INVESTIGADORES
CANDAL roberto Jorge
artículos
Título:
Analytical Techniques for Nucleation Studies in Lipids Advantages and Disadvantages
Autor/es:
MARINA CERDEIRA; ROBERTO J. CANDAL; MARÍA LIDIA HERRERA
Revista:
JOURNAL OF FOOD SCIENCE
Editorial:
Institute of Food Technologists
Referencias:
Lugar: Chicago, USA; Año: 2004 vol. 69 p. 185 - 191
ISSN:
0022-1147
Resumen:
Crystallization is generally considered a 2-step process. The 1st step, nucleation, involves the formation
of molecular aggregates with a critical size great enough to become stable. During the 2nd step, nuclei grow and
develop into crystals. Distinguishing between nucleation and growth constitutes a major challenge in lipid crystallization
studies. Thus, it is of great importance to discuss the information obtained from the different techniques that
are usually used to study nucleation behavior such as nuclear magnetic resonance (NMR), differential scanning
calorimetry (DSC), rheological techniques, light-scattering techniques such as turbidimetry and scanning diffusive
light scattering (SDLS), polarized light microscopy (PLM), and laser polarized optical sets such as laser polarizedlight
turbidimetry (LPLT). Techniques to describe the nucleation process must be very sensitive to disregard growth.
When crystallization is followed by methods such as DSC, NMR, and rheological measurements, at times, small
amounts of crystals are present in the melt before any solids are detected. Clearly, at this stage, well beyond the
induction time for nucleation (), these methods are measuring crystal growth. Techniques of low sensitivity for solid
fat contents lower than 0.1% must not be used to evaluate nucleation effects. Sensitive turbidimeters with detectors
that saturate below 0.3% solid fat content give good results as do scanning diffusive light-scattering equipment.
Although the PLM technique is sensitive enough for these kinds of studies, an understanding of important basic
concepts is essential. Laser optical sets are the most appropriated methods to study nucleation in fats systems.
Keywords: nucleation, analytical techniques, induction time, activation-free energy of nucleation
fat contents lower than 0.1% must not be used to evaluate nucleation effects. Sensitive turbidimeters with detectors
that saturate below 0.3% solid fat content give good results as do scanning diffusive light-scattering equipment.
Although the PLM technique is sensitive enough for these kinds of studies, an understanding of important basic
concepts is essential. Laser optical sets are the most appropriated methods to study nucleation in fats systems.
Keywords: nucleation, analytical techniques, induction time, activation-free energy of nucleation
fat contents lower than 0.1% must not be used to evaluate nucleation effects. Sensitive turbidimeters with detectors
that saturate below 0.3% solid fat content give good results as do scanning diffusive light-scattering equipment.
Although the PLM technique is sensitive enough for these kinds of studies, an understanding of important basic
concepts is essential. Laser optical sets are the most appropriated methods to study nucleation in fats systems.
Keywords: nucleation, analytical techniques, induction time, activation-free energy of nucleation
fat contents lower than 0.1% must not be used to evaluate nucleation effects. Sensitive turbidimeters with detectors
that saturate below 0.3% solid fat content give good results as do scanning diffusive light-scattering equipment.
Although the PLM technique is sensitive enough for these kinds of studies, an understanding of important basic
concepts is essential. Laser optical sets are the most appropriated methods to study nucleation in fats systems.
Keywords: nucleation, analytical techniques, induction time, activation-free energy of nucleation
fat contents lower than 0.1% must not be used to evaluate nucleation effects. Sensitive turbidimeters with detectors
that saturate below 0.3% solid fat content give good results as do scanning diffusive light-scattering equipment.
Although the PLM technique is sensitive enough for these kinds of studies, an understanding of important basic
concepts is essential. Laser optical sets are the most appropriated methods to study nucleation in fats systems.
Keywords: nucleation, analytical techniques, induction time, activation-free energy of nucleation
fat contents lower than 0.1% must not be used to evaluate nucleation effects. Sensitive turbidimeters with detectors
that saturate below 0.3% solid fat content give good results as do scanning diffusive light-scattering equipment.
Although the PLM technique is sensitive enough for these kinds of studies, an understanding of important basic
concepts is essential. Laser optical sets are the most appropriated methods to study nucleation in fats systems.
Keywords: nucleation, analytical techniques, induction time, activation-free energy of nucleation
), these methods are measuring crystal growth. Techniques of low sensitivity for solid
fat contents lower than 0.1% must not be used to evaluate nucleation effects. Sensitive turbidimeters with detectors
that saturate below 0.3% solid fat content give good results as do scanning diffusive light-scattering equipment.
Although the PLM technique is sensitive enough for these kinds of studies, an understanding of important basic
concepts is essential. Laser optical sets are the most appropriated methods to study nucleation in fats systems.
Keywords: nucleation, analytical techniques, induction time, activation-free energy of nucleation