Attached
A natural convective solar dryer was constructed
and it was found that the dryer was able to dehydrate
vegetables while retainins 76.6% of p-carotene. This
amount is significantly higher when compared with the
p-carotene content retained in vegetables dehydrated by
exposing to direct sun light. The latter process showing
~nly trace amount of p-carotene.
The effect of pretreatments on the quality of
prbcessed ve~etables were examined. Blanching was found
to be an effective pretre~tment in retaininG ascorbic acid
and p-carotene content of these ve~8t~~les. The retention
of ascorbic acid was increased when the blanching solution
contained 0.1% K~S ( Potassium meta bisulphite). In the
case of frozen bittergourd, the retention of ascorbic acid
was 87.7 % L: the s~,r;rplbelanched in 0.1 % KI"iS solution
an~ at storage for 28 weeks at _18
0
C (-O.4
0
F).
Cf these three ve'~atablcs, sLuke;ourd and ~idgegourd
could be p.re ser-v ed by r'c rt.c rrtati cn , The I'e r-rnen tatLon VIas
carried out b;:/ pr-o vi.di.ng the r;ro':jthof na tur-a Ll.y present
lactic acid pro(ucinS orGanisms on these comodities and
the process was able to reach the 1% acid in the media
within 1~ iays of fsrmentation. Durin~ this period, the
total solujle BUbar content was fOUDd to 6ecrease by 90.8 %
in snake gour-d and 94.0 % ill rid,:,egourd. In the case of
bittergourd, the f ern.en tati.on VIdS incomplete and the production of aci~ did not exceed 0.5 % during 12 days
of fermentation. However, the development of a new
product was possible by preserving bittergourd in
acid-salt suspension. In this preservation, the
ascorbic acid content was found to reduce gradually
during storage, and at the end of the 6th month, the
retention of ascorbic acid was 32.5 %. The variation
of p-carotene in fermented vegetables was similar to
frozen products. The overall results showed the possibility
of preserving these three vegetables by freezing or
fermentation. Dehydration possibilities exist with
respect to bittergourd compared to snakegourd and ridgegourd.
