Extraction treatments and date syrup CIE L* a* b*
color values
The CIE L*a*b* color values for date syrup prepared
by autoclaving as well as enzyme treatment methods
were measured with a Mcbeth ColorChecker as per the
procedure described by Al-Hooti et al. (1997a, 1997b),and the results are presented in Table 7. The CIE L*a*b*
color values were found to be affected significantly by
different treatments as well as by the variety. The diluted
syrup was found to possess lighter color (higher
Lightness value) for both the treatments for the Birhi
variety than the Safri. The autoclaving treatment resulted
in darker color for both the varieties (a* b* values
approaching zero) compared with the enzyme-treated
syrup. The higher a* b* values (indicating color intensity
or hue) for the enzyme-treated date syrup prepared
from Birhi variety indicate their tinge to be on the red/
yellowside compared with the enzyme-treated syrup
from the Safri variety. Autoclaving treatment was
reported earlier to darken the visual color of syrup from
other date fruit varieties (El-Shaarawy, Messalam, El-
Nakahal, & Wahdan, 1986). Comparing these results,
enzyme treatment holds great promise in obtaining better
quality date syrup for further use in food products.
The CIE L*a*b* color values of pooled concentrated
date syrup (about 80oBrix) were also measured by this
procedure and the results are presented in Table 8. The
concentrated syrup from the Birhi variety possessed a
significantly lighter color (higher Lightness value) than
the Safri variety. As the a* b* values (indicating color
intensity or hue) approached zero, it indicated that the
color of these concentrated syrup samples attained a
darker red/yellowcolor, in spite of the fact that these
syrup samples were concentrated under vacuum in a
rotary evaporator at 60 C. Visually, the concentrated syrup samples had the appearance of a natural honey as
far as their color, appearance, taste and viscosity were
concerned. As the date syrup had color and flavor similar
to honey, it was used in the preparation of a few baked
products, the results of that study are being reported separately. The apparent viscosity of concentrated syrup
of Birhi and Safri was measured in the same way as
explained earlier, except that spindle no. 3 and RPM of 10
were used. The apparent viscosity values for the concentrated
syrup from Birhi and Safri varieties were found
to be 389 and 446 cP, respectively. The physico-chemical
composition and mineral contents of concentrated date
syrup have been presented in Tables 9 and 10, respectively