Comparison of nine common coffee extraction methods: instrumental and sensory analysis

The preparation of a cup of coffee may vary between countries, cultures and individuals. Here, an analysis of nine different extraction methods is presented regarding analytical and sensory aspects for four espressi and five lunghi. This comprised espresso and lungo from a semi-automatic coffee machine, espresso and lungo from a fully automatic coffee machine, espresso from a single-serve capsule system, mocha made with a percolator, lungo prepared with French Press extraction, filter coffee and lungo extracted with a Bayreuth coffee machine. Analytical measurements included headspace analysis with HS SPME GC/MS, acidity (pH), titratable acidity, content of fatty acids, total solids, refractive indices (expressed in °Brix), caffeine and chlorogenic acids content with HPLC. Sensory analysis included visual, aroma, flavor and textural attributes as well as aftersensation. The technical differences in the extraction methods led to a higher concentration of the respective quantities in the espressi than in the lunghi. Regarding the contents per cup of coffee, the lunghi generally had a higher content than the espressi. The extraction efficiency of the respective compounds was mainly driven by their solubility in water. A higher amount of water, as in the extraction of a lungo, generally led to higher extraction efficiency. Comparing analytical data with sensory profiles, the following positive correlations were found total solids ↔ texture/body, headspace intensity ↔ aroma intensity, concentrations of caffeine/chlorogenic acids ↔ bitterness and astringenc

Following cocoa beans to chocolate : The search for intrinsic characteristics

The assessment of cocoa’s natural characteristics can be used to link cocoa beans and chocolate. Establishing a link between the raw material and the finished product is complicated not only because of complex characteristics of the supply chain but also because of the technology involved in the production and the composition of the ingredients. One may wonder why a link between raw material and the finished product is relevant. Nowadays, more and more attention is given to sustainability, pushing the cocoa manufacturers to take into account social, economic and environmental issues while producing. As a consequence, the demand in cocoa-importing countries for certified sustainable cocoa has increased considerably and is expected to show continuous growth over the next years. Moreover, more consumers have become increasingly aware of the existence of different cocoa varieties and their origins, and the market of specialty chocolates such as chocolates with single-origin bean, organic and fair-trade chocolate has largely grown in the last decades. The aforementioned trends in the chocolate sector and the growing concerns regarding food quality and safety led to a growing effort in the implementation of traceability systems. This trend has facilitated the need to verify and guarantee the origin of the cocoa beans along with the cocoa-chocolate supply chain and to establish a link between raw material and the finished product. For these reasons, the main objective of this thesis is to discover cocoa beans’ traits in terms of the botanical and geographical origin carried along the cocoa–chocolate supply chain. Compositional characteristics of botanical and geographical origin of cocoa beans after fermentation and drying, after manufacturing chocolate and during chocolate consumption were analysed. This information can be used to derive a link between raw material and the finished product, which in turn can be used to support traceability systems. To investigate the cocoa-chocolate botanical and geographical origin information, markers related to intrinsic properties were used: volatile and non-volatile characteristics. The latter include small non-volatile compounds, elemental composition, isotope ratios and hyperspectral profiles. The reflectance of the cocoa beans origin along the supply chain is investigated starting from the consumer perspective with the analysis of the nosespace (NS) profile of consumers eating chocolates manufactured from beans of different origins. Moving back along the supply chain, the possibility to extract botanical and geographical traits from both volatile and non-volatile profiles is further tested in chocolates available in the supermarket. To extract more information cocoa beans and corresponding chocolates to extract raw material markers in a finished product analysing their volatile, elemental and isotopic compositional traits. Finally, the raw material analysis completes the assessment of cocoa beans origin traits along the supply chain. Regarding the botanical traits carried along the supply chain, the volatile intrinsic characteristic showed the potential to track and trace raw material origin along the entire supply chain. It was possible to identify typical volatile compounds of the raw material in chocolate bar and chocolate during chocolate consumption. VOCs were found to be the most robust markers that were carried from cocoa beans to consumer products, revealing a constant shift/change between the raw materials and the finished products. Potential markers (i.e. acetic acid) were detected to reveal botanical traits from raw material to chocolate to chocolate consumption. However, in general, it was difficult to identify specific individual markers carried along the supply chain highlighting the fact that the botanical traits are more related to a general volatile pattern. The same is valid for the small non-volatile compounds analysed in chocolate. Interestingly, when analysing the non-volatile compositional traits, the botanical trend explained the samples overlapping according to the geographical origin. This occurred despite the impact of the processing step or the ingredient added on the origin expression. The brand influence was confirmed also when the elemental and stable isotope fingerprints of cocoa beans and chocolates were compared. Stable isotope signatures appear less sufficient for tracing the characteristics of cocoa in chocolate products without previously estimating the isotope signature of all the ingredients reducing the possibility to use them as origin markers. Our results support the botanical traits’ influence as highlighted for the volatile and non-volatile profiles of chocolate and the volatile NS profile of chocolate during consumption and it indicates that intrinsic features of the beans are retained after processing and even during consumption. Regarding the geographical origin traits carried along the supply chain, volatile compounds reflected the geographical trait from cocoa beans to consumers. Within the non-volatile compositional traits Cr, Fe and Cd appeared to be distinct geographical markers although they are susceptible to environmental contamination. However, along the supply chain, the geographical traits were hidden by other factors. During chocolate consumption, geographical discrimination was possible only within each botanical group. In chocolate, the geographical information was evidently contained by the volatile compounds. However, we highlighted an interference with botanical and brand traits. This was particularly clear when analysing the small non-volatile compounds. Only when reducing the influence of the brands, it becomes clear that the samples are spread according to the three origins. Regarding the raw material, the impact of the geographical origin on the volatile and hyperspectral profile of cocoa beans is influenced by the variability related to differences in fermentation and drying within a country and between countries. Despite these interferences, a similar trend both in cocoa beans and in chocolates is visible for certain compounds, making them usable as cocoa-chocolate linking markers. The evidence from this study suggests that volatile and non-volatile compositional traits of cocoa and cocoa products can be used to verify and/or follow origin traits along the supply chain and link raw material and the finished product. However, more research is needed on how to reduce botanical and geographical interaction and improve the product characterisation along the supply chain. Within the compositional traits that were measured, the volatile profile is the most suitable for gathering information at the beginning of the production and at different stages in the supply chain

Ionization effects on the partitioning behavior of food and beverage aroma compounds between aqueous phases and air and organic matrices

Aroma compounds in the Flavornet database were screened for ionizable functional groups such as carboxylic acids, aliphatic and aromatic amines, phenols, alcohols, and thiols. Of the 738 aroma compounds listed in this database, 101 molecules have ionizable moieties with estimated monomeric aqueous pK~a~ values ranging between 1.75 and 10.97. pH dependent effective air/water partitioning coefficients (K~aw,eff~) and n-octanol/water partitioning coefficients (D~ow~) were estimated for all ionizable aroma compounds over the pH range from 0 to 14. The ionizable aroma compounds display a broad range of K~aw,eff~ (1.8×10^-23^ to 6.1 atm M^-1^) and log D~ow~ (-6.2 to +7.2 units) values. For many aroma compounds, pH dependent ionization will have a significant effect on the K~aw,eff~ and D~ow~, leading to variations in these physico-chemical properties by up to 11 orders of magnitude over the composite pH range of common foods and beverages. Changes in food and beverage pH affect not only the relative contributions of neutral versus charged forms of ionizable aroma compounds (which directly affects analyte volatility and olfactory reception), but also partitioning between freely dissolved and sorbed forms of the analyte in solution (which indirectly affects analyte volatility)

Effect of sugar and acid composition, aroma release and assessment conditions on aroma enhancement by taste in model wines

Context: When congruent taste and retronasal aroma are perceived simultaneously, aroma can be enhanced by taste. Different explanations have been proposed: (i) physico-chemical interactions between tastants and aroma compounds, inducing a change of the aroma stimulus before it reaches the receptors, (ii) a contextual bias during sensory tests (dumping), when at least one relevant attribute is not proposed to the panelists to assess a product, (iii) a misunderstanding of the conceptual difference between aroma and taste, or (iv) a perceptual incapability of panelists to distinguish between two congruent percepts. This study was undertaken to better understand aroma enhancement by taste in model wines containing different sugar and acid concentrations but the same volatile composition. Method: We used a twofold approach: model wine retronasal aroma intensity was assessed twice by trained panelists. During the first session, panelists only assessed aroma intensity. During the second session, taste intensity was assessed before aroma intensity, to reduce dumping effects. In-mouth release of volatile compounds was measured by nosespace analysis with the same panelists. Results: Acid concentration influenced aroma compounds release, but it did not impact perceived aroma intensity. Increasing sugar concentration delayed ethyl octanoate (EO) release after swallowing. When taste was not assessed, perceived aroma intensity was not explained by aroma compounds release, but it increased with sugar concentration, probably because of a dumping effect. When taste was assessed, aroma intensity also depended on sugar concentration, but it was significantly correlated to the time of release of EO. Our hypothesis is that when taste declined, late aroma was more easily individualized, and thus assessed with a higher intensity. This entails that panelists focused on aroma to individualize it from taste. We concluded that trained panelists understand the conceptual difference between taste and aroma, but are not completely able to distinguish congruent and simultaneous taste and aroma percepts

Coupling of temporal-check-all-that-apply and nose-space analysis to investigate the in vivo flavor perception of extra virgin olive oil and carriers’ impact

The perceived quality of extra virgin olive oil (EVOO) arises from the multisensory integration of multimodal stimuli, primarily driven by non-volatile and volatile organic compounds (VOCs). Given that EVOO is frequently consumed in combination with other foods, cross-modal interactions, encompassing both internal and external elements, play a crucial role in shaping its sensory perception. A more realistic representation of EVOO perception can be achieved by considering these cross-modal effects and their temporal dynamics. This study employed dynamic sensory and instrumental techniques to investigate the product-related mechanisms that influence EVOO flavor perception. Ten trained panelists (mean age = 41.5 years; 50% female) evaluated two EVOO samples under two consumption conditions: alone and accompanied by a solid carrier (bread or chickpeas). Temporal Check-All-That-Apply (TCATA) and nose-space analysis using Proton-Transfer-Reaction Time-of-Flight Mass Spectrometry (PTR-ToF-MS) were conducted simultaneously. Sensory descriptors and mass spectral peaks were analyzed through temporal curve indices (Area Under the Curve, Maximum Citation/Concentration, Time to Maximum), which were then used to construct multi-dimensional sensory and VOC release maps. Findings revealed that the composition and texture of the food carriers had a greater influence on temporal flavor perception than the variability in VOCs released by the different EVOO samples. These results underscore the importance of considering cross-modal sensory interactions when predicting EVOO flavor perception. The carriers modulated both the perception and VOC release, with effects dependent on their specific composition and texture. This methodological approach enabled a deeper understanding of the dynamic relationship between VOC release and EVOO sensory experienc

Drivers of the in-mouth interaction between lupin protein isolate and selected aroma compounds: a proton transfer reaction–mass spectrometry and dynamic time intensity analysis

Plant proteins often carry off-notes, necessitating customized aroma addition. In vitro studies revealed protein-aroma binding, limiting release during consumption. This study employs in vivo nose space proton transfer reaction-time-of-flight-mass spectrometry and dynamic sensory evaluation (time intensity) to explore in-mouth interactions. In a lupin protein-based aqueous system, a sensory evaluation of a trained "green" attribute was conducted simultaneously with aroma release of hexanal, nonanal, and 2-nonanone during consumption. Results demonstrated that enlarging aldehyde chains and relocating the keto group reduced maximum perceived intensity (Imax_R) by 71.92 and 72.25%. Protein addition decreased Imax_R by 30.91, 36.84, and 72.41%, indicating protein-aroma interactions. Sensory findings revealed a perceived intensity that was lower upon protein addition. Aroma lingering correlated with aroma compounds' volatility and hydrophobicity, with nonanal exhibiting the longest persistence. In vitro mucin addition increased aroma binding four to 12-fold. Combining PTR-ToF-MS and time intensity elucidated crucial food behavior, i.e., protein-aroma interactions, that are pivotal for food desig

Influence of chewing rate and food composition on in vivo aroma release and perception of composite foods

This study investigated the effects of chewing rate and food composition on in vivo aroma release and perception of composite foods. Bread or sponge cake paired with varying sugar content and viscosity strawberry jams, spiked with citral and limonene, were examined. In-nose release was characterized using Proton-Transfer-Reaction-Time-of-Flight-Mass-Spectrometry (PTR-ToF-MS). Simultaneously, Time-Intensity (TI) profiling assessed citrus aroma perception (n = 8, triplicate) while fast and slow chewing protocols were applied (fast: 1.33 chews/s; slow 0.66 chews/s; each for 25 s). Chewing rate did not significantly impact the area under the curve and maximum intensity of in vivo citral and limonene release and citrus aroma perception. Faster chewing rates significantly decreased the time to reach maximum intensity of aroma release (p < 0.05) and citrus aroma perception (p < 0.001). Faster chewing rates probably accelerated structural breakdown, inducing an earlier aroma release and perception without affecting aroma intensity. Adding carriers to jams significantly (p < 0.05) increased aroma release, while perceived citrus aroma intensity significantly (p < 0.05) decreased regardless of chewing rate. In conclusion, chewing rate affects the temporality of in vivo aroma release and perception without affecting its intensity, and carrier addition increases in vivo aroma release while diminishing aroma perceptio

Influence of Fat Replacers on the Rheological, Tribological, and Aroma Release Properties of Reduced-Fat Emulsions

Reduced-fat food products can help manage diet-related health issues, but consumers often link them with poor sensory qualities. Thus, high-quality fat replacers are necessary to develop appealing reduced-fat products. A full-fat model emulsion was reduced in fat by replacing fat with either water, lactose, corn dextrin (CD), inulin, polydextrose, or microparticulated whey protein (MWP) as fat replacers. The effect of fat reduction and replacement, as well as the suitability of different types of fat replacers, were determined by analyzing fat droplet size distribution, composition, rheological and tribological properties, and the dynamic aroma release of six aroma compounds prevalent in cheese and other dairy products. None of the formulations revealed a considerable effect on droplet size distribution. MWP strongly increased the Kokini oral shear stress and viscosity, while CD exhibited similar values to the full-fat emulsion. All four fat replacers improved the lubricity of the reduced-fat samples. Butane-2,3-dione and 3-methylbutanoic acid were less affected by the changes in the formulation than butanoic acid, heptan-2-one, ethyl butanoate, and nonan-2-one. The aroma releases of the emulsions comprising MWP and CD were most similar to that of the full-fat emulsion. Therefore, CD was identified as a promising fat replacer for reduced-fat emulsions

Correlating instrumental and sensory analyses of flavour

The relationship between in vivo captured data from an atmospheric pressure chemical ionisation mass spectrometer (APCI-MS) and sensory/psychophysical analyses was investigated. The stimuli used were mainly single volatiles under gas phase control or calibration by development of different olfactometry methods. Gas phase concentration retronasal (via the mouth to the nasal cavity) and orthonasal (via the nostrils) thresholds were determined for a trained panel of 13 individuals. Four volatiles were used with different sensory/physico-chemical properties and an adapted staircase method was employed to measure the individual thresholds. The data showed good repeatability over short durations of one week and also longer ones of eight months. It was used to test the hypothesis that thresholds varied between people due to differences in their in-nose concentration as measured or estimated by the APCI-MS. The analysis did not support this theory but relationships between orthonasal and retronasal thresholds were shown, in which the latter were -50 times lower than the former. Threshold determination of a larger group of 20 individuals revealed clusters of individuals. Methods of producing square edged pulses of aroma compound in the gas phase were developed using a modified chromatograph autosampler with a gas flow of 5 mL. min 1 and pulse rate of 0.6 secs. A trained panel of 23 individuals performed two types of sensory test using pulsed and constant olfactometer outputs of isoamyl acetate. The original intention was to reveal whether pulsed odorants were perceived as the same as or different to constant concentration. Initial experiments yielded results that were difficult to interpret, although the nature of the results was clarified when simultaneous breath by breath analysis techniques were employed. Here it was shown that each individual in different repetitions disrupted the olfactometer output pattern in unpredictable ways. This pattern disruption was measured in two instrumental configurations, as either volatiles in an exhalation or volatiles as they were inhaled together with two types of sensory test. In both sensory tests the pattern of aromas in an inhalation revealed a relationship with perception. In particular, the sensory response in the time intensity study was related to differences in the inhalation profiles between people, which in turn was related to an individual's breathing. This shows that physiological differences such as breathing and the structure of the nasal cavity have an impact on perception