The syneresis of starch gels from 19 yam cultivars (belonging to 4
Dioscorea
species and complex of species) and 5 modified starches were
studied during refrigeration (4°C) and freezing (-20°C).
Syneresis of starch gels evolved on refrigeration at the onset from zero and
remained constant between 20% to 60% after 8 weeks of storage for all the yam
species. The cultivars
Daminangba
(
Dioscorea alata
) and
Assawa
(
Dioscorea cayenensis
) were the most
refrigeration-resistant. During freezing, syneresis of yam gels evolved from
zero and remained constant in the 56 - 70% interval for the
D. alata, 35 - 70% for the
D.
cayenensis-
rotundata
complex, and 37 - 55% for
D. dumetorum and
D. esculenta. The
Kpokpokpo(
D.
cayenensis-rotundata) was the most freeze-resistant cultivar. The
resistance during refrigeration of
Daminangbaand
Assawa, as well
as the freeze resistance of
Kpokpokpo were in all cases less than those
of
Amiocaand
Colflo 67, the best modified commercial starches.
Treatment of yam gels with appropriate doses of hydrophilic ingredients might be
necessary to reduce their syneresis to acceptable levels.
