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Potatoes with hollow heart or brown center are considered to be of poor quality for both fresh and processing markets. A reliable nondestructive method, which can distinguish affected and normal potatoes, is described here. A Varian 4.7 Tesla, 33-cm horizontal-bore spectroscopy/imaging system was used to obtain nuclear magnetic resonance (NMR) images of potatoes. A two-dimensional multi-slice spin-echo imaging technique was used to acquire the cross-sectional images along the longitudinal direction. The echo time was 35 msec and the repetition time was 1.2 sec. A total of 13 slice images were taken for each potato. A one-dimensional projection technique was also performed to evaluate the possibility of using fast-scan method. The brown center showed high intensity in long echo scans due to its longer TL relaxation time. A suberin-like layer resembling the periderm developed on the cavity wall of hollow heart causing a tan or dark brown coloration. This cavity wall also appeared in high intensity on the image. The affected potatoes can easily be sorted out using this nondestructive NMR imaging technique.

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each year. At each harvest, a 10-fruit subsample was selected from each plot for measurements of percent surface blush, internal ethylene concentration (IEC), flesh firmness, SSC, starch index rating, and TA. Comparisons of sensory, mineral

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was graded into four size classes: A = 113 to 285 g, B = <113 g, oversize = >285 g, and pickouts = unmarketable. Tubers >8.3 cm in diameter or >285 g in weight were scored for incidence of external and internal defects, and samples of A-sized tubers

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Abstract

Viable larvae of the Oriental fruit fly (Dacus dorsalis Hendel) were found in Carica papaya L. ‘Kapoho’ fruit after hot water double-dip quarantine treatment in Hawaii. Two types of blossom end defects, navel and definite pinhole, were responsible for the failure of the quarantine treatment. These defects resulted from abnormal placental growth near the blossom end of fruit. Defective fruit also had higher incidences of internal infection by Cladosporium sp. and Fusarium spp. A survey conducted in the Puna district of the island of Hawaii showed that the incidence of trees bearing defective fruit ranged from 5.3% to 31%.

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Potato tuber tissue is calcium-deficient. Consequently, increasing Ca concentration is desirable to improve tuber quality. The purpose of the present study was to determine the influence of supplemental Ca and N fertilization on internal quality of potato. Three products (calcium nitrate, calcium chloride, and gypsum) were used to increase tuber calcium concentration. We tested combinations of both soluble sources of calcium and gypsum. Each treatment had five replications and received same total amount of N, supplied either from ammonium nitrate, liquid N (UAN: 50% urea + 50% ammonium nitrate) and calcium nitrate or combination of these sources (at rate of 225 kg·ha–1). The total Ca was applied at the rate of 168 kg·ha–1. Application of N at emergence and hilling (nonsplit) was compared to split application of N and Ca at hilling, 2, 4, and 6 weeks after hilling. At harvest, ≈100 tubers from each replication were cut in half along longitudinal axis and visually inspected for internal defect in both years. Application of Ca, especially in split schedule and from soluble sources, significantly increased tuber tissue Ca concentration. In 1998, the incidences of hollow heart (HH) and internal brown spots (IBS) were very low. The treatment containing calcium nitrate and calcium chloride combination produced the lowest total defects, whereas application of gypsum was not effective at reducing defects. In 1999, application of all Ca sources including gypsum, reduced HH and IBS. Data from these studies suggest that tuber calcium level is increased by field applications of moderate amount of Ca and tuber quality is impacted by N and Ca application. Furthermore, seasonal climatic variations appear to have dramatic influence on the incidence of internal defects in potato tubers.

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Abstract

Fruit of cucumbei plants (Cucumis sativus L.) of a gynoecious and 2 monoecious cultivars treated at the 2-3 leaf stage with 0 or 240 ppm (2-chloroethyl)phosphonic acid (ethephon) were harvested at 3 weekly intervals, and processed as either fresh-pack pickles or brine stock. Experienced judges detected differences in shape and degree of seed development attributable to ethephon treatment. There were no significant differences in texture, flavor, external or internal color, firmness or internal defects. Differences caused by ethephon treatment were less apparent in fruit of the gynoecious than monoecious cultivars.

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Comparisons were made of the major physical and chemical characteristics of seven cultivars of apples (Malus domestica Borkh.) produced and imported into Western Europe from 13 origins. During the 1990-91 marketing season, `Delicious', `Golden Delicious', `Granny Smith', `Elstar', `Jonagold', `Gala', and `Fuji' apples were included in the study. Physical characteristics evaluated were length-to-diameter ratio, shape, external defects, internal defects, water core, bruises, firmness, blush surface, and color. Chemical characteristics evaluated were starch, juice content, soluble solids, acids, and ascorbic acid. Significant differences in some of these quality characteristics were found between the different origins. Apples produced in the United States, particularly `Delicious', had some superior quality characteristics compared to fruit from other origins.

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Three Ca sources and two application schedules were compared for their effectiveness for increasing tissue Ca concentrations in 170 to 284 g field-grown tubers of `Atlantic' potato (Solanum tuberosum L.). Additional observations were made of internal physiological defects. Paired measures of tissue (periderm and nonperiderm) Ca concentration and internal quality (±hollow heart, ±internal brown spot) were made on individual tubers produced in plots fertilized with N at 224 kg·ha-1 and Ca at either 0 or 168 kg·ha-1, supplied from either gypsum, calcium nitrate or NHIB (9N-0P-0K-11Ca, a commercial formulation of urea and CaCl2). Application of N and Ca at emergence and hilling (nonsplit) was compared to application at emergence, hilling, and 4 and 8 weeks after hilling (split). Tuber yield and grade were unaffected by treatments. Split Ca application (from either calcium nitrate or NHIB) increased mean tuber nonperiderm tissue Ca concentrations and the percentage of tubers with an elevated Ca concentration in both years compared with non-Ca-supplemented controls. Split Ca application also resulted in greater increases in Ca in nonperiderm tissue than nonsplit Ca application in 1994. Although the correlation coefficient between Ca level in periderm and nonperiderm tissue of >400 individual tubers was highly significant in both study years, linear regression analyses suggested the Ca level in the two tissues were poorly related. Split application was associated with a 37% reduction in the incidence of internal tuber defects, relative to nonsplit application in 1994. Calcium application did not affect tuber internal quality based on means analysis, but chi-square analysis suggested that Ca concentration and internal quality of individual tubers may be related. The incidence of internal defects was 16.4% in tubers with nonperiderm tissue Ca >100 μg·g-1 dry weight compared to 10.6% in tubers with nonperiderm tissue Ca >100 μg·g-1 dry weight. These data suggest that 1) it is feasible to increase tuber Ca levels by field applications of moderate amounts of Ca, 2) tuber quality is impacted by N and Ca application schedule, and 3) Ca concentrations in tuber periderm and nonperiderm tissues may be controlled independently.

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This study quantifies the discounts and premiums associated with various quality factors for processing apples (Malus domestica Borkh.). Discounts and premiums were estimated using a hedonic price model and quality data from a total of 137 samples representing three processing apple cultivars (45 `York Imperial', 43 `Rome Beauty', and 49 `Golden Delicious'). Price discounts in the sample were statistically significant for fruit size, bruising, bitter pit, decay, misshapen apples, and internal breakdown. Commonly cited defects, such as insect damage and apple scab, did not cause significant price discounts.

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Potato (Solanum tuberosum) cv. `Russet Burbank' response to source of side-dress Ca fertilization applied at 0, 28 and 56 kg·ha-1 Ca on fine sandy loam soil was evaluated. Side-dress Ca source and rate did not affect number or total weight of tubers/hill, average tuber weight, or tuber macronutrient concentrations at mid-season. Tuber B concentration was significantly greater with the 12-0-0-10.5 source as compared to the check. Tuber Fe concentration decreased linearly as 22-0-0-7 rate increased from 0 to 56 kg·ha-1 Ca. No other micronutrient concentration was affected by the applied treatments. Calcium fertilization had no effect on tuber yield, grade distribution, or specific gravity. The predominant internal defect observed was brown center, which was reduced at harvest by side-dress Ca application. Internal quality and french fry color were evaluated after storage for 4 months.

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