Unraveling roasting-induced cocoa flavor changes : a comparison between conventional and microwave-assisted roasting

Roasting plays a critical role in the production process of cocoa liquor and chocolate. Besides desirable changes in color and moisture content, flavor development is one of the most important reasons to roast cocoa. By means of a convective and/or conductive heat transfer, cocoa and nutty flavors are generated within the roasted beans, while the bitter taste and astringent mouthfeel are reduced. Roasting via a convective and/or conductive heat transfer is easy applicable and therefore also commonly used. However, these roasting techniques are lately questioned due to the long roasting times needed to sufficiently heat the core of the beans. Therefore, a growing interest is encountered to search for optimal roasting conditions and/or alternative roasting techniques, with the development of a desirable flavor profile as primary criterion. Within this research a comparison was made between conventional and microwave-assisted roasting with the main focus on flavor. The impact of varying roasting conditions (i.e. time, temperature and power input) on the flavor profile of cocoa liquor and chocolate was investigated via both instrumental (i.e. HS-SPME-GC-MS, UPLC-HRMS) and sensory (i.e. trained panel, consumer panel) techniques. Results confirmed that microwave-assisted roasting has the potential to be used as alternative technique

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

The performance of appropriate instrumental and/or sensory analyses is essential to gain insights into the flavor profile of cocoa products. This three-part review is compiled of an overview of the most commonly used instrumental techniques to study cocoa liquor and chocolate flavor, their perception by a trained panel and the potential relationship between them. Each part is the result of a thorough literature study, principally focusing on the assumptions, features and limitations of these techniques. Reviewing of the literature revealed that cocoa matrix effects and methodology restraints were not always considered when instrumentally analyzing cocoa flavor. With respect to sensory analyses, various studies lacked reporting of accomplished trainings and performance of panelists. Moreover, a discrepancy was noticed in the descriptive flavor lexicon employed. Finally, when linking instrumental and sensory data, linear modeling is regularly applied, which might not always be appropriate. This review paper addresses the challenges associated with flavor assessment, intending to incite researchers to critically study cocoa flavor and apply standardized protocols and procedures

Microwave roasting as an alternative to convection roasting : sensory analysis and physical characterization of dark chocolate

Roasting cocoa beans by means of microwave radiations seems to be a potential alternative to convection roasting, but little is known about the impact of this method on the perceived flavor profile of the chocolate. Therefore, this research focused on revealing the flavor perception of chocolate produced with microwave roasted cocoa beans assessed by both a trained panel and chocolate consumers. Samples of 70% dark chocolate produced from cocoa beans microwave roasted at 600 W for 35 min were compared with samples of 70% dark chocolate produced from cocoa beans convectively roasted at 130 degrees C for 30 min. Non-significant differences (p > 0.05) in the measured physical properties, such as color, hardness, melting, and flow behavior, showed that chocolate produced from microwave roasted cocoa beans can exhibit the same physical qualities as convection roasted chocolate. Moreover, combined discriminative triangle tests, with 27 judgements in total, performed by a trained panel, showed that each type of chocolate exhibited distinctive characteristics (d'-value = 1.62). Regarding the perceived flavor, "cocoa aroma" was cited as significantly higher for the chocolate produced from microwave roasted cocoa beans (n = 112) compared to chocolate produced from convection roasted cocoa beans (n = 100) by consumers. Both preference and willingness to buy were higher, though insignificant at a 5% level, for the microwave roasted chocolate. A final potential benefit (studied in this research) of microwave roasting cocoa beans is the reduced energy consumption, which was estimated at 75%. Taking all these results together, the microwave roasting of cocoa is shown to be a promising alternative to convection roasting

Antioxidant activity and quality attributes of white chocolate incorporated with Cinnamomum burmannii Blume essential oil

White chocolate is often considered as an unhealthy product with low phenolic content and antioxidant activity since it does not contain cocoa liquor. In this study, investigation on the phytochemical composition of cinnamon essential oil as well as its potential use to improve the antioxidant activity of white chocolate were carried out. The effect of the essential oil incorporation on the quality attributes of white chocolate was also examined. The results show that cinnamon essential oil was rich in cinnamaldehyde and exhibited antioxidant activity. The incorporation of cinnamon essential oil at a level of 0.1% (w/w) increased the antioxidant activity of the white chocolate more than twofold without significant effect on its hardness, melting properties and colour. However, a slight alteration on the flow behaviour of the white chocolate was observed. This study clearly shows that natural cinnamon essential oil could be an alternative to synthetic additives in foods to improve their antioxidant activity

Roasting-induced changes in cocoa beans with respect to the mood pyramid

The mood pyramid of cocoa, which was previously proposed as a new concept, consists of four levels (flavan-3-ols, methylxanthines, minor compounds and orosensory properties). Roasting is a crucial process for flavor development in cocoa but is likely to have a negative impact on the phytochemicals. We investigated the effect of roasting time (10-50 min) and temperature (110-160 degrees C) on the potential mood-enhancing compounds corresponding to the distinct mood pyramid levels. Phytochemicals were analyzed using UPLC-HRMS, while the flavor was mapped via aroma (HS-SPME-GC-MS) and generic descriptive analysis (trained panel). Results revealed that roasting at 130 degrees C for 30 min did not significantly affect the levels of epicatechin, procyanidin B2 and theobromine, while salsolinol significantly increased. Moreover, bitterness and astringency were reduced and the desired cocoa flavor was developed. Thus, through selection of appropriate roasting time and temperature conditions phytochemicals of interest could be retained without comprising the flavor

Impact of alkalization conditions on the phytochemical content of cocoa powder and the aroma of cocoa drinks

Alkalization is an important process in cocoa powder production that affects color and flavor. In this study, the impact of alkalization temperature (60, 70, 80, 90, 100 degrees C), NaOH concentration (0.59, 1.17, 2.34, 3.59% w/w of cocoa powder) and alkalization time (1 and 10 min) on the physicochemical properties (pH, color) and phytochemical profile (theobromine, caffeine, epicatechin, catechin) of cocoa powder were investigated, while the aroma was studied on the corresponding cocoa drinks. High-performance liquid chromatography coupled to an ultra-violet detector (HPLC-UV) was used for screening the non-volatiles and headspace solid - phase microextraction - gas chromatography - mass spectrometry (HS-SPME-GC-MS) for the aromatic compounds. Major changes of the cocoa properties occurred during the first minute of alkalization. Increase of temperature and alkali concentration generally reduced the levels of epicatechin and the lightness (L*), while the pH of the cocoa powder was affected by changing the alkali concentration. On the other hand, the reddish (a*) and yellowish (b*) color component values and theobromine levels were not significantly affected by varying temperature and alkali concentration. A higher temperature did not affect the concentration of the volatile compounds, while a decrease in certain chemical classes was observed by increasing the alkali concentration

A multipronged flavor comparison of Ecuadorian CCN51 and Nacional cocoa cultivars

Two cocoa types are predominantly being cultivated in Ecuador, the highly appreciated fine Nacional and the high-yielding and disease-resistant CCN51, classified as bulk. With the introduction of foreign germplasm in Ecuador and the international demand for high-quality Nacional cocoa, the present study aims to characterize and compare the flavor profile of Nacional hybrids (EET103, EET559, EET576 and EET577) and CCN51, and to assess the effect of the genotype. The fermented dried beans were processed into liquor and their sensory properties, volatile composition and odor fingerprint were analyzed by trained panelists, headspace–solid phase microextraction gas chromatography–mass spectrometry (HS–SPME–GC–MS), and GC electronic nose (e-nose), respectively, combined with multivariate statistics. Seventy volatiles were identified and semi-quantified, among them, 16 and 14 volatiles conferring fruity and floral aroma notes, respectively. CCN51 was mainly characterized by undesirable odor-active volatiles, whereas the EET cultivars contained the highest concentration of most fruity and floral volatiles, with differences in between EET cultivars. Sensory data highlighted organoleptic differences between the fine and bulk liquors, i.e. the fruity and acid EET flavor strongly differed from the bitter, astringent and off-flavor attributes of CCN51. Principal component analysis (PCA) discriminated firstly between fine and bulk, and secondly between EET identity. Partial least squares analysis identified possible correlations between sensory attributes and volatile compounds. Besides, e-nose proved its usefulness for rapid assessment of the liquors’ sensory profile. The results provide a foundation for understanding the genotype’s contribution to and the compositional basis of Ecuadorian fine and bulk cocoa flavor.status: publishe

A multipronged flavor comparison of Ecuadorian CCN51 and Nacional cocoa cultivars

Two cocoa types are predominantly being cultivated in Ecuador, the highly appreciated fine Nacional and the high-yielding and disease-resistant CCN51, classified as bulk. With the introduction of foreign germplasm in Ecuador and the international demand for high-quality Nacional cocoa, the present study aims to characterize and compare the flavor profile of Nacional hybrids (EET103, EET559, EET576 and EET577) and CCN51, and to assess the effect of the genotype. The fermented dried beans were processed into liquor and their sensory properties, volatile composition and odor fingerprint were analyzed by trained panelists, headspace-solid phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS), and GC electronic nose (e-nose), respectively, combined with multivariate statistics. Seventy volatiles were identified and semi-quantified, among them, 16 and 14 volatiles conferring fruity and floral aroma notes, respectively. CCN51 was mainly characterized by undesirable odor-active volatiles, whereas the EET cultivars contained the highest concentration of most fruity and floral volatiles, with differences in between EET cultivars. Sensory data highlighted organoleptic differences between the fine and bulk liquors, i.e. the fruity and acid EET flavor strongly differed from the bitter, astringent and off-flavor attributes of CCN51. Principal component analysis (PCA) discriminated firstly between fine and bulk, and secondly between EET identity. Partial least squares analysis identified possible correlations between sensory attributes and volatile compounds. Besides, e-nose proved its usefulness for rapid assessment of the liquors' sensory profile. The results provide a foundation for understanding the genotype's contribution to and the compositional basis of Ecuadorian fine and bulk cocoa flavor