Cocoa beans are a rich source of polyphenolic compounds with anti-inflammatory and enzyme inhibitory activities which could aid in obesity management. Cocoa processing steps like hot air roasting have been shown to reduce the total polyphenol content (TPC) by more than 50%. Superheated steam roasting has been reported to retain higher TPC levels in cocoa as compared to hot air roasting. Changes in TPC might not be indicative of changes in bioactivity of these cocoas. Some studies have shown that the digestive enzyme inhibitory and anti-inflammatory properties of cocoa remain intact under certain processing conditions irrespective of TPC loss. This suggested that the composition of polyphenols rather than the total amount may be a more important determinant of bioactivity. Hot air roasting at three temperatures (150C, 175C, 200C) was compared to superheated steam roasting in terms of its impact on the polyphenol composition, bioactivity, and flavor development in cocoa. Cocoa beans roasted using these two methods were analyzed for TPC using Folin-Ciocalteau assay. The inhibitory effect of cocoas against Phospholipase A<sub>2</sub> was determined. TPC of hot air and superheated steam roasted beans was not significantly different (α=0.05). However, the IC50 of cocoa extracts obtained from superheated steam roasted beans at 175C against Phospholipase A<sub>2 </sub>was about 62% lower (α=0.05) than that of extracts from hot air roasted beans, indicating higher bioactivity of superheated steam roasted beans. The volatile compound profiles of the cocoa beans roasted by both methods were compared using GC-MS. Cocoa beans roasted for 30 min at 150C with superheated steam exhibited 30-50% higher levels of desirable volatile compounds like pyrazines as compared to hot air roasted beans. The procyanidin composition of beans prepared by these different roasting methods is being compared using LC-MS to offer insight into the higher bioactivity of superheated steam roasted cocoa.

Impact of superheated steam roasting on the polyphenol composition, bioactivity and volatile compound profile of cocoa beans

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