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1.
J Food Sci ; 85(12): 4319-4326, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33175398

RESUMO

In many confectionery systems, an understanding of crystallization behavior is essential for proper control of product texture. While this knowledge is well developed in sucrose-based systems, there is little information on controlling crystallization in sugar-free systems, such as those formulated with sorbitol. By leveraging such advances in time domain-nuclear magnetic resonance (TD-NMR) methodology, the impact of mannitol and maltitol on modulating sorbitol crystal growth in sugar-free systems. Binary and ternary systems of sorbitol mixed with mannitol, maltitol, or a mixture thereof were evaluated at total impurity addition levels of 10% and 20%. Polyol mixtures were dissolved in water, evaporated to 10% moisture, and mixed with γ sorbitol seed crystals to create a sugar-free fondant. Fondants were crystallized at 25 °C, and crystal content was measured using TD-NMR over time. Crystal content increased rapidly at the start but quickly tapered off to a final asymptote indicating phase equilibrium. In all systems, the addition of impurities decreased the extent and rate of sorbitol crystallization, with mannitol having the greatest impact on rate. When both mannitol and maltitol were present as impurities, the rate of crystallization was reduced to a greater extent. At the highest level of mannitol, the final crystal content increased, presumably because mannitol also crystallized. PRACTICAL APPLICATION: Controlling sorbitol crystallization in the presence of impurities is a key to controlling quality in certain confections.

2.
J Food Sci ; 85(11): 3885-3898, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33063351

RESUMO

Although the ice phase greatly influences the properties of ice cream, other structural components also affect its rheological behavior, particularly after melting. In this study, mix viscosity (serum phase viscosity), extent of fat destabilization (FD), and overrun were manipulated to produce different microstructures. The effects of these structural components were evaluated on the rheological properties of the ice creams and melted ice creams. In oscillatory thermorheometry, mix viscosity and then overrun, influenced G' and tanδ below -10 °C. When ice phase decreased (between -10 and -2.7 °C), mix viscosity had reduced effects, but continued to strongly affect G' and tanδ, followed by FD, and with lower effects from overrun. When the ice phase was completely melted at 0 °C, FD had most influence on G' and tanδ, followed by overrun, and with lower effects from mix viscosity. In creep/recovery test, six-element model described well creep behavior of melted ice cream at 0 °C. Viscous behavior at lower shear rate (η0 0 °C) was most influenced by mix viscosity, followed by FD, and lower overrun effects. In stress growth measurement, transient behavior, represented by σY 0 °C, of melted matrix at 0 °C was most influenced by FD, followed by mix viscosity, with lower overrun effects. In flow ramp measurement, Hysteresis Area was most affected by mix viscosity, followed by overrun, and with lower FD effects. Moreover, correlation between Hyst 0 °C and tanδ Peak suggested that structure formation affected the magnitude of tanδ Peak. These results document the importance of microstructure on properties of melted ice cream. PRACTICAL APPLICATION: The understanding of how structural components, such as mix viscosity, fat destabilization, and overrun, affect the ice cream matrix can help manufacturers to control its rheological behavior. The influence of these structural components on the G', tanδ, η0 0 °C , σY 0 °C , and Hyst 0 °C can be also used to understand the structural rearrangements that occur in meltdown tests and sensory analyses for future studies. Therefore, elucidation of these mechanisms on the rheological properties can directly assist in quality control and new product development in the ice cream industry.

3.
Soft Matter ; 16(23): 5506-5513, 2020 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-32495759

RESUMO

Arrested, or partial, coalescence of viscoelastic emulsion droplets can occur when elastic resistance to deformation offsets droplet surface area minimization. Arrest is a critical element of food and consumer product microstructure and performance, but direct studies of structural arrest and rearrangement have been carried out using only two or three droplets at a time. The question remains whether the behavior of small numbers of droplets also occurs in larger, more realistic many-droplet systems. Here we study two-dimensional aggregation and arrested coalescence of emulsions containing ∼1000 droplets and find that the restructuring mechanisms observed for smaller systems have a large effect on local packing in multidroplet aggregates, but surprisingly do not significantly alter overall mass scaling in the aggregates. Specifically, increased regions of hexagonal packing are observed as the droplet solids level, and thus elasticity, is decreased because greater degrees of capillary force-driven restructuring are possible. Diffusion-limited droplet aggregation simulations that account for the restructuring mechanisms agree with the experimental results and suggest a basis for prediction of larger-scale network properties and bulk emulsion behavior.

4.
Rev. chil. nutr ; 47(1): 50-56, feb. 2020. tab, graf
Artigo em Inglês | LILACS-Express | LILACS | ID: biblio-1092743

RESUMO

ABSTRACT Using technical procedures, the fatty acid (FA) profile and solid fat content (SFC) of the Peruvian cultivar cacao beans CCN 51 and ICS 6 and the "optimal chocolate", obtained from the mixture of the first two, were determined to assess their quality. These cacao beans were found to have important nutritional values. The FA profile of the cacao beans were similar (p>0.05); however, in the FA profile, the 'optimal chocolate' had significant differences (p≤0.05) in terms of palmitic, arachidic and linolenic acid. The n6:n3 ratio for "optimal chocolate" was 12.0 ± 1.7. Cacao beans had the same SFC, and SFC was highly temperature dependent, as determined using a mathematical model for chocolate. The SFC of chocolate refers to hard cacao butter content at temperatures between 20 and 25°C, and solid fat was heat resistant from 25 to 30°C, which is considered valuable in trade chocolate production. The quality-related properties of these lipid fractions imparted nutritional and physical aspects to the optimal dark chocolate for human consumption.


RESUMEN La composición de ácidos grasos (CAG) y el contenido de sólidos grasos (CSG), de la fracción lipídica de los cultivares peruanos de cacao CCN 51 e ICS 6 así como del "chocolate óptimo", obtenido de las mezclas de las primeras dos, fueron determinados por técnicas analíticas para conocer su calidad. Estas variedades tuvieron valores nutricionales importantes. La CAG de los granos de cacao fueron similares, sin embargo la CAG del "Chocolate óptimo" tuvo diferencias significativas (p<0,05) para los acidos grasos palmitico, araquidico y linoleico. El ratio n6:n3 fue de 12,0 ± 1,7. El CSG de los granos de cacao fueron los mismos y tuvo una fuerte dependencia con la temperatura, también se definió un modelo matematico para el chocolate. El CSG le confiere al chocolate una consistencia dura a temperaturas de 20 a 25°C y resistentes al calor de 25 a 30°C, siendo tales propiedades una ventaja en la comercialización de chocolates. La calidad de estas fracciones lipidicas tuvieron aspectos nutricionales y fisicos en el chocolate oscuro para consumo humano.

5.
J Texture Stud ; 51(1): 92-100, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31251392

RESUMO

Air incorporated during dynamic freezing influences the development of the microstructure and the final texture of frozen desserts. Frozen desserts were manufactured with 100-175% overrun from a constant ice cream mix formulation. Microstructural elements (fat, air, and ice phases) of the frozen desserts were then investigated and related to the melting, rheological, and sensory properties of the product. Mean ice crystal and air cell size were found to decrease with increasing overrun, and the extent of fat destabilization increased. Frozen desserts manufactured with higher overrun had slower drip-through rate and better shape retention after melting at ambient conditions, demonstrating that fat destabilization and the interplay of fat, air, and serum phases affect the melting behavior. Structural elements also influenced the rheological behavior, as measured by oscillatory thermo-rheometry. Frozen desserts had similar rheological properties at temperatures below the freezing point due to the presence of ice, and the values of G' and G″ (solid-like and viscous-like character, respectively) increased with increasing overrun above the freezing point, corresponding to a more solid-like structure. Slight differences in sensory denseness and breakdown were detected, but sensory texture was not significantly different for the frozen desserts studied. This study provided insights into the role of air in ice cream and frozen desserts, and its influence on product texture.

6.
J Food Sci ; 84(9): 2562-2571, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31423589

RESUMO

This study aims at exploring ice cream meltdown behavior by changing the levels of stabilizer (ST), polysorbate 80 (PS80), and overrun (OR). By adjusting the formulation of ice cream, the degree of fat destabilization (FD), mix viscosity (MV), and overrun can be controlled within a certain range, which in turn presents different meltdown behaviors for study. In addition to the drip-through test, the shape of ice cream as it melts was recorded as height change to further investigate ice cream meltdown. Mix viscosity (at 50 s-1 ) and fat destabilization were found to have a significant effect not only on drip-through rate, but also the induction time, final weight of the drip-through part, height-change rate, and final height of melted ice cream. On the other side, overrun was found only to have an effect on meltdown when no stabilizers were added. These results indicate serum phase viscosity (mix viscosity) and fat destabilization are important parameters to describe ice cream meltdown. Besides, the entire ice cream meltdown curve and height collapse curve provide important information on ice cream meltdown behavior. PRACTICAL APPLICATION: A new direction of analysis of ice cream meltdown behavior is provided in this study. The induction time, the final drip-through weight, and the height change during the meltdown process were found to be the indicators on the influence of microstructure on ice cream meltdown behavior for the future study.


Assuntos
Gorduras/química , Manipulação de Alimentos/métodos , Sorvetes/análise , Leite/química , Animais , Bovinos , Congelamento , Polissorbatos/química , Viscosidade
7.
J Food Sci ; 83(3): 639-647, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29388677

RESUMO

Ice cream is a multiphase frozen food containing ice crystals, air cells, fat globules, and partially coalesced fat globule clusters dispersed in an unfrozen serum phase (sugars, proteins, and stabilizers). This microstructure is responsible for ice cream's melting characteristics. By varying both formulation (emulsifier content and overrun) and processing conditions (dasher speed), the effects of different microstructural elements, particularly air cells and fat globule clusters, on ice cream melt-down properties were studied. Factors that caused an increase in shear stress within the freezer, namely increasing dasher speed and overrun, caused a decrease in air cell size and an increase in extent of fat destabilization. Increasing emulsifier content, especially of polysorbate 80, caused an increase in extent of fat destabilization. Both overrun and fat destabilization influenced drip-through rates. Ice creams with a combination of low overrun and low fat destabilization had the highest drip-through rates. Further, the amount of remnant foam left on the screen increased with reduced drip-through rates. These results provide a better understanding of the effects of microstructure components and their interactions on drip-through rate. PRACTICAL APPLICATIONS: Manipulating operating and formulation parameters in ice cream manufacture influences the microstructure (air cells, ice crystals, and fat globule clusters). This work provides guidance on which parameters have most effect on air cell size and fat globule cluster formation. Further, the structural characteristics that reduce melt-down rate were determined. Ice cream manufacturers will use these results to tailor their products for the desired quality attributes.


Assuntos
Emulsificantes/química , Manipulação de Alimentos/métodos , Sorvetes/análise , Leite/química , Animais , Bovinos , Manipulação de Alimentos/instrumentação , Congelamento , Polissorbatos/química
8.
Soft Matter ; 13(14): 2686-2697, 2017 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-28332667

RESUMO

The stability of shapes formed by three viscoelastic droplets during their arrested coalescence has been investigated using micromanipulation experiments. Addition of a third droplet to arrested droplet doublets is shown to be controlled by the balance between interfacial pressures driving coalescence and internal elasticity that resists total consolidation. The free fluid available within the droplets controls the transmission of stress during droplet combination and allows connections to occur via formation of a neck between the droplets. The anisotropy of three-droplet systems adds complexity to the symmetric case of two-droplet aggregates because of the multiplicity of orientations possible for the third droplet. When elasticity dominates, the initial orientation of the third droplet is preserved in the triplet's final shape. When elasticity is dominated by the interfacial driving force, the final shape can deviate strongly from the initial positioning of droplets. Movement of the third droplet to a more compact packing occurs, driven by liquid meniscus expansion that minimizes the surface energy of the triplet. A range of compositions and orientations are examined and the resulting domains of restructuring and stability are mapped based on the final triplet structure. A geometric and a physical model are used to explain the mechanism driving meniscus-induced restructuring and are related to the impact of these phenomena on multiple droplet emulsions.

9.
J Food Sci ; 79(10): E2005-13, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25220600

RESUMO

UNLABELLED: Commercial vanilla ice cream products from the United States (full fat, low fat, and nonfat) were analyzed for their structural, behavioral (i.e., melt rate and drip-through), compositional, and sensorial attributes. Mean size distributions of ice crystals and air cells, drip-through rates, percent partially coalesced fat, percent overrun and total fat, and density were determined. A trained panel carried out sensory analyses in order to determine correlations between ice cream microstructure attributes and sensory properties using a Spectrum(TM) descriptive analysis. Analyses included melt rate, breakdown, size of ice particulates (iciness), denseness, greasiness, and overall creaminess. To determine relationships and interactions, principle component analysis and multivariate pairwise correlation were performed within and between the instrumental and sensorial data. Greasiness and creaminess negatively correlated with drip-through rate and creaminess correlated with percent total fat and percent fat destabilization. Percent fat did not determine the melt rate on a sensorial level. However, drip-through rate at ambient temperatures was predicted by total fat content of the samples. Based on sensory analysis, high-fat products were noted to be creamier than low and nonfat products. Iciness did not correlate with mean ice crystal size and drip-through rate did not predict sensory melt rate. Furthermore, on a sensorial level, greasiness positively correlated with total percent fat destabilization and mean air cell size positively correlated with denseness. These results indicate that commercial ice cream products vary widely in composition, structure, behavior, and sensory properties. PRACTICAL APPLICATION: There is a wide range of commercial ice creams in the United States market, ranging from full fat to nonfat. In this research we showed that these ice creams vary greatly in their microstructures, behaviors (the melt/drip-though, collapse, and/or stand up properties of ice cream products at ambient temperatures), and sensory properties.


Assuntos
Sorvetes/análise , Gorduras na Dieta/análise , Gorduras/química , Aromatizantes/análise , Congelamento , Humanos , Sensação , Estados Unidos
10.
J Food Sci ; 79(3): R257-72, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24517206

RESUMO

In the dairy industry, crystallization is an important separation process used in the refining of lactose from whey solutions. In the refining operation, lactose crystals are separated from the whey solution through nucleation, growth, and/or aggregation. The rate of crystallization is determined by the combined effect of crystallizer design, processing parameters, and impurities on the kinetics of the process. This review summarizes studies on lactose crystallization, including the mechanism, theory of crystallization, and the impact of various factors affecting the crystallization kinetics. In addition, an overview of the industrial crystallization operation highlights the problems faced by the lactose manufacturer. The approaches that are beneficial to the lactose manufacturer for process optimization or improvement are summarized in this review. Over the years, much knowledge has been acquired through extensive research. However, the industrial crystallization process is still far from optimized. Therefore, future effort should focus on transferring the new knowledge and technology to the dairy industry.


Assuntos
Lactose/química , Leite/química , Animais , Cristalização , Humanos , Cinética , Lactose/isolamento & purificação
11.
Food Chem ; 139(1-4): 184-95, 2013 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-23561095

RESUMO

The crystallisation and polymorphic properties of three sunflower hard stearins (SHSs) and cocoa butter equivalents (CBEs) formulated by blending SHSs and palm mid fraction (PMF) were studied and compared with those from cocoa butter (CB), to explore their possibilities as confectionery fats. The isothermal crystallisation kinetics of these fats were examined by pNMR and DSC at three different temperatures. All samples studied displayed a two-step crystallisation profile that could be fitted to an exponential-Gompertz equation. Stop-and-return DSC studies showed that SHSs and CBEs exhibited different crystallisation mechanisms according to their triacylglycerol composition, with a quick formation of metastable crystals, followed by a polymorphic transition to the more stable ß or ß' forms. X-ray diffraction (XRD) was used to investigate the polymorphic forms of tempered SHSs and CBEs in the long term. In all cases the resulting fats displayed short spacing patterns associated with ß polymorphism. These formulations based on SHSs and PMF met all the requirements to be considered as CBEs; therefore they could be used as an alternative to traditional confectionery fats.


Assuntos
Gorduras/química , Helianthus/química , Triglicerídeos/química , Cristalização , Cinética , Temperatura , Difração de Raios X
12.
Annu Rev Food Sci Technol ; 4: 277-92, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23464574

RESUMO

Crystals often play an important role in food product quality and shelf life. Controlling crystallization to obtain the desired crystal content, size distribution, shape, and polymorph is key to manufacturing products with desired functionality and shelf life. Technical developments in the field have improved the tools with which we study and characterize crystals in foods. These developments also help our understanding of the physico-chemical phenomena that govern crystallization and improve our ability to control it during processing and storage. In this review, some of the more important recent developments in measuring and controlling crystallization are discussed.


Assuntos
Manipulação de Alimentos/métodos , Conservação de Alimentos/métodos , Qualidade dos Alimentos , Alimentos , Carboidratos , Fenômenos Químicos , Cristalização , Gelo , Transição de Fase , Soluções
13.
Faraday Discuss ; 158: 341-50; discussion 351-70, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23234175

RESUMO

There are many new approaches to designing complex anisotropic colloids, often using droplets as templates. However, droplets themselves can be designed to form anisotropic shapes without any external templates. One approach is to arrest binary droplet coalescence at an intermediate stage before a spherical shape is formed. Further shape relaxation of such anisotropic, arrested structures is retarded by droplet elasticity, either interfacial or internal. In this article we study coalescence of structured droplets, containing a network of anisotropic colloids, whose internal elasticity provides a resistance to full shape relaxation and interfacial energy minimization during coalescence. Precise tuning of droplet elasticity arrests coalescence at different stages and leads to various anisotropic shapes, ranging from doublets to ellipsoids. A simple model balancing interfacial and elastic energy is used to explain experimentally observed coalescence arrest in viscoelastic droplets. During coalescence of structured droplets the interfacial energy is continuously reduced while the elastic energy is increased by compression of the internal structure and, when the two processes balance one another, coalescence is arrested. Experimentally we observe that if either interfacial energy or elasticity dominates, total coalescence or total stability of droplets results. The stabilization mechanism is directly analogous to that in a Pickering emulsion, though here the resistance to coalescence is provided via an internal volume-based, rather than surface, structure. This study provides guidelines for designing anisotropic droplets by arrested coalescence but also explains some observations of "partial" coalescence observed in commercial foods like ice cream and whipped cream.


Assuntos
Água/química , Ceras/química , Anisotropia , Elasticidade , Emulsões , Sorvetes/análise , Pressão , Termodinâmica
14.
Food Chem ; 134(3): 1409-17, 2012 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-25005960

RESUMO

Cocoa butter equivalents (CBEs) are produced from vegetable fats by blending palm mid fraction (PMF) and tropical butters coming from shea, mango kernel or kokum fat. In this regard, high oleic-high stearic (HOHS) sunflower hard stearins from solvent fractionation can be used in CBE production since their compositions and physical properties are similar to those found in the above-mentioned tropical butters. In this work, three sunflower hard stearins (SHS) ranging from 65% to 95% of disaturated triacylglycerols and a shea stearin (used as reference) were blended with PMF to evaluate their potential use in CBEs formulation. Isosolid phase diagrams of mixtures of PMF/SHS showed eutectic formation for SHS 65 and SHS 80, but monotectic behaviour with softening effect for SHS 95. Three CBEs from SHS and shea stearin were formulated according to phase behaviour diagrams and solid fat content data at 25 °C. Isosolid phase diagrams of mixtures of these CBEs with cocoa butter showed no eutectic behaviour. Therefore, CBEs elaborated from SHS exhibited full compatibility with cocoa butter.


Assuntos
Gorduras na Dieta/metabolismo , Helianthus/química , Ácido Oleico/química , Triglicerídeos/química
15.
Crit Rev Food Sci Nutr ; 46(3): 207-19, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16527753

RESUMO

Scraped surface heat exchangers (SSHEs) are commonly used in the food, chemical, and pharmaceutical industries for heat transfer, crystallization, and other continuous processes. They are ideally suited for products that are viscous, sticky, that contain particulate matter, or that need some degree of crystallization. Since these characteristics describe a vast majority of processed foods, SSHEs are especially suited for pumpable food products. During operation, the product is brought in contact with a heat transfer surface that is rapidly and continuously scraped, thereby exposing the surface to the passage of untreated product. In addition to maintaining high and uniform heat exchange, the scraper blades also provide simultaneous mixing and agitation. Heat exchange for sticky and viscous foods such as heavy salad dressings, margarine, chocolate, peanut butter, fondant, ice cream, and shortenings is possible only by using SSHEs. High heat transfer coefficients are achieved because the boundary layer is continuously replaced by fresh material. Moreover, the product is in contact with the heating surface for only a few seconds and high temperature gradients can be used without the danger of causing undesirable reactions. SSHEs are versatile in the use of heat transfer medium and the various unit operations that can be carried out simultaneously. This article critically reviews the current understanding of the operations and applications of SSHEs.


Assuntos
Manipulação de Alimentos/instrumentação , Temperatura Alta , Fenômenos Químicos , Físico-Química , Temperatura Baixa , Cristalização , Reologia , Termodinâmica , Viscosidade
16.
J Agric Food Chem ; 51(22): 6550-7, 2003 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-14558777

RESUMO

The effects of addition of the sucrose esters (SE) P-1670, P-170, and S-170 to a high-melting fraction of milk fat (HMF) and its blends with sunflower oil (SFO) on nucleation and growth were studied by laser polarized light turbidimetry and polarized light microscopy (PLM). The three SE delayed nucleation of HMF at the temperatures selected. P-1670 did not modify average crystal size after 3 h at crystallization temperature (T(c)) or crystal size distribution and modified crystallization kinetics only slightly. P-170 and S-170, however, markedly diminished crystal size and narrowed crystal size distribution. Activation free energies of nucleation at equivalent supercooling, calculated using the Fisher-Turnbull equation, significantly increased with addition of SE. According to these results, among the mechanisms described in the literature for fats or emulsions, the cocrystallization hypothesis is the one that better described the effects of sucrose esters on crystallization behavior in these systems.


Assuntos
Ésteres/administração & dosagem , Lipídeos/química , Leite/química , Óleos Vegetais/química , Sacarose/administração & dosagem , Animais , Varredura Diferencial de Calorimetria , Fenômenos Químicos , Físico-Química , Cristalização , Tecnologia de Alimentos , Microscopia de Polarização , Óleo de Girassol , Termodinâmica , Difração de Raios X
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