• The Plant Pathology Journal
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• v.37 no.3
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• pp.268-279
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• 2021

Citrus scab, caused by the fungal pathogen Elsinoë fawcettii, is one of the most important fungal diseases affecting Citrus spp. Citrus scab affects young tissues, including the leaves, twigs, and fruits, and produces severe fruit blemishes that reduce the market value of fresh fruits. To study the molecular responses of satsuma mandarin (C. unshiu) to E. fawcettii, plant hormone-related gene expression was analyzed in response to host-compatible (SM16-1) and host-incompatible (DAR70024) isolates. In the early phase of infection by E. fawcettii, jasmonic acid- and salicylic acid-related gene expression was induced in response to infection with the compatible isolate. However, as symptoms advanced during the late phase of the infection, the jasmonic acid- and salicylic acid-related gene expression was downregulated. The gene expression patterns were compared between compatible and incompatible interactions. As scabs were accompanied by altered tissue growth surrounding the infection site, we conducted gibberellic acid- and abscisic acid-related gene expression analysis and assessed the content of these acids during scab symptom development. Our results showed that gibberellic and abscisic acid-related gene expression and hormonal changes were reduced and induced in response to the infection, respectively. Accordingly, we propose that jasmonic and salicylic acids play a role in the early response to citrus scab, whereas gibberellic and abscisic acids participate in symptom development.

• Journal of dental hygiene science
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• v.19 no.1
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• pp.1-8
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• 2019

Background: Erosion is a gradual process that occurs fairly quickly, and the full extent of the erosive effects of acidic beverages is not yet clear. The present study aimed to determine the differences in the erosive potentials among four naturally acidic fruit nectars within the same range of titratable acidity and to determine the influence of the components of organic acids on tooth erosion. Methods: Diluted fruit nectars (mandarin 1:1.1, orange 1:1.7, lemon 1:15, grapefruit 1:20) with the same range of titratable acidity (7.9 ml) and their corresponding organic acids (0.05%, 0.1%, 0.3%, and 0.5% citric acid, malic acid, and a citric and malic acid mixture [pH 2.8], respectively) were used. Specimens were placed in conical tubes with 50 ml of each of the test solutions for 1 hour. A microhardness test and scanning electron microscopy were used to measure enamel erosion. Acid separation was carried out using high-performance liquid chromatography to analyze the composition of each test solution. Results: Similar decreases in the Vickers hardness number (VHN) were observed among the groups treated with the following diluted fruit nectars: diluted mandarin nectar ($75.9{\Delta}VHN$), diluted lemon nectar ($89.1{\Delta}VHN$), diluted grapefruit nectar ($91.7{\Delta}VHN$), and diluted orange nectar ($92.5{\Delta}VHN$). No statistically significant differences were found in the enamel surface hardness after erosion (p>0.05). Citric and malic acids were the major organic acids in the test fruits. The lemon and orange groups had the highest malic acid concentrations, and the mandarin group had the lowest malic acid concentration. Conclusion: The titratable acidity and the citric and malic acid contents of the fruits could be crucial factors responsible for enamel erosion. Therefore, fruit-based drinks should be regarded as potentially erosive.

• Korean Journal of Food Science and Technology
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• v.53 no.2
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• pp.149-153
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• 2021

Mandarin peel (MP) is a by-product of the processing of citrus juice or other products. This study aimed to investigate the potential anti-obesity effect of an enzymatic extract of MP on the inhibition of adipogenesis in 3T3-L1 adipocytes. The enzymatic extract (MPCE) was prepared using the commercial food-grade carbohydrase Celluclast. Lipid accumulation and triglyceride levels were significantly lower in MPCE-treated cells than in untreated cells. In addition, MPCE treatment reduced the protein expression levels of peroxisome proliferator-activated receptor-γ, CCAAT/enhancer-binding protein α, sterol regulatory element-binding protein 1, and fatty acid-binding protein 4. These results suggest that MPCE inhibits adipogenesis by downregulating the expression levels of adipogenesis-related proteins. Therefore, the current findings demonstrate that MPCE possesses potent anti-obesity properties and could be a potential ingredient in functional food industries.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.5
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• pp.9-15
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• 2022

Discarded bio-wastes, such as seeds and rinds, cause environmental problems. Multiple studies have recycled bio-wastes as eco-friendly energy sources to solve these problems. This study uses bio-waste to fabricate a mandarin peel powder based triboelectric nanogenerator (MPP-TENG). The MPP-TENG is based on the contact separation mode. It generates an open-circuit voltage and short-circuit current of 156V and 2µA, respectively. In addition, MPP-TENG shows stable operation over continuous 3000s without any deviation in output. Also, the device exhibits maximum power density of 5.3㎼/cm² when connected to a resistance of 100MΩ. In an energy storage capacity test for 1000s, the MPP-TENG stores an energy of 171.6µJ in a 4.7µF capacitor. The MPP-TENG can power 9 blue LEDs and 54 green lettering LEDs. These results confirm that the MPP-TENG can provide a new avenue for eco-friendly energy harvesting device fabrication.

• Horticultural Science & Technology
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• v.34 no.5
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• pp.665-676
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• 2016

As high temperature during citrus growing season has caused a serious problems including inferior coloration in production of mandarins in Korea, we were to investigate the expression pattern of several genes related with coloration during the ripening in high temperature condition of citrus fruits. The expression of genes related with sugar metabolism, cell wall degradation, and flavonoid synthesis in high temperature conditions was investigated in fruits of 'Haryejosaeng' (Citrus unshiu) and 'Shiranuhi' mandarin (C. reticulata). While the expression of beta-amylase (BMY), phenylalanine ammonia-lyase (PAL), chalcone synthase (CHS), and flavanone 3-hydroxylase (F3H) was differently induced, expression of polygalacturonase (PG) decreased dependently on temperature conditions. In 'Haryejosaeng' mandarin, while the expression of genes related to the skin coloration, such as CHS and F3H genes increased at $25^{\circ}C$, the expression of PAL and stilbene synthase (STS) genes were induced at $30-35^{\circ}C$ in all ripening stages. In 'Shiranuhi' mandarin, the expression of the BMY gene decreased at early time point in all temperature condition and then increased at $30-35^{\circ}C$ than at $25^{\circ}C$ in the ripening stage 2 to 3 of fruits. F3H and STS genes also showed the tendency to decrease at $30-35^{\circ}C$. Although the expression levels of genes in ripening stage 1 and stage 2 of fruits showed similar patterns in both 'Haryejosaeng' and 'Shiranuhi', the expression levels of genes were down-regulated in late ripening stage of 'Shiranuhi' fruits compared to 'Haryejosaeng'. In general, the mRNA levels of seven tested genes were higher in 'Haryejosaeng' than in 'Shiranuhi' mandarin, and expression of genes by high temperature was regulated sensitively in 'Haryejosaeng' compared to 'Shiranuhi' mandarin. Further investigations of expression of various genes based on transcriptome analysis in early ripening stage can provide valuable information about the responses to climatic changes in ripening citrus fruits.

• Food Science and Preservation
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• v.11 no.3
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• pp.304-312
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• 2004

Early harvested Satsuma mandarin (Citrus unshiu) was treated with hot air at 45$^{\circ}C$ for 2, 4, and 6 hours and stored at 5$^{\circ}C$ for 3 weeks and additional one week at 18$^{\circ}C$ (simulated shelf-life) in order to examine the effect of mild heat treatment on the storage quality of the citrus fruits. Quality attributes of the sample fruits evaluated during storage included the respiration rate, internal gas composition, pH, titratable acidity, soluble solids content, flesh weight loss, firmness, peel color, decay ratio, and sensory properties. The initial respiration rates, just after hot air treatment, were significantly higher in the heat-treated fruits compared to the untreated. However, during storage at 5$^{\circ}C$, the respiration rates showed a similar level in all treatments. Internal gas composition exhibited no significant difference between the heat-treated and untreated samples. Hot air treatment also exerted no significant effects on the pH, titratable acidity, soluble solid contents, flesh weight loss, firmness, and peel color of the fruits during the whole storage period. The decay ratio was manifestly lower in the heat-treated fruits than the untreated. For sensory attributes including visual and organoleptic quality, no significant difference was observed among sample fruits. Results suggested that mild heat treatment with hot air at 45$^{\circ}C$ for 4-6 hours could be used as an effective preconditioning method to keep the postharvest quality of Satsuma mandarin by reducing the decay incidence remarkably during storage.

• Food Science and Preservation
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• v.15 no.6
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• pp.847-851
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• 2008

The handling and processing of agricultural products in Korea is done manually. Small plastic boxes, nets, and corrugated cardboard boxes are used as containers during harvesting, sorting and other product handling operations. However, these practices are labor-intensive, time-consuming, require various kinds of packing materials, and are expensive because of high operating costs. To overcome these problems, the use of pallet bins with pre-cooling and storage features for handling and processing bulk farm products was investigated. The airflow resistances through bulk potato, onion and mandarin stocks were measured, and the pallet bins and a pressure pre-cooling device were manufactured. The opening ratio, bed depth and airflow rate through bulk potato, onion and mandarin in the pallet bin were defined with regression equations. The cooling rates of bulk potato, onion and mandarin were 0.8C/h ($21.7{\rightarrow}0C$, 14.5 h), 0.4C/h ($15.4{\rightarrow}.0C$, 32.2 h) and 0.7C/h ($13.7{\rightarrow}C$, 18.8 h), respectively, with the pressure pre-cooling system. Temperature deviances for storage of bulk potato, onion and mandarin were 0.12C, 0.12C and 0.17C, respectively.

• Korean Journal of Ichthyology
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• v.9 no.2
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• pp.228-234
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• 1997

This study was carried out to confirm the taxonomical status by comparison of morphological and chromosomal charateristics and cross breeding in the two types of black and yellow body color of Korean mandarin fish, Siniperca sherzeri from Han River, Korea. Black and yellow types of Korean mandarin fish were similar in having 90-98 lateral line scale pores, 13 dorsal fin rays and XII XIII spines, 9 anal fin rays and 15 pectoral fin rays, but yellow type was differ from blacks type by yellow body color pattern. Diploid chromosome and arm number (fundamental number, NF) of the two types were the same to 2n=48 and NF=52. Karyotypes in the two types are consisted of 2 pairs submetacentric chromosome and 22 pairs of acro and/or telocentric chromosome. The black type females of Siniperca scherzeri were artificially crossed with yellow type males and black type males, respectively. The progenies from each cross breeding produced the normal individuls that possessed with parent types in the body color pattern. These data suggest that two types of Korean mandarin fish were same species, and yellow type was mutant by albino.

• 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.

• Horticultural Science & Technology
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• v.29 no.6
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• pp.617-622
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• 2011

The study was conducted to determine the efficiency in producing spontaneous polyploids in some mandarin hybrids with different seed embryony. Seed formation by open pollination, frequency of spontaneous polyploids, and plant growth characteristics were evaluated in four mandarin hybrids with polyembryony such as 'Amakusa', 'Haruka', 'Hayaka', and 'Seminole' and two with monoembryony such as 'Benibae' and 'Harehime'. The mean number of the developed seeds per fruit was 10.0 and frequency of small seeds was 25.1%. Polyploids were selected from plants germinated in vitro by a flow cytometry and confirmed by chromosome analysis. One triploid was produced from 'Harehime', one tetraploid, 'Amakusa', and one tetrapoid, 'Benibae'. There were little differences in leaf shape, thickness, petiole length, and internode length between diploids and polyploids such as tri- or tetraploid. However, polyploids had larger stomata and lower density of stomata in abaxial epidermis than diploids. SPAS indicating chlorophyll content and photosynthetic rate were significantly affected by ploidy level. The results indicated that spontaneous polyploids might be produced by open pollination in some mandarin hybrids and monoembryony had higher frequency in polyploid occurrence than polyembryony.