Changes in free amino acid, peptide-N, sugar and pyrazine concentration during cocoa fermentation

✍ Scribed by Hashim, Puziah; Selamat, Jinap; Syed Muhammad, Sharifah Kharidah; Ali, Asbi

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 115 KB
• Volume: 78
• Category: Article
• ISSN: 0022-5142
• DOI: 10.1002/(sici)1097-0010(199812)78:4<535::aid-jsfa151>3.0.co;2-6

✦ Synopsis

The free amino acids, peptide-N, reducing sugars (the Ñavour precursors in cocoa) and pyrazine proÐles of mix hybrid cocoa beans fermented in a rotary drum reactor were monitored over a period of 6 days. As fermentation progressed, the acidic free amino acid concentration decreased signiÐcantly (P \ 0É05) by 15%, whereas total, hydrophobic and other free amino acids increased signiÐcantly by 148, 280 and 127%, respectively. In terms of hydrophobic/acidic/other free amino acids ratio, the unfermented cocoa beans contained 30% : 18% : 52%, whereas those of fermented beans contained 46% : 6% : 48%. Concentrations of peptide-N and total reducing sugars were signiÐcantly (P \ 0É05) increased by 55 and 208%, respectively during fermentation ; however, those of sucrose and total sugars decreased signiÐcantly (P \ 0É05) by 89% and 75%, respectively. The unfermented cocoa beans contained no pyrazine ; however during fermentation, the 2-methyl-, 2,5-dimethyl-, 2,6-dimethyl-, 2,3-dimethyl-, trimethyl-and tetramethylpyrazine were formed. The two principle pyrazines were tetramethyl-(2099É30 lg kg~1) and trimethylpyrazine (692É00 lg kg~1).