• Applied Biological Chemistry
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• v.38 no.2
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• pp.141-146
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• 1995

Changes of physicochemical properties of citron juice prepared by two different extraction methods, rotary-crushing and belt-pressing method, were investigated during the storage at $5^{\circ}C$ and $-20^{\circ}C$. Temperature drop of citron juice extracted by belt-pressing method was faster than that of citron juice prepared by rotary-crushing method and its freezing point was $0.8{\sim}0.9^{\circ}C$. During the storage, pH of stored citron juice with rotary-crushing method was increased up to 3.5 after 6 months storage while that of citron juice extracted by belt-pressing method was not changed significantly during the same storage time. Acidity of rotary-crushed citron juice was reduced a little more than that of belt-pressed citron juice during the storage. However, changes of soluble solid content were influenced largely by the storage temperature than by the extraction method. Contents of formol nitrogen and vitamin C were reduced remarkably in all of stored citron juice and $92{\sim}82%$ of farmol nitrogen and $72{\sim}43%$ of vitamin C were remained after 6 months of storage. Among the changes of color value, L values were reduced in the whole stored citron juice and a and b value had a different change pattern respectively according to the extraction and storage temperature. Changes in the content of both amino acid and fatty acid compositions was also observed after same storage period. Especially, in the case of change of fatty acid composition, content of linoleic acid and linolenic acid were reduced after 6 months storage, while those of palmitic acid, stearic acid and oleic acid were increased.