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pp.797-803
건조방법이 복분자 분말의 갈변 및 흡습 특성에 미치는 영향을 조사하기 위하여, 신선 복분자를 천일, 적외선 및 동결 건조한 다음 분쇄하고 이 분말의 색도와 수분활성도 () 0.11-0.90 범위에서 평형수분함량(EMC)을 각각 측정하였다. 갈변지표인 값과 값은 동결 건조한 복분자 분말이 다른 방법으로 건조한 분말보다 높고 낮은 값을 나타내었고, 황색도인 값은 동결 건조 분말에서 가장 높은 수준을 보였다. EMC는 의 증가와 함께 증가하는 경향을
The effects of drying methods on the browning and moisture sorption characteristics of Rubus coreanus were studied. Fruits were steamed for 5 min at , dried by sun drying, infrared drying, or freeze drying, and powdered to a size of 20 mesh. Color values were measured and equilibrium moisture contents (EMC) were determined at , over a range of water activity () from 0.11 to 0.90. The browning indices and values were higher and lower, respectively, in freeze-dried Rubus coreanus compared with other samples. The value was greatest in freeze-dried Rubus coreanus. EMC tended to increase with increasing values, and a particularly sharp increment was observed above 0.75 . The EMC of freeze-dried Rubus coreanus was significantly higher compared with the EMC of sun-dried and infrared-dried fruit at constant aw. The moisture sorption isotherms showed a typical sigmoid shape, and the Halsey, Kuhn, and Oswin models were the best fits for the sun-dried, infrared-dried, and freeze-dried powder isotherms, respectively. With respect to monolayer moisture content, the Guggenheim-Anderson-Boer (GAB) equation showed that the various drying methods yielded very different results, with monolayer moisture contents of 0.005 g dry solid in infrared-dried and 0.019 g dry solid in sun- and freeze-dried powders, respectively. These results indicate that the drying method affects the browning and moisture sorption characteristics of Rubus coreanus.
