Subunit structure of the vicilin-like globular storage protein of cocoa seeds and the origin of cocoa- and chocolate-specific aroma precursors

Kratzer, Ulrich; Frank, Ronald; Kalbacher, Hubert; Biehl, Böle; Wöstemeyer, Johannes; Voigt, J.

doi:10.1016/j.foodchem.2008.08.017

Cited by 57 publications

(54 citation statements)

References 28 publications

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“…The resulting polypeptide chains would are then susceptible to the action of previously inactive endopeptidases and, eventually, to that of carboxypeptidases (CP) (Abecia-Soria, Pezoa-García & Amaya-Farfan, 2005;Dunaevsky, Sarbakanova & Belozersky, 1989). Among cacao proteins, proline (0.72-1.97 g/100 g of cacao) predominates, and because of its specific conformation it poses many restrictions on the structural aspects of peptides and proteins, and grants particular biological properties to a large range of physiologically important biomolecules (Kalvatchev, Garzaro & Guerra, 1998;Kratzer et al, 2009). In contrast to the plethora of reports regarding Xaa-prolyl dipeptidyl aminopeptidase (XaaPro-DAP2, EC 3.4.14.5) in lactic acid bacteria, there are few reports on this enzyme in plants (Besanova, Kovacs, Psenak & Barth, 1987;Davy et al, 2000;.…”

Section: Introductionmentioning

confidence: 99%

Characterization of protease activities in a crude extract of germinated cacao

Sánchez-Mundo

Bautista-Muñoz

Jaramillo-Flores

2015

CyTA - Journal of Food

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Dynamic light scattering (DLS) was applied to the analysis of the hydrodynamic diameter distribution of proteins in extract of germinated cacao. The interactions among divalent cations and their relation with the activity of Xaa-prolyl dipeptidyl aminopeptidase 2 (Xaa-Pro-DAP2) enzyme were evaluated. The peptidases were isolated by 80% saturation of ammonium sulfate from acetone extract of germinated cacao seeds. The results showed a higher activity of Xaa-Pro-DAP2, besides aminopeptidase (APE) and carboxypeptidase (CP) enzymes. Using DLS analysis the size distribution was found to be multi-modal; however with Cu 2+ and Cd 2+ at 1 mM, the size distribution was found to be monomodal with a hydrodynamic diameter of 158.5 and 119 nm, respectively. The distribution remained constant from 60 to 80°C, suggesting that thermal stability is related to increase in Xaa-Pro-DAP2 activity an lower protein aggregation. APE activity was slightly activated by Co 2+ at 1 mM, whereas no significant effect was observed on CP activity.Keywords: cacao; crude extract; proteases; dynamic light scattering La dispersión dinámica de luz (DLS) fue aplicada para el análisis de la distribución de diámetros hidrodinámicos de proteínas en un extracto germinado de cacao. Se evaluaron las interacciones con cationes divalentes y su relación con la actividad de la enzima Xaa-prolyl dipeptidyl aminopeptidasa 2 (Xaa-Pro-DAP2). Las peptidasas fueron aisladas de los extractos cetónicos de semillas de cacao germinadas, por precipitación con sulfato de amonio al 80% de saturación. Los resultados mostraron una alta actividad de Xaa-Pro-DAP2, además de las enzimas de aminopeptidasa (APE) y carboxipeptidasa (CP). De acuerdo con el análisis DLS, la distribución de tamaños es multi-modal con diámetros hidrodinámicos de 158.5 y 119 nm, respectivamente. La distribución permaneció constante desde 60°C hasta 80°C, sugiriendo estabilidad térmica relacionada con el incremento de la actividad de Xaa-Pro-DAP2 y la baja agregación de proteínas. La actividad de APE fue ligeramente activada por Co 2+ a 1 mM, mientras que no se observó efecto importante sobre la actividad de CP.Palabras clave: cacao; extracto crudo; proteasas; dispersión dinámica de luz

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Section: Introductionmentioning

confidence: 99%

Characterization of protease activities in a crude extract of germinated cacao

Sánchez-Mundo

Bautista-Muñoz

Jaramillo-Flores

2015

CyTA - Journal of Food

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“…The fermentation process breaks down the mucilaginous pulp surrounding the beans and causes cotyledon death (Sanchez et al 1985;Gotsch 1997;Afoakwa et al 2008). This triggers biochemical transformation inside the beans, leading to reduction in bitterness and astringency, development of flavour precursors such as, free amino acids, peptides and sugars (Thompson et al 2007;Kratzer et al 2009;Rodriguez-Campos et al 2011). Cocoa fermentation is influenced by many factors such as type of cocoa, disease, climatic and seasonal differences (Afoakwa 2010), turning, batch size (Lehrian and Patterson 1983), quantity of beans (Mamot and Samarakhody 1984;Wood and Lass 1985) and also pulp pre-conditioning .…”

mentioning

confidence: 99%

Chemical composition and physical quality characteristics of Ghanaian cocoa beans as affected by pulp pre-conditioning and fermentation

et al. 2011

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Investigations were conducted to evaluate the effects of pod storage (as a means of pulp preconditioning) and fermentation on the chemical composition and physical characteristics of Ghanaian cocoa beans. A 4×2 full factorial design with factors as pod storage (0, 7, 14, 21 days) and cocoa treatment (fermented and unfermented) were conducted. Samples were analyzed for their chemical composition (moisture, crude fat, crude protein, ash and carbohydrate content) and mineral content using standard analytical methods. The physical qualities of the beans were analyzed for their proportions of cocoa nibs, shells and germ. Fermentation and increasing pod storage resulted in significant (P<0.05) decreases in ash (3.48-2.92%), protein (21.63-17.62%) and fat (55.21-50.40%) content of the beans while carbohydrate content increased from 15.47% to 24.93% with both treatments. As well, increasing pod storage and fermentation significantly (P<0.05) increased the copper content of the beans from while reductions in Mg and K occurred. Amongst the minerals studied, potassium was the most abundant mineral followed by magnesium, phosphorus and calcium in the fermented cocoa beans. Proportion of cocoa nibs also increased from with increasing pod storage and fermentation whiles reductions in shell content and no appreciable changes in germ proportions were noted.

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“…By the same approach, the other constituents of the mature cocoa vicilinclass globulin were localized in the same precursor region. The results were further corroborated by epitope mapping of polyclonal antibodies raised against the particular polypeptide subunits using 185 overlapping pentadecapeptides covering the whole sequence of the precursor [ 54 ] .…”

Section: Structure Of the Vicilin (7s)-class Globulin Of Cocoa Beansmentioning

confidence: 73%

“…Localization of the cocoa vicilin subunits on their common precursor by N-terminal sequencing was, however, impossible because all these subunits were found to be resistant against Edman degradation, presumably due to N-terminal protection. MALDI-ReTOF-MS analyses of the tryptic fragments of the puri fi ed 47-kDa subunit revealed that this particular subunit was derived from the C-terminal domain of the 66-kDa precursor [ 54 ] . By the same approach, the other constituents of the mature cocoa vicilinclass globulin were localized in the same precursor region.…”

Section: Structure Of the Vicilin (7s)-class Globulin Of Cocoa Beansmentioning

confidence: 99%