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  • Author or Editor: L. J. Kushman x
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Abstract

Weight and volume losses of roots of sweet potato (Ipomoea batatas (L.) Lam. cv. Centennial) during curing were reduced by increasing relative humidity (RH) from 80 to 90, 90 to 97, but not from 97 to 100%. Loss of skin increased loss of weight at all RH but significantly only at 80% RH. Loss of weight during storage was about the same for injured and non-injured roots unless weight loss during curing was high (above 6%), which resulted in a high loss during storage. Loss of weight during curing was highly and positively correlated with subsequent development of decay. During curing RH should be near saturation but during storage RH should not exceed 90%.

Open Access
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Abstract

After harvest, sweetpotato roots are usually cured for about a week at 85°F with high relative humidity before storage at 55° to 60°. If the curing period exceeds a week, or the storage temperature after curing cannot be kept as low as 60°, sprouts grow and often become excessively long. In most storages, sprout growth is difficult to control in the top part of storage rooms where heat and moisture tend to accumulate. Consequently, sprouts often must be removed by hand during preparation for marketing and this labor increases the cost of grading.

Open Access

Abstract

One hundred 2-year old ‘Wolcott’ blueberry plants were grown in sand culture with 5 levels each of N, P, K, Ca, and Mg and fruited in 1962 and 1963 in the greenhouse. The content of each of the 5 nutrient-elements in the leaves varied widely. Level of N affected the number of leaves and fruit per plant (+, −), fruit size (−), acidity (−), and ripening date (+), and the fruit-to-leaf ratio (F/L) of the bush (+). Foliar levels of P greater than 0.40% were associated with foliar interveinal chlorosis and abscission; low levels of P were associated with few leaves, a high F/L, and low berry weight. Leaves containing between 0.28 and 0.36% K showed foliar deficiency symptoms of K. High K was associated with high fruit acidity. No effects of nutrition upon the keeping quality of fruit were noted. High F/L had a greater effect than treatments upon fruit and was related to late ripening, low soluble-solids, and small size of the berries. With bushes having a high F/L, fruit weight and soluble solids decreased as the harvest season progressed until the ratio was between 1 and 2; thereafter, soluble solids content increased. Content of soluble solids varied inversely with per cent of crop ripening at a given time until a F/L between 1 to 2 was reached.

Open Access

Abstract

‘Wolcott’ blueberries were harvested at 8 stages of development (small, deep green to overripe) on 3 dates in 1963 and on 4 dates in 1964 from 2 plantings in eastern North Carolina. As the fruit developed, per cent acid decreased while pH, per cent soluble solids, sugar (per cent of fresh weight and mg/berry), soluble solids/acid ratio (SS/A), anthocyanin content and berry weight increased. Acid content (mg/berry) increased during early stages but decreased rapidly during later stages of development. Anthocyanin content (mg/cm2 of berry surface) was significantly correlated with sugar/acid ratio and SS/A ratio. An increase in incidence of decay of 10 punctured or bisected fruit samples after 9 to 11 days at 70°F, or 21 days at 32° plus 6 days at 70°, was associated with an increase in ripeness. In culture solutions with acid and sugar levels paralleling those of fruit of various degrees of ripeness, growth of both Alternaria and Botrytis spp. decreased as the level of acid in culture solution increased. Thus, the acid composition of blueberry fruit appears to afford a mechanism of resistance to decay-producing organisms. This indicates a potential for selecting varieties with high-keeping quality through selection of clones high in acid. The increase in anthocyanin (Acy) content as berries develop indicates a potential means of sorting blueberries electronically, according to their Acy content.

Open Access
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Abstract

Intercellular space measurements of ‘Nugget’ and ‘Centennial’ sweetpotatoes were significantly different due to variety, evacuation and holding periods, and the interaction of curing with evacuation and holding periods but not different because of curing alone, root length, dry-matter content, or uncorrected specific gravity. To determine intercellular space accurately, evacuation time should be no less than 10 min and holding in water after evacuation no less than 15 min.

Open Access

Abstract

Individual fruit pH, total acidity (AC as %), soluble solids (SS as %), and SS/AC ratios correlated significantly with anthocyanin contents of ‘Wolcott’, ‘Morrow’, ‘Jersey’, and ‘Tifblue’ blueberries as measured by light transmission (ΔOD740-800 nm). Fruit orientation with respect to the light path influenced readings. The relationships of the light transmission values to the quality indices differed among cultivars.

Open Access

Abstract

A technique is described for pulling a 1/8-inch wide strip of periderm (skin) from a sweetpotato root with an Instron Model TM. Peeling force values from 3.6 to 14.0 g were recorded. Root skin of ‘Earlyport’ and ‘Julian’ showed lower peeling forces than those of ‘Gem’ and ‘Centennial’. Failure force values were 2 to 4 times as great as peeling force values and did not differ significantly among cultivars. The data are related to known cultivar differences in skin characteristics.

Open Access
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Abstract

Changes in pH and total acidity, comparable to those that occur in chilled roots during storage, take place in the field while the roots are still in the ground if wet, cold, soil conditions develop.

Open Access
Authors: and

Abstract

Recent studies showed that at harvest sweetpotato storage roots contain as much as 10 milliliters of intercellular space per 100 milliliters of root; during storage intercellular space increases to the extent that it becomes visible and is classified as pithiness or internal breakdown (1). A preliminary report shows that by accounting for the intercellular space tissue specific gravity values can be computed and correlated with drymatter content in much the same manner as for Irish potatoes (2). At harvest intercellular space for each of four varieties was relatively constant for a given variety and differed significantly among varieties (4).

Open Access

Abstract

‘Nugget’, ‘Gem’, ‘Goldrush’ and ‘Centennial’ sweet potato cultivars were grown for 3 yr at 3 locations in North Carolina. Root samples were collected at peak harvest (about October 1) each year and examined for intercellular space (IS). At 1 location each year a collection was made 3 wk prior to peak harvest, at peak harvest, and 3 wk after peak harvest. Cultivars differed significantly from one another in IS at harvest and averaged 6.26, 7.32, 8.41 and 9.85 ml/100 ml of root for ‘Nugget’, ‘Gem’, ‘Goldrush’ and ‘Centennial’, respectively. Over the 3-yr period IS did not differ significantly due to location, time of harvest, or years.

Open Access