• Research in Plant Disease
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• v.13 no.2
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• pp.88-92
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• 2007

A total of 41 Pseudomonas syringae pv. syringae, the causal agent of bacterial blossom blight, were isolated from kiwifruit plants in Korea. Among them, two strains showing streptomycin resistance were examined to investigate the structure of resistant determinants by PCR and nucleotide sequence analysis. PCR results suggested that the streptomycin resistance is mediated by strA-strB genes carried on Tn5393a. Insertion sequences, IS6100 and IS1133, which were located within or downstream of tnpR gene in Xanthomonas campestris and Erwinia amylovora were not found. Nucleotide sequences of strA-strB were 100% identical with Tn5393a. Two stretomycin resistant strains had three plasmids. Southern blot hybridization using strA-strB probe indicated that the resistant genes were carried on a 100kb plasmid.

• Horticultural Science & Technology
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• v.18 no.6
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• pp.808-810
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• 2000

The chemical components of xylem sap collected from kiwifruit (Actinidia chinensis Planch cv. Hayward) trees were analyzed and processing of xylem sap drink were accomplished to increase utilization of xylem sap as a drink. Water content, soluble solids, viscosity, and pH of the xylem sap were 99.60%, 0.90%, 1.01, and 6.50, respectively. In the xylem sap, fructose was the highest among free sugars followed by glucose, sucrose, galactose, and mannitol. The major inorganic components in the sap were calcium, potassium, and magnesium, and calcium was the dominant among them. Ten kinds of amino acids in the xylem sap were detected by amino acid analyzer, and the major amino acids were glutamic acid, lysine, and isoleucine. Glutamic acid was the most dominant amino acid in the xylem sap. Major compositions of xylem sap drink were 74.5% xylem sap, 15% kiwifruit puree and 10% high fructose. Nutritional facts in drink (252 mL) processed by using the xylem sap were 21.8 g sugar, 23.1 mg calcium, 14.1 mg potassium, 554.5 mg amino acid, and 15.6 mg ascorbic acid.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.4
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• pp.641-645
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• 2001

To utilize the by-products from whelk processing, whelk internal organ jeotgal was manufactured by adding pineapple and kiwifruit juices containing bromelain and actinidin, respectively. The protease activities of pineapple and kiwifruit juices were 52 and 248 unit/mL, respectively. 1 kg ground whelk internal organ was immersed to 12.5% salt concentration and then the 20, 50, or 100 mL of fruit juice were added in it. the quality of products fermented for up to 70 day at 1$0^{\circ}C$ was observed. Jeotgal wit pineapple juice showed lower pH and higher amino nitrogen content than with kiwifruit juice on 70 day of fermentation. the total nitrogen contents was the highest on 30 day of fermentation and stable thereafter. Although total numbers of microorganism were increased as fermentation progressed, there were no correlations among the juices or its adding amounts. It was thought that interactions between kinds of natural microflora and the proteases from fruit juices, and other constituents in jeotgal affected total nitrogen content of jeotgal and the growth rate of natural microorganisms. Of the all jeotgals in this study, no coliform was found It is suggested that the preparation of jeotgal with pineapple or kiwifruit juice is effective aspect of safety and quality.

• Research in Plant Disease
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• v.21 no.2
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• pp.67-73
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• 2015

Bacterial blossom blight of kiwifruit (Actinidia deliciosa) caused by Pseudomonas syringae pv. syringae is known to be largely affected by weather conditions during the blooming period. While there have been many studies that investigated scientific relations between weather conditions and the epidemics of bacterial blossom blight of kiwifruit, no forecasting models have been developed thus far. In this study, we collected all the relevant information on the epidemiology of the blossom blight in relation to weather variables, and developed the Pss-KBB Risk Model that is based on the Maryblyt model for the fire blight of apple and pear. Subsequent model validation was conducted using 10 years of ground truth data from kiwifruit orchards in Haenam, Korea. As a result, it was shown that the Pss-KBB Risk Model resulted in better performance in estimating the disease severity compared with other two simple models using either temperature or precipitation information only. Overall, we concluded that by utilizing the Pss-KBB Risk Model and weather forecast information, potential infection risk of the bacterial blossom blight of kiwifruit can be accurately predicted, which will eventually lead kiwifruit growers to utilize the best practices related to spraying chemicals at the most effective time.

• Korean Journal of Microbiology
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• v.52 no.1
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• pp.98-109
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• 2016

The study was aimed to investigate the mixing ratio of kiwi and persimmon juices for the production of good quality wine by Saccharomyces cerevisiae Y28. Firstly, the optimum condition of rapidase treatment for the kiwi and persimmon juices was established, thereafter various mixing ratio (10:0, 9:1, 8:2, 7:3, 6:4, 5:5) of kiwi and persimmon was investigated regarding physiochemical properties and flavor compounds of wine. As the result, the optimum conditions were obtained as 0.3% rapidase for 1 h in kiwi and 0.3% rapidase for 3 h in persimmon. According to higher ration of persimmon, the pH of wines increased from 3.69 to 3.77, while the acidity of wines decreased from 2.07% to 1.51% at 14 days fermentation. The ranges of brix and reducing sugar in wines were decreased which ranges around 9.6 to 8.8 and 6.07 to 6.90 g/L, respectively, after fermentation. Major organic acid in wines were identified as tartaric acid, malic acid, and citric acid. A small amount of free sugar such as sucrose and glucose were detected in wines, but fructose was completely absent. The soluble phenolic contents were decreased that ranges around 1.00 to 1.25 g/L, in contrast, browning degree were increased ranges around 0.212 to 0.412 after fermentation. The major flavor components were identified as ethyl acetate and hydrazine, and 1,1-dimethyl. Importantly, phenylethyl alcohol was detected from the all wines that have a typical rose like flavor. But sensory test results and preference of kiwi-persimmon (7:3) mixing wine was better than the other wines.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.3
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• pp.343-349
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• 2011

The chemical composition and antioxidative activity of kiwifruit varieties in Jeju, such as Jecy Gold (Actinidia chinensis var. 'Jecy Gold'), Halla Gold (A. chinensis var. 'Halla Gold'), Jecy Sweet (A. deliciosa var. 'Jecy Sweet') and Hwabuk 94 (A. deliciosa var. 'Hwabuk 94') were investigated. The crude protein, crude lipid, and pH showed no differences among variety and maturity whereas the moisture contents showed differences among the variety and maturity. Jecy Sweet in mature stage showed the highest values in soluble solid, crude protein, crude lipid, and crude ash. The changes in chemical components of kiwifruit by maturity stage were as follows: during ripening, the glucose and the fructose contents increased considerably with the decrease of sucrose content. Potassium, phosphorus, sodium, and magnesium were estimated as the major minerals in kiwifruit and Jecy Sweet contained the highest amounts of potassium and magnesium. At maturity stage, ascorbic, malic and lactic acid were increased with the decrease of citric acid content. The polyphenol contents were 26.81~56.10 ${\mu}g/g$ and 8.64~26.45 ${\mu}g/g$, respectively, in immature and mature fruits. During ripening, the polyphenol content was decreased. The DPPH radical scavenging activity of methanol extracts were 84.47~89.37% and 43.94~76.96% at 500 ppm, respectively, in immature and mature fruits. The immature varieties of kiwifruit have a high DPPH radical scavenging activity. Therefore the chemical composition and physiological activity of kiwifruit was affected by variety and maturity.

• Korean Journal of Environmental Agriculture
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• v.33 no.4
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• pp.403-408
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• 2014

BACKGROUND: Kiwifruit is a warm-temperate, deciduous fruit tree. It is sensitive to frost or freeze damage during winter. Therefore, the farmers cover kiwifruit trunk with rice straw to preclude freeze injury. This study was conducted to evaluate trunk wraps for protection of freeze injury of kiwifruit (Actinidia deliciosa) vines. METHODS AND RESULTS: The experimental orchard was located in Sacheon (lat. $34^{\circ}56'N$, long. $128^{\circ}03'E$) of Gyeongsangnam-do, South Korea. The vines were 5-6-year-old 'Hayward'. Two wrap materials, rice straw and silver-cushioned mat (reflective foil-coated, plastic-foamed mat, Ganan Industry, Rep. of Korea) were evaluated for their heat-retaining ability. The trunks of kiwifruit vines were wrapped in late December, and the wraps were removed in mid-April the following year (2012/13 and 2013/14). Temperature inner wraps were recorded from January to March in 2013 and 2014 by WatchDog 2450 (Spectrum Technologies, Inc., USA). In 2013, the lowest ambient temperature of January and February was $-10.2^{\circ}C$, $-10.9^{\circ}C$, respectively. The lowest temperature of inner-wrap of silver -cushioned mat was $-6.3^{\circ}C$, $-2.6^{\circ}C$ in January and February, respectively. However, rice straw showed $-9.8^{\circ}C$ and $-9.9^{\circ}C$ in its lowest value of January and February. And also silver cushioned mat appeared to be superior to rice straw in its ability of heat-retaining during night time.

• Food Science and Preservation
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• v.13 no.3
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• pp.369-374
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• 2006

Optimum extraction conditions were investigated for the manufacture of Kiwi liqueur. Eight-weeks of storage was found to be the optimal extraction time for unsliced fruit, but 4 week of storage was found to be optimal extinction time when the fruit was sliced into 4 pieces. There were no changes in the brix, pH and total acidity during extraction. However 24.92 ppm of methanol and acetaldehyde was detected after extracting the liqueur after 8 week extraction time when the fruit was sliced into 4 pieces. The sensory evaluation showed the highest over all acceptability. The Kiwi liqueur was contained 48.90 mg% of total phenolic compounds, 16.7 mg% of vitamin C, 1.77% of malic acid, 1.18% of fructose, 1.12% of glucose and 0.08% of maltose at the optimum extraction conditions. The sensory quality of the Kiwi liqueur was estimated to be best when 0.035% of stevioside, 0.0085% of citric acid and 0.005% of salts were added to the Kiwi liqueur.

• Food Science and Preservation
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• v.17 no.2
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• pp.174-181
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• 2010

The yeast strains used for fermentation are known to influence the qualities of wine. We investigated the effects of fermentation using different yeast strains on the properties of wine produced from 'Hayward' kiwifruit (Actinidia deliciosa). The physicochemical characteristics of wine produced using various yeast strains for fermentation were also analyzed. Saccharomyces cerevisiae Gervin No.5 strain (GVN), S. bayanus Lavin strain EC1118 (EC1118), and S. cerevisiae Red star Davis No. 796 (No.796) are commercial dry yeast strains selected for optimization of fermentation. Although the soluble solid contents of samples fermented by all three yeast strains decreased by a similar extent, the levels of alcohol production differed, particularly during the first week of fermentation. Use of the GVN strain resulted in the highest alcohol concentration (13.8%, v/v), whereas fermentation with No.796 and EC1118 strains yielded alcohol contents of 13.0% and 12.5% (both v/v), respectively. Upon sensory evaluation, GVN-fermented wine had a strong taste and bitterness, with high acid and alcohol contents. Wine fermented using No.796 had a chemical profile similar to that of GVN-fermented product, but the taste remained sweet, consistent with the lower alcohol content. EC1118-fermented wine was soft and sweet in taste, high in flavor, and had a low alcohol content. Total phenolic levels and antioxidant activities in wine fermented by EC1118 were significantly higher than in wines prepared using No.796 or GVN. When previously described characteristics were additionally considered, EC1118 was selected as an optimum strain for further study. In conclusion, fermentation of kiwifruit using different yeast strains yielded wines with distinct characteristics. The yeast strain EC1118 had the most desirable properties, and is considered suitable for kiwifruit fermentation. Valuable attributes of wine fermented by this yeast include overall sensory acceptance, an appropriate level of total phenolics, and good antioxidant activity.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.5
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• pp.603-608
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• 2007

Changes in physicochemical quality and antioxidant activity of kiwifruits by the low dose electron beam irradiated(0, 0.3, 0.6 kGy) were investigated. Fruits were stored at $20^{\circ}C$ for 28 days and evaluated after 0, 1, 2, 3, and 4 week storage. Irradiation did not affect 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities, and pH. Vitamin C contents of irradiated fruits were higher than non-irradiated fruits. Irradiation caused no significant change in total sugar contents and reducing sugar contents. Soluble solid contents in irradiated fruits were higher than non-irradiated fruits for the initial storage period but showed lower increment rate during the storage period. Organic acid contents of irradiated fruit did not show significant effect for the initial and during the storage periods, rate of decline in organic acid content of irradiated fruit were not significantly changed. Results indicated that electron beam irradiation of kiwifruit up to 0.6 kGy is effective in was delayed ripening with no significant changes on antioxidant activity and physicochemical qualify of kiwifruit.