via modulation of macromolecular hydration.

Sheared edible oils studied using dissipative particle dynamics and ultra small angle X-ray scattering: TAGwood orientation aggregation and disaggregation.

Previous work on the computer simulation of edible fats and oils showed that triglyceride crystalline nanoplatelets (CNPs) aggregated into cylindrical structures dubbed "TAGwoods". This was experimentally verified using Ultra Small Angle X-ray Scattering experiments. In this paper, the aggregation of these TAGwoods was studied using the fluid simulation technique, Dissipative Particle Dynamics. The intent was to predict the TAGwood aggregation structures which arise via the application of a series of shear rates, [small gamma, Greek, dot above]. The effect of shear on TAGwood orientational order was also investigated. Three aggregation regimes were identified: At shear rates below a certain critical value, 0 < [small gamma, Greek, dot above] < [small gamma, Greek, dot above]t aggregation was enhanced. The value of the critical shear rate depended on the size of the CNPs. With large CNPs possessing a side length of ∼500 nm, the critical shear rate was [small gamma, Greek, dot above]t ≈ 0.6 s-1. However, if the CNPs were smaller with a side length of ∼100 nm, then [small gamma, Greek, dot above]t ≈ 75 s-1. For shear rates above the critical shear rate, [small gamma, Greek, dot above] > [small gamma, Greek, dot above]t aggregation was inhibited. The USAXS data was analyzed using the Unified Fit model and the observations were in accord with the simulation results. Three regimes were identified based on the values of the linear slope P2 of the USAXS data. P2 increased as [small gamma, Greek, dot above] increased, indicating increased aggregation of the TAGwoods as the shear rate was increased. P2 ceased increasing and began to decrease when [small gamma, Greek, dot above] ≈ [small gamma, Greek, dot above]t. With further increases in [small gamma, Greek, dot above], P2 decreased as [small gamma, Greek, dot above] increased further, which is indicative of a decrease in aggregation. The orientational quadrupole order parameter, S = 〈Q33〉 = 1/2〈cos2θ - 1〉, was computed, where θ is the angle between the axis of the TAGwood and the axis of flow, and showed that, for large [small gamma, Greek, dot above], it achieved a near-maximum value. This indicates that at high shear rates, the long axis of the cylindrical TAGwoods aligns in a direction parallel to that of the fluid flow.

Insights into the mechanism of the formation of the most stable crystal polymorph of milk fat in model protein matrices.

The effect of incorporation and presence of various ingredients in a model sodium caseinate-based imitation cheese matrix on the polymorphism of milk fat was comprehensively described using powder x-ray diffraction, differential scanning calorimetry, and microscopy. With anhydrous milk fat (AMF) in bulk used as control, the embedding of AMF as droplets in a protein matrix was found to result in a greater extent of formation of the ß polymorph than AMF alone and AMF homogenized with water and salts solution. The use of other protein matrices such as soy and whey protein isolate gels revealed that the nature of the protein and other factors associated with it (i.e., hydrophobicity and molecular structure) do not seem to play a role in the formation of the ß polymorph. These results indicated that the most important factor in the formation of the ß polymorph is the physical constraints imposed by a solid protein matrix, which forces the triacylglycerols in milk fat to arrange themselves in the most stable crystal polymorph. Characterization of the crystal structure of milk fat or fats in general within a food matrix could provide insights into the complex thermal and rheological behavior of foods with added fats.

Effects of Organogel Hardness and Formulation on Acceptance of Frankfurters.

Different organogel formulations used as beef fat (BF) replacement (0%, 20%, 40%, 60%, and 80%) were utilized to optimize the mechanical properties of frankfurters. Organogels, made of canola oil (CO), included different concentrations of ethyl cellulose (EC) and sorbitan monostearate (SMS). They consisted of: 8% EC + 1.5% SMS referred to as organogel-I (OG-I), 8% EC + 3.0% SMS (OG-II), and 10% EC + 1.5% SMS (OG-III), which were found promising in a previous study when used at 100% replacement. Replacement of BF with organogels at all levels could bring down the very high hardness values (texture profile analysis and sensory) of frankfurters prepared using CO by itself, relative to the BF control. OG-I and OG-II quantity had no significant effect on hardness and springiness, being similar in many cases to the BF and lower than the CO control. Shear force values of all organogel treatments were not significantly different from one another, and were between the BF and CO controls. Smokehouse yield showed a pattern of decreasing losses with increasing organogel replacement level. Sensory analysis revealed that using CO by itself significantly increased hardness, but structuring the oil (via organogelation), brought it down to the BF control value in all OG-I and OG-II formulations. Juiciness was significantly reduced by using liquid oil but increased with raising the amount of organogels. Oiliness sensation increased with higher organogel substitution and was actually higher than the beef control. The study demonstrates the potential use of vegetable oil structuring in replacing the more saturated BF in emulsion-type meat products.

Investigations of in vitro bioaccessibility from interesterified stearic and oleic acid-rich blends.

Interesterification was previously found to impact stearic acid absorption in a randomized cross-over study, when human volunteers consumed a 70 : 30 wt% high-oleic sunflower and canola stearin blend (NIE) compared to the same blend which had undergone either chemical (CIE) or enzymatic (EIE) interesterification. In this research, in vitro lipid digestion, bioaccessibility, and changes in undigested lipid composition and melting behavior of these same test fats were investigated using the dynamic, multi-compartmental TIM-1 digestion model and compared with the previous human study. Overall, TIM-1 bioaccessibility was higher with interesterification (p < 0.05). Oleic acid bioaccessibility was higher than stearic acid bioaccessibility for NIE, and vice versa for the interesterified blends (p < 0.05). Stearic acid was more concentrated in the undigested triacylglycerols (TAG) from NIE, corresponding to a relatively higher melting temperature of the undigested lipids. The results confirm the impact of TAG composition, fatty acid position and/or physical properties on lipid digestion. TIM-1 bioaccessibility was linearly correlated (R(2) = 0.8640) with postprandial serum TAG concentration in the human study. Therefore, the in vitro digestion model offered predictive insights related to the impacts of lipid interesterificaton on absorption.

Development, Characterization, and Utilization of Food-Grade Polymer Oleogels.

The potential of organogels (oleogels) for oil structuring has been identified and investigated extensively using different gelator-oil systems in recent years. This review provides a comprehensive summary of all oil-structuring systems found in the literature, with an emphasis on ethyl-cellulose (EC), the only direct food-grade polymer oleogelator. EC is a semicrystalline material that undergoes a thermoreversible sol-gel transition in the presence of liquid oil. This unique behavior is based on the polymer's ability to associate through physical bonds. These interactions are strongly affected by external fields such as shear and temperature, as well as by solvent chemistry, which in turn strongly affect final gel properties. Recently, EC-based oleogels have been used as a replacement for fats in foods, as heat-resistance agents in chocolate, as oil-binding agents in bakery products, and as the basis for cosmetic pastes. Understanding the characteristics of the EC oleogel is essential for the development of new applications.

Influence of solvent quality on the mechanical strength of ethylcellulose oleogels.

Ethylcellulose (EC) is the only known food-grade polymer able to structure edible oils. The gelation process and gel properties are similar to those of polymer hydrogels, the main difference being the nature of the solvent. The present study examines the influence of solvent quality on the large deformation mechanical behavior of EC oleogels. Two alternative strategies for manipulating the mechanical response of these gels were evaluated; manipulating the bulk solvent polarity and the addition of surface active small molecules. Gel strength was positively correlated to solvent polarity when blending soybean oil with either mineral oil or castor oil. This behavior was attributed to the ability of the polar entities present in the oil phase to interact with the EC gel network. The addition of the small molecules oleic acid and oleyl alcohol resulted in a substantial enhancement in gel strength up to 10wt% addition, followed by a gradual decrease with increasing proportions. Binding interactions between EC and these molecules were successfully modeled using a Langmuir adsorption isotherm below 10wt% addition. Furthermore, the thermal behavior of stearic acid and stearyl alcohol also indicated a direct interaction between these molecules and the EC network. Differences in the mechanical behavior of gels prepared using refined, bleached, and deodorized canola or soybean oils, and those made with cold-pressed flaxseed oil could be attributed to both oil polarity, and the presence of minor components (free fatty acids). Shorter pulsed NMR T2 relaxation times were observed for stronger gels due to the more restricted mobility of the solvent when interacting with the polymer. This work has demonstrated the strong influence of the solvent composition on the mechanical properties of EC oleogels, which will allow for the tailoring of mechanical properties for various applications.

The role of surfactants on ethylcellulose oleogel structure and mechanical properties.

The effects of surfactant addition to ethyl-cellulose (EC) based oleogels were examined with respect to the chemical nature of the "head" and "tail" groups of the surfactant. Unique sigmoidal temperature dependent rheological behavior was observed upon surfactant addition, suggesting additional organized structure formation. Glycerol-based surfactant addition lead to greatest decrease in the sol-gel and gel-sol transition temperatures compared to sorbitan-based surfactants. This behavior can be attributed to the plasticizing nature of the small head group of glycerol compared to the larger head group of sorbitan surfactants. A significant increase in the penetration force of the gels was observed upon surfactant addition, suggesting possible surfactant-polymer interactions which stiffen the polymer network. Thermal analysis detected a reduction in both SMS and GMS crystallization peak temperature and enthalpy. In the case of GMS, two melting peaks were observed upon EC addition to the oil phase, suggesting EC/surfactant interactions. These results demonstrate the effects of surfactant head group structure on EC oleogel rheological properties.

The gelation of oil using ethyl cellulose.

The characterization of the thermo-gelation mechanism and properties of ethyl cellulose/canola oil oleogels was performed using rheology and thermal analysis. Thermal analysis detected no evidence for thermal transitions contributed to secondary conformational changes, suggesting a gelation mechanism that does not involve secondary ordered structure formation. Rheological analysis demonstrated a relationship between the polymer molecular weight and the final gel strength, the cross-over behavior as well as the gel point temperature. Increasing polymer molecular weight led to an increase in final gel strength, the modulus at cross-over, and the gel point temperature. Cooling/heating rates affect gel modulus only for the low molecular weight samples. A decrease in gel strength with increasing cooling rate was detected. The cross-over temperature was not affected by the cooling/heating rates. Cooling rate also affected the gelation setting time where slow cooling rates produced a stable gel faster.

Comparing the crystallization and rheological behavior of organogels developed by pure and commercial monoglycerides in vegetable oil.

We investigated the crystallization and rheological behavior of organogels developed with commercial (MSGC) and pure (MSGP) monoglycerides in safflower oil solutions (0.5% to 8% wt/wt). The MSGC was composed of 1-mono-stearoyl-glycerol (1-MSG, 37.7%) and 1-mono-palmitoyl-glycerol (1-MPG, 54.0%), and the MSGP essentially by 1-MSG (93.51%). The elastic (G') and loss (G″) moduli of the MSGC and MSGP-oil solutions were measured from 80°C until achieving 5°C, and then during isothermal conditions. The d(G')/d(time) rheograms, where d(G')/d(time) is the difference in G' between subsequent time-temperature conditions during cooling, followed closely the phase transition observed by the monoglycerides (MG). The d(G')/d(time) profile showed that the formation of the inverse lamellar α mesophase provided a limited structure to the vegetable oil. In contrast, the crystallization of the sub-α phase in the MSGC-oil system, and of the sub-α1 and sub-α2 phases in the MSGP-oil system structured the vegetable oil through the uptake and retention of oil within their microstructure. Additionally, smaller crystals formed the three-dimensional crystal structure in the MSGC organogels. This is in comparison with the larger crystal size observed in MSGP organogels. Nevertheless, for a similar MG concentration the MSGC organogels showed higher G' and solid fat content (SFC) than the MSGP organogels, and the differences were greater as the MG concentration increased. We consider that the mixed sub-α structure developed by 1-MSG and 1-MPG in the MSGC-oil systems favored the incorporation and retention of higher amounts of oil, in comparison with the sub-α1 and sub-α2 structures developed just by 1-MSG in the MSGP-oil systems.

Modeling of a two-regime crystallization in a multicomponent lipid system under shear flow.

The kinetics of phase transitions of milk fat triacylglycerols, as model multicomponent lipid systems, were studied under shear in a Couette cell at 17 degrees C, 17.5 degrees C and 20 degrees C under shear rates ranging from 0 to 2880s;-1 using synchrotron X-ray diffraction. Two-dimensional diffraction patterns were captured during the crystallization process. No effect of shear on onset time for phase alpha from the liquid was observed. Afterwards a two-regime crystallization process was observed. During the first regime, as observed in other systems, shear reduced the onset time of the phase transition from phase alpha to 2880s(-). The model previously developed for palm oil (ODE model) worked well to describe this regime, confirming the general value of the proposed ODE model. However, the ODE model did not satisfactorily describe the second regime. We found that, as the system gets closer to equilibrium, the growth regime becomes controlled by diffusion, manifested by the kinetics following a square roott dependence. This regime was found to be consistent with a mechanism combining step growth at a kink with progressive selection of the crystallizing moieties. This mechanism is in agreement with the displacement of the diffraction peak positions, which revealed how increased shear rate promotes the crystallization of the higher melting fraction affecting the composition of the crystallites.

The water vapor permeability of polycrystalline fat barrier films.

The water vapor permeability of fat barrier films has been associated with structural characteristics such as polymorphism, crystal size, and chemical composition, among others. However, no mechanistic models have been proposed to describe this relationship. In this study, we have determined the effects of processing conditions on the structure and physicochemical characteristics of four fats and their relationship to water vapor permeability. Results suggest that the solids' volume fraction and the domain size of the fat crystals seem to be the most important factors controlling water vapor migration. Moreover, materials with relatively large crystalline domains will yield malleable films with relatively low storage and loss moduli and strain/stress at the limit of linearity high tan delta values. The structural effects on the permeability of fat films are related to the nanoscale of the material.

Effects of canola oil dilution on anhydrous milk fat crystallization and fractionation behavior.

Blends of anhydrous milk fat (AMF) and canola oil (CO) were cooled from 35 to 5 degrees C at 0.1 degrees C/min, held for 24 h, and centrifuged to separate the liquid and crystalline fractions. The blends' crystallization behaviors and microstructures depended on the level of CO present. Onset and half times of crystallization reflected a slower crystallization mechanism at higher levels of CO dilution. These differences were accompanied by a change in microstructure from large spherulites to smaller particles. The biggest change occurred between the 1:4 and 1:5 blends. Canola oil dilution also influenced the polymorphism of milk fat. Whereas only the beta' polymorph was observed in the crystallized 1:2 blend, the beta polymorph predominated in the 1:8 blend. Some solubilization of AMF solids into CO was observed. This increased gradually with increasing CO concentration. Compositional analysis revealed the exchange of AMF and CO species between the liquid and crystalline fractions. The crystalline fractions were slightly enriched in AMF triacylglycerols, particularly with the more dilute blends (1:7 and 1:8). Large amounts of oil were trapped in the crystalline fractions, particularly for the concentrated AMF:CO blends where the beta' crystals and spherulitic microstructures were observed. Although the solid fat content profiles of the fractionated blends were marginally higher than those of the starting blends, the samples were very soft and oily. This strategy of using CO to fractionate milk fat was limited by the poor separation of solids and liquid during centrifugation.

Fractionation of milk fat by short-path distillation.

Fractionation of milk fat by short-path distillation changes the chemical composition and physical properties of the resulting fractions. Increases in distillation temperature from 125 to 250 degrees C increased distillate yield from 0.3 to 42.7% (wt/wt). The distillate was enriched in short- and medium-chain fatty acids and low molecular weight acylglycerols, while the retentate was enriched in long-chain saturated and unsaturated fatty acids as well as high molecular weight acylglyerols. As distillation temperature increased, dropping points of the distillate increased. Relative to native milk fat, the solid fat content (SFC) vs. temperature melting profile of the distillate was depressed and that of the retentate was augmented, which correlated with the saturated long-chain fatty acid content in the fractions. Retentate crystallization parameters obtained by fitting the Avrami model to SFC-time data, did not change as a function of distillation temperature, but varied as a function of the degree of undercooling. Changes in microstructure observed by polarized light microscopy also appeared to be solely a function of the degree of undercooling, with no observable differences between retentates obtained at the different distillation temperatures. In addition, no changes in the retentate's free energy of nucleation (deltaGc) as a function of distillation temperature were found. The compressive storage modulus of the crystallized retentate increased as a function of increasing distillation temperature.

Solvent effects on the crystallization behavior of milk fat fractions.

The high- and medium-melting fractions of milk fat (HMF and MMF, respectively) were crystallized in the presence of various solvents, including the low-melting fraction of milk fat (LMF), canola oil (CO), hexane, and ethyl acetate. Choice of solvent was shown to have a strong influence on phase behavior and crystallization kinetics. Dilution and solubilization effects were observed for all the blends. More solids were formed in the HMF and MMF blends with LMF than with CO, and complexes were formed between the milk fat fractions possibly because of molecular complementarity. Solids were slightly higher for the more polar ethyl acetate than for hexane. Crystallization proceeded more rapidly in the presence of LMF and ethyl acetate than in the presence of CO and hexane, respectively. According to the Hildebrand equation, HMF and MMF were ideally soluble in LMF and CO. X-ray diffraction spectroscopy (XRD) revealed the existence of liquid-state structure in mixtures of HMF/CO, HMF/LMF, MMF/CO, and MMF/LMF. The observed liquid-state structure was reminiscent of liquid crystals. No differences were observed in the structure of the liquid phase between LMF- and CO-containing mixtures.