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1.
Food Res Int ; 174(Pt 1): 113651, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37986489

RESUMO

Substituting animal-based fats with plant-based fats of similar stability and functionality has always posed a significant challenge for the food industry. Enzymatic glycerolysis products are systems formed by converting native triacylglycerols in liquid oils into monoacylglycerols and diacylglycerols, mainly studied in the last few years for their unique structural ability. This study aims to modify and scale up the glycerolysis process of different plant oils, e.g., shea olein, palm olein, tigernut, peanut, cottonseed, and rice bran oils, with the goal of producing animal fat mimetics. The reactions were conducted at 65 °C, with a plant oil:glycerol molar ratio of 1:1, and without the addition of water, using a lab-scale reactor to convert up to 2 kg of oil into solid fat. Product characteristics were comparable at both laboratory and pilot plant scales, supporting the commercial viability of the process. Oil systems containing higher levels of both saturated and monounsaturated fatty acids, such as shea olein and palm olein, displayed higher solid fat content at elevated temperatures and broader melting profiles with significantly higher melting points. Comparison of the thermal softening behavior and mechanical properties of these systems with those of pork, beef, and lamb fat showed their high potential to replace adipose fat in the new generation of plant-based meat analogs.


Assuntos
Ácidos Graxos Monoinsaturados , Óleos de Plantas , Bovinos , Animais , Ovinos , Óleos de Plantas/química , Triglicerídeos , Diglicerídeos , Monoglicerídeos
2.
Sci Rep ; 12(1): 15832, 2022 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-36138091

RESUMO

Co-contamination by organic solvents (e.g., toluene and tetrahydrofuran) and metal ions (e.g., Cu2+) is common in industrial wastewater and in industrial sites. This manuscript describes the separation of THF from water in the absence of copper ions, as well as the treatment of water co-polluted with either THF and copper, or toluene and copper. Tetrahydrofuran (THF) and water are freely miscible in the absence of lauric acid. Lauric acid separates the two solvents, as demonstrated by proton nuclear magnetic resonance (1H NMR) and Attenuated Total Reflection-Fourier Transform Infrared Spectroscopy (ATR-FTIR). The purity of the water phase separated from 3:7 (v/v) THF:water mixtures using 1 M lauric acid is ≈87%v/v. Synchrotron small angle X-Ray scattering (SAXS) indicates that lauric acid forms reverse micelles in THF, which swell in the presence of water (to host water in their interior) and ultimately lead to two free phases: 1) THF-rich and 2) water-rich. Deprotonated lauric acid (laurate ions) also induces the migration of Cu2+ ions in either THF (following separation from water) or in toluene (immiscible in water), enabling their removal from water. Laurate ions and copper ions likely interact through physical interactions (e.g., electrostatic interactions) rather than chemical bonds, as shown by ATR-FTIR. Inductively coupled plasma-optical emission spectrometry (ICP-OES) demonstrates up to 60% removal of Cu2+ ions from water co-polluted by CuSO4 or CuCl2 and toluene. While lauric acid emulsifies water and toluene in the absence of copper ions, copper salts destabilize emulsions. This is beneficial, to avoid that copper ions are re-entrained in the water phase alongside with toluene, following their migration in the toluene phase. The effect of copper ions on emulsion stability is explained based on the decreased interfacial activity and compressional rigidity of interfacial films, probed using a Langmuir trough. In wastewater treatment, lauric acid (a powder) can be mixed directly in the polluted water. In the context of groundwater remediation, lauric acid can be solubilized in canola oil to enable its injection to treat aquifers co-polluted by organic solvents and Cu2+. In this application, injectable filters obtained by injecting cationic hydroxyethylcellulose (HEC +) would impede the flow of toluene and copper ions partitioned in it, protecting downstream receptors. Co-contaminants can be subsequently extracted upstream of the filters (using pumping wells), to enable their simultaneous removal from aquifers.


Assuntos
Cobre , Poluentes Químicos da Água , Cobre/química , Descontaminação , Emulsões , Furanos , Íons/análise , Lauratos , Ácidos Láuricos , Micelas , Pós , Prótons , Óleo de Brassica napus , Sais , Espalhamento a Baixo Ângulo , Solventes , Tolueno/análise , Águas Residuárias/análise , Água/análise , Poluentes Químicos da Água/análise , Difração de Raios X
3.
Food Chem ; 377: 131991, 2022 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-34995963

RESUMO

The physical properties of butter are impacted by the fatty acid and triacylglycerol composition of the milkfat. Increased butter hardness and melting temperature results in decreased consumer satisfaction since these affect the culinary performance and spreadability. During the winter of 2021, consumers reported anecdotal evidence of an increase in butter hardness, leading to news reports blaming the increased hardness on palm oil-based supplementation of cows' feed. Commercial butter samples were collected from across Canada to test the correlation between fatty acid and triacylglycerol composition, and hardness. We determined that palmitic acid (r = 0.74) and dipalmitoyloleate (r = 0.72) were significantly and positively correlated to commercial butter hardness (P < 0.01). However, due to restricted access to existing historical data on the chemical composition of milk fat and hardness of butter, it was not possible to compare the firmness of butter in 2021 with butter produced in the past.


Assuntos
Manteiga , Ácido Palmítico , Animais , Bovinos , Ácidos Graxos , Feminino , Leite , Triglicerídeos
4.
Food Res Int ; 147: 110431, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34399448

RESUMO

Partial fat replacement in cooked salamis was formulated using organogels made with canola oil, ethylcellulose (EC; 6, 8, 9, 10, 11, 12 and 14%) and three types of surfactants; i.e., glycerol monostearate (GMS), stearyl alcohol/stearic acid (SOSA) and soybean lecithin (Lec). Texture profile analysis (TPA) and back extrusion tests indicated that increasing EC polymer concentration leads to harder gels regardless of the surfactant used. However, using GMS resulted in the hardest gel, whereas Lec did not strengthen the gel (mechanical stress test), but plasticized it. In general, gel hardness had a distinct effect on the binding of the organogel particle to the meat matrix, with softer gels adhering better under progressive compression. Substituting animal fat with organogel did not affect the main TPA parameters in most salami formulations, and canola oil by itself was also not significantly different from the pork and beef fat control. Using canola oil resulted in very small oil globules compared to the animal fat control, while structuring the oil yielded a microstructure with larger fat particles/globules, similar to the control. Color evaluation revealed a shift to yellow of the treatments with organogels compared to the control, but lightness and redness were not altered. The results demonstrate the potential use of structured vegetable oil to manufacture coarse ground meat products with lower saturated fat and a more favorable nutritional profile while resembling the traditional ground products.


Assuntos
Produtos da Carne , Animais , Bovinos , Celulose/análogos & derivados , Culinária , Manipulação de Alimentos , Produtos da Carne/análise , Óleo de Brassica napus
5.
Food Chem ; 338: 128010, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-32932084

RESUMO

Potential improvements to the physical properties of brittle, self-assembled zein networks through microbial transglutaminase crosslinking were investigated. The formation of crosslinked heteropolymers was also explored with networks containing zein and either soy or pea protein isolates as supplemented lysine sources. The observed SDS-PAGE bands did not show any evidence of zein crosslinking. Soy and pea isolates underwent extensive crosslinking on their own, but heteropolymers were not observed in multiprotein networks with zein. Despite the lack of crosslinking observed, rheological and textural analysis revealed that the enzymatic treatment of zein produced a weaker, more brittle structure. With no significant changes in secondary structure, determined through FTIR, the observed behaviour was primarily attributed to glutamine deamidation by microbial transglutaminase in the absence of sufficient lysine through changes to the hydrophobicity of the protein such that non-covalent bonding within network was modified.


Assuntos
Transglutaminases/metabolismo , Zeína/química , Reagentes de Ligações Cruzadas/química , Eletroforese em Gel de Poliacrilamida , Interações Hidrofóbicas e Hidrofílicas , Lisina/química , Pisum sativum/química , Estrutura Secundária de Proteína , Reologia , Proteínas de Soja/química , Proteínas de Soja/metabolismo , Espectroscopia de Infravermelho com Transformada de Fourier , Transglutaminases/química , Zeína/metabolismo
6.
J Food Sci ; 84(9): 2646-2651, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31429478

RESUMO

Five canola oil organogel formulations were used to replace pork fat in pâtés to increase unsaturated fat content, and to determine their effects on texture and sensory properties. While pâtés made with canola oil were softer than the control pork fat product at room temperature, pâtés made with gelled canola oil (organogel pâtés) had similar hardness values to the control. Back extrusion results (also a measure of spreadability) showed that pâté made with canola oil only was softer than the control at 4 °C, but the pâtés made with organogels were similar to the control. Organogel pâtés were perceived to have similar sensory hardness, oiliness, and juiciness as the control. Pâtés made with organogels showed higher oil loss, over time, compared to control; however, pâtés made with organogels containing glycerol monostearate showed lower oil loss after 24 hr (P < 0.05) compared to the other organogel treatments. Light microscopy showed that fat globule size was notably larger in pâtés made with organogels than in the pork fat and the canola oil control pâtés. The color of organogel pâtés was darker compared to pâtés made with pork fat or canola oil only. Sensory data showed that all fat replaced pâtés had very similar flavor profiles. Overall, organogel pâtés showed comparable textural, physical, and sensory properties to the traditional pâté made with pork fat, while reducing the saturated fat content by 60%. PRACTICAL APPLICATION: Use of vegetable oil in highly emulsified liver pâté has been shown to be possible via the use of organogels prepared with ethylcellulose. This has been a challenge because some of the meat proteins are heat denatured prior to the emulsification process. Overall, the use of organogels, with specific hardness and oil retention values, is possible as demonstrated in this publication.


Assuntos
Manipulação de Alimentos/métodos , Fígado/química , Produtos da Carne/análise , Carne de Porco/análise , Óleo de Brassica napus/química , Animais , Emulsões/química , Géis/química , Suínos
7.
Food Res Int ; 116: 79-89, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30717009

RESUMO

The objective of this study was to characterize a novel soy lecithin (SL) based oleogel (LOG) and oleogel emulsion (LOGE) prepared with different proportions of stearic acid (SA). Oleogels were developed with 1 wt% of water, and two gelator concentrations (20 wt% and 30 wt%) with SL:SA ratios (0:10, 3:7, 5:5, 7:3, 10:0). The same SL:SA proportions were used to prepare LOGE with 10 wt% and 20 wt% of water. Small (SAXD) and wide (WAXD) angle x-ray diffraction studies and polarized light microscopy were conducted to determine the nano- and microstructure of the samples. The hardness of the samples was analyzed using a texture analyzer and the thermal properties with a differential scanning calorimeter. The results indicate that LOG were primarily formed through the entanglement of bundles of reverse worm-like micelles of SL; however, LOGE were structured mainly through SA crystals that interacted in a synergistic fashion with the SL reverse micelles network to stabilize the three dimensional network. The hardness of the LOG and LOGE increased with an increase in SA, however, in samples containing both SL and SA, LOGE were harder than LOG, demonstrating that the oleogelators have a synergistic effect. The novel hybrid LOG and LOGE formulated with SA can be used as a more stable alternative to SL oleogels particularly when the objective is to achieve semi-solid characteristics.


Assuntos
Emulsões/química , Lecitinas/química , Ácidos Esteáricos/química , Varredura Diferencial de Calorimetria , Dureza , Compostos Orgânicos/química , Fosfolipídeos , Difração de Raios X
8.
Sci Rep ; 8(1): 15271, 2018 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-30323241

RESUMO

A cocoa butter equivalent (CBE) was synthesized enzymatically from readily available edible fats with fatty acid and triacylglycerol compositions that closely resemble the fat present in chocolate, cocoa butter. A commercially available immobilized fungal lipase, Lipozyme RM IM, was used as the reaction catalyst. Reaction parameters were a temperature of 65 °C, water activity of 0.11, a 4 h reaction time, and a substrate mass ratio of a commercial enzymatically synthesized shea stearin (SS) to palm mid-fraction (PMF) of 6:4 (w/w). Fractionation was also used after reaction completion to further approach the triacylglycerol composition of cocoa butter by removing trisaturated and unsaturated triacylglycerols. The yield of the triglyceride 1-palmitoyl-2-oleoyl, 3-stearoyl-glycerol (POS) produced was 57.7% (w/w). The amounts of 1,3-dipalmitoyl-2-oleoyl-glycerol (POP), (POS) and 1,3-stearoyl-2-oleoyl-glycerol (SOS) in the final CBE were 11.2%, 36.3%, and 34.8%, respectively. In comparison, the amounts of POP, POS and SOS in the cocoa butter used in this study were 15.2%, 38.2%, and 27.8%, respectively. No significant differences (P > 0.05) in melting point and enthalpy of fusion between CB and the CBE were observed. In comparison, a non-interesterified blend of SS and PMF (60:40 w/w) showed significantly (P < 0.05) higher melting point and lower enthalpy of fusion compared to CB. The crystal polymorphic form V of CB (ß2-3L) was similar to that of CBE and SS/PMF (60:40 w/w). The solid fat content (SFC) vs. temperature profile of the CBE generally resembled that of CB, except that the CBE had significantly (P < 0.05) higher SFCs at 5, 10, 15, 20 and 25 °C compared to both CB and SS/PMF (60:40 w/w). Addition of 15% (w/w) CBE to CB did not cause any changes in physical properties (melting point, SFC and crystal polymorphic forms) of the CB. This study demonstrates the potential for synthesizing a CB-like CBE using a green, rapid, straightforward one step enzymatic conversion followed by fractionation from widely available edible fats.


Assuntos
Gorduras na Dieta/síntese química , Ácidos Graxos/síntese química , Lipase/química , Óleos de Plantas/síntese química , Cacau/química , Catálise , Enzimas Imobilizadas/química , Ácidos Graxos/química , Humanos , Óleos de Plantas/química , Triglicerídeos/síntese química , Triglicerídeos/química
9.
J Oleo Sci ; 67(6): 737-744, 2018 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-29760328

RESUMO

The in situ polymorphic forms and thermal transitions of refined, bleached and deodorized palm oil (RBDPO), palm stearin (RBDPS) and palm kernel oil (RBDPKO) were investigated using coupled X-ray diffraction (XRD) and differential scanning calorimetry (DSC). Results indicated that the DSC onset crystallisation temperature of RBDPO was at 22.6°C, with a single reflection at 4.2Å started to appear from 23.4 to 17.1°C, and were followed by two prominent exothermic peaks at 20.1°C and 8.5°C respectively. Further cooling to -40°C leads to the further formation of a ß'polymorph. Upon heating, a of ß'→ßtransformation was observed between 32.1 to 40.8°C, before the sample was completely melted at 43.0°C. The crystallization onset temperature of RBDPS was 44.1°C, with the appearance of the α polymorph at the same temperature as the appearance of the first sharp DSC exothermic peak. This quickly changed from α→ߴ in the range 25 to 21.7°C, along with the formation of a small ß peak at -40°C. Upon heating, a small XRD peak for the ß polymorph was observed between 32.2 to 36.0°C, becoming a mixture of (ß´+ ß) between 44.0 to 52.5°C. Only the ß polymorph survived further heating to 59.8°C. For RBDPKO, the crystallization onset temperature was 11.6°C, with the formation of a single sharp exothermic peak at 6.5°C corresponding to the ß' polymorphic form until the temperature reached -40°C. No transformation of the polymorphic form was observed during the melting process of RBDPKO, before being completely melted at 33.2°C. This work has demonstrated the detailed dynamics of polymorphic transformations of PKO and PS, two commercially important hardstocks used widely by industry and will contribute to a greater understanding of their crystallization and melting dynamics.


Assuntos
Varredura Diferencial de Calorimetria , Óleo de Palmeira/química , Óleos de Plantas/química , Triglicerídeos/química , Difração de Raios X , Cristalização , Congelamento , Transição de Fase , Pós , Termodinâmica , Temperatura de Transição
11.
Food Res Int ; 107: 110-118, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29580468

RESUMO

In this study, we show that the replacement of milk fat with canola oil in a model caseinate-based imitation cheese product to increase its nutritional value can be done by treating processed cheese as a particle filled gel network. Using microscopy, model imitation cheese products with different lipid phases were found to have similar microstructures where fat or oil appears as inert particle fillers in a continuous protein network. Using a texture profile analyzer, we show that the textural properties of model imitation cheese are dependent on the material properties of the inert filler. Addition of rigid particle fillers generally results in greater reinforcement of the matrix (i.e., increased hardness). The addition of oat fiber particles at 5% volume fraction to model cheese containing 51% milk fat and 49% canola oil resulted in a product with similar functionalities (i.e., hardness, oil stability, and meltability) as that of model cheese containing 100% milk fat. The current study therefore shows that the addition of edible non-fat particles for matrix reinforcement can be used as an alternative method for reducing saturated fats in foods while keeping other desirable properties of the product.


Assuntos
Avena , Queijo/análise , Fibras na Dieta/análise , Manipulação de Alimentos/métodos , Óleo de Brassica napus/química , Avena/química , Microscopia Crioeletrônica , Géis , Dureza , Microscopia Eletrônica de Varredura , Valor Nutritivo , Tamanho da Partícula , Propriedades de Superfície
12.
Food Funct ; 8(12): 4433-4440, 2017 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-29090299

RESUMO

Ethylcellulose (EC) forms a complex oleogel network that entraps lipids. The digestibility of an oleogel is influenced by the types of oils used in its preparation. This randomised, controlled, crossover study aimed to compare lipidemic, glycemic, and appetitive responses to a test meal alone (no oil control), or to palm oil (PO, 22.25 g), rice bran oil (RBO, 22.25 g), palm oleogel (PG, 22.25 g oil + 2.75 g EC), or rice bran oleogel (RBG, 22.25 g oil + 2.75 g EC). Eighteen healthy Chinese males (age: 28 ± 6 years, weight: 65.9 ± 8.5 kg, and BMI: 21.6 ± 2.0 kg m-2) completed all test visits. The participants consumed a standard dinner and fasted overnight before attending the test session in the following morning. Blood samples were taken before the participants consumed the test meal, and subsequently at fixed intervals. Plasma was analysed for triglycerides, glucose, insulin, and non-esterified fatty acids (NEFA). Appetite sensations were also measured every 30 minutes for 360 minutes. After the test meal consumption, a significant interaction effect (repeated measures ANOVA) was found on temporal changes in triglycerides (p < 0.001). Plasma triglycerides increased significantly in both PO and RBO only, but not in oleogel test meals. PO and RBO also suppressed the rise of glucose (time × treatment effect, p = 0.011) at 20, 30 and 45 min. However, no significant differences were found between palm and rice bran oils in triglycerides and glucose. Changes in insulin, NEFA and appetite did not differ among all treatments. Transformation of oils to oleogels is a novel approach to reduce after-meal triglycerides. This trial was registered with ClinicalTrials.gov as NCT02969057.


Assuntos
Glicemia/análise , Gorduras na Dieta/metabolismo , Óleos de Plantas/química , Óleos de Plantas/metabolismo , Período Pós-Prandial , Triglicerídeos/sangue , Adulto , Apetite , Glicemia/metabolismo , Celulose/análogos & derivados , Celulose/química , Celulose/metabolismo , China , Estudos Cross-Over , Ácidos Graxos não Esterificados/sangue , Feminino , Índice Glicêmico , Humanos , Insulina/sangue , Masculino , Pessoa de Meia-Idade , Compostos Orgânicos/química , Compostos Orgânicos/metabolismo , Adulto Jovem
13.
Food Funct ; 8(11): 3964-3969, 2017 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-28972217

RESUMO

Phytosterols and phytosterol esters were encapsulated within large unilamellar liposomes prepared with soy phospholipids using a microfluidizer. The average particle diameter of these liposomal vesicles increased with increasing amounts of encapsulated phytosterols, especially with increasing free sterol content. The phytosterol content, liposomal particle size, and phytosterol encapsulation efficiency started to plateau when liposomes were prepared with MOPS buffer dispersions that contained 50 mg ml-1 soy phospholipid and more than 4% phytosterol blend, suggesting the saturation of phytosterol encapsulation. We proposed an encapsulation mechanism of free sterols and phytosterol esters in liposomes, where free sterols were mainly encapsulated within the lumen of these liposomes as crystals, and sterol esters and some free sterols were incorporated within the phospholipid bilayer of the liposomal membrane. The results from this work could provide the pharmaceutical and nutraceutical industries a practical method to produce loaded liposomes using inexpensive phospholipid mixtures for the delivery of bioactive ingredients.


Assuntos
Ésteres/química , Glycine max/química , Lipossomos/química , Fosfolipídeos/química , Fitosteróis/química , Extratos Vegetais/química , Composição de Medicamentos , Tamanho da Partícula
14.
Food Res Int ; 96: 54-63, 2017 06.
Artigo em Inglês | MEDLINE | ID: mdl-28528108

RESUMO

Two hydrogenated roll-in shortenings (A & B), one non-hydrogenated roll-in shortening and butter were used to prepare croissants. The impact of the laminated dough matrix on fat crystallization was then investigated using powder X-ray diffraction (XRD), pulsed nuclear magnetic resonance (p-NMR) and differential scanning calorimetry (DSC). The fat contained within a croissant matrix has never before been analyzed using these techniques. In each case, XRD revealed that the polymorphism of a roll-in fat will be different when baked within the dough matrix than when simply heated and cooled on its own. Both hydrogenated roll-in shortenings and butter experienced only minor changes, largely retaining their ß' polymorphs, but the non-hydrogenated shortening experienced significant conversion from ß' to the ß form. However, this conversion did not take place immediately upon cooling, but after approximately 24h of storage time. The fat contained within the croissants exhibited a significantly lower SFC than the same fats in bulk. Further, DSC results demonstrated that a greater temperature was required to completely melt all of the fat in a croissant than the same fat in bulk, observed visually as broader peaks in the melting endotherms. Analysis of croissant firmness over storage time, measured as the maximum force required to cut a croissant was used as an indication of potential sensory consequences. Results suggested that only croissants prepared with non-hydrogenated shortening experienced significant changes in firmness over one week of storage. These results indicate that there is an interaction between the shortenings and the ingredients of the croissant matrix, and given the differences observed between roll-in fats used, the extent of interaction is potentially influenced by the composition of the roll-in fat itself.


Assuntos
Manteiga/análise , Culinária/métodos , Temperatura Alta , Óleos de Plantas/química , Varredura Diferencial de Calorimetria , Cristalização , Cristalografia por Raios X , Tecnologia de Alimentos/métodos , Gossypium/química , Hidrogenação , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Óleo de Palmeira/química , Difração de Pó , Óleo de Brassica napus/química , Sementes/química , Óleo de Soja/química , Fatores de Tempo
15.
J Cosmet Sci ; 68(2): 159-172, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29619940

RESUMO

A petroleum-free skin cream was developed using food-grade ingredients. The rheological and sensorial properties of this petroleum-free skin cream were compared to a commercially available petroleum-based skin cream. Specifically, large-amplitude oscillatory shear (LAOS) characterization of the two skin creams was performed. The petroleum-free skin cream showed similar linear and nonlinear viscoelastic rheological properties, comparable skin hydration functions, and consumer acceptance as the commercially available skin cream. A schematic diagram aiming to correlate the physical and sensorial properties of skin cream was also proposed at the end of the work. Results of this work could provide the cosmetic industry necessary information for the development of alternatives for petroleum-based skin creams.


Assuntos
Petróleo/análise , Creme para a Pele/química , Comportamento do Consumidor , Humanos , Reologia , Sensação
16.
J Food Sci ; 78(12): C1845-51, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24329951

RESUMO

The objective of this study was to investigate the influence of emulsifiers, waxes, fat concentration, and processing conditions on the application of wax oleogel to replace solid fat content and create optimal fat structure in ice cream. Ice creams with 10% or 15% fat were formulated with rice bran wax (RBW), candelilla wax (CDW), or carnauba wax (CBW) oleogels, containing 10% wax and 90% high-oleic sunflower oil. The ice creams were produced using batch or continuous freezing processes. Transmission electron microscopy (TEM) and cryo-scanning electron microscopy were used to evaluate the microstructure of ice cream and the ultrastructure of oleogel droplets in ice cream mixes. Among the wax oleogels, RBW oleogel had the ability to form and sustain structure in 15% fat ice creams when glycerol monooleate (GMO) was used as the emulsifier. TEM images revealed that the high degree of fat structuring observed in GMO samples was associated with the RBW crystal morphology within the fat droplet, which was characterized by the growth of crystals at the outer edge of the droplet. Continuous freezing improved fat structuring compared to batch freezing. RBW oleogels established better structure compared to CDW or CBW oleogels. These results demonstrate that RBW oleogel has the potential to develop fat structure in ice cream in the presence of GMO and sufficiently high concentrations of oleogel.


Assuntos
Manipulação de Alimentos/métodos , Sorvetes/análise , Gorduras na Dieta/análise , Emulsões/química , Congelamento , Glicerídeos/química , Ácido Oleico/química , Compostos Orgânicos/química , Óleos de Plantas/química , Óleo de Girassol , Ceras/química
17.
J Food Sci ; 78(9): C1334-9, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24024686

RESUMO

The development of structure in ice cream, characterized by its smooth texture and resistance to collapse during melting, depends, in part, on the presence of solid fat during the whipping and freezing steps. The objective of this study was to investigate the potential application of 10% rice bran wax (RBW) oleogel, comprised 90% high-oleic sunflower oil and 10% RBW, to replace solid fat in ice cream. A commercial blend of 80% saturated mono- and diglycerides and 20% polysorbate 80 was used as the emulsifier. Standard ice cream measurements, cryo-scanning electron microscopy (cryo-SEM), differential scanning calorimetry (DSC), and transmission electron microscopy (TEM) were used to evaluate the formation of structure in ice cream. RBW oleogel produced higher levels of overrun when compared to a liquid oil ice cream sample, creating a lighter sample with good texture and appearance. However, those results were not associated with higher meltdown resistance. Microscopy revealed larger aggregation of RBW oleogel fat droplets at the air cell interface and distortion of the shape of air cells and fat droplets. Although the RBW oleogel did not develop sufficient structure in ice cream to maintain shape during meltdown when a mono- and diglycerides and polysorbate 80 blend was used as the emulsifier, micro- and ultrastructure investigations suggested that RBW oleogel did induce formation of a fat globule network in ice cream, suggesting that further optimization could lead to an alternative to saturated fat sources for ice cream applications.


Assuntos
Gorduras Insaturadas na Dieta/análise , Gorduras/química , Sorvetes/análise , Oryza/química , Ceras/química , Varredura Diferencial de Calorimetria , Manipulação de Alimentos/métodos , Congelamento , Microscopia Eletrônica de Transmissão e Varredura , Compostos Orgânicos/química , Tamanho da Partícula , Óleos de Plantas/química , Óleo de Girassol
18.
Food Funct ; 4(1): 153-61, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23165763

RESUMO

The use of ethylcellulose (EC) polymers as a means to structure edible oils for fat replacement is beginning to show great promise and the use of these 'oleogels' has recently been shown to be feasible in food products. These gels are very versatile, as the mechanical properties can be tailored by altering either the fatty acid profile of the oil component, or the viscosity or concentration of the polymer component. Here we report the observation that certain formulation of EC oleogels tend to separate into two distinct phases; a soft interior core surrounded by a firm exterior sheath. It was found that the extent of this effect depends on EC viscosity, and can also be induced through the addition of certain surfactants, such as sorbitan monostearate and sorbitan monooleate, though not by glycerol monooleate. Although the two visually distinct regions were shown to be chemically indistinct, the cooling rate during gel setting was found to play a large role; rapid setting of the gels reduces the fractionation effect, while slow cooling produced a completely homogeneous structure. In addition, by reheating only the soft region of the gel, a firm and soft fractionated gel could again be produced. Finally, it was observed that oleogels prepared with castor oil or mineral oil have the ability to remove or induce the gel separation, respectively. Taken together, these results indicate chemical interactions may incite the separation into two distinct phases, but the process also seems to be driven by the cooling conditions during gel setting. These findings lend insight into the EC-oleogel gelation process and should provide a stepping stone for future research into the manufacturing of these products.


Assuntos
Celulose/análogos & derivados , Celulose/química , Óleo de Rícino/química , Fracionamento Químico , Géis/química , Óleo Mineral/química , Óleo de Soja/química
19.
Faraday Discuss ; 158: 171-94; discussion 239-66, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23234167

RESUMO

This article reports on the effect of laminar shear on structural and mechanical properties of physical mixtures of fully hydrogenated soybean oil (FHSO) in soybean oil (SO). Blends were crystallized statically and under laminar shear rates of 30 and 240 s(-1) at different wall temperatures (-10, 0, 20 degrees C). The micro- and nanocrystalline structures were characterized using Polarized Light Microscopy (PLM), and Cryogenic Transmission Electron Microscopy (Cryo-TEM). Rheological analysis was used to determine changes in mechanical properties. Oil-binding capacity was analyzed through the measurement of the oil lost from the fat samples (OL). Shearing greatly affected the structure at the nano- and mesoscale. At low shear rates, blends displayed the largest increase in crystal size with an increase in wall temperature at both the nano- and mesoscale. On the other hand, at shear rates of 240 s(-1), the effect of crystallization temperature was observed only at the nanoscale since no changes in meso-crystal sizes were observed at different temperatures. Crystallization under laminar shear promoted the growth of spherical crystalline particles at the mesoscale, called here "solid-lipid meso-particles". Crystallization under higher shear rates led to the formation of a weak network with low oil-binding capacity and promoted the asymmetric growth of nanoplatelets. In statically crystallized blends, nanoplatelets had an aspect ratio of -2, while in sheared blends this value increased significantly. These results revealed the existence of critical shear rate values above which strong alterations in the structure of the solid crystalline network took place. Shearing also affected the material's strength. Laminar shear induced a decrease in elastic modulus and yield stress values which was more pronounced at higher shear rate-temperature combinations. Shear-temperature combinations were successfully used to structure fats at the nano and mesoscale.


Assuntos
Nanoestruturas/química , Óleo de Soja/química , Microscopia Crioeletrônica , Cristalização , Módulo de Elasticidade , Hidrogenação , Microscopia de Polarização , Modelos Químicos , Nanoestruturas/ultraestrutura , Reologia , Temperatura
20.
Langmuir ; 28(46): 16207-17, 2012 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-23046015

RESUMO

The effects of processing using a scraped surface heat exchanger (SSHE) before and after adding unsaturated monoglyceride (UM) on blends of fully hydrogenated soybean oil (FHSO) and soybean oil (SO) were studied. Mixtures of 40:60 and 45:55 FHSO:SO were melted at 80 °C for 30 min and crystallized statically or in the SSHE (shear rate of 25 s(-1)) at a cooling rate of 9 °C/min. Upon shearing and UM addition, polymorphic transformations toward more (ß) or less (ß') stable forms were governed by the combination between system concentration, composition, and crystallization conditions, as determined by differential scanning calorimetry and powder X-ray diffraction. Nuclear magnetic resonance was used to measure the solid fat content (SFC) development which showed to increase with processing conditions due to the high nucleation rate induced. Processing conditions greatly affected the nano- and microcrystalline structures which were characterized by polarized light microscopy (PLM), cryogenic transmission electron microscopy (Cryo- TEM), and Scherrer analysis of the powder X-ray diffraction data. Crystallization under shear promoted the longitudinal growth of the nanoplatelets; nevertheless, meso structural elements showed a decrease in their dimensions under the same crystallization conditions. The relative oil loss determined gravimetrically was inversely related to the elastic modulus and yield stress of the sheared fat blends, and values were closer to the desirable usability ranges for bakery applications. Our results suggest that fully hydrogenated fats can be functionalized by crystallization in a SSHE and/or by judicious addition of an unsaturated emulsifier.


Assuntos
Emulsificantes/química , Óleo de Soja/química , Microscopia Crioeletrônica , Cristalização , Módulo de Elasticidade , Gorduras/química , Hidrogenação , Microscopia Eletrônica de Transmissão , Monoglicerídeos , Difração de Raios X
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