Effect of processing conditions on physical-chemical and structural characteristics of cacao (Theobroma cacao L.)

Abstract

Three cocoa bean (Theobroma cacao L.) fermentations were carried out with a duration of 6 days simulating the box technique, with the aim to observe the biochemical changes and their effect on chemical and physicochemical characteristics, the temperature at the last fermentation stage was modified 50 °C for control, 40 °C (F40), and 60 °C (F60). Therefore, there were changes in pH into the cotyledons with 5.3, 5.7, and 5.0 for control, F40 and F60, respectively, which developed variations in the chemistry and structure of the cocoa bean. A proximal analysis was carried out (moisture, ash, proteins, lipids, and carbohydrates) as well as the determination of Free Amino Nitrogen (FAN), Phenolic Compounds (PC), Antioxidant Activity, Enzyme Activity, and Image structural Analysis. According to a Pearson Correlation Analysis and a Principal Component Analysis (PCA), the most significant response variables on day 6 of fermentation are FAN, with 11.41 ± 0.31, 10.38 ± 0.23, 12.50 ± 0.65 g / kg obtained for control, F40 and F60; and phenolic compounds with 42.00 ± 0.96, 66.43 ± 0.07 and 22.41 ± 0.96 mg Gallic Acid / g cocoa for control, F40 and F60 respectively. Changes in the behavior of enzymatic activity related to FAN and PC were also observed since proteases and amylases decreased their activity in F60, while they increased in lipases, inverse to the F40 treatments, compared with control. The degree of fermentation was determined with the cracking of the cotyledons as a parameter where 39% is observed for control, 32% for F40, and 49% for F60, showing that low and over fermentation temperatures cause variations in enzyme behavior, metabolite production and structure of cacao bean.