New Zealand Journal of Crop and Horticultural Science abstracts
Free sugar composition of sweetpotato cultivars after storage
S. L. LEWTHWAITE
New Zealand Institute for Crop & Food
Research Limited
Pukekohe Research Centre
Cronin Road, RD 1
Pukekohe, New Zealand
K. H. SUTTON
New Zealand Institute for Crop & Food
Research Limited
Canterbury Agriculture & Science Centre
Private Bag 4704
Christchurch, New Zealand
C. M. TRIGGS
Department of Statistics
University of Auckland
Private Bag 92 019
Auckland, New Zealand
Abstract The concentrations of fructose, glucose, sucrose,
and maltose in sweetpotato (
Ipomoea batatas (L.) Lam.) roots, following
an 8-month storage period, were assessed by high performance liquid
chromatography (HPLC). Imported cultivars and breeding lines were compared in
both the raw and cooked state against New Zealand standards. Strong linear
relationships were demonstrated between concentrations of the sugars (fructose,
glucose, and sucrose) in cooked roots, and the corresponding sugars in raw
roots (
R2 of 93.5, 93.8, and 88.8% respectively). The
relative proportion of fructose to glucose 0.44 : 0.56 was very stable across
all cultivars, and independent of the total concentration of the three
sugars--fructose, glucose, and sucrose. The negative relationship between
sucrose and the levels of fructose + glucose was significant (
P <
0.001) excluding cultivars `Jewel' and `Toka Toka Gold'. All of the clones
produced considerable amounts of maltose during cooking, which was
significantly (
P < 0.001) related to % dry weight. Using canonical
variates to group the clones, `Owairaka Red', the New Zealand standard
cultivar, was shown to cluster with the Japanese cultivar, `Beniazuma', and the
Taiwanese breeding line, `93N12/1', on the basis of high dry matter and low
fructose + glucose levels. The minor New Zealand cultivar, `Toka Toka Gold',
clustered near the North American cultivar, `Jewel', on the basis of low
maltose, high sucrose, and medium dry weight. `Toka Toka Gold' had a higher
fructose + glucose than its sucrose concentration would predict, as well as a
lower maltose level than estimated from its dry matter content.
Keywords sweetpotato; Ipomoea batatas; cultivar;
sugar; storage; microwave
New Zealand Journal of Crop and Horticultural Science, 1997, Vol. 25:
33-41
0114-0671/97/2501-0033 $2.50/0 (c) The Royal Society of New Zealand
1997
PDF file of entire paper: medium quality (674K); (scanned from paper original: notes about this process)
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