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William J. Sciarappa*, Qing-Li Wu, Ming-Fu Wang, and James Simon

Medical benefits derived from grape extracts and red wine have been recently documented. In these regards, fresh grapes were collected from six Italian table grape varieties grown at the Rutgers Fruit Research and Extension Center in Cream Ridge, N.J. These samples were analyzed for proanthocynidins (PACs) which are the nutraceutical compounds considered to be bioactive in grapes. Seeded red grapes, seedless red grapes, seeded purple grapes and seedless green table grapes were also purchased from a New Jersey supermarket and analyzed for PACs. An LC/ESI-MS analytical method under low CID level of 20% was used to quantitate the PACs. Separated proanthocynidins (PACs) were individually analyzed and determined by their molecular ion peaks under positive ion mode, and led to the identification of dozens of proanthocynidins (PAC). Using HPLC/ESI-MSD, the proanthocyanidin monomers, (+)-catechin (C), (-)-epicatechin (EC), (-)-catechin gallate (CG), and (-)-epicatechin gallate (ECG) in these fresh grape samples were quantified under MRM mode. These identified catechins are the same phytochemicals that exist in green tea which is renowned for these same healthful components. This research revealed that the total concentration of PAC monomers in the six fresh table grape samples from New Jersey grown grapes ranged from 0.009% to 0.04%, which is much higher than that found in the four fresh table grape samples purchased from supermarket that contained concentrations from trace level to 0.005%. While the New Jersey grown grapes could not be directly compared to the supermarket grapes, this study provides a base-line data of expected PAC levels from standard supermarket grapes, and shows that these Italian grape varieties grown in New Jersey were rich in PACs.

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K. Yonemori, M. Oshida, and A. Sugiura

In order to study the nature of tannins in vivo, we developed a method for collecting the vacuolar contents from intact tannin cells in persimmon fruit. We used a micropipette controlled with a MMS-77 micromanipulator system (Shimadzu Co., Kyoto, Japan) under an inverted microscope. Fruit flesh of mature persimmon fruit (cv. Miyazakimukaku) was cut into 300-μm-thick sections with a DSK-100 miaoslicer (Dosaka EM, Kyoto, Japan). The sections were then put on a glass slide, and a micropipette was inserted into a tannin cell to withdraw its contents. After determination of the sap volume collected, the sample was injected into a 25-μl drop of water on a glass slide. Then, the water-drop containing the tannin sample was transferred to a small microfuge tube and stored in a freezer until analysis. Based on calculations, we could collect approximately 7 to 12 nl of vacuolar contents per tannin cell. When tannin and sugar contents per tannin cell were determined, we found that tannin cells contain tannins at 10% to 15% as catechin equivalents (w/v) and 8% to 10% total sugars (w/v), while a whole fruit contains tannins at 1% to 1.5% as catechin equivalents and 10% to 13% total sugars on fresh weight basis. We are currently continuing more detailed analysis of tannin cell constituents.

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M. López-Serrano and A. Ros Barceló

Levels and histochemical localization of peroxidase and polyphenol oxidase, and levels of anthocyanins and (+)-catechin, were studied in fruit of two strawberry (Fragaria ×ananassa Duch.) cultivars (`Oso Grande' and `Chandler'), which show different degrees of susceptibility to enzymatic browning after processing. Although the levels of anthocyanins at the processing-ripe stage may be important in determining pigment stability, and therefore market suitability, the color stability of `Chandler' is apparently determined by the lower endogenous levels of peroxidase and polyphenol oxidase in the processing-ripe stage, which are also accompanied by a lower (+)-catechin content. Polyphenol oxidase was localized almost exclusively in the cortex and to a lesser extent in the pith, showing a complementary pattern to that shown by peroxidase, which was localized in the vascular bundles. Since peroxidase and polyphenol oxidase showed a complementary localization pattern in the fruit, these results strongly suggest a synergic role for these two oxidative enzymes in pigment decay and the associated browning reaction, which occurs in processed strawberry fruit and their derived foods.

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Keizo Yonemori, Masayoshi Oshida, Fumio Fukuda, and Akira Sugiura

A method for collecting the vacuolar contents of intact tannin and parenchyma cells of persimmon (Diospyros kaki Thunb.) fruit using a micropipette was developed. Thin sections of the mesocarp tissue from mature persimmon fruit, `Miyazaki-mukaku' and `Hiratanenashi', were placed on a glass slide. Using a micromanipulator and an inverted microscope, a micropipette was inserted into a vacuole and its contents were withdrawn. A 5-nL sample of vacuole sap was collected per tannin cell from `Hiratanenashi' and 7 nL from `Miyazaki-mukaku', whereas only 2 nL was withdrawn from adjacent parenchyma cells. Analyses of the vacuolar sap revealed that the tannin cells of both cultivars contained 10% to 12% (m/v) of tannin as (+)-catechin equivalents and 10% to 13% (m/v) of soluble sugars, whereas the parenchyma cells contained trace amounts of tannins and ≈20% of soluble sugars. Tannin cells contain only a slight amount of sucrose, in contrast to a relatively large amount in parenchyma cells.

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Yuko Yoshizawa, Kenji Sakurai, Satoru Kawaii, Masayoshi Asari, Junichi Soejima, and Noboru Murofushi

Aqueous ethanol extracts prepared from 19 apple (Malus ×domestica Borkh.) cultivars were studied to explore their antiproliferative activity. Half of them showed strong inhibition on proliferation of human leukemic HL-60 cells, while the others were weak. Total polyphenols, 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, and total anthocyanins were measured and the results indicated that the antiproliferative activity was more strongly correlated to the polyphenols and radical scavenging activity than to the anthocyanin content. Several polyphenols in `Jonathan' were identified and quantified by high-performance liquid chromatography (HPLC) analysis. Among those compounds found during HPLC, catechin and epicatechin seemed partially responsible for HL-60 antiproliferation. A careful examination on parentage of the apple cultivars tested revealed that `Jonathan' and its progeny showed high antiproliferation toward HL-60. This is the first observation about the relationship between antiproliferative activity and parentage of apples, and the information would be useful to create new apple cultivars that posses more anticancer potential.

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Annick Moing, Jean-Luc Poëssel, Laurence Svanella-Dumas, Michèle Loonis, and Jocelyne Kervella

Prunus davidiana (Carr.), a wild species with poor fruit quality that is related to peach [Prunus persica (L.) Batsch], is used as a source of resistance to pests and diseases in peach breeding programs. Two genotypes of P. davidiana were studied for fruit biochemical composition and compared to three genotypes of P. persica (`Summergrand', `Bailey' and `Pamirskij'), and two P. persica × P. davidiana hybrids. Fruit of P. davidiana clones had higher malic acid, neochlorogenic and cryptochlorogenic acid and lower sucrose concentrations than fruit of all P. persica genotypes, even poor-quality Bailey. Differences in biochemical composition could be related to sensory evaluation. P. persica × P. davidiana hybrids had intermediate values between their parents for neochlorogenic acid concentration. They were similar to the P. persica parent for total soluble sugar, malic and citric acid, amino acid and catechin concentrations, indicating possible rapid progress for fruit quality in a breeding program.

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D.R. Rudell, J.P. Mattheis, X. Fan, and J.K. Fellman

Effects of artificial ultraviolet-visible light and methyl jasmonate (MJ) treatment on `Fuji' apple [Malus sylvestris (L.) Mill. var. domestica (Borkh.) Mansf.] fruit peel anthocyanin, phenolic, carotenoid, and chlorophyll production were examined using tristimulus color analysis and reverse-phase high performance liquid chromatography. Anthocyanin synthesis was enhanced by light and MJ treatment. Chlorogenic acid and most cyanidin, quercetin, and phloretin glycosides increased with MJ treatment concentration. Light alone also promoted increased production of most of these compounds. Production of catechin, (-)epicatechin, quercetin, and quercetrin was not enhanced by either light or MJ treatment. Light and MJ enhanced ß-carotene and chlorophyll b, synthesis but not xanthophyll or chlorophyll a synthesis. The chlorophyll a/b ratio decreased with MJ dosage. Results suggest MJ may provide a viable means of enhancing apple fruit coloration and other photoprotective mechanisms. Chemical name used: methyl 3-oxo-2-(2-pentenyl)cyclopentane-1-acetate (methyl jasmonate).

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Shahidul Islam, M. Jalaluddin, and Navam Hettiarachchy

Bitter melon (Momordica charantia L.), an annual vegetable of Cucurbitaceae family, is a vegetable with important nutritional and medicinal qualities. Four adaptable lines/varieties were tested in replicated field trials for productivity, and biochemical and medicinal characteristics at the University of Arkansas at Pine Bluff. The total phenolic contents of the oven-dried and freeze-dried tissues, and seeds, ranged from 5.39–7.75, 6.72–8.02, 6.40–8.90, and 4.67–6.69 mg·g-1 on a dry weight basis, respectively. The total phenolic content of bitter melon from India green (IG), India white (IW), China green (CG) and China white (CW) varieties were 4.67–6.72, 6.03–8.02, 5.39–7.81, and 6.69–8.90 mg·g-1 dry material, respectively. The main phenolic acids in bitter melon flesh were gallic acid, gentisic acid, catechin, chlorogenic acid, and epicatechin. Bitter melon seeds had the phenolic acids, gallic acid, catechin, and epicatechin. The antioxidant activities of methanolic extracts from the bitter melons varieties IG, IW, CG, and CW ranged from 79% to 85%, 79% to 83, 80% to 85, and 79% to 86% inhibition, respectively. The antioxidant activities of the seed ranged from 79% to 84% inhibition. Methanolic extracts of freeze-dried flesh and seed from var. IW and CG showed very high antimutagenic effects against benzo(a)pyrene with Salmonella TA98 (92% to 100% inhibition) TA100 (79% to 86% inhibition), but lower antimutagenicity activities against sodium azide that ranged from 46% to 54% and 17% to 32% inhibition, respectively. The popular belief that bitter melon improves glucose tolerance in Type II diabetes and lowers blood cholesterol is being investigated. It has not been determined which alkaloids, polypeptides, or combination of chemicals found in bitter melon are responsible for the beneficial medicinal effect.

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Richard J. McAvoy, Bernard B. Bible, and Michael R. Evans

The early onset of bract necrosis in poinsettia (Euphorbia pulcherrima Willd. ex. Klotzch) is characterized by small dark-stained spots that precede the development of enlarged necrotic lesions. Electron micrographs of adaxial epidermal and subepidermal tissues with early symptoms of necrosis revealed large, electron-dense deposits in cell vacuoles. These spherical bodies resembled condensed tannins observed in the epidermal tissues of peach and apple fruit. Chemical analysis of bract tissues confirmed the presence of condensed tannins. Furthermore, there were higher concentrations of condensed tannin in bract samples with 2-mm-diameter lesions than in samples with lesions <0.5 mm (equivalent to catechin concentrations of 59 and 13 mg·g-1 fresh mass, respectively). No tannin bodies were observed in parallel samples of healthy-appearing bracts in which only trace concentrations of condensed tannins were measured (0.2 mg·g-1 fresh mass). The evidence suggests an association between condensed tannin accumulation in localized areas of the bract and the early appearance of bract necrosis symptoms.

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Jose E. Villarreal, Leonardo Lombardini, and Luis Cisneros-Zevallos

Pecans nuts from `Kanza' and `Desirable' cultivars were irradiated with 0, 1.5, and 3.0 kGy using electron beam (E-beam) irradiation and stored under accelerated conditions (40 °C and 55% to 60% RH). Antioxidant capacity (AC), phenolic (TP) and condensed tannin (CT) content, HPLC phenolic profile, tocopherol content, peroxide value (PV), and fatty acid profile were evaluated in kernels after 0, 7, 21, 55, and 134 days of storage. Irradiation had no detrimental effects in AC and TP; however, variation was found throughout storage. Tocopherol content of 1.5 and 3.0 kGy kernels decreased after irradiation, but no further decrease was observed thereafter. Irradiated `Desirable' samples had greater PV than controls, while `Kanza' 1.5 kGy samples had increased PV only after 134 days of storage. No change in fatty acid composition was detected for any cultivar. Color modification induced by storage included a decrease in lightness and yellowness and an initial increase of redness followed by a decrease after 98 days of storage. No differences in phenolic profile were observed after irradiation. Compounds identified by HPLC in hydrolyzed extracts were gallic and ellagic acid, catechin, and epicatechin. In general, beside the decrease in tocopherol content, no detrimental effects were found in antioxidant composition caused by irradiation treatments. While a faster oxidation rate was seen in irradiated kernels for `Desirable' cultivar, no other quality attribute was affected by E-beam irradiation.