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1.
Curr Res Food Sci ; 7: 100632, 2023.
Article in English | MEDLINE | ID: mdl-38021262

ABSTRACT

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.

2.
Soft Matter ; 19(36): 6871-6874, 2023 Sep 20.
Article in English | MEDLINE | ID: mdl-37682026

ABSTRACT

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.

3.
Food Waterborne Parasitol ; 32: e00197, 2023 Sep.
Article in English | MEDLINE | ID: mdl-37333686

ABSTRACT

Toxoplasmosis occurs worldwide and is considered one of the most important food-borne parasitic zoonoses. The consumption of undercooked meat containing viable tissue cysts and ingestion of environmental oocyst are the most important sources of infection. The aim of this retrospective study was to evaluate the spread of Toxoplasma gondii in the province of Bologna (Emilia-Romagna region) in northern Italy, with a One Health approach, comparing seropositivity rates in different animal species and in humans over the last 19 and 4 years respectively. Analyses were performed on serological data collected over different periods at three separate locations: Istituto Zooprofilattico Sperimentale della Lombardia e della Emilia-Romagna (IZSLER); Veterinary University Hospital Clinical Pathology Service, Department of Veterinary Medical Sciences, University of Bologna; and Unit of Microbiology, St. Orsola Hospital, Bologna. Most relevant seropositivity rates observed in animals were 15.5% (wild boar), 25% (roe deer), 18.7% (goat), 29.9% (sheep), 9.7% (pigs), 42.9% and 21.8% in cat and dog, respectively. A comprehensive screening was conducted on a population of 36,814 individuals, revealing a prevalence of 20.4%. Among pregnant women, a frequence of 0.39% for active toxoplasmosis was observed. Despite certain limitations, this study provided valuable insights into the extensive distribution of this parasitic infection among diverse animal species and human populations in the province of Bologna. These findings underscore the importance of implementing consistent and proactive toxoplasmosis screening protocols during pregnancy, while emphasizing the critical need for adopting a One Health approach for effective control of this parasitic disease.

4.
Food Chem ; 382: 132326, 2022 Jul 15.
Article in English | MEDLINE | ID: mdl-35152026

ABSTRACT

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.


Subject(s)
Polysorbates , Water , Crystallization , Digestion , Emulsions/chemistry , Particle Size , Polysorbates/chemistry , Water/chemistry
6.
J Intellect Disabil Res ; 65(2): 162-172, 2021 02.
Article in English | MEDLINE | ID: mdl-33230890

ABSTRACT

BACKGROUND: We aimed to validate the Italian version of the two parallel short forms of the Prudhoe Cognitive Function Test (s-PCFT-I) in adults and seniors with intellectual disabilities (ID) of any aetiology and level of severity. METHODS: Our validation is a multicentre study attended by 211 subjects with ID, 125 male and 86 female, aged 40 years and above for people with Down syndrome and aged 50 years for people with other forms of disabilities. RESULTS: The s-PCFT-I shows a wide range of scores in the absence of floor effects with minimal ceiling effects. A Cronbach's α coefficient of 0.85 and a mean inter-item correlation of 0.21 indicate high internal consistency. The tool demonstrates good agreement between testers and near excellent temporal stability with intraclass correlation coefficients respectively of 0.85 and 0.90. s-PCFT-I total scores do not differ by sex or age, while statistically significant differences are observed between people with different levels of severity of ID. Moderate to good and highly significant correlations (-0.40 to -0.66) among the s-PCFT-I total scores and subscores and the Sum of Cognitive Score of the informant-based Dementia Questionnaire for Persons with Intellectual Disabilities suggest an acceptable level of concurrent criterion validity. Cognitive decliners according to Prasher's Dementia Questionnaire for Persons with Intellectual Disabilities cut-off scores perform significantly lower on s-PCFT-I than non-decliners. CONCLUSIONS: The s-PCFT-I has good psychometric properties and user friendliness and may therefore be a valuable addition to the current informant-rated tools for screening and assessment of cognition in aging people with ID.


Subject(s)
Intellectual Disability , Adult , Aging , Cognition , Female , Humans , Intellectual Disability/diagnosis , Intellectual Disability/epidemiology , Male , Psychometrics , Reproducibility of Results , Surveys and Questionnaires
7.
Food Res Int ; 122: 471-478, 2019 08.
Article in English | MEDLINE | ID: mdl-31229102

ABSTRACT

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.


Subject(s)
Emulsifying Agents/chemistry , Calorimetry, Differential Scanning , Elasticity , Fatty Acids/analysis , Glycerol/analogs & derivatives , Glycerol/chemistry , Monoglycerides/chemistry , Oleic Acid/analysis , Organic Chemicals/chemistry , Rheology , Ricinoleic Acids/chemistry , Safflower Oil/chemistry , Waxes/chemistry , X-Ray Diffraction
8.
Meat Sci ; 149: 9-13, 2019 Mar.
Article in English | MEDLINE | ID: mdl-30448475

ABSTRACT

The effects of fat/oil type (regular and rendered beef fat, canola, soy and flaxseed oils), form (native or organogel), and heating rate (0.7 and 3.5 °C/min) were investigated in a comminuted meat system. Converting beef fat to organogel resulted in higher hardness values of the cooked meat products, but the opposite was observed with the vegetable oils. Springiness was lower for all organogels compared to the native fat/oil used. Fat globule size was larger in the organogels prepared from vegetable oils compared to the native oils, but that was not the case for beef fat. Increasing heating rate reduced cooking loss, and while employing organogels did not affect the regular beef fat, it significantly increases losses from the vegetable oil treatments. Overall, using the organogel technology should be attractive to processors and consumers alike as products with high unsaturated fatty acids can be produced.


Subject(s)
Cooking , Food Handling/methods , Meat Products , Plant Oils , Animals , Cattle , Fats , Linseed Oil , Rapeseed Oil , Soybean Oil
9.
Carbohydr Polym ; 205: 98-105, 2019 Feb 01.
Article in English | MEDLINE | ID: mdl-30446154

ABSTRACT

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).

10.
Sci Rep ; 8(1): 9744, 2018 06 27.
Article in English | MEDLINE | ID: mdl-29950573

ABSTRACT

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.


Subject(s)
Glass/chemistry , Microspheres , Water/chemistry , Cell Line, Tumor , Escherichia coli/growth & development , Germination/physiology , Humans , Leukemia , Lymphoma , Seeds/physiology
11.
Food Funct ; 8(10): 3621-3635, 2017 Oct 18.
Article in English | MEDLINE | ID: mdl-28891575

ABSTRACT

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.


Subject(s)
Plant Oils/chemistry , Computer Simulation , Triglycerides/chemistry , Viscosity , X-Rays
12.
J Dairy Sci ; 100(9): 6930-6937, 2017 Sep.
Article in English | MEDLINE | ID: mdl-28668535

ABSTRACT

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.


Subject(s)
Crystallization , Dietary Fats , Fats/chemistry , Milk/chemistry , Animals , Cheese , Triglycerides/chemistry , X-Ray Diffraction
13.
Benef Microbes ; 8(4): 625-633, 2017 Aug 24.
Article in English | MEDLINE | ID: mdl-28618863

ABSTRACT

Vaginal lactobacilli offer protection against recurrent urinary and vaginal infections. The precise mechanisms underlying the interaction between lactobacilli and the host epithelium remain poorly understood at the molecular level. Deciphering such events can provide valuable information on the mode of action of commensal and probiotic bacteria in the vaginal environment. We investigated the effects exerted by five Lactobacillus strains of vaginal origin (Lactobacillus crispatus BC1 and BC2, Lactobacillus gasseri BC9 and BC11 and Lactobacillus vaginalis BC15) on the physical properties of the plasma membrane in a cervical cell line (HeLa). The interaction of the vaginal lactobacilli with the cervical cells determined two kinds of effects on plasma membrane: (1) modification of the membrane polar lipid organisation and the physical properties (L. crispatus BC1 and L. gasseri BC9); (2) modification of α5ß1 integrin organisation (L. crispatus BC2, L. gasseri BC11 and L. vaginalis BC15). These two mechanisms can be at the basis of the protective role of lactobacilli against Candida albicans adhesion. Upon stimulation with all Lactobacillus strains, we observed a reduction of the basal oxidative stress in HeLa cells that could be related to modifications in physical properties and organisation of the plasma membrane. These results confirm the strictly strain-specific peculiarities of Lactobacillus and deepen the understanding of the mechanisms underlying the health-promoting role of this genus within the vaginal ecosystem.


Subject(s)
Candida albicans/physiology , Cell Membrane/microbiology , Lactobacillus/physiology , Vagina/microbiology , Female , HeLa Cells , Humans , Reactive Oxygen Species/metabolism , Vagina/metabolism
14.
Meat Sci ; 122: 155-162, 2016 Dec.
Article in English | MEDLINE | ID: mdl-27552678

ABSTRACT

The replacement of beef fat (BF) with regular or structured canola oil [organogel produced with ethylcellulose (EC) 0.0%, 1.5% or 3.0% sorbitan monostearate (SMS)] was conducted in frankfurters. Substitution with regular oil doubled the hardness of the frankfurters relative to BF. Using an organogel prepared with 8% EC and 1.5 or 3.0% SMS resulted in a hardness value similar to that of BF, by both sensory and texture profile analysis. Without SMS addition, sensory results showed (P<0.05) lower hardness values than regular oil but still higher than BF. Gels prepared using higher EC concentrations (12 and 14%) yielded meat products with a higher sensory hardness than BF (P<0.05). Liquid oil based frankfurters had very small fat globules compared to BF, but structuring the oil yielded larger fat globules. Color measurements indicated that oil-containing frankfurters were lighter than the ones with BF. Smokehouse yields were generally higher for canola oil and organogel containing treatments compared to the beef fat treatment. When SMS was included, fat losses increased over the canola oil treatment. The results demonstrate the possibility to use organogels to replace beef fat and depending on the formulation to manipulate textural properties to resemble traditional products but with lower saturated fat content.


Subject(s)
Cooking , Food Handling/methods , Plant Oils , Animals , Cattle , Cellulose/analogs & derivatives , Color , Fats , Hardness , Hexoses , Humans , Meat Products/standards , Rapeseed Oil , Taste
15.
Meat Sci ; 122: 84-89, 2016 Dec.
Article in English | MEDLINE | ID: mdl-27501232

ABSTRACT

Organogels made with canola oil, ethyl cellulose (EC; 8, 10, 12 and 14%), and sorbitan monostearate (SMS; 1.5, 3.0%) were used to replace pork fat in breakfast sausages. Some of the formulations with SMS matched the objective hardness (texture analyzer) of the pork fat control; however, sensory hardness was not so easily matched. Using canola oil by itself resulted in lower objective and subjective hardness values than the control. Sensory cohesiveness was not affected by the replacements, but springiness was lower in the treatments without SMS and some of the high EC treatments with SMS. Lightness of organogel treatments was lower than the control, but redness and yellowness values were not affected. Sensory juiciness and oiliness were in general lower in the organogel treatments. Overall, the study demonstrates the potential for the use of organogels in coarse ground meat products, as a means of improving the nutritional profile by replacing saturated fat with mono and poly unsaturated oils.


Subject(s)
Cellulose/analogs & derivatives , Food Handling/methods , Hexoses , Meat Products/analysis , Plant Oils , Animals , Color , Food Quality , Hardness , Humans , Rapeseed Oil , Sus scrofa
16.
J Food Sci ; 81(9): C2183-8, 2016 Sep.
Article in English | MEDLINE | ID: mdl-27514694

ABSTRACT

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.


Subject(s)
Consumer Behavior , Gels/chemistry , Meat Products , Red Meat , Animals , Cattle , Cellulose/analogs & derivatives , Cellulose/analysis , Emulsions , Food Handling , Hardness , Hexoses/analysis , Humans , Plant Oils/analysis , Rapeseed Oil , Taste
17.
Food Funct ; 7(4): 1932-40, 2016 Apr.
Article in English | MEDLINE | ID: mdl-26961726

ABSTRACT

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.


Subject(s)
Fatty Acids, Monounsaturated/metabolism , Oleic Acid/metabolism , Plant Oils/metabolism , Stearic Acids/metabolism , Animals , Biological Availability , Cattle , Cross-Over Studies , Digestion , Esterification , Fatty Acids, Monounsaturated/chemistry , Humans , Kinetics , Models, Biological , Oleic Acid/chemistry , Plant Oils/chemistry , Rapeseed Oil , Stearic Acids/chemistry , Sunflower Oil , Swine
18.
Annu Rev Food Sci Technol ; 7: 65-91, 2016.
Article in English | MEDLINE | ID: mdl-26735799

ABSTRACT

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.


Subject(s)
Food Technology , Cellulose/analogs & derivatives , Cellulose/chemistry , Chemical Phenomena , Cosmetics , Fat Substitutes , Food Additives , Gels/chemistry , Hot Temperature , Oils/chemistry , Organic Chemicals/chemical synthesis , Organic Chemicals/chemistry , Phase Transition , Polymers/chemistry
19.
Carbohydr Polym ; 135: 169-79, 2016 Jan 01.
Article in English | MEDLINE | ID: mdl-26453865

ABSTRACT

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.


Subject(s)
Cellulose/analogs & derivatives , Gels/chemistry , Oils/chemistry , Solvents/chemistry , Calorimetry, Differential Scanning , Cellulose/chemistry , Fatty Acids, Nonesterified/analysis , Magnetic Resonance Spectroscopy , Organic Chemicals/chemistry , Rheology , Stress, Mechanical
20.
Carbohydr Polym ; 127: 355-62, 2015.
Article in English | MEDLINE | ID: mdl-25965494

ABSTRACT

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.


Subject(s)
Cellulose/analogs & derivatives , Surface-Active Agents/chemistry , Cellulose/chemistry , Gels , Molecular Structure , Stress, Mechanical , Thermodynamics
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