• Korean journal of food and cookery science
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• v.19 no.4
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• pp.511-520
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• 2003

This study was carried out to determine the effects of various contents of kiwifruit contents on the quality characteristics of mixed polysaccharide gels made from $\kappa$-carrageenan and locust bean gum. The color value, gelling temperature, melting temperature, break down rate, syneresis, rupture properties, TPA properties and sensory properties of mixed polysaccharide gels with various contents of kiwifruit contents were measured. As the kiwifruit contents was increased, the lightness (L), yellowness (b) and greenness (-a) of the mixed polysaccharide gels increased. There were no differences in the color values of gels during storage. As the kiwifruit content was increased, the gelling and melting temperatures of the mixed polysaccharide gels also increased. The mixed polysaccharide gels with high kiwifruit contents were difficult to melt, and it seemed that the addition of kiwifruit to the mixed polysaccharide gels could improve the thennal stability of the gels. The syneresis of the gel increased with increasing storage time, whereas the addition of kiwifruit to the gel resulted in suppression of syneresis. With regard to the rupture properties, stress, energy and strain, they were all decreased with increasing kiwifruit contents. The TPA properties, adhesiveness, hardness and chewiness increased and cohesiveness decreased with increasing kiwifruit contents. The results showed that the gel became tough and adhesive, and could be easily broken under small deformation, with increasing kiwifruit contents. The sensory evaluation showed that the green color, aroma, sweetness and sourness increased with increasing kiwifruit contents. The texture, adhesiveness, springiness and cohesiveness decreased, and brittleness and hardness increased, with increasing kiwifruit contents. The overall acceptability of the gel with 30% kiwifruit content was the highest. Thus, mixed polysaccharide gels made from kiwifruits could be useful, as the addition of kiwifruit to a mixed polysaccharide gel results in a good aroma, taste and stability, despite a lowering of the textural properties.

• Food Science of Animal Resources
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• v.29 no.3
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• pp.317-324
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• 2009

In order to reduce the increased hardness of beef bulgogi due to hydrostatic pressure (HP), kiwifruit (Actinidia chinensis) was applied. To understand the changes of shear force in beef bulgogi with kiwifruit induced by HP, changes in chemical properties of myofibril (Mf) with 10% kiwifruit induced by HP were investigated. From the SDS-PAGE patterns of Mf with 10% kiwifruit, there was an observed increase in the degradation of myosin heavy chain (MHC) by HP (300-500 MPa) to that by 0.1 MPa. This result indicates that HP may enhance enzyme action from a kiwifruit for the degradation of MHC, and the similar phenomenon occurred in the beef bulgogi with kiwifruit induced by HP. The shear force of beef bulgogi without a kiwifruit induced by 400 and 500 MPa significantly increased compared to that by 0.1 MPa (p<0.05). However, in the beef bulgogi with 10% or 20% kiwifruit, the shear force induced by 400 or 500 MPa was similar or slightly lower than that by 0.1 MPa. Consequently, adding kiwifruit to bulgogi could reduce the hardness of HP-induced beef bulgogi due to the enzyme action in the kiwifruit accelerated by HP.

• Korean journal of food and cookery science
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• v.19 no.6
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• pp.758-764
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• 2003

This study was performed to determine the quality characteristics of mixed polysaccharide gels made from kcarrageenan and locust bean gum with various kiwifruit content after freeze-thawing. The syneresis, rupture properties, TPA properties and sensory properties of the mixed polysaccharide gels with various kiwifruit contents after freeze-thawing were measured. The syneresis of the gel with various kiwifruit contents by freeze-thawing was not significantly different, whereas repeating freeze-thawing resulted in remarkable increase in the syneresis of the mixed polysaccharide gels with 5％, 20％ and 40％ kiwifruit. In terms of the rupture properties, the rupture stress, rupture energy and rupture strain decreased with increasing kiwifruit content after freeze-thawing. In terms of the TPA properties, the adhesiveness, hardness and chewiness increased and the cohesiveness decreased with increasing kiwifruit content after freeze-thawing. The rupture properties, springiness and cohesiveness of the gel by freeze-thawing were lower than those of the gel stored in the refrigerator. In contrast, the gumminess, hardness and chewiness of the gel after freeze-thawing were higher than those of the gel stored in the refrigerator. The results showed that the gel became crumbly and tough as a result of freeze-thawing. In the sensory evaluation, He overall acceptability of the gel after freeze-thawing was highest at the 30％ kiwifruit content, and differences in the sensory properties between the gel after freeze-thawing and that stored in the refrigerator were small. Therefore, mixed polysaccharide gels with kiwifruit after freeze-thawing could be useful despite the small decrease in quality.

• The Plant Pathology Journal
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• v.33 no.4
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• pp.351-361
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• 2017

Bacterial canker is the largest limiting factor in the cultivation and production of kiwifruit worldwide. Typical symptoms comprise necrotic spots on leaves, canker and dieback on canes and trunks, twig wilting, and blossom necrosis. Pseudomonas syringae pv. actinidiae (Psa), which is the causal agent of kiwifruit bacterial canker, is divided into four biovars based on multilocus sequence analysis of different genes, additional PCR testing of pathogenic genes (argKtox cluster, cfl, and various effector genes), and biochemical and physiological characterization. Bacterial canker caused by Psa biovar 2 designated Psa2 was detected for the first time on the green-fleshed kiwifruit cultivar Hayward in 1988 and the yellow-fleshed kiwifruit cultivar Hort16A in 2006 in Korea. Psa biovar 3 designated Psa3, responsible for the current global pandemics of kiwifruit bacterial canker, began to appear in Korea in 2011 and caused tremendous economic losses by destroying many vines or orchards of yellow-fleshed kiwifruit cultivars in one or several growing seasons. Bacterial canker epidemics caused by both Psa2 and Psa3 are prevalent in Korea in recent years. In this review, we summarize the symptomatology, etiology, disease cycle, diagnosis, and epidemiology of kiwifruit bacterial canker in Korea.

• The Plant Pathology Journal
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• v.35 no.5
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• pp.473-485
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• 2019

Kiwifruit (Actinidia spp.) is an economically important crop and a bacterial canker disease, caused by Pseudomonas syringae pv. actinidiae (Psa), is the most destructive disease in kiwifruit production. Therefore, prevent and control of the disease is a critical issue in kiwifruit industry worldwide. Unfortunately, there is no reliable control methods have been developed. Recently, interest in disease control using microbial agents is growing. However, kiwifruit microbiota and their roles in the disease control is mainly remaining unknown. In this study, we secured bacterial libraries from kiwifruit ecospheres (rhizosphere, endospere, and phyllosphere) and screened reliable biocontrol strains against Psa. As the results, Streptomyces racemochromogenes W1SF4, Streptomyces sp. W3SF9 and S. parvulus KPB2 were selected as anti-Psa agents from the libraries. The strains showed forcible antibacterial activity as well as exceptional colonization ability on rhizosphere or phyllosphere of kiwifruit. Genome analyses of the strains suggested that the strains may produce several anti-Psa secondary metabolites. Our results will contribute to develop biocontrol strains against the kiwifruit canker pathogen and the disease management strategies.

• Research in Plant Disease
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• v.10 no.4
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• pp.304-309
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• 2004

Girdling of trunk and rainproof installation over kiwifruit (Actinidia deliciosa) trees were turned out to alleviate bacterial blossom blight effectively in kiwifruit orchards. The disease was most effectively prevented by girdling of tree trunks with 20 mm width around April 10 before about 45 days of flowering stage of kiwifruit, but control efficiencies were not affected by height of girdling on trunks above the ground. Use of a transparent polyvinyl film to protect kiwifruit trees from rain was more effective than windbreak net to prevent the disease, irrespective of kinds of rainproof installation. Installation of partial rainproof vinyl cover over kiwifruit trees around March 10 before about 75 days of flowering stage of kiwifruit prevented most of the disease occurrence on kiwifruit. It is expected that girdling of tree trunks and installation of partial rainproof vinyl cover over kiwifruit trees will be practical as environmentally friendly control methods to manage bacterial blossom blight in kiwifruit orchards.

• Food Science and Biotechnology
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• v.16 no.2
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• pp.294-298
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• 2007

The actinidin (EC 3.4.22. 14) found in kiwifruit is a cysteine protease. In order to obtain the actinidin gene from the Chinese wild kiwifruit, primers were designed on the basis of the actinidin gene of Actinidia deliciosa, the New Zealand kiwifruit. The 1.2 kb DNA fragment was acquired from the total RNAs of Chinese wild kiwifruit via reverse transcription polymerase chain reaction (RT-PCR), and its DNA sequence was analyzed. Its sequence was determined to share 98.4% homology with the actinidin gene of A. deliciosa. In order to verity the actinidin gene isolated from the Chinese wild kiwifruit in Escherichia coli, the mature gene was amplified via PCR and expressed in E. coli under the control of the T7lac promoter. The actinidin was expressed in E. coli as inclusion bodies, which were solubilized with urea and refolded. The protease activity of the refolded protein was approximately twice as high as that of E. coli BL2l (DE3).

• Food Science of Animal Resources
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• v.30 no.4
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• pp.669-673
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• 2010

The purpose of this study was to evaluate kiwifruit as a tenderizer by its effects in improving the quality of various beef parts. Basic data are provided for development of standard recipes for convenient cooking in foodservice. The optimum temperature of the crude proteolytic enzymes in the kiwifruit was determined to be $65^{\circ}C$. The substrate specificity of the enzymes was higher in beef than in pork, chicken, or duck. The enzymes had their greatest effects on chuck and rib parts, and had lower effects on loin, breast, and round parts, in that order. As the amount of kiwifruit extract increased, the moisture content of the cooked beef also increased. The addition of 10% kiwifruit improved the sensory quality of the cooked beef. In particular, the texture scores of cooked beef samples treated with 10% and 15% kiwifruit extract were significantly higher than the other samples (p<0.001), and juiciness and overall acceptability scores were also highest. In summary, 10% kiwifruit extract is deemed an appropriate addition to improve.

• The Plant Pathology Journal
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• v.32 no.6
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• pp.537-544
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• 2016

We developed a model, termed D-PSA-K, to estimate the accumulated potential damage on kiwifruit canes caused by bacterial canker during the growing and overwintering seasons. The model consisted of three parts including estimation of the amount of necrotic lesion in a non-frozen environment, the rate of necrosis increase in a freezing environment during the overwintering season, and the amount of necrotic lesion on kiwifruit canes caused by bacterial canker during the overwintering and growing seasons. We evaluated the model's accuracy by comparing the observed maximum disease incidence on kiwifruit canes against the damage estimated using weather and disease data collected at Wando during 1994-1997 and at Seogwipo during 2014-2015. For the Hayward cultivar, D-PSA-K estimated the accumulated damage as approximately nine times the observed maximum disease incidence. For the Hort16A cultivar, the accumulated damage estimated by D-PSA-K was high when the observed disease incidence was high. D-PSA-K could assist kiwifruit growers in selecting optimal sites for kiwifruit cultivation and establishing improved production plans by predicting the loss in kiwifruit production due to bacterial canker, using past weather or future climate change data.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.94.1-94
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• 2003

Control of bacterial blossom blight of kiwifruit (Actinidia deliciosa) has been mainly depended on chemical control. Recently cultural practices such as trunk girdling of kiwifruit trees and rainproof installation over kiwifruit trees also were conducted as the alternative control practices. Each of the control methods was evaluated for the best practicing conditions for the control of bacterial blossom blight of kiwifruit. Among the various combinations of spray times and spray periods, optimum spray program of antibiotics was turned out to be 3 times with intervals of 10 days from early May during the flowering season of kiwifruits. Optimum periods of trunk girdling of kiwifruit trees were from late March to late April. Trunk girdling with 20-30 mm wide showed best control efficacies on bacterial blossom blight, irrespective of the heights of girdling on trunks of kiwifruit trees. Optimum period of rainproof installation over kiwifruit trees was from March till late April, irrespective of installation methods.