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Soon O. Park, Hye Y. Hwang and Kevin M. Crosby

Melon, an economically important horticultural crop grown in many temperate, subtropical, and tropical regions of the world ( Wang et al., 1997 ), is a significant source of ascorbic acid, beta-carotene, folic acid, and potassium ( Lester, 1997

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Wilmer A. Barrera and David H. Picha

below the skin compared with the center pith area ( Bradbury and Singh, 1986 ). It is unknown whether other sweetpotato root tissues differ in their WSV content. The objective of this study was to determine the ascorbic acid, thiamin, riboflavin, and

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Mingjun Li, Xuesen Chen, Pingping Wang and Fengwang Ma

–80 °C until use. For the final harvest, at 120 DAA, the peel and flesh samples were directly sliced from the sunny side of fruit using a knife. Assays of ascorbic acid. Samples of skin or flesh (3 g each) or leaves (0.5 g) were homogenized in 8 mL of

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Hakan Aktas, Derya Bayındır, Tuba Dilmaçünal and M. Ali Koyuncu

bunches were treated with a mineral water solution (MAS), which contained 1% (w/v) potassium nitrate, 0.5% (w/v) zinc sulfate, 1% (w/v) calcium chloride, 0.1% (w/v) boron, 0.2% (w/v) copper sulfate, 0.5% (w/v) ascorbic acid (an antioxidant), and 0.1% (w

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Giacomo Cocetta, Ilaria Mignani and Anna Spinardi

prevent ethylene action and its impact on the nutritional quality of fruit, in particular on the content of ascorbic acid in winter pear tissues during storage. Materials and Methods Fruit material and experimental setup. Pears ( P. communis L., cv. Passe

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Masayasu Nagata and Ichiji Yamashita

Allylisothiocyanate (ATTC) is known as a main pungent compound in cabbage, which indicates several biological activities. Our previous studies have suggested that AITC acts as a natural regulator which inhibits browning and ethylene evolution of shredded cabbage. It was found that AITC mainly inhibits de novo protein synthesis and in some case, it partially inhibits enzymatic reactions directly. This time we investigated the changes in ascorbic acid (AsA) content and AsA oxidase activity of shredded cabbage, treated with various amounts of AITC.

AsA content of shredded cabbage was initially 16.9 mg/100g fresh wt. After 24 h incubation at 10°C, it was reached to 26.3 mg/100g fresh wt. This increase was suppressed by AITC and also by cycloheximide, well known inhibitor of protein synthesis. It was suggested that the increase in AsA was a result of wounding reaction that took place in shredded cabbage. AsA oxidase activity increased during incubation, which was suppressed by AITC, too.

From these results, AITC was thought to be a natural regulator of wounding reactions in cabbage.

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Muhammad Irshad, Hafiz Muhammad Rizwan, Biswojit Debnath, Muhammad Anwar, Min Li, Shuang Liu, Bizhu He and Dongliang Qiu

phenolic inhibitors such as AgNO 3 , which act directly on the explant tissue to inhibit phenolic secretion in the target site ( Kumar et al., 2016 ). Ascorbic acid is a strong antioxidant; it scavenges oxygen radicals produced during explant injury

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Stephen L. Love, Thomas Salaiz, Bahman Shafii, William J. Price, Alvin R. Mosley and Robert E. Thornton

Ascorbic acid (vitamin C) is an essential nutrient in the human diet and potatoes are a valuable source. As a first step in breeding for potatoes (Solanum tuberosum L.) with higher levels of ascorbic acid, 75 clones from 12 North American potato-breeding programs were evaluated for concentration, and 10 of those for stability of expression. Trials were grown in Idaho, Oregon, and Washington in 1999 and 2000, tubers sampled, and ascorbic acid quantified. There were significant differences among clones and clone by environment interaction was also significant. Concentration of ascorbic acid of the clones was continuously distributed over a range of 11.5 to 29.8 mg/100 g. A subgroup of 10 clones was analyzed using an additive main effects and multiplicative interaction (AMMI) model, to diagnose interaction patterns and measure clone stability. The first two principal component axes accounted for over 80% of the variability. Bi-plot analysis showed `Ranger Russet' to be highly unstable across the environments tested. A plot of Tai's stability statistics found six of the 10 clones to be stable for ascorbic acid expression. Appropriate evaluation methods for ascorbic acid concentration must involve multi-year testing.

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Durward Smith and Susan Cuppett

Both fresh and frozen asparagus rapidly deteriorate in quality due, in part, to the formation of oxidative off-flavors. Anti-oxidants and chelating agents prevent lipid oxidation in vegetables, but increasing the levels of such compounds in whole vegetables is difficult. Vacuum infusion was optimized to saturate asparagus spears with ascorbic acid without damaging tissues. The combination of vacuum infusion of ascorbic acid and thermal blanching effectively prevented the formation of oxidative off-flavors and hexanal during frozen storage. Sensory evaluations correlated with hexanal levels following frozen storage.

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G. Préstamo and P. Manzano

The various isozymes of peroxidase of a range of vegetables and kiwifruit were compared using sodium dodecyl sulfate polyacrylamide gel electrophoresis followed by specific activity staining. Peroxidase isozymes were determined in potato (Solanum tuberosum L.), carrot (Daucus carota L.), tomato (Lycopersicon esculentum Mill.), kiwifruit [Actinidia deliciosa (A. Chev.) C.F. Liang et A.R. Ferguson], cauliflower [Brassica oleracea (Botrytis group)], green beans (Phaseolus vulgaris L.), and horseradish (Armoracia rusticana Gaertn, Mey Scherb.). There was only one isozyme in cauliflower (70 kDa), two in kiwifruit (45-43 kDa), and a range of isozymes (120-36 kDa) in horseradish. Ascorbic acid inhibited peroxidase activity in the extracts.