Effect of Enzymatic Hydrolysis Combined with High Temperature Processing on the Flavor of Cocoa Powder

The study aimed to evaluate the effect of enzymatic hydrolysis and high temperature on the flavor of cocoa. First, the effect of five proteases on free amino acids in enzymatic hydrolysate were investigated. Subsequently, headspace gas chromatography mass spectrometry (HS-GC-MS), odor activity value (OAV) and sensory valuation were applied to explore the influence of high temperature (90~180 ℃) on the volatile compounds of cocoa. The results showed that amino acids content increased by 1.4~5.0 times after enzymatic hydrolysis, and compared with the control sample untreated by enzyme (12 volatiles), five combinatorial treated samples promoted volatiles, which were identified 29 (asparaginase), 31 (acid protease), 29 (flavourzyme), 30 (bromelain), 32 (papain) volatiles, respectively. More heterocyclic compounds with nutty and creamy aroma were generated when the temperature was up to 150 ℃, and the sensory evaluation indicated that flavor protease hydrolysis combined with 150 ℃ heating for 2 h presented the best flavor characteristics. Meanwhile, partial least squares (PLS) analysis model based on OAV and sensory evaluation showed that enzymatic hydrolysis combined with high temperature gave cocoa more flower, fruit and milk aroma while still maintained chocolate flavor, confirming its contribution to flavor promotion.