New Zealand Journal of Crop and Horticultural Science abstracts
Physical and sensory changes during the development
and storage of buttercup squash
W. J. HARVEY
New Zealand Institute for Crop & Food
Research Limited
Canterbury Agriculture & Science Centre
Private Bag 4704
Christchurch, New Zealand
D. G. GRANT
New Zealand Institute for Crop & Food
Research Limited
Pukekohe Research Centre
Cronin Road, RD 1
Pukekohe, New Zealand
J. P. LAMMERINK
New Zealand Institute for Crop & Food
Research Limited
Canterbury Agriculture & Science Centre
Private Bag 4704
Christchurch, New Zealand
Abstract Changes in composition and sensory quality of
buttercup squash (Cucurbita maxima Duch. `Delica') during fruit
development and postharvest temperature and humidity conditions simulating
shipment to Japan were studied at three representative growing sites in New
Zealand. Fruit of a known setting date were harvested at 10-day intervals and
data were collected on heat accumulation, days after flowering, flesh colour,
seed development, soluble solids, dry matter (DM) content, skin hardness,
glucose, fructose, sucrose and starch content, and sensory properties before
and after simulated shipment. Physical properties at harvest were related to
sensory quality at the point of sale to identify an optimal harvest time. As
fruit was left for longer on the vine the skin hardened, the flesh became
redder, DM increased then decreased, the soluble solids and sucrose content
increased and the sensory properties improved. Once harvested the flesh
continued to become redder, sucrose and soluble solids increased, and starch
and DM levels decreased. Starch and DM did not accumulate significantly after
40 days from flowering at any sites. Temperature accumulation affected the rate
of increase in the maturity indicators measured. Sucrose levels, deg.Brix, and
flesh colour varied too much with site and season to be used to indicate
optimum harvest dates. Skin hardness and heat accumulation levels were the most
effective means of estimating the optimum harvest date. The earliest time to
harvest fruit to ensure an acceptable level of sensory quality after the
simulated refrigerated shipment conditions imposed was at a skin hardness
penetrometer score of 7 kgf. This point occurred between 240 and 300 growing
degree days (base temperature 8deg.C) from flowering. Fruit harvested at this
early stage required a postharvest ripening period to enhance sweetness and
texture and to optimise sensory quality.
Keywords buttercup squash; Cucurbita maxima; maturity;
sensory quality; composition; heat accumulation; harvest; postharvest
New Zealand Journal of Crop and Horticultural Science, 1997, Vol. 25:
341-351
0114-0671/97/2504-0341 $7.00/0 (c) The Royal Society of New Zealand
1997
PDF file of entire paper: medium quality (822K); (scanned from paper original: notes about this process)
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