Discrimination of Cocoa Bean Origin by Chocolate Polyphenol Chromatographic Analysis and Chemometrics

A General Strategy for Food Traceability and Authentication Based on Assembly-Tunable Fluorescence Sensor Arrays

Food traceability and authentication systems play an important role in ensuring food quality and safety. Current techniques mainly rely on direct measurement by instrumental analysis, which is usually designed for one or a group of specific foods, not available for various food categories. To develop a general strategy for food identification and discrimination, a novel method based on fluorescence sensor arrays is proposed, composed of supramolecular assemblies regulated by non-covalent interactions as an information conversion system. The stimuli-responsiveness and tunability of supramolecular assemblies provided an excellent platform for interacting with various molecules in different foods. In this work, five sensor arrays constructed by supramolecular assemblies composed of pyrene derivatives and perylene derivatives are designed and prepared. Assembly behavior and sensing mechanisms are investigated systematically by spectroscopy techniques. The traceability and authentication effects on several kinds of food from different origins or grades are evaluated and verified by linear discriminant analysis (LDA). It is confirmed that the cross-reactive signals from different sensor units encompassing all molecular interactions can generate a unique fingerprint pattern for each food and can be used for traceability and authentication toward universal food categories with 100% accuracy.

Dark-Chocolate-Coated BRS Clara Raisins: Phenolic Composition and Sensory Attributes

Dark chocolate dragée confectionary was made with BRS Clara raisins pre-treated with extra virgin olive oil (EVOO). The evaluation of the changes in the phenolic composition (flavonols, hydrocinnamic acid derivatives (HCADs), stilbenes and flavan-3-ol monomers, dimers, and proanthocyanidins (PAs)) resulting from the covering process showed that the chocolate coating was responsible for an increase in the concentrations of flavan-3-ols and PAs when compared to just the raisins. For the flavonols and HCADs, a reduction in the total concentration of compounds was observed when comparing the dragées to the raisins. Furthermore, there was a strong influence of chocolate in the qualitative profile with the emergence of new compounds (quercetin-3-pentoside, kampfterol-3-rutinoside, p-coumaric acid, and caffeoyl-aspartate). The combination of these ingredients (raisins and chocolate) resulted in a dark chocolate coated raisin (DC) with good sensory acceptance and a more complex phenolic composition that may positively contribute to its functional quality.

UHPLC-MS Characterization, and Antioxidant and Nutritional Analysis of Cocoa Waste Flours from the Peruvian Amazon

Cocoa (Theobroma cacao) is a food product used worldwide and a key raw material for chocolate manufacturing. Cocoa possesses bioactive compounds such as methylxanthines, flavonoids, procyanidins, and related molecules with medicinal or health-promoting properties. Cocoa shell and pod husk have been proposed as a by-product with several interesting bioactivities, and the gummy residue or glue (a sticky, gluey by-product known as “mucilage” in Spanish) is used to produce liquors and is eaten as a food in Perú. However, little is known about the chemical composition and bioactivity of flours made from Peruvian cocoa ecotype wastes such as those from the vein and pod husk of the fruits. This study aimed to characterize the in vitro antioxidant properties and nutritional values of flours made from the waste from a special ecotype of cocoa (CCN-51). The chemical fingerprinting was performed using UHPLC–HESI orbitrap mass spectrometry and allowed the detection of 51 compounds. GC-FID was used for the determination of individual fatty acid contents, and the antioxidant activity was assessed by several assays (DPPH, FRAP, and ABTS). The flours obtained were composed of a good amount of dietary fiber, carbohydrates, and minerals, as well as several bioactive polyphenolic compounds, fatty acids, and amino acids with nutraceutical properties, making the flours a rich and promising food as well as a good source for the preparation of functional foods or nutraceuticals.

Characterization and Classification of Cocoa Bean Shells from Different Regions of Venezuela Using HPLC-PDA-MS/MS and Spectrophotometric Techniques Coupled to Chemometric Analysis

The cocoa bean shell (CBS) is one of the main cocoa byproducts with a prospective to be used as a functional food ingredient due to its nutritional and sensory properties. This study aims to define the chemical fingerprint of CBSs obtained from cocoa beans of diverse cultivars and collected in different geographical areas of Venezuela assessed using high-performance liquid chromatography coupled to photodiodes array and mass spectrometry (HPLC-PDA-MS/MS) and spectrophotometric assays combined with multivariate analysis for classification purposes. The study provides a comprehensive fingerprint and quantitative data for 39 compounds, including methylxanthines and several polyphenols, such as flavan-3-ols, procyanidins, and N-phenylpropenoyl amino acids. Several key cocoa markers, such as theobromine, epicatechin, quercetin-3-O-glucoside, procyanidin_A pentoside_3, and N-coumaroyl-l-aspartate_2, were found suitable for the classification of CBS according to their cultivar and origin. Despite the screening methods required a previous purification of the sample, both methodologies appear to be suitable for the classification of CBS with a high correlation between datasets. Finally, preliminary findings on the identification of potential contributors for the radical scavenging activity of CBS were also accomplished to support the valorization of this byproduct as a bioactive ingredient in the production of functional foods.

Fine cocoa beans production: Tracking aroma precursors through a comprehensive analysis of flavor attributes formation

The fine flavor cocoa (FFC) market offers cocoa farmers better monetary and nonmonetary benefits than the bulk market. In this work, during cocoa fermentation, flavor formation was studied at different fermentation times based on sensory profiles, volatile compound contents and untargeted metabolomics. It was observed that chocolate quality is influenced by fermentation time. Thus, at 72 h, the sensory profiles showed no outstanding attributes, while at 96 h, the global quality presented a stronger influence of fine attributes, such as fruitiness, florality, spices and nuttiness. Finally, at 120/144 h, these FFC features diminished. Metabolomic fingerprint of cocoa beans (related to peptides, sugars, amino acids, and phenolic compounds) and the volatile fingerprint of chocolate showed a change according to the fermentation time. This allowed the proposal of 96 h as the optimal fermentation time to produce FFC beans. Additionally, 20 volatiles and 48 discriminating metabolites were defined as potential quality biomarkers.

Antioxidant Activities and Volatile Flavor Components of Selected Single-Origin and Blend Chocolates

The biological activity of chocolates gains more and more attention of consumers. Its antioxidant properties depend, among other factors, mainly on the origin of cocoa and the characteristics that this origin gives to the final product. Therefore, the aim of the study was to measure and compare the total content of polyphenols, antioxidant activity, and key odorants of commercial chocolates made from blend cocoa with single-origin ones. The highest content of polyphenols was found in 90% blend cocoa chocolate and single-origin samples, while the lowest content was exhibited by 100% chocolate from blend cocoa mass. The highest antioxidant activity measured by 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) and ferric reducing antioxidant power (FRAP) assays was observed in the sample of chocolate with 90% cocoa solids from blend mass, followed by single-origin chocolates. A high positive correlation between ABTS assay and the total polyphenol and phenolic acids' content, as well as among the total content of polyphenols, flavonoids, and phenolic acids was found. Mineral composition analysis showed that dark chocolate is a valuable source of some elements, especially Mg, Fe, and Zn. Potentially toxic elements were not detected or below permitted limits. Moreover, it was noticed that the main volatile compound in all tested samples was acetic acid, but pyrazines were considered the most important group of chocolate odorants.

Thermal properties and volatile compounds profile of commercial dark-chocolates from different genotypes of cocoa beans (Theobroma cacao L.) from Latin America

There is a growing interest in the identification of chemometric markers that allow the distinction and authentication of dark-chocolates according to their cocoa geographical origin and/or genotype. However, samples derived from Latin American cocoa, including specimens from North and South America, have not been studied in this context. An exploration of the melting behavior, fat composition, bioactive content, and volatile profile of commercial darkchocolates was conducted to identify possible patterns related to the genotype and/or origin of cocoa from Latin America. The melting properties were evaluated by DSC and related to fat content and fatty acids profile. Total polyphenol, anthocyanin, methylxanthine, and catechin content were analyzed. Finally, the volatile compounds were extracted and identified by HS-SPME/GC-MS and were analyzed through Principal Component Analysis (PCA) and the Hierarchical Cluster Analysis Heatmap (HCA Heatmap). The fatty acids profile showed a relationship with the melting properties of dark chocolate. The samples exhibited two glass-transition temperatures (T_g) at ≈19 °C and ≈25.5 °C, possibly related to traces of unstable polymorphic forms of monounsaturated triacylglycerides. The analysis of bioactive compounds demonstrated great variability among samples independent of the cocoa origin, genotype, and content. The PCA and HCA Heatmaps allowed discriminating against the chocolates in relation to the cocoa origin and genotype. Compounds like tetramethylpyrazine, trimethylpyrazine, benzaldehyde, and furfural could be considered as dark-chocolate aroma markers derived from Latin American cocoas (North American region). The 2-phenylethyl alcohol, 2-methylpropanoic acid, 2,3-butanediol, 2-nonanone, and limonene for derived from South America. And the 2-phenylethyl acetate, 3-methyl-butanal, and cinnamaldehyde could allow to distinguishing between regional genotypes.

Fast analysis of polyphenols and alkaloids in cocoa-based products by ultra-high performance liquid chromatography and Orbitrap high resolution mass spectrometry (UHPLC-Q-Orbitrap-MS/MS)

The cocoa varieties Criollo, Forastero and Trinitario, which have different organoleptic properties, quite often are mixed together in cocoa-based products. The objective of this work was to develop a rapid method for the simultaneous determination of polyphenols (n = 35) and alkaloids (n = 2) in cocoa-based products by using the high throughput advantages provided by the Q Exactive Hybrid Quadrupole-Orbitrap Mass Spectrometer (HRMS). The proposed procedure was optimized and validated in terms of selectivity and specificity (mass accuracy <5 ppm), sensitivity (instrumental limit of detection from 15 to 30 fg), linearity (r² > 0.990), accuracy (recovery range from 89.1 to 112.4%) and precision (relative standard deviation <10%). The method was applied to 80 cocoa-based samples. Alkaloids represented on average the 57.7% of assayed compounds. Flavanols and procyanidins were the most abundant polyphenols being quantified in a range between 261 and 668 mg/kg and from 127 to 405 mg/g, respectively. Mass equivalents but structural isomers bioflavonoids were characterized by using the HRMS-Orbitrap methodology here developed.