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Particle development in apple juice determined by light scattering and electron microscopy
T Beveridge1, J H Harrison, D G Dalgleish
1Pacific Agri-Food Research Centre, Agriculture and Agri-Food Canada, Summerland, British Columbia, Canada.
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|March 11, 1998
Summary
Particle formation in apple juice, whether oxidized or not, appears enzymatically driven. However, oxidized juice extracts show linear particle growth, indicating aggregation or coalescence, unlike unoxidized extracts.
Area of Science:
- Food science
- Biochemistry
- Physical chemistry
Background:
- Haze formation in fruit juices is a significant quality concern.
- Understanding particle development kinetics is crucial for juice stability.
- Procyanidins are key polyphenols influencing juice properties.
Purpose of the Study:
- To investigate the kinetic development of haze particles in apple juices and their procyanidin extracts.
- To differentiate particle formation mechanisms in oxidized versus unoxidized apple juice systems.
- To elucidate the role of procyanidins in haze particle genesis.
Main Methods:
- Light scattering techniques to monitor particle size development over time.
- Preparation of procyanidin extracts from oxidized and unoxidized apple juices.
- Electron microscopy for visualizing particle morphology.
- Kinetic analysis of particle growth patterns.
Main Results:
- Particle size increased exponentially in both oxidized and unoxidized apple juices, suggesting enzymatic reactions.
- Procyanidin extracts from oxidized juices exhibited linear particle growth, indicative of diffusion-controlled aggregation.
- Procyanidins from unoxidized juices did not show significant particle development over 60 days.
- Electron microscopy revealed diverse particle morphologies.
Conclusions:
- Enzymatic processes are likely responsible for initial particle formation in apple juice.
- Procyanidin aggregation mechanisms differ significantly between oxidized and unoxidized juice conditions.
- Light scattering and electron microscopy provide complementary insights into haze formation mechanisms.