• Korean Journal of Food Science and Technology
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• v.37 no.5
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• pp.816-821
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• 2005

Chemical characteristics and physiological activities of plums (Oishiwase and Formosa) were evaluated. Proximate composition of plums consisted of (w/w) 1.9-6.2% protein, 2.3-7.1% fat, 3.5-4.1% ash, and 84,1-88,7% carbohydrate. Organic acids, such as oxalic, malic, succinic, and acetic acids were detected, except in Oishiwse acetic acid was not detected. Free sugars consisted of sorbitol, glucose, fructose and sucrose. Total fiber and total phenolics compounds of plum rind were higher than those of flesh. Electron-donating abilities of rind ethanol extracts were higher than those of BHA and tocopherol, and were twofold higher than those of flesh extracts. Nitrite-scavenging abilities of rind and flesh extracts were significantly higher (over 97%) at pH 1.2 and 3.0. Tyrosinase-inhibitory activities ranged 88.5 to 100%. SOD-like activities of all extracts were weak at 22.7 to 27.2%.

• Horticultural Science & Technology
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• v.29 no.6
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• pp.592-599
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• 2011

Plum is a climacteric fruit and softening is a serious problem for storage and transportation. Thus $1{\mu}L{\cdot}L^{-1}$ of 1-methylcyclopropene (1-MCP) was applied to plums to prolong their shelf life and maintain quality. Japanese plums (Prunus salicina cv. Formosa) were stored at $20^{\circ}C$ and $0^{\circ}C$ for 14 days and 46 days respectively, with or without 1-MCP treatment. Fruits were treated with $1{\mu}L{\cdot}L^{-1}$ 1-MCP at $10^{\circ}C$ for 24 h. Ethylene production and respiration rate were strongly inhibited in 1-MCP-treated fruits at $20^{\circ}C$. It was also observed that there was less ethanol and acetaldehyde evaporation in 1-MCP-treated fruits stored at $20^{\circ}C$ compared to those in control fruits not treated with 1-MCP. Fruit qualities, such as firmness, titratable acidity (TA), skin color, and decay, changed more slowly in 1-MCP-treated fruits stored at $20^{\circ}C$ than in untreated fruits. There were no differences in the ethylene production or respiration rate between the groups of fruits stored at $0^{\circ}C$ throughout the experiment. Chilling injury was also inhibited by the application of 1-MCP during storage at $0^{\circ}C$. When the fruits stored at $0^{\circ}C$ with or without 1-MCP were transferred to $20^{\circ}C$ after 25 days, the differences in ethylene production and respiration rate, firmness, TA, TSS, and acetaldehyde and ethanol evaporation between the initial (after being stored at $0^{\circ}C$ for 25 days) and the final measurements (after being stored at $0^{\circ}C$ for 25 days and then transferred to $20^{\circ}C$ for three days) were lower in 1-MCP treated fruits than in non-treated fruits. The postharvest application of 1-MCP in Formosa plums showed positive effects at both $0^{\circ}C$ and $20^{\circ}C$ storage conditions with regard to quality, such as low ethylene production and low respiration rates, firmness, TA, ethanol, and acetaldehyde evaporation, chilling injury, and decay.

• Food Science and Preservation
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• v.15 no.6
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• pp.891-896
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• 2008

Total phenolics and flavonoids, and the antioxidant capacity of plum cultivar wines (Prunus salicina L. cv. Soldam and P. salicina L. cv. Formosa) were determined using spectrophotometric methods. The total phenolic and flavanoid contents of Soldam wine were $478.4\;{\pm}\;5.6\;mg$ GAE and $202.4\;{\pm}\;7.5\;mg$ CE per L,respectively, and in Formosa wine were $200.6\;{\pm}\;7.5\;mg$ GAE and $64.4\;{\pm}\;6.8\;mg$ CE per L, respectively. Neutral and acidic phenolics in Soldam wine were extracted with ethyl acetate and 0.01 N HCl, respectively. In the 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging assay, neutral phenolics (64.5 EDA%) had $3{\sim}4$ times higher antioxidant activity than acidic phenolics (21.5 EDA%) and other related phenolic compounds such as chlorogenic acid (15.5 EDA%) and quercetin (24.6 EDA%) at a concentration of $100\;{\mu}g/mL$. The antiviral activities of neutral and acidic phenolics in Soldam wine were investigated in vitro using a virus-induced cytopathic effect (CPE) inhibition assay. Results showed that neutral and acidic phenolics at concentrations of $100\;{\mu}g/mL$ inhibited porcine epidemic diarrhea virus (PEDV) replication at rates of 78.12% and 58.37%, respectively. The inhibition rate of 10 g/mL neutral phenolics (69.42%) was higher than that of ribavirin as an antiviral reagent (57.86%). At concentrations of $100\;{\mu}g/mL$ or less, neutral and acidic phenolics of Soldam wine had no cytotoxic effect against vero cells.