마이크로웨이브 Roasting 중 Cocoa Bean의 이화학적 성분 변화

Changes in Chemical Components of Cocoa Beans during Microwave Roasting

마이크로웨이브를 이용한 cocoa bean의 roasting을 수행하여 pH, 적정산도, 색의 변화, 갈변도, 유기산의 변화, 당조성의 변화를 조사하였다. pH는 roasting 온도와 시간에 따른 변화가 거의 없었고 적정산도 역시 roasting 여부에 따른 차이는 있었으나 roasting 온도와 시간에 따른 차이는 거의 없었다. 색의 변화, 갈변도, 당조성은 roasting 온도와 시간에 따라 변화하였으나 대조군과 비교하였을 때 변화의 폭이 작았고 이로부터 Maillard reaction이 대조군에 비해 덜 일어난 것으로 판단되었다. 유기산은 raw bean에 비해 roasting을 한 모든 시료에서 증가하였으며 그 정도는 유기산의 종류에 따라 차이가 있었다.

The physicochemical properties of microwave-roasted cocoa beans such as color, degree of browning, pH, titrable acidity, organic acid, and sugar content were determined and compared with those of conventionally-roasted beans. Microwave roasting temperatures were 110, 120, 130, 140 and $150^{\circ}C$. Roasting times were 0, 5, 10, 20, and 30 min. Conventional roasting was done at $120^{\circ}C$ and 15 min as a reference. The pH had no relations with roasting temperature or roasting time. As roasting time and roasting temperature were increased, the titrable acidity values of roasted cocoa beans became higher than those of raw bean. But there were no differences among each condition. Color, degree of browning, and sugar content changed as roasting temperature and roasting time increased. The organic acid content of roasted beans increased but the degree of increase was different from organic acid to organic acid. Roasting by microwaves resulted in higher inner temperature of samples than the surface temperature. To increase roasting efficiency, the other heat sources should be used together with microwave.