Color Stability of Freeze-dried Date Fruits (Barhi CV.) during Storage | Chapter 08 | Advances in Applied Science and Technology Vol. 5
Fresh Date fruits “Barhi CV.” were
freeze dried as slices to characterize the dried fruit quality. CIELAB color
parameters (L*, a*, and b*) were measured as well as Chroma, the hue angle, the
browning index and the total
color difference parameters
were derivative. The
samples were stored
for 12 months at
three temperatures of 5, 15
and 25°C with
an uncertainty of
±1°C to assess
the color change kinetics and
quantify the degree of change during storage. The L*, a* and b* values for
fresh samples at room temperature were 93.16±0.15, 18.76±0.45 and 61.70±0.32,
respectively, while they were 78.72±0.51, 29.52±0.07 and 62.75±0.14 after 12
months. To explain the
changing kinetics of
the date slices,
zero, first and second
order models were attempted. Based on statistical
analysis, the first-order model was found to be the best model for all CIELAB
parameters. Analysis on the kinetic constants reveals that the temperature
could affect the resulting color of the dried product, in turn, it contributes to the color changes
of the freeze dried Barhi during storage. The values obtained for the
activation energy for freeze-dried Barhi based on the selected models were
between 4930 and 10850 kJ. mol-1 which were somewhat different from the
reported values due to the variation in sample’s type, treatment or process. In
the present study, Barhi fruit slices were freeze-dried (FD) and examined. The
effect of the FD process on the color change, water activity, and moisture content
was determined over 12-month storage time. Based on the experimental data, all
CIELAB color parameters were significantly affected by temperature and storage
time. Based on the statistical analysis, the first-order model could be used to
fit the data for of color change in freeze-dried Barhi fruit slices.
Author(s) Details
Khaled A. M. Ahmed
Chair of Dates Technologies
and Industry, College of Food and Agriculture Sciences, King Saud University,
Saudi Arabia.
Agricultural Engineering
Research Institute (AEnRI), Giza, Egypt.
Nasser M. El Ashmawy
Chair of Dates Technologies
and Industry, College of Food and Agriculture Sciences, King Saud University,
Saudi Arabia.
Agricultural Engineering
Research Institute (AEnRI), Giza, Egypt.
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