Abstract:

The differently processed cocoa beans such as unfermented, fermented and roasted cocoa beans were anzlyzed for
total polyphenol contents, total flavonoid contents, chroma, and flavors by HPLC, color difference meter and electronic nose.
The results showed that total polyphenol and flavonoid contents in unroasted unfermented cocoa beans were significantly
higher than those of the unroasted fermented ones. By roasting at 105–145 ℃ for 30 min, total polyphenol content ranged
from 419.5 to 129.8 mg/10 g in unfermented cocoa beans and ranged from 182.53 to 86.25 mg/10 g in fermented cocoa
beans. Total flavonoid content was in the range of 77.8–16.8 mg/10 g for unfermented cocoa beans, and 34.7–7.0 mg/10 g
for fermented cocoa beans. By roasting at 125 ℃ for 20–40 min, total polyphenol content ranged 353.74–289.45 mg/10 g in
unfermented cocoa beans and ranged from 152.08 to 123.55 mg/10 g in fermented cocoa beans. Total flavonoids were found
to be between 42.86 mg/10 g and 32.20 mg/10 g for unfermented cocoa beans, and 25.12–21.14 mg/10 g for fermented
cocoa beans. The content of gallic acid was significant changed by roasting temperature in the range of 105–145 ℃ for
30 min. The range of chromaticity values in cocoa beans were in the range of 40.0–47.0 for L*, and 5.0–6.8 for a*, and 4.0–8.5
for b*. Unfermented cocoa beans were different from fermented cocoa beans by sensory quality and flavor. By roasting at
105–145 ℃ for 30 min, cocoa beans presented a large difference in electronic sensory evaluation.

Key words: cocoa beans from Hainan, roast, polyphenols, flavonoids, flavor