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Density and Porosity in Drying Starch Materials
Author(s) -
MAROUSIS S.N.,
SARAVACOS G.D.
Publication year - 1990
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1365-2621.1990.tb03939.x
Subject(s) - porosity , particle density , bulk density , moisture , materials science , water content , starch , particle size , corn starch , particle (ecology) , mineralogy , composite material , chemistry , food science , soil science , volume (thermodynamics) , thermodynamics , physics , environmental science , geotechnical engineering , oceanography , soil water , engineering , geology
The particle density of granular and gelatinized corn starches was determined in the moisture range 0 to 1 kg water/kg dry solids, using a gas stereopycnometer. The bulk porosity (void fraction) of spherical starch samples at various moisture contents was estimated from the bulk and particle densities during air drying at 60°C. The particle density data fitted a polynomial function of moisture content (X), passing through a maximum value of 1500 kg/m 3 at X = 0.15. The bulk porosity of the starch samples increased linearly during drying, reaching a value of 0.45 near dryness. Differences in structure between granular and gelatinized starches during drying were observed by stereomicroscopy. The changes in porosity could be related to variations of the effective moisture and thermal diffusivities of starch materials.