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Vicky W. Lee, H.P. Vasantha Rupasinghe*, and Chung-Ja Jackson

Apples are excellent sources of dietary phenolics, in particular flavonoids and chlorogenic acid, which are potent antioxidants that may play important roles in the prevention of chronic diseases. This study investigated the major phenolics profiles of apple fruit in relation to (1) the distribution among 8 Ontario-grown cultivars, (2) the different fruit parts, and (3) the effect of processing of fresh-cuts. In addition, total antioxidant capacity (TAC) and total phenols content (TPC) were measured in apples by spectrophotometric assays. Flavonoids and chlorogenic acid were quantified using HPLC/PDA. Vitamin C was quantified using HPLC/Fluorescence. TAC, TPC and flavonoids levels were the highest in Honey Crisp and Delicious, moderate in Idared, Spartan, Granny Smith, and Cortland, and the lowest in Crispin and Empire. Apple peel contained 2 to 10-fold higher TAC, TPC and total of 10 major phenolics than that of core and flesh indicating peeling of apples during processing could reduced significantly the nutritional quality of fresh-cut apples. Dihydrochalcone (phloridzin) and chlorogenic acid levels were 2 to 21-fold higher in apple core than skin and flesh. TAC levels and vitamin C contents could be increased up to 3-fold and 14 to 20-fold, respectively by the post-cut dipping treatment with an ascorbic acid-based antioxidant formula. The phenolic profiles of sliced apples were stable up to 21 days at 4°C.

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D. G. Mortley, J. Y. Lu, P. Grant, and G. W. Carver

The effect of periodic removal of peanut foliage for use as a green vegetable on final foliage and nut production was evaluated in a field experiment in the summer of 1992. Georgia Red peanut cultivar was grown in Norfolk sandy loam soil in a randomized complete block design with four replications. Treatments consisted of removing peanut foliage at 2, 4, and 6 weeks, starting six weeks after planting, and an untreated check. Fresh foliage yield declined an average of 30% while dry weight declined 34% when harvested at 2 and 4 weeks. Nut yield declined 33% when harvested at 2 and 4 weeks but yield decreased only 10% when harvested at 6 weeks. Peanut greens are highly nutritious especially as a rich source of vitamin C and protein. For good balance between foliage and nut production, it appears that harvest intervals should be after four weeks.

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Yaseen Mohamed-Yaseen, Raymond J. Schnell, Robert J. Knight, and T. L. Davenport

Guava (Psidium guajava L.) is an exceptional source of vitamin. C. It is also considered to be the most important cultivated species of the Myrtel family. Shoot tip and stem node were taken from seedling germinated in Murashige and Skoog medium (MS) and cultured in the same medium supplemented with 1-3mg/l benzylaminopurine (BA) and 0.1mg/l naphthaleneacetic acid (NAA) or 0.2-2mg/l thidiazuron (TDZ) and 0.1mg/l NAA. Multiple shoots (4-6) were obtained in 4-5 weeks from culture in 1-2mg/l BA and 0.1mg/l NAA, while TDZ caused abnormal shoot growth. Shoots were rooted successfully with 100% frequency in MS medium containing 2mg/l indolebutyric acid and further elongation of shoots was achieved in MS medium, supplemented with lg/l activated charcoal. Regenerated plantlets were successfully established in soil.

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Chaim Kempler and Todd Kabaluk

Kiwifruit (A. chinensis, A. deliciosa) seedlings were propagated from seeds collected from their native habitat in China. They were planted at the Pacific Agri. Res. Center in 1988 for the purpose of selecting superior fruit. Out of 2212 Actinidia seedlings, 1425 flowered by 1994, with 794 being male and 631 female. Some selections flowered 1 month earlier and matured 3 weeks earlier than `Hayward' kiwifruit. One accession had fruit of comparable size to `Hayward' while maturing about 2 to 3 weeks earlier. Some hairless selections had an average fruit weight of 90 g, °Brix index of 18%, light flesh color, 207 mg/100 g of vitamin C, and early maturation. Most of the seedlings were hardy under a coastal British Columbia climate.

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Hassan A. Al-Kahtani

Eleven pomegranate (Punica granatum L.) cultivars were first evaluated, dried for 9 days at 20C and 47% relative humidity (RH), 30C and 33% RH, and 40C and 25% RH before storage at 20 ± 2C and 47% RH. `Taifi-A' was given the highest scores for sensory evaluation. `Kab El-Jameel' contained significantly more edible portion and more juice, and had lower pH and higher acidity than any other cultivar. The highest vitamin C content was found in `Taifi-A', `Red Balady', and `Mellasi'. Drying at 40C and 25% RH seriously damaged the pomegranates. `De-Jativa, `Molar', `Succary', and `Taifi-R' softened on the 4th day of drying and were more sensitive to drying conditions than the others. Drying at 30C and 33% RH and at 20C and 47% RH did not appear to have visually deleterious effects on the internal portion of the fruit, but the edible portion was slightly inferior to that of fresh (refrigerated) fruits, particularly those dried at 30C and 33% RH. The juices of most dried fruits had higher pH, acidity, and total soluble solids content, but less vitamin C than fresh fruits. Fruits dried at 30C and 33% RH or 20C and 47% RH remained acceptable at 20 ± 2C and 47% RH for up to 3 months or more, depending on the cultivar. Fungal decay (Aspergillus niger. Tiesh. and some Penicillum spp. were found) appeared only in fruits previously dried at 20C and 47% RH. Partial drying of pomegranates maybe useful for processed juice products.

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Francesco Montesano, Cristina Ferulli, Angelo Parente, Francesco Serio, and Pietro Santamaria

Nutrient solutions (NS) containing moderate to high concentrations of salts are frequently supplied to improve the taste of tomato fruits grown in soilless systems. The aim of this study was to determine whether salinity and water stress affect the tomato fruit quality similarly. The research was conducted in Mola di Bari, Italy, during Autumn 2004, and compared the nutrient film technique (NFT) with the trough-bench technique [Subirrigation (SUB)] in terms of tomato (Lycopersicon esculentum Mill. cv. Kabiria) fruit quality. In the NFT, the plants were grown with two electrical conductivity (EC) levels (2–4 and 6–8 dS·m-1) of NS. The highest EC was obtained by increasing all the ions in the NS. In the SUB system, two water tensions (-4 and -8 kPa) of substrate (perlite) were examinated. At harvest, in each cluster (six/plant), fruit dry matter (DM) and total soluble solids (TSS) were determinated. In the fourth and sixth cluster, vitamin C content and titratable acidity were determined. Total yield was not influenced by either soilless system, while the average weight of the fruit was lower in the SUB. The DM and TTS were influenced by soilless system (on average, 6.6 vs 7.3 g/100 g of fresh matter and 5.3 vs. 5.9 °Brix, with NFT and SUB, respectively). Both of the stresses resulted in the increase of DM and TSS, principally in SUB (water stress) in respect to NFT (salinity stress), while vitamin C and titratable acidity were not influenced by soilless system or water/salinity stress (25.2 mg/100 g fresh matter and 0.45 g/100 mL of citric acid juice, respectively). Results of NFT with the highest EC of NS exceeded 9 dS·m-1, without any stress symptoms in the plants, while EC in the SUB system remained unchanged (about 2.5 dS·m-1).

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J. Emilio Villarreal, L. Lombardini, and L. Cisneros-Zevallos

The objective of this study was to evaluate kernels of different pecan (Carya illinoinensis) cultivars for their antioxidant capacity and characterize the nature of the antioxidant compounds. Nuts collected from four pecan cultivars `Cheyenne', `Cape Fear', `Desirable', and `Pawnee' were shelled, chopped and analyzed for their antioxidant capacity (AC), and for their phenolic, tannin, and vitamin C content. AC was measured using one spectrophotometrical [DPPH (2,2-diphenyl-1-picrylhydrazyl)] and one fluorescence method [ORAC (Oxygen Radical Absorbance Capacity)]. Total phenolic and tannin content were determined using spectrophotometrical assays. Finally, ascorbic and dehydroascorbic acid were determined using a high performance liquid chromatograph. Both AC methodologies, DPPH and ORAC, gave similar results with marked differences between cultivars. `Desirable' had the highest antioxidant capacity (47,747 μg TEq/g DW with DPPH method) followed closely by `Cheyenne' (36,192 μg TEq/g DW) and, with smaller amounts, by `Cape Fear' and `Pawnee' (16,540 and 13,705 μg TEq/g DW, respectively). Total phenolic content showed a similar trend but `Pawnee' showed a higher phenolic content than `Cape Fear'. `Cheyenne' had the highest amount of tannins, 9,114 μg/g DW, followed by `Cape Fear', `Pawnee' and `Desirable' with 7,764, 6,043 and 5,508 μg/g DW respectively),. `Cheyenne' had also the highest vitamin C content, up to ≈10-fold greater than `Cape Fear' and `Pawnee', the highest difference within the antioxidants analyzed. There is the need to determine the phenolic profile and degree of polymerization of tannins, their contribution to the AC and how they are affected by horticultural practices in order to better understand the nutraceutical potential of each cultivar.

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Sasivimon Chomchalow, N.M. El Assi, S.A. Sargent, and J.K. Brecht

Green tomato (Lycopersicon esculentum `Sunny') fruit were stored at 2.5, 5, 7.5, 10, or 12.5 °C (36.5, 41, 45.5, 50, or 54.5 °F) for 1, 3, 5, or 7 days to determine their sensitivity to chilling injury. In subsequent experiments, fruit were treated with ethylene at 20 °C (68 °F) until the breaker stage was reached, either before or after storage at 12.5 °C for 0, 1, 3, 5, or 7 days, or 2.5 °C for 3, 5, 7, or 9 days. Number of days to reach the breaker stage was used as an indicator of initial maturity. The chilling threshold temperature for green `Sunny' tomatoes was near 7.5 °C, with delayed ripening occurring in fruit stored for ≥5 days. Longer exposure times at chilling temperatures resulted in reduced marketable life, dull color, flaccidity, and delayed, uneven (blotchy) and nonuniform ripening. Chemical composition was generally unaffected by chilling, while loss of firmness as a result of chilling exposure time rather than chilling temperatures per se was observed. Increased storage time at either 2.5 or 12.5 °C accentuated the initial differences in fruit maturity and thus resulted in less uniform ripening, especially for tomatoes stored before ethylene treatment, but the effect was much greater following 2.5 °C storage. Exposure to 2.5 °C for as little as 3 days before ethylene treatment caused blotchy ripening and decay, and reduced the marketable life of tomatoes by half compared to storage at nonchilling temperature. Treatment with ethylene before storage prevented chilling injury for up to 5 days at 2.5 °C and prolonged the marketable life of tomatoes stored at either chilling or nonchilling temperature. Tomatoes became less responsive to poststorage ethylene treatment with increased storage time at either 2.5 or 12.5 °C. More mature tomatoes and those treated with ethylene before 12.5 °C storage lost less weight. Vitamin C content was lower in more mature tomatoes, but ethylene treatment resulted in better maintenance of vitamin C by shortening the time to reach the red stage. No other significant differences in color, firmness or chemical composition at the red stage were found between fruit with different initial maturities or fruit treated with ethylene before or after 2.5 or 12.5 °C storage. Treating green tomatoes with ethylene before storage or transport is preferable to poststorage treatment because of faster and more uniform ripening, and also increased marketable life and reduced risk of injury in the event of exposure to chilling temperatures.

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Harbans Bhardwai and Ron Eitenmiller

Guar or cluster bean (Cyamopsis tetragonoloba (L.) Taubert), a leguminous plant, is grown in many parts of the world for consumption as green beans. However, information on green bean yield and their nutritional quality is lacking. Our objectives were to determine yield potential, optimum harvesting time, and nutritional quality of green guar beans. We planted 10 guar varieties in a RCBD with 4 replications on 1 June 1990 at Fort Valley, Georgia. The guar bean production was recorded at 55, 70, 85, and 100 days after planting (DAP). Significant variation for bean yield existed among genotypes. The bean yield (kg ha-1) varied from 9549 (Kinman) to 1629 (HG-75), at 85 DAP. The highest yield at 100 DAP was recorded for Lewis. The ideal harvesting time, based on degree of yellowness and bean texture, for Durga Jay, Esser, Hall, SPS-119, and Lewis seemed to be 100-115 DAP whereas the beans of Brooks, HG-75, HSB-130, Kinman, and Santa Cruz became tougher and yellow by 100 DAP. A comparison with published results of snap beans and edible-pod peas indicated that green guar beans contained greater amounts of protein, total carbohydrates, vitamin C, calcium, iron, manganese, phosphorus, potassium, and sodium. These results indicate that green guar beans can be a potential alternate source of income for farmers in Georgia and other states.

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John A. Juvik

Extensive epidemiological evidence suggests that carotenoids (including vitamin A), ascorbate (vitamin C), tocols (including vitamin E), and glucosinolate breakdown products exert anticarcinogenic effects in a range of human tissues. Consumption of fresh and processed vegetables with enhanced levels of these phytochemicals could reduce human risk of cancer. The vitamins play a major role as antioxidants, offering protection against cancer by preventing or reversing oxidative damage to DNA and other cellular components. Cruciferous vegetables contain glucosinolates (GSs), which, during mastication, are hydrolyzed by the enzyme myrosinase into bioactive breakdown products (BBPs), including sulforaphane. BBPs appear to induce synthesis of drug metabolism enzymes resulting in increased detoxification rates of carcinogens. This paper describes an interdisciplinary investigation designed to develop vegetable cultivars that offer chemoprotection from cancer at doses commensurate with a normal American diet. Initial work has focused on surveying sweet corn and Brassicae oleraceae germplasm for variation in vitamin and glucosinolate content in conjunction with in vitro and in vivo bioassays to determine which compounds and concentrations optimize chemoprotectant activity. Segregating populations from crosses between sweet corn and Brassica lines that vary in vitamin and GS concentrations will be assayed for chemical content and chemoprotectant activity, and genetically characterized using DNA marker technology to identify and map genes controlling these traits. This information will improve selection methodology in a breeding program aimed to develop brassica and sweet corn germplasm with enhanced cancer chemoprevention.