• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.10
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• pp.1715-1719
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• 2004

In order to help the preservation of the unshiu orange and pear, antimicrobial paper incorporating grapefruit seed extract and zeolite was applied to pack fruits. Unshiu orange was packed in a box (24${\times}$24${\times}$22 cm) attached with antimicrobial paper and then stored respectively at l$0^{\circ}C$. Pears were wrapped individually before storage at l$0^{\circ}C$. During the storage, weight loss, pH, total acidity, soluble solid content, microbial load and decay were measured as quality indices. Steady pH increase in unshiu orange was observed to slightly decrease total acidity during the storage with little difference between the packaging treatments. The microbial loads of total aerobic bacteria, and yeast/mold counts were suppressed during storage by the antimicrobial paper packaging, which also contributed to reducing the decayed unshiu orange. Limited reduction of total aerobic bacteria and yeast/mold counts was observed only for initial storage period for the pears wrapped with 9 and 12% antimicrobial agent-added papers. Antimicrobial paper was useful for the reduction of microbial load in unshiu orange and pear without other quality deterioration.

• Korean Journal of Food Science and Technology
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• v.43 no.5
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• pp.577-582
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• 2011

Greenhouse satsuma mandarins (Citrus unshiu Marc., cv. Gungchun) of an early harvesting cultivar were treated by hot water showering at 65$^{\circ}C$ for 10 s at a commercial scale in a packing house and then stored at 5$^{\circ}C$ for 3 weeks and subsequently at 18$^{\circ}C$ for 1 week (simulated shelf-life) to examine the potential use of hot water treatment (HWT) as an environmentally benign method to maintain mandarin quality characteristics during postharvest storage and sale. The respiration rate just after heat treatment or during storage was at a similar level in both the treated and untreated fruit. HWT also had no detrimental effects on quality attributes including pH, titratable acidity, soluble solids content, weight loss, firmness, and peel color. The development of stem-end rot, mold decay, and black rot was lower in the heat-treated fruit compared to those in the untreated control. A sensory evaluation showed that HWT markedly improved fruit appearance, making the fruit cleaner and glossier. The results suggested that HWT can be applied to satsuma mandarin as an effective pretreatment to maintain postharvest quality during storage and marketing.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.8
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• pp.1233-1238
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• 2016

Combined treatment of chlorine dioxide ($ClO_2$) gas, mild heat, and fumaric acid was performed to reduce microbial growth and maintain quality of Citrus unshiu during storage at $4^{\circ}C$. Citrus unshiu fruits were treated with $ClO_2$ gas (15 or 30 ppmv), mild heat (40, 50, or $60^{\circ}C$), and fumaric acid (0.1, 0.3, or 0.5%). Combined treatment of 15 or 30 ppmv $ClO_2$ gas, $50^{\circ}C$ mild heat, and 0.5% fumaric acid reduced populations of inoculated Listeria monocytogenes by 3.5~3.7 log CFU/g. In addition, combined treatment decreased populations of yeast and molds in Citrus unshiu by 2.54 log CFU/g after 30-day storage at $4^{\circ}C$. Combined treatment also reduced the decay rate by 48% after 30 days of storage compared with the control. Total solid content, titratable acidity, and color values were not significantly affected by the combined treatment. Therefore, combined treatment of $ClO_2$ gas, mild heat, and fumaric acid can be a useful hurdle technology to improve microbial safety and quality of Citrus unshiu during storage.

• Food Science and Preservation
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• v.23 no.6
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• pp.772-777
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• 2016

Activity of the noncontacted low temperature atmospheric pressure surface discharged plasma (LASDP) converts stable gas to ionized gas known as discharge or plasma. This ionized gas exhibits the antimicrobial activity. We examined the effects of 3 different storage treatments for 80 days on 'Setoka' : ambient storage (AS), low-tempperature storage (LTS), and low-temperature atmospheric pressure plasma+low-tempperature storage (PLTS). Total soluble solids showed no the significant differences between the 3 treatments. Acidity gradually decreased, and was 0.5% under AS after 30 days of storage. Fruit firmness increased by a few percent until 40 days of storage. Weight loss in AS was higher than for other treatments. After 80 days of storage, the decay ratio was significantly low in PLTS treatment: (AS, 50.5%; LTS, 5.6%; PLTS, 1.9%). In AS treatment, 73% of the rotten fruits were infected particularly with green and blue mold; however, only 1% of the rotten fruits were infected in case of PLTS treatment. In conclusion, LASDP treatment can prevent postharvest decay caused by fungi and is an efficacious alternative extending the shelf-life of citrus fruits.

• Research in Plant Disease
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• v.17 no.1
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• pp.78-81
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• 2011

Soft rot caused by Rhizopus oryzae occurred on unshiu orange (Citrus unshiu Marc.) sampled from commercial markets in Jinju, Korea, 2010. The first symptom of soft rot on orange is a water-soaked appearance of the affected tissue. The infected parts later disintegrated into a mushy mass of disorganized cells followed by rapid softening of the diseased tissue. The lesion on orange was rapidly softened and rotted, then became brown or dark brown. Optimum temperature for mycelial growth of the causal fungus on potato dextrose agar was $30^{\circ}C$ and growth was still apparent at $37^{\circ}C$. Sporangiophores were $6{\sim}20\;{\mu}m$ in diameter. Sporangia were globose and $40{\sim}200\;{\mu}m$ in size. The color of sporangia was brownish-grey to blackish-grey at maturity. Sporangiospores were sub-globose, brownish- black streaked and $4{\sim}10\;{\mu}m$ in size. Columella were globose to sub-globose and $85{\sim}120\;{\mu}m$ in size. On the basis of mycological characteristics, pathogenicity test, and the ITS sequence analysis, the causal fungus was identified as Rhizopus oryzae. To our knowledge, this is the first report of soft rot caused by R. oryzae on unshiu orange in Korea.

• Food Science and Preservation
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• v.10 no.4
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• pp.435-440
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• 2003

Such fruits as nut persimmons, mandarin oranges and apples stored in the far-infrared radiated chamber at 5$^{\circ}C$ under 90% of relative humidity had been maintained in the fresh state for longer times than the control stored only in the cold chamber. Fruits stored in the far-infrared radiated chamber showed lower values in weight loss rate, microbial colony count and decay ratio and higher ascorbic acid content than the control stored only in the told room through the storage period. We confirmed that fruits stored in the far-infrared radiated chamber under low temperature and high humidity showed least changes in quality properties through the storage period and the far-infrared radiated facilities could be a good storage system.

• Applied Biological Chemistry
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• v.41 no.3
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• pp.228-233
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• 1998

The storage life of satsuma mandarin(Citrus unshiu Marc. var. miyagawa) by the various pretreatment of temperatures; non-treated, room temperature, $10,\;20^{\circ}C$ and $35^{\circ}C$ were investigated. The pretreated citrus fruits were stored at $4^{\circ}C$, 85% relative humidity. Weight loss of citrus fruits by the pretreatment at $35^{\circ}C$ for 24 hrs was the lowest among that of others. Decay ratio of $35^{\circ}C$ pretreated fruits was increased at initial stages of storage, but was maintained low level after that, compared to other treatments. After 115 days storage, firmness of fruits was lowered by the softening, and decayed fruits were occurred increasingly. Ethylene evolution was increased between $55{\sim}65$ days after storage, and the amount was increasing rapidly after 115 days. It seemed to be derived from decayed fruits and physiological activities. $CO_2$ content in fruit was decreased at initial stages of storage, but was increased between $55{\sim}100$ days during storage periods. Acid content, soluble solids, total sugar and vitamin C were reduced gradually during cold storage, but the difference among treatments was not so great. Pretreated fruits at $35^{\circ}C$ for 24 hrs before cold storage was effective on preventing from weight loss and respiration ratio. Optimum storage period of early variety of Satuma mandarin was regarded for 100 days on the basis of appeareance and taste.

• The Korean Journal of Pesticide Science
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• v.5 no.2
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• pp.37-44
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• 2001

The biological effects of the iminoctadine tris (albesilate) and kresoxim-methyl for the protection of citrus postharvest diseases caused by penicillium spp. were assayed. In vitro tests, $EC_{50}$ values of iminoctadine tris(albesilate) were $0.01{\sim}0.02\;and\;0.01{\mu}g$ a.i./mL against mycelial growth of P. italicum and P. digitatum, respectively, but iminoctadine tris(albesilate) at $0.64{\mu}g$ a.i. /mL inhibited a little mycelial growth of unknown Penicillium sp. which produced another symptom different to blue and green mold caused by P. italicum and P. digitatum, respectively. And against germination and growth of germ tube of P. italicum and P. digitatum, $EC_{50}$ value of iminoctadine tris(albesilate) was $0.0013{\sim}0.0025{\mu}g$ a.i./mL. But spore germination of unknown Penicillium spp. was not nearly inhibited at $0.2{\mu}g$ a.i./mL. $EC_{50}$ values of kresoxim-methyl were $0.08{\sim}0.16$, 0.04 and $0.16{\mu}g$ a.i./mL against mycelial growth of P. italicum, P. digitatum and unknown Penicillium sp., respectively, and $0.04{\sim}0.08{\mu}g$ a.i./mL and $0.01{\sim}0.02{\mu}g$ a.i./mL against germination and growth of germ tube of P. italicum and unknown Penicillium sp., and P. digitatum, respectively. Iminoctadine tris(albesilate) and kresoxim-methyl were markedly effective to control the postharvest disease by 7 days spray prior to harvest. When the fruits were sprayed with iminoctadine-tris(albesilate) ($200{\mu}g$ a.i./mL) and kresoxim-methyl ($155{\mu}g$ a.i./mL) 7 days prior to harvest and subsequently stored for 90 days, the percentage of diseased fruit by Penicillium spp. was $3.6{\pm}1.8%$ in treatment of kresoxim-methyl and $5.9{\pm}1.8%$ in iminoctadine-tris(albesilate), respectively. On the other hand, tile percentage of diseased fruit was relatively high, $20.3{\pm}10.0%\;and\;19.5{\pm}9.6%$ in thiophanate-methyl ($700{\mu}g$ a.i./mL) and non-treatment, respectively. Maximum residue amount (ppm) among fruits (flesh and peel) assayed 0, 30, 60 and 90 days after storage was 0.45 and 0.10 ppm in treatment of kresoxim-methyl and iminoctadine, respectively.

• Food Science and Preservation
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• v.16 no.5
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• pp.644-649
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• 2009

We investigated quality changes in Setoka ([Citrus unshiu$\times$Citrus sinensis]$\times$Citrus reticulate]$\times$[Citrus reticulata$\times$Citrus sinensis]) wrapped in 30-m pore size low-density polyethylene film (LDPE) and stored at different temperatures. LDPE wrapping effectively inhibited weight loss, and fruits seemed fresh even after room temperature storage. The decay rate was higher at room temperature and with LDPE wrapping. The respiration rate of LDPE- wrapped fruits was somewhat higher than that of control samples. Thus, no modified atmosphere packaging (MAP) effect was observed when 'Setoka' citrus was studied. Acidity decreased at a constant but different rate with each storage method used, and these rates were correlated with respiration rates. Soluble solid content (SSC), however, increased during 45 days of storage a subsequent rapid decrease was then observed.

• Applied Biological Chemistry
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• v.42 no.3
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• pp.223-228
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• 1999

The storage effects of satsuma mandarin(Citrus unshiu Marc. var. miyagawa) by humidity control during storage; 90% relative humidity (RH) and 85% RH at $3^{circ}C$, and room temperature were investigated. After 98 days' storage, weight losses were 3.40% for 90% RH, 6.92% for 85% RH, and 11.87% for room temperature storage. Decay ratio was increased rapidly from 3.87% on 98 days' to 48.75% on 126 days' storage for 90% RH. Soluble solids and flesh ratio were declined gradually, but the differences were not significantly. Firmness of fruits was continuously reduced during storage, especially on room temperature storage by the softening of the fruits. Acid content and vitamin C were gradually reduced during storage. Coloration was continuously progressed on room temperature, compared to cold storage. In order to keep freshness of the fruits, optimum storage period of early variety of Satuma mandarin was regarded for 100 days at $3^{circ}C$, 85% RH on the basis of sensory evaluation and chemical compositions.