• Korean Journal of Food Science and Technology
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• v.37 no.4
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• pp.678-684
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• 2005

Extraction conditions, spectrometric, and sensory properties of pigment extracts from green discolored garlic (GDG) were studied for development of green index to evaluate degree of green discoloration of garlic. GDG pigments were extracted using polar solvents, such as methanol, ethanol, and water. Methanol with 1% HCl resulted in highest extraction of green pigments. Extraction of pigments was affected by temperature, and extracted pigments were partially destroyed at high temperatures. Optimum conditions for extraction of green pigments were $20^{\circ}C$ for 30 min. Because green pigments are unstable at room temperature, and no method has been reported to evaluate degree of green discoloration of garlic, color chart was designed by mixing varying amounts of control and GDG. High correlation was observed between sensory scores and "a" value of color chart samples (y=-3.465x - 11.676) with $R^2$ of 0.993. Green index (GI) was developed based on linear regression equation between sensory scores and "a" values. Sensory panel recognized green discoloration of garlic at $GI{\geq}3.0$. GI developed in this study could be utilized to evaluate degree of green discoloration of garlic during cold storage and distribution of garlic.

• Korean Journal of Food Science and Technology
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• v.35 no.6
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• pp.1007-1016
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• 2003

Garlic was stored at 4, 8, and $12^{\circ}C$ to investigate the development of green discoloration. Green discoloration developed after 7 day of storage ar $4^{\circ}C$, while it developed after 15 day of storage at 8 and $12^{\circ}C$. The effect of maleic hydrazide fertilization on green discoloration of garlic was not observed. Green discoloration of garlic was accelerated by gamma-radiation treatment. The addition of cysteine did not prevent green discoloration, which decreased the commercial value of the garlic due to the presence of white specks on the surface. When 3% ascorbic acid was added to the garlic, green discoloration developed in 6 and 24 hr at room temperature and $4^{\circ}C$, respectively. The tendency of garlic to discolor was also investigated at various storage temperatures. Discolored garlic stored for 30 day at low temperatures was conditioned at $20{\sim}45^{\circ}C$ for 20 day. The green discoloration of garlic conditioned at 20 and $25^{\circ}C$ did not disappear in 20 day, but disappeared in 20 day when conditioned at $30^{\circ}C$. The L, a, and b values of garlic conditioned at 35, 40, and $45^{\circ}C$ for 4 day were similar to those of normal garlic. Conclusively, our results indicated that the best method for suppressing green discoloration was conditioning discolored garlic at $35^{\circ}C$ for 4 day.

• Korean Journal of Food Science and Technology
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• v.36 no.1
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• pp.1-8
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• 2004

Effects of temperature, discoloration, and conditioning on garlic compositions before and after storage were examined. Proximate composition, soluble solids, pH, organic acids, and total sugars of all samples were not significantly different. Sugar contents were sucrose > fructose > glucose, and included such fructooligosaccharide as 1-kestose, 1-nystose, and 1-F-fructosyl nystose. Allicin contents in control, green discolored, and conditioned garlics were 647,9, 613.8, and 648.0 mg%, respectively. Thirty-two flavor compounds were identified by GC/MSD, including 11 sulfide compounds, 5 acids, and 3 aldehydes. Contents of sulfur compounds, including disulfide(di-propenyl), 2-thiophene methanethiol, thiophene, 3,4 dihydro-3-vinyl-1,2-dithiin, and 2-vinyl-4H-1,3-dithin, and water-soluble pectins in low temperature-stored garlic were higher than those in control, and decreased by conditioning or inducing green discoloration. These results show sulfur compounds and water-soluble pectins accumulated in low temperature stored-garlic, and are then converted into green pigments by alliinase in disintegrated garlic tissues.