Physical and sensory changes during the development and storage of buttercup squash

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 H97-23 Received 16 June 1997; accepted 18 September 1997 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, °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 8°C) from flowering. Fruit harvested at this early stage required a postharvest ripening period to enhance sweetness and texture and to optimise sensory quality.

Physical and chemical characterization in fruit from 22 summer squash (Cucurbita pepo L.) cultivars

“…Although fruit with a dry matter (DM) content of <20 g 100 g À1 is watery and lacks flavor, fruit with over 28 g 100 g À1 DM may be unacceptably dry except for processing purposes (Harvey, Grant, & Lammerink, 1997).…”

Winter squash (Cucurbita maxima) texture: Sensory, chemical, and physical measures

“…Hurst et al (1995). Seasonal growing conditions can have a major influence on squash fruit development (Harvey et al 1997). Decreases in both starch and total DM are generally attributed to the conversion of starch to sugars, and the loss of some of those sugars by respiration of the fruit (Phillips 1946), resulting in an increase in the percentage water content.…”

“…In the case of squash, different markets have different preferences for textural attributes. The majority of the New Zealand export crop goes to Japan, where reported preferences range from a sweet, dry textured squash (e.g., Harvey & Grant 1992) to a sweet squash with a more moist texture (Nagao et al 1991). Murphy et al (1966) state that dryness is a characteristic linked with the preferred texture of squash, although presumably there is an optimum for this.…”

“…Murphy et al (1966) state that dryness is a characteristic linked with the preferred texture of squash, although presumably there is an optimum for this. Although fruit with a dry matter (DM) of <20% is watery and lacks flavour, fruit with over 28% DM may be unacceptably dry except for processing purposes (Harvey et al 1997). Hurst et al (1995) found no correlation between squash texture (moist-dry ratings) and acceptability ratings of three squash cultivars ranging in DM from 21.2 to 29.0%.…”

Effects of pre‐shipping storage conditions on buttercup squash quality rots

“…Sweetness of buttercup squash fruit flesh has been found to be highly correlated with soluble solids (Harvey et al 1997). At the first assessment of fruit, juice was extracted into micro fiige tubes from small pieces (c. 5 g) of fruit flesh using plastic syringes and centrifuged at 8 540 g for 5 min.…”