• Korean Journal of Environmental Agriculture
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• v.28 no.4
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• pp.347-355
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• 2009

Grape fruit quality can be deteriorated with leaf chlorosis caused by magnesium (Mg) deficiency during fruit coloring season in several grapevine varieties. The occurrence of leaf chlorosis and soil Mg states for four grapevine varieties (Campbell Early, Muscat bailey A (MBA), Sheridan, and Kyoho) in the vineyards of Gyeongsan and Youngcheon were surveyed. The relationships between leaf chlorosis and fruit qualities were also investigated. Leaf chlorosis was more widely found and the symptom was stronger in Campbell Early in comparison to the other varieties. Sugar content and Hunter values (L, a, b) of grape fruit were significantly lower in the trees of chlorosis when compare to healthy grapevine trees. Soil Mg contents in the vineyards where leaf chlorosis was found were lower than the optimum level for grapevine. Also Mg content in the petioles of chlorosis grapevines was significantly lower than healthy grapevines. Application of Mg through foliar spray and soil fertigation was quite effective in correcting deficiencies of Mg in grapevine. Proper management of soil Mg availability and K/Mg ratio is strongly recommended to prevent Mg deficiency in grapevine.

• Korean Journal of Food Science and Technology
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• v.41 no.5
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• pp.528-535
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• 2009

Three domestic varieties of red grapes were utilized for the fermentation of wines, including Campbell, Muscat Bailey A (MBA), and Sheridan. The grapes were treated by four different methods before fermentation, which included conventional fermentation for red wine, fermentation with skin-removed grapes, fermentation with grapes and addition of removed skins, and fermentation with grape juice. Three different grape varieties with four different treatments did not show any differences in terms of $^{\circ}Bx$ and alcohol changes during fermentation. However, the L value of the MBA wine was lower and darker than the L values of wines prepared from Campbell and Sheridan grapes. The wines prepared from grapes with the addition of removed skins were darker and had 30% higher polyphenol concentrations than those of wines made from grapes by the conventional method, regardless of the grape varieties. Sensory evaluations of dry-type wines demonstrated that quality was higher for those made from Campbell and MBA grapes with the addition of removed skins than for wines made by the conventional method. Whereas for sweet-type wines, the wine that was made from the skin-removed grapes (Sheridan) was more favorable than that made by the conventional method.

• Food Science and Preservation
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• v.16 no.4
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• pp.463-471
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• 2009

We evaluated the physicochemical properties and sensory characteristics of, bioactive compounds in grape juice prepared from different grape varieties grown in Korea, such as Campbell Early, Steuben, and Muscat Bailey A (MBA), with respect to heating time (30, 45, or 60 min) and temperature ($60^{\circ}C$, $70^{\circ}C$, $80^{\circ}C$, or $90^{\circ}C$). We found that long heating time and high temperature, especially treatment at $90^{\circ}C$ for 60 min, significantly affected the physicochemical properties and bioactive compound levels of grape juice. Among the grape juice varieties, Campbell Early juice had the highest level of bioactive compounds. Sensory evaluation scores showed that heating of musts at $80^{\circ}C$ for 30 min was associated with the most preferred sensory attributes for Campbell Early grape juice, whereas the most preferred juices from Steuben and MBA grapes were from musts heated at $70^{\circ}C$ for 60 min and at $70^{\circ}C$ for 30 min, respectively. The bioactive compounds of juice from the three grape varieties were optimal using the above-mentioned processing times and temperatures.

• Food Science and Preservation
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• v.15 no.6
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• pp.791-795
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• 2008

In order to establish the method to prepare and use the sulfur dioxide gas generating agent in low temperature storage of grape fruits, the $SO_2$ generation capacity from various sulfite compounds was investigated, and the method to regulate $SO_2$ gas generation and to detect the gas was developed. The conidial germination and mycelium growth of Botrytis cinerea which causes gray mold disease during grape fruit storage was completely inhibited at the $SO_2$ gas concentration of 400 ppm and 3200 ppm, respectively. Sodium hydrosulfite generated the most amount of $SO_2$ gas among the investigated 5 different sulfite or bisulfite compounds. By adjusting the number of pinholes on packaging film of the compound or by adding pH adjusting agent, e.g. citric acid or phosphates, it was possible to regulate the amount and duration of $SO_2$ gas generation from the compound. Because malachite green was quantitatively discolored by $SO_2$ gas, the solution or impregnated paper with the compound could be practically utilized as a indicator detecting $SO_2$ gas. Finally, when Muscat Bailey A grape was stored at low temperature with $SO_2$ gas generating agent, the disease incidence was reduced after storage.