Inactivation of microorganisms and enzymes in juices by supercritical carbon dioxide method with continuous flow system
2005
Tsuji, M.(Yamanashi-ken. Industrial Technology Center, Kofu (Japan)) | Sato, Y. | Komiyama, Y.
Inactivation of microorganisms and pectinesterase (PE) in fruit juices by supercritical CO2 was investigated. For this experiment, an original device equipped with a mixer for mixing CO2 into juices and a zigzag steel pipe (phi 10 cm x 12 m) for keeping CO2 in a supercritical state (40 deg C, 100 kg/cm(2)) was constructed. Four kinds of fruit juice (orange, grapefruit, grape and apple) were treated with this device. When the juices were mixed with CO2 at a rotation speed of 400 rpm, the viable cell count of each juice was reduced to 1/10 of the initial number. In addition, in the orange juice treated at a rotation speed of 800 rpm, viable cell and yeast counts were remarkably reduced to 1/100 and 1/1000 of the initial values, respectively. Residual activities of PE in each juice treated by supercritical CO2 decreased by values varying from 0(grape) to 34% (apple) when treated at a rotation speed of 400rpm. The sugar, organic acid and free amino acid contents of orange juice treated by supercritical CO2 at a rotation speed of 800 rpm were approximately equal to those of non-treated juice. When treated orange juice was stored at 5 deg C, the quality of juice was maintained at a high level for 21 days.
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