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  • Author or Editor: J.B. Magee x
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The origins, demise and current status of some common misconceptions about the role of fruit and vegetables in human nutrition are discussed. Most, but not all, of the misconceptions were held by the public. The early widespread belief that tomatoes were poisonous was gradually overcome, and today the tomato is one of the most versatile and widely used foods in the diet. Recent reports suggest that consumption of tomatoes and tomato products has the potential to reduce the risk of certain cancers. Our current awareness of the potential of spinach in nutrition and health evolved from an early misconception that its only important nutritive value was as a source of iron. The connection between foods from the nightshade family and arthritis and the connection of cherries and gout relief are discussed briefly. The misconception that a wide variety of fruit and vegetables was not needed in the human diet was rejected long ago. Today fruit and vegetables are considered essential for their intrinsic nutritive value and for their potential health functionality because of the phytochemicals they contain.

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The organic acid composition of blueberries of three highbush (Vaccinium corymbosum) cultivars, three rabbiteye (V. ashei cultivars and nine southern highbush (V. corymbosun hybrids) cultivars or selections was determined by HPLC. Species means off the individual acids (citric, malic, succinic, and quinic), expressed as a percentage of total acid, formed profiles or patterns that are thought to be characteristic of the species. Citric (75%) was the predominant acid in highbush fruit with lesser percentages of succinic (13%), quinic (9.6%), and malic (2.7%). The percent composition of rabbiteye berries [quinic (49%), succinic (39%), citric (6.7%), malic (5%)] was distinctly different from highbush. The acid profile of southern highbush fruit reflected their V. corymbosum heritage with an acid profile similar to that of highbush. When related to a clone's pedigree, these results suggest that organic acid profiles may be a useful screening tool for studying the contribution of southeastern native species such as V. darrowi or V. ashei to the inheritance of organic acids.

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Control of muscadine diseases is necessary to minimize yield loss and is especially important for highest quality fresh-market berries. In a systematic disease control spray program, four fungicides registered for grapes were applied sequentially at 10- to 20-day intervals from early bloom until just before harvest to five muscadine cultivars. Objectives of the study were to: 1) determine the effects of the spray schedule on foliage and berry diseases; and 2) study the relationship between disease incidence and resveratrol content of the berries. Resveratrol, a phytoalexin, has shown potential value in prevention and treatment of cardiovascular disease and certain cancer processes. Foliar diseases were rated visually twice during the season. Berry disease ratings were made at harvest. All fungal foliage and berry diseases were significantly reduced by fungicide treatments. Resveratrol was determined separately on berry skins, seed and pulp/juice by gas chromatography/mass spectroscopy (GC/MS). Overall, resveratrol levels in berry skins from unsprayed vines were much higher than those of sprayed vines. Concentrations varied by cultivar and within cultivar by treatment. The relationship between resveratrol concentration in skins and total disease score or scores of specific diseases was not established. Seed resveratrol concentrations differed by cultivar but were not affected by the fungicide treatments. Resveratrol concentration of seed was lower than that of skins. Accumulation of resveratrol in juice/pulp was much lower than in skins and seeds.

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Control of muscadine diseases is necessary to minimize yield loss and is especially important for highest quality if the berries are to be marketed fresh. Throughout the 1998 growing season, vines of five muscadine cultivars (`Noble', `Summit', `Cowart', `Higgins', and `Carlos') were treated under a systematic disease control spray program; four fungicides registered for use on grapes were applied sequentially at 10- to 20-day intervals from early bloom until just before harvest. Control plants received no fungicide. The objectives of the study were to determine the effects of the spray schedule on foliage and berry diseases and to study the relationship between disease incidence and resveratrol content of the berries. Resveratrol is a phytoalexin and has been favorably implicated in cardiovascular disease and certain cancer processes. Foliar diseases were rated visually twice during the season. Berry disease ratings were made at harvest. All fungal foliage and berry diseases were significantly reduced by the fungicide treatments. Resveratrol concentrations were determined separately on berry skins, seed and pulp/juice by GC/MS. Overall, resveratrol levels in berry skins from unsprayed vines were much higher than those of sprayed vines. Concentrations varied by cultivar and within cultivar by treatment. The relationship of skin concentration and total disease score or scores of specific diseases has not been established. Seed resveratrol concentrations differed by cultivar but were not affected by the fungicide treatments. Mean concentration of seed was lower than that of skins. Accumulation of resveratrol in juice/pulp was much lower than in skins and seeds.

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The southern highbush (Vaccinium mostly corymbosum) blueberry cultivars Jubilee, Magnolia, and Pearl River, released by the USDA in 1994, were compared with `Premier' and `Climax', two widely planted rabbiteye (V. ashei) cultivars, on the basis of flowering and harvest dates, yield, and physical and chemical quality parameters. The southern highbush cultivars flowered later and ripened at least 1 week before `Climax', one of the earliest rabbiteyes. `Pearl River' berries had less waxy “bloom” and appeared almost black when fully ripe; they had significantly less anthocyanins than the other cultivars compared. `Premier' was lower in titratable acidity and higher in sugars than the southern highbush cultivars. Although data analysis indicated statistical differences in glucose and fructose concentrations among the other four cultivars, these differences were not pronounced. Based on the quality factors used in this study, the southern highbush cultivars compared acceptably to the rabbiteye cultivars.

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Three varieties of rabbit eye (Vaccinium ashei) blueberries (`Climax',, `Premier', and `Tifblue') were harvested in Mississippi and two varieties of highbush (v. corymbosum blueberries (`BlueCrop' and `Jersey') were harvested in Michigan. Each variety was harvested at three different locations as replications. The berries were rapidly cooled to 5°C after harvest, placed in 1-pint containers, and analyzed at 7-day intervals for 28 days with day 0 being 48 h after harvest.

Shear, compression and puncture forces were higher for rabbiteye spp. than for highbush spp. `Bluecrop' blueberries showed the lowest shear force whereas, Climax, had the most shear force. Puncture force (skin toughness) was lower for `Bluecrop' and `Jersey' and higher for, Climax, There was an increase in shear force by all varieties with storage time. `Premier, and `Climax' had lower soluble solids, but they increased with storage time. `Jersey' had the highest pH and `Tifblue' the lowest. Although all varieties lost moisture with time, `Bluecrop' always had higher moisture. Mold growth varied with time; however, `Bluecrop' had a higher percentage of moldy berries throughout refrigeration. The percent decay was higher for highbush blueberries after 16 d of refrigeration. Rabbiteye's toughness and firmness give them a longer refrigerated shelf-life over highbush blueberries.

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Abstract

In addressing the subject of nondestructive evaluation of internal quality of horticultural crops, the establishment of an understanding of quality is needed at the outset. Dull (4) has defined nondestructive quality evaluation (NDQE) as “a gaining of meaningful information which can be used in making judgments, both positive and negative, about the degree of excellence of a food with out altering the physical and chemical properties of that food.” In order to make judgments about a specific quality situation, one must select specific physical and/or chemical properties to be measured. A list of those properties would include weight, diameter, titratable acidity, pH, total nitrogen and concentration of soluble solids, sucrose, glucose, fructose, malic acid, citric acid, chlorophyll, carotene, anthocyanins, dry matter, proteins, amino acids, fat, starch, cellulose, pectins, and hemicellulose.

Open Access

Abstract

Body transmittance spectroscopy and analytical measurements of chlorophyll, carotenoids, and soluble solids concentrations were used to develop a nondestructive technique for estimating the maturity of papayas (Carica papaya L.). Optical measurements were taken between 500−900 nm with a scanning monochromator and a tilting-filter, abridged monochromator. Immature and mature-green fruit which were indistinguishable by visual examination could be separated by body transmittance spectroscopy into nonripening and ripening groups.

Open Access