Experimental Methodology

Campos, Rodrigo

doi:10.1201/9781420030549.ch9

Cited by 13 publications

(28 citation statements)

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“…The Avrami constant, k, is affected primarily by the crystallization temperature and reflects the velocity of this process (Campos, 2005). The highest values for this constant were observed for the industrial blends, indicative of the higher crystallization rates of these samples.…”

Section: Crystallization Kineticsmentioning

confidence: 98%

“…For each slide, three visual fields were captured, representative of the crystals observed. The evaluation parameters selected for a quantitative analysis of the images, performed through the software Image Pro-Plus version 7.0 (Media Cybernetics, Bethesda, USA), were the mean diameter of the crystals and the the percentage of crystallized areas (Campos, 2005;Silva et al, 2009).…”

Section: Methodsmentioning

confidence: 99%

“…The characterization of the crystallization kinetics was performed according to the induction period (t SFC ) -relative to the onset of the formation of crystals, maximum solid fat content (SFC max ) and relative time to obtain 50% of the maximum content of solids (t 1/2SFCmáx ). The induction time was obtained graphically and reflects the time required for a stable nucleus to be formed in the liquid phase (Campos, 2005). The original Avrami equation was used to model the crystallization process:…”

Section: Methodsmentioning

confidence: 99%

“…Under low rates (1 °C/ min or less), the limited heat load allows for the accomplishment of molecular rearrangements. Some thermal events, such as the melting of previously existing polymorphic forms, polymorphic transformations and the subsequent melting of newly formed polymorphs can be observed when the sample is slowly melted (Campos, 2005).…”

Section: Polymorphic Transitions (Dsc)mentioning

confidence: 99%

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Physicochemical properties of Brazilian cocoa butter and industrial blends. Part II Microstructure, polymorphic behavior and crystallization characteristics

Ribeiro¹,

Basso²,

Gonçalves³

et al. 2012

Grasas y Aceites

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The microstructural behavior of industrial standardized cocoa butter samples and cocoa butter samples from three different Brazilian states is compared. The cocoa butters were characterized by their microstructural patterns, crystallization kinetics and polymorphic habits. The evaluation of these parameters aided in establishing relationships between the chemical compositions and crystallization behavior of the samples, as well as differentiating them in terms of technological and industrial potential for use in tropical regions.<br><br>En este trabajo se presenta el comportamiento de la microestructura y la cristalización de mantecas de cacao representativas de las mezclas industriales, y de la manteca de cacao original de tres regiones geográficas diferentes de Brasil. Las muestras se evaluaron de acuerdo a la microestructura, la cinética de cristalización y el comportamiento polimórfico. La evaluación de estos parámetros nos permite establecer relaciones entre la composición química y el comportamiento de la cristalización de las muestras, así como las diferencias sobre la adecuación del potencial tecnológico e industrial para su aplicación en las regiones tropicales

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Section: Crystallization Kineticsmentioning

confidence: 98%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Polymorphic Transitions (Dsc)mentioning

confidence: 99%

See 2 more Smart Citations

Physicochemical properties of Brazilian cocoa butter and industrial blends. Part II Microstructure, polymorphic behavior and crystallization characteristics

Ribeiro¹,

Basso²,

Gonçalves³

et al. 2012

Grasas y Aceites

View full text Add to dashboard Cite

show abstract

“…The conditions of analysis were as follows: sample weight,~10 mg; crystallization curves, 80°C for 10 min, 80°C to −40°C (10°C/min), and −40°C for 30 min; and melting curves, −40°C to 80°C (5°C/min). The following parameters were used in evaluating the results: crystallization and melting onset temperatures (T oc and T om ), crystallization and melting peak temperatures (T pc and T pm ), crystallization and melting enthalpies (ΔH c and ΔH m ) and crystallization and melting end temperatures (T fc and T fm ) (Campos 2005).…”

Section: Thermal Propertiesmentioning

confidence: 99%

Lipase catalyzed interesterification of Amazonian patauá oil and palm stearin for preparation of specific-structured oils

2015

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This study showed that enzymatic interesterification of Amazonian oils could be an important tool in order to produce new oils with physicochemical properties that improve the applications of these raw materials. Structured oils of Amazonian patauá oil and palm stearin using two lipases were produced in three different enzymatic systems: first, a crude lipase from the fungus Rhizopus sp (a microorganism isolated in our laboratory); second, a commercial lipase; and third, to check any synergistic effect, a mixture of both lipases (Rhizopus sp and commercial). The lipase from Rhizopus sp was specific in the incorporation of oleic acid at the sn-1,3 positions of the triacylglycerol, resulting in an oil richer in saturated fatty acid in the sn-2 position. This enzyme, produced by solid-state fermentation, even though crude, was fatty acid and positional specific and able to operate at low concentration (2.5 %, w/w). In the second enzyme system, the commercial lipase from Thermomyces lanuginosus was not specific in the tested conditions; there was no change in the distribution of saturated and unsaturated fatty acids in the three positions of the triacylglycerol profile, there was only a replacement by the type of fatty acid at the same position. In the third enzyme system, the mixture of both lipases shows no synergic effect. The structured oils retained the concentration of bioactive α-and γ-tocopherol in the three enzyme systems.Triacylglycerol classes and Thermal behavior tests indicated the formation of more homogeneous triacylglycerols, especially the mono and di-unsaturated.

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Structural and Mechanical Behavior of Tristearin/Triolein-rich Mixtures and the Modification Achieved by Interesterification

2009

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The effects of chemical and enzymatic interesterification on the structure and rheological behavior of blends of fully hydrogenated canola oil (FHCO) with high oleic acid sunflower oil in the range of 10-90% was studied. Relationships between chemical composition, crystallization temperature (20-50°C), solid fat content (SFC) of the blends, and their rheological properties, characterized using both small and large deformation mechanical testing, were investigated. The storage modulus (G′) and yield force increased with FHCO concentration in the blends and was affected strongly by interesterification. The SFC in the interesterified samples was lower than in the non-interesterified blends, but they had higher values of G′. This increase in G′ at 30°C upon interesterification was attributed to a decrease in the fractal dimension of the fat crystal network which translates into a decrease in crystal cluster size in the interesterified samples. The higher G′ in the chemically interesterified samples relative to the enzymatic interesterified samples, on the other hand, was due to a higher λ parameter which is directly proportional to the strength of interparticle interactions and inversely proportional to crystal size. Microscopy and nucleation kinetics studies allowed for the independent determination of λ.

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Experimental Methodology

Cited by 13 publications

References 0 publications

Physicochemical properties of Brazilian cocoa butter and industrial blends. Part II Microstructure, polymorphic behavior and crystallization characteristics

Physicochemical properties of Brazilian cocoa butter and industrial blends. Part II Microstructure, polymorphic behavior and crystallization characteristics

Lipase catalyzed interesterification of Amazonian patauá oil and palm stearin for preparation of specific-structured oils

Structural and Mechanical Behavior of Tristearin/Triolein-rich Mixtures and the Modification Achieved by Interesterification

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