Assessing the flavor of cocoa liquor and chocolate through instrumental and sensory analysis: a critical review

Exploring the Impact of Fermentation Time and Climate on Quality of Cocoa Bean-Derived Chocolate: Sensorial Profile and Volatilome Analysis

The market for fine-flavor cocoa provides significant benefits to farmers. However, identifying the sensory qualities of chocolate under specific environmental conditions and measuring how its chemical compounds may be affected by climate differences and postharvesting practices remain a challenge. This study investigates how fermentation time and agroclimatic conditions in Colombia's fine cocoa-producing region of Arauca influence the sensory profile and volatile compound composition (volatilome) of chocolate derived from cocoa beans. Sensory evaluation was conducted on chocolates fermented for 48, 72, 96, and 120 h, revealing that fermentation time critically affects the development of fine-flavor attributes, particularly fruitiness and nuttiness. The optimal fermentation period to enhance these attributes was identified at 96 h, a duration consistently associated with peak fruitiness under all studied climatic conditions. Analysis of 44 volatile compounds identified several key aroma markers, such as acetoin, 1-methoxy-2-propyl acetate, and various pyrazines, which correlate with desirable sensory attributes. These compounds exhibited varying amounts depending on fermentation time and specific agroclimatic conditions, with a 96 h fermentation yielding chocolates with a higher quantity of volatile compounds associated with preferred attributes. Our findings highlight the complex interaction between fermentation processes and agroclimatic factors in determining cocoa quality, providing new insights into optimizing the flavor profiles of chocolate.

Odor and taste characteristics, transduction mechanism, and perceptual interaction in fermented foods: a review

Fermentation is a critical technological process for flavor development in fermented foods. The combination of odor and taste, known as flavor, is crucial in enhancing people's perception and psychology toward fermented foods, thereby increasing their acceptance among consumers. This review summarized the determination and key flavor compound screening methods in fermented foods and analyzed the flavor perception, perceptual interactions, and evaluation methods. The flavor compounds in fermented foods could be separated, purified, and identified by instrument techniques, and a molecular sensory science approach could identify the key flavor compounds. How flavor compounds bind to their respective receptors determines flavor perception, which is influenced by their perceptual interactions, including odor-odor, taste-taste, and odor-taste. Evaluation methods of flavor perception mainly include human sensory evaluation, electronic sensors and biosensors, and neuroimaging techniques. Among them, the biosensor-based evaluation methods could facilitate the investigation of the flavor transduction mechanism and the neuroimaging technique could explain the brain's signals that relate to the perception of flavor and how they compare to signals from other senses. This review aims to elucidate the flavor profile of fermented foods and highlight the significance of comprehending the interactions between various flavor compounds, thus improving the healthiness and sensory attributes.

Sensory attributes of fine flavor cocoa beans and chocolate: A systematic literature review

Fine flavor cocoa (FFC) is known for its unique flavor and aroma characteristics, which vary by region. However, a comprehensive overview of the common sensory attributes used to describe FFC beans and chocolate is lacking. Therefore, a systematic review was conducted to analyze existing literature and identify the most commonly used sensory attributes to describe FFC beans and chocolate. A systematic search of the Web of Science and Scopus databases was conducted in May 2023, and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed to ensure transparency and reproducibility. This review summarizes the origins of cocoa and explores their unique flavor profiles, encompassing caramel, fruity, floral, malty, nutty, and spicy notes. Although some origins may exhibit similar unique flavors, they are often described using more specific terms. Another main finding is that although differences in sensory attributes are anticipated at each production stage, discrepancies also arise between liquor and chocolate. Interestingly, fine chocolate as the final product does not consistently retain the distinctive flavors found in the liquor. These findings emphasize the need for precise descriptors in sensory evaluation to capture flavor profiles of each origin. As such, the exploration of attributes from bean to bar holds the potential to empower FFC farmers and chocolate producers to effectively maintain quality control.

Characterization of the differences in aroma-active compounds in strong-flavor Baijiu induced by bioaugmented Daqu using metabolomics and sensomics approaches

Bioaugmenting Daqu is an effective strategy to improve the quality of Baijiu, but its effect on overall flavor profiles and aroma-active compounds is unknown. Here, 168 volatiles were determined from fresh strong-flavor Baijiu (SFB) and bioaugmented Daqu increased their diversity and altered the flavor characteristics. Among 49 odorants identified by aroma extraction dilution analysis, 29 aroma-active compounds had odor activity values ≥1, of which 18, 8, and 3 components exhibited the highest content in the SFB fermented by fortified-, space- and conventional-Daqu, respectively. The contribution of increasing ethyl hexanoate and decreasing ethyl lactate of fresh SFB by bioaugmented Daqu was confirmed, and their content changed from 4650 and 1890 mg/L (conventional-SFB) to 6680 and 1760 mg/L (fortified-SFB) and 6130 and 1710 mg/L (space-SFB). Meanwhile, the discriminators among different samples were determined by multivariate statistical analysis. These findings are beneficial for the optimization and improvement of Baijiu aroma.

Interactions between Beer Compounds and Human Salivary Proteins: Insights toward Astringency and Bitterness Perception

Beer is one of the most consumed beverages worldwide with unique organoleptic properties. Bitterness and astringency are well-known key features and, when perceived with high intensity, could lead to beer rejection. Most studies on beer astringency and bitterness use sensory assays and fail to study the molecular events that occur inside the oral cavity responsible for those perceptions. This work focused on deepening this knowledge based on the interaction of salivary proteins (SP) and beer phenolic compounds (PCs) and their effect toward these two sensory attributes. The astringency and bitterness of four different beers were assessed by a sensory panel and were coupled to the study of the SP changes and PC profile characterization of beers. The human SP content was measured before (basal) and after each beer intake using HPLC analysis. The beers’ PC content and profile were determined using Folin–Ciocalteu and LC-MS spectrometry, respectively. The results revealed a positive correlation between PCs and astringency and bitterness and a negative correlation between SP changes and these taste modalities. Overall, the results revealed that beers with higher PC content (AAL and IPA) are more astringent and bitter than beers with a lower PC content (HL and SBO). The correlation results suggested that an increase in whole SP content, under stimulation, should decrease astringency and bitterness perception. No correlation was found between the changes in specific families of SP and astringency and bitterness perception.

Key Aromatic Volatile Compounds from Roasted Cocoa Beans, Cocoa Liquor, and Chocolate

The characteristic aromas at each stage of chocolate processing change in quantity and quality depending on the cocoa variety, the chemical composition of the beans, the specific protein storage content, and the polysaccharides and polyphenols determining the type and quantity of the precursors formed during the fermentation and drying process, leading to the formation of specific chocolate aromas in the subsequent roasting and conching processes. Bean aroma is frequently profiled, identified, and semiquantified by headspace solid-phase microextraction combined with gas chromatography-mass spectrometry (HS-SPMEGC-MS) and by gas chromatography olfactometry (GC-O). In general, the flavors generated in chocolate processing include fruity, floral, chocolate, woody, caramel, earthy, and undesirable notes. Each processing stage contributes to or depletes the aroma compounds that may be desirable or undesirable, as discussed in this report.

The effect of cocoa alkalization on the non-volatile and volatile mood-enhancing compounds

Alkalization is a process to improve color, dispersibility and flavor of cocoa powder but is likely to have a negative effect on the phytochemicals. Hereto, the impact of alkalization degree (none, medium and high) on the potential mood-enhancing compounds corresponding to the four levels of the mood pyramid model (flavanols, methylxanthines, biogenic amines and orosensory properties) was investigated. The phytochemical content, analyzed via UPLC-HRMS, showed reduction of specific potential mood-enhancing compounds upon alkalization, implying a decrease in bitterness and astringency. Moreover, volatile compounds analysis via HS-SPME-GC-MS indicated that alkalization reduced the levels of volatile compounds, responsible for acidity, fruity, floral and cocoa aromas. With respect to the orosensory properties, the cocoa powder palatability was suggested to be increased due to reduced acidity, bitterness, and astringency, while the desired volatile compounds were reduced. However, sensorial analysis is required to link the volatile results with the overall effect on the flavor perception.

Optimizing consumer acceptability of 100% chocolate through roasting treatments and effects on bitterness and other important sensory characteristics

Chocolate is a highly appreciated food around the world which is rich in polyphenols but usually sweetened to mask inherent bitterness and astringency. Here we aim to determine how roast time and temperature in cacao roasting affect bitterness intensity and consumer liking of chocolate. We have also determined the relationship between consumer liking and perceived bitterness, astringency, sourness, sweetness, and cocoa intensity. Unroasted cacao from three different origins was roasted according to a designed experiment into a total of 27 treatments which were evaluated for overall liking and sensory attribute intensities by 145 chocolate consumers. We demonstrate that bitterness, sourness and astringency of 100% chocolate can be reduced through optimizing roasting temperature and time. Reduction of bitterness, sourness and astringency were significantly correlated with increased acceptability of the unsweetened chocolate samples. Aside from roasting, cacao origin including base levels of bitterness, astringency, and sourness should also be considered when optimizing consumer acceptability. Perceived cocoa flavor intensity, being highly positively correlated to liking, is likely to also be an important consideration for raw material selection. As for optimal roast profiles, for the cacao origins in our study, more intense roasting conditions such as 20 min at 171 °C, 80 min at 135 °C, and 54 min at 151 °C, all led to the most acceptable unsweetened chocolate. Conversely, for the purposes of optimizing consumer acceptability, our data do not support the use of raw or lightly roasted cacao, such as 0 min at 24 °C, 11 min at 105 °C, or 55 min at 64 °C.

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Bitterness and astringency in chocolate can be reduced through optimizing roasting.

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Bitterness, sourness, and astringency are negatively correlated to consumer liking.

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Sweetness and cocoa intensity are correlated with increased liking of chocolate.

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Generally, more intense roasting conditions lead to more acceptable chocolate.

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Use of raw or lightly roasted cacao leads to less acceptable chocolate.