Various Temperature of Vacuum and Conventional Roasting on Color Alteration and Polyphenols Content of Cocoa Powder

Abstract

This study has the objective to found out the temperature and raosting time of cocoa powder in order to gain color, aroma and taste favored by the panelist and has high polyphenol content. The roasting time in this research has been determined 35 min, and roasting temperature of 80, 90, 100, 110, 120, 130, 140 and 150 °C with vacuum and conventional system. From those temperatures ranges, we would take the three best levels according to organoleptic test result. The three selected temperatures would be tested for changing in polyphenol content during roasting process. Color alteration would be physically analyzed using color reader (PCE-RGB). However, phenol total content was analyzed using colorimetric method of Folin-Ciocalteu. Result of this study showed that color alteration percentage (RGB model analysis) during conventional roasting is higher (43%) compared with vacuum roasting system (2%). Subsequently, organoleptic test result showed that from roasting temperatures between 80 °C and 150 °C, cocoa powder favored by the panelist were those that was treated in temperature 100 °C, 110 °C and 120 °C. Other results indicated that vacuum roasting implementation could increase polyphenol content. While vacuum roasting of 60.8 cm Hg in 120 °C with roasting time of 25 min has obtained 10.57% total phenolic, or increasing as much as 1.22%.