A systematic study of key odourants, non-volatile compounds, and antioxidant capacity of cascara (dried Coffea arabica pulp)

Major Bioactive Compounds, Volatile and Sensory Profiles of Coffea canephora Flowers and Infusions for Waste Management in Coffee Production

This study aimed to investigate the content of major bioactive compounds and characterize the volatile and sensory profiles of Coffea canephora flowers and their infusions. Dried flowers from six selected genotypes of C. canephora trees and their infusions were analyzed for bioactive compounds using HPLC-DAD, while volatile organic compounds (VOC) were analyzed using GC-MS. Eight chlorogenic acids (CGA), seven phenolic acids, and the alkaloids caffeine and trigonelline were quantified in all methanolic flower extracts. Total CGA, phenolic acids, caffeine, and trigonelline contents in the methanolic extracts ranged between 342.8 and 1079.4 mg/100 g, 27.1 and 41.0 mg/100 g, 515.6 and 745.9 mg/100 g, and 453.8 and 645.2 mg/100 g, respectively. CGA, caffeine, and trigonelline were well extracted (84%, 91%, and 74%, respectively) when the flowers were infused in hot water. No free phenolic acids were identified in the infusions. Eighty-five VOC were identified in the flowers. Aldehydes, monoterpenes, esters, alcohols, monoterpene alcohols, acids, and ketones prevailed in order of the number of compounds. In the infusions, 38 VOC were accurately identified. Monoterpenes and monoterpene alcohols prevailed. In general, floral, jasmine and orange blossom, herbal, green coffee, woody, and sweet were the most cited sensory attributes for fragrance, aroma, and flavor. Considering the typically weak aroma of C. canephora seeds, the aroma and flavor of the flower's infusions were surprisingly strong and pleasant, showing great marketing potential.

Coffee Pulp from Azores: A Novel Phytochemical-Rich Food with Potential Anti-Diabetic Properties

Coffee pulp, a by-product of wet coffee processing, shows significant potential in the food and health domains, but its real applications remain underexplored. This work investigated the chemical composition and bioactive properties of coffee pulp from São Miguel Island (Azores, Portugal). The studied coffee pulp exhibited high fiber content (52% dw), mostly insoluble; notable mineral levels (10.6%), mainly K, Ca, and Mg; and 6% dw of total amino acids, with hydroxyproline, aspartic acid, glutamic acid, and leucine in higher amounts. Despite containing low fat (1.6% dw), mainly saturated, it also showed considerable amounts of polyunsaturated fatty acids with a favorable n6/n3 ratio (1.40) and vitamin E (α-, β-, and γ-tocopherols). Its antioxidant capacity can be partially explained by the chlorogenic acid content (9.2 mg/g dw), and caffeine (0.98%) was present in similar amounts to those observed in some arabica coffee beans. A decrease in glucose uptake in Caco-2 cells was found, but not in fructose, suggesting selective inhibition of SGLT1 and potential antidiabetic effects. These results show that Azorean coffee pulp has potential as a sustainable and bioactive ingredient for incorporation into functional foods or dietary supplements.

Bioactive Compounds and Valorization of Coffee By-Products from the Origin: A Circular Economy Model from Local Practices in Zongolica, Mexico

The by-products of green coffee processing are rich in compounds that can be recycled for their possible use in the production of beverages, fertilizers and weed control in production areas. The objective of this work was to identify the organic and inorganic bioactive compounds of green coffee and the coffee by-products related to the production of origin, such as dried cascara (skin-pulp), parchment and silverskin (unroasted), in order to investigate the role their biomolecules may have in reuse through practices and local knowledge, not yet valued. The metabolomic profile by HPLC-ESI-HRMS of the aqueous extract of the dried cascara highlighted 93 non-volatile molecules, the highest number reported for dried cascara. They belong to groups of organic acids (12), alkaloids (5), sugars (5), fatty acids (2), diglycerides (1), amino acids (18), phospholipids (7), vitamins (5), phenolic acids (11), flavonoids (8), chlorogenic acids (17), flavones (1) and terpenes (1). For the first time, we report the use of direct analysis in real-time mass spectrometry (DART-MS) for the identification of metabolites in aqueous extracts of dried cascara, parchment, silverskin and green coffee. The DART analysis mainly showed the presence of caffeine and chlorogenic acids in all the extracts; additionally, sugar adducts and antioxidant compounds such as polyphenols were detected. The mineral content (K, Ca, P, S, Mg and Cl) by EDS spectrometry in the by-products and green coffee showed a relatively high content of K in the dried cascara and green coffee, while Ca was detected in double quantity in the silverskin. These metabolomic and mineral profile data allow enhancement of the link between the quality of green coffee and its by-products and the traditional local practices in the crop-growing area. This consolidates the community's experience in reusing by-products, thereby minimizing the impact on the environment and generating additional income for coffee growers' work, in accordance with the principles of circular economy and bioeconomy.

The Impact of the Drying Process on the Antioxidant and Anti-Inflammatory Potential of Dried Ripe Coffee Cherry Pulp Soluble Powder

Coffee fruit cascara, which is the skin and pulp of the coffee cherry, has been authorized as a novel food for commercialization in the European Union. The present research assessed the feasibility of using spray drying to produce a soluble powder called instant cascara (IC), employing sun-dried ripe coffee cherry pulp as a raw material. Although there were no significant differences (p > 0.05) in the overall antioxidant capacity between the freeze-dried and spray-dried samples, after an in vitro simulation of the digestion process, the spray-dried sample was significantly (p < 0.05) more antioxidant. Both samples reduced physiological intracellular ROS and significantly decreased (p < 0.05) the secretion of the pro-inflammatory factor NO. Alkaloids and phenolic compounds were detected in intestinal digests. In conclusion, spray drying is a good technique for producing IC as its use does not affect its properties and causes less environmental impact than freeze drying, as calculated by life cycle assessment. Sensory analysis did not show significant differences between the commercial beverage and the IC beverage in the adult population. IC at 10 mg/mL was significantly less accepted in adolescents than the commercial beverage. Future work will include the reformulation of the IC beverage at 10 mg/mL, which has antioxidant and anti-inflammatory potential, to increase its hedonic acceptance in all consumer segments.

Volatilome, Microbial, and Sensory Profiles of Coffee Leaf and Coffee Leaf-Toasted Maté Kombuchas

Kombucha is a fermented beverage traditionally made from the leaves of Camelia sinensis. The market has drastically expanded recently, and the beverage has become more elaborated with new, healthy food materials and flavors. Pruning and harvesting during coffee production may generate tons of coffee leaves that are discarded although they contain substantial amounts of bioactive compounds, including those found in maté tea and coffee seeds. This study characterized the changes in volatilome, microbial, and sensory profiles of pure and blended arabica coffee leaf tea kombuchas between 3-9 days of fermentation. Acceptance was also evaluated by consumers from Rio de Janeiro (n = 103). Kombuchas (K) were prepared using black tea kombucha starter (BTKS) (10%), sucrose (10%), a symbiotic culture of Bacteria and Yeasts (SCOBY) (2.5%), and a pure coffee leaf infusion (CL) or a 50:50 blend with toasted maté infusion (CL-TM) at 2.5%. The RATA test was chosen for sensory profile characterization. One hundred volatile organic compounds were identified when all infusions and kombucha samples were considered. The potential impact compounds identified in CL K and CL-TM K were: methyl salicylate, benzaldehyde, hexanal, nonanal, pentadecanal, phenylethyl-alcohol, cedrol, 3,5-octadien-2-one, β-damascenone, α-ionone, β-ionone, acetic acid, caproic acid, octanoic acid, nonanoic acid, decanoic acid, isovaleric acid, linalool, (S)-dihydroactinidiolide, isoamyl alcohol, ethyl hexanoate, and geranyl acetone. Aroma and flavor descriptors with higher intensities in CL K included fruity, peach, sweet, and herbal, while CL-TM K included additional toasted mate notes. The highest mean acceptance score was given to CL-TM K and CL K on day 3 (6.6 and 6.4, respectively, on a nine-point scale). Arabica coffee leaf can be a co-product with similar fingerprinting to maté and black tea, which can be explored for the elaboration of potentially healthy fermented beverages in food industries.

Volatile fingerprinting, sensory characterization, and consumer acceptance of pure and blended arabica coffee leaf teas

Coffee leaves contain several bioactive compounds and have been traditionally consumed as a medicinal infusion in the East for centuries. Coffee production generates large amounts of leaves as by-products, which are often wasted in most producing countries because of the low acceptability in the West. Nevertheless, processing and blending coffee leaves may increase aroma and flavor complexity. This study evaluated the volatile and sensory profiles and consumer acceptance of coffee leaf teas compared to two among the most consumed teas (black and maté teas) in Rio de Janeiro. Infusions were made with one experimental and one commercial coffee leaf tea (CLT), two black teas (BT), and one toasted maté tea (TMT) for volatile (GC-MS/MS) and sensory profiles. As an attempt to improve coffee leaf tea acceptance, CLT were also blended (50%) with BT or TMT. Acceptance, Check All That Apply (CATA), and Projective Mapping sensory tests were performed with untrained assessors aged 18-49 (n = 100). Volatile data were standardized by centering and normalization. Sensory data were treated by ANOVA/Fisher test, PCA, and AHCMFA, considering differences at p < 0.05. Ninety-two volatile compounds distributed in 12 classes were identified in different samples. CLT, BT, and TMT infusions shared 19 compounds, including 9 potential impact compounds for aroma and flavor: α-ionone, β-ionone, hexanal, nonanal, decanal, benzaldehyde, trans-linalool oxide, linalool, and dihydroactinidiolide. The most cited flavor attributes for CLT infusions were herbs/green leaf, woody and refreshing. For TMT and BT, herbs/green leaf, woody, burnt, and fermented were the most cited. These attributes agreed with the volatile profiles. CLT shared 22 compounds with TMT and 28 with BT. Considering pure infusions, TMT presented the highest mean acceptance scores (6.7), followed by Com. and Exp. CLT (6.1 and 5.8, on a 9-point-hedonic scale, respectively). Blending with TMT increased mean acceptance of Exp. CLT (6.4), while blending with BT, downgraded the mean acceptance of Com. CLT (5.3). In Projective Mapping, CLT was considered to have a higher sensory resemblance with TMT than BT. If produced adequately, CLT was shown to have good market potential to support sustainable coffee production and promote health.

The impact of different drying methods on the physical properties, bioactive components, antioxidant capacity, volatile components and industrial application of coffee peel

This study evaluated the effects of hot air drying (HAD), microwave drying (MD), vacuum drying (VD), sun drying (SD) and vacuum freeze drying (VFD) on the physical properties, bioactive components, antioxidant capacity, volatile components and industrial application of coffee peel. The results showed VFD could retain the appearance color, total phenolics (19.49 mg GAE/g DW), total flavonoids (9.65 mg CE/g DW), caffeine (3.15 mg/g DW), trigonelline (2.71 mg/g DW), and antioxidant capacities of fresh sample to the greatest extent, but its operating cost was significantly higher than other treatments and total volatile components were in the minimum levels. HAD and SD exhibited the highest loss rates of total phenols and antioxidant capacities, exceeding 50%. MD offered the lowest operating cost, superior retention of bioactive components, and the richest variety and quantity of volatile compounds. Therefore, it is recommended to use MD to dehydrate the coffee peel in actual production.

Volatile, Microbial, and Sensory Profiles and Consumer Acceptance of Coffee Cascara Kombuchas

Given the substantial world coffee production, tons of coffee fruit cascara rich in bioactive compounds are discarded annually. Using this by-product to produce potentially healthy and acceptable foods is a sustainable practice that aggregates value to coffee production and may help improve people's lives. This study aimed to elaborate kombuchas from coffee cascara tea, evaluate their microbial profile, and monitor the changes in the volatile profile during fermentation, together with sensory attributes and acceptance by consumers from Rio de Janeiro (n = 113). Arabica coffee cascaras from Brazil and Nicaragua were used to make infusions, to which black tea kombucha, a Symbiotic Culture of Bacteria and Yeasts (SCOBY), and sucrose were added. Fermentation of plain black tea kombucha was also monitored for comparison. The volatile profile was analyzed after 0, 3, 6, and 9 days of fermentation via headspace solid phase microextraction GC-MS. A total of 81 compounds were identified considering all beverages, 59 in coffee cascara kombuchas and 59 in the black tea kombucha, with 37 common compounds for both. An increase mainly in acids and esters occurred during fermentation. Despite the similarity to black tea kombucha, some aldehydes, esters, alcohols, and ketones in coffee cascara kombucha were not identified in black tea kombucha. Potential impact compounds in CC were linalool, decanal, nonanal, octanal, dodecanal, ethanol, 2-ethylhexanol, ethyl acetate, ethyl butyrate, ethyl acetate, β-damascenone, γ-nonalactone, linalool oxide, phenylethyl alcohol, geranyl acetone, phenylacetaldehyde, isoamyl alcohol, acetic acid, octanoic acid, isovaleric acid, ethyl isobutyrate, ethyl hexanoate, and limonene. The mean acceptance scores for cascara kombuchas varied between 5.7 ± 0.53 and 7.4 ± 0.53 on a nine-point hedonic scale, with coffee cascara from three-day Nicaragua kombucha showing the highest score, associated with sweetness and berry, honey, woody, and herbal aromas and flavors. The present results indicate that coffee cascara is a promising by-product for elaboration of fermented beverages, exhibiting exotic and singular fingerprinting that can be explored for applications in the food industry.

Effects of roasting on the chemical compositions, color, aroma, microstructure, and the kinetics of changes in coffee pulp

Roasting is a critical process that affects the quality attributes of coffee beans; however, how roasting conditions affect the physical, chemical, biological, and organoleptic changes of coffee pulp needs more research. In the present study, we investigated the effects of roasting temperatures and times on chemical compositions and quality attributes of coffee pulp. The results showed that the contents of total soluble sugar (TSS) and free amino acid (FAA) followed a temporal pattern of first increasing and then decreasing under the roasting temperatures between 100 and 160°C. Total phenolic content (TPC) and antioxidant activity of coffee pulp significantly (p < 0.05) increased after roasting, reaching the maximum values of 83.09 mg gallic acid equivalent (GAE) /g and 360.45 µM 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox) /g, respectively, when coffee pulp was roasted at 160°C for 18 min. Drying rates of coffee pulp fitted the Logarithmic kinetic model, while color (L*, a*, and b*) changes and 5-caffeoylquinic acid degradation followed the first-order kinetic model. Electronic nose analysis showed that the main aroma compounds of the coffee pulp are sulfur-containing organics that were reduced with the extended roasting time. Scanning electronic microscopy analysis presented the loosened, shrunk, and cracked microstructure on the surface of the roasted coffee pulp, which might contribute to the increased TSS, FAA, TPC, and antioxidant activity of coffee pulp roasted under specific conditions. In conclusion, our research provides valuable information for preparing high-quality coffee pulp tea. PRACTICAL APPLICATION: This article investigates the effects of roasting on the chemical composition, color, flavor, microstructure, and the kinetics of changes in the moisture, color, and 5-caffeoylquinic acid (5-CQA) of the coffee pulp. We have found that high-temperature and short-time roasting helps retain the total phenolic contents, antioxidant activity, and aroma. The drying kinetic fits the Logarithmic model, and the changes in color and 5-CQA fit the first-order kinetic model. This study provides meaningful information for preparing coffee pulp tea with high-quality attributes and antioxidant activity.

Risk Assessment of Coffee Cherry (Cascara) Fruit Products for Flour Replacement and Other Alternative Food Uses

Coffee bean harvesting incurs various by-products known for their long traditional use. However, they often still end up being a waste instead of being used to their full potential. On the European market, coffee cherry (cascara) products are not yet common, and a novel food approval for beverages made from coffee cherry pulp was issued only recently. In this article, exposure and risk assessment of various products such as juice, jam, jelly, puree, and flour made from coffee cherry pulp and husk are reviewed. Since caffeine in particular, as a bioactive ingredient, is considered a limiting factor, safe intake will be derived for different age groups, showing that even adolescents could consume limited quantities without adverse health effects. Moreover, the composition can be influenced by harvesting methods and processing steps. Most interestingly, dried and powdered coffee cherry can substitute the flour in bakery products by up to 15% without losing baking properties and sensory qualities. In particular, this use as a partial flour substitute is a possible approach to counteract rising grain prices, transport costs, and disrupted supply chains, which are caused by the Russia-Ukraine war and changing climatic conditions. Thus, the supply of affordable staple foods could be partially ensured for the inhabitants of countries that depend on imported wheat and cultivate coffee locally by harvesting both beans and by-products.

Oxidative stability of chicken burgers using organic coffee husk extract

The antioxidant capacity of organic coffee husk extract (Coffee arabica L.) added to chicken burgers was evaluated. Two formulations were prepared: with addition of the extract (100 and 200 ppm CAE/kg), in addition to control formulations without the addition of antioxidant, and with the addition of synthetic antioxidant. The products were characterized by physical and chemical analysis and analyzed for oxidative stability during 45 days of storage under freezing. The addition of extract in the proportion of 200 ppm CAE/kg of hamburger revealed efficacy against lipid oxidation equivalent to treatment with a synthetic antioxidant. As for protein oxidation, there was no pro or antioxidant influence in the treatments. The addition of organic coffee husk extract to chicken hamburgers is thus indicated, being considered as a potential natural additive. In addition, the use of coffee husks helps to minimize the lager amounts of agro-industrial by-products generated by the coffee industry.

Volatile Fingerprinting and Sensory Profiles of Coffee Cascara Teas Produced in Latin American Countries

Coffee is one of the most produced and consumed food products worldwide. Its production generates a large amount of byproducts with bioactive potential, like the fruit skin and pulp, popularly called cascara. This study aimed to evaluate the volatile and sensory profiles and the consumption potential of commercial Coffea arabica cascara teas by Rio de Janeiro consumers. Analyses of volatile organic compounds in unfermented (n = 2) and fermented (n = 4) cascara tea infusions were performed by GC-MS. RATA and acceptance sensory tests were performed with untrained assessors (n = 100). Fifty-three volatile organic compounds distributed in 9 classes were identified in different samples. Aldehydes, acids, alcohols, esters, and ketones prevailed in order of abundance. With mild intensity, the most cited aroma and flavor attributes were sweet, herbal, woody, prune, fruity, honey, toasted maté and black tea for unfermented teas. For the fermented teas, sweet, woody, black tea, prune, herbal, citric, fruity, honey, raisin, peach, toasted maté, tamarind, and hibiscus were rated as intense. A good association between the attributes selected by the assessors and the volatile compounds was observed. Unfermented teas, with a mild flavor and traditional characteristics, showed better mean acceptance (6.0−5.9 points) when compared to fermented teas (6.0−5.3 points), with exotic and complex attributes. These were well accepted (>8.0 points) by only about 20% of the assessors, a niche of consumers that appreciate gourmet foods.

Biovalorisation of spent Konacha tea leaves via single-culture fermentation involving wine yeasts and lactic acid bacteria

AIMS

The objective of this study was to explore the potential of fermentation as a biovalorisation strategy for spent tea leaves (STL), a major agri-food waste generated from the tea extraction industry. Fermentation by wine yeasts or lactic acid bacteria (LAB) have shown promising results in previous studies across various substrates.

METHODS AND RESULTS

Konacha (green tea) STL slurries were inoculated with single strains of wine yeasts or LAB, respectively. After a 48-h fermentation, changes in selected non-volatile and volatile compositions were evaluated. Fermentation by LAB increased organic acid content by 5- to 7-fold (except Lactobacillus fermentum) and modulated the composition of major tea catechins, while wine yeast fermentation resulted in a 30% increase in amino acid content. Strain-specific production of specific volatile compounds was also observed, such as butanoic acid (L. fermentum), isoamyl acetate (Pichia kluyveri) and 4-ethylphenol (L. plantarum).

CONCLUSIONS

Both volatile and non-volatile compound compositions of Konacha STL were successfully modified via wine yeast and LAB fermentation.

SIGNIFICANCE AND IMPACT OF STUDY

Our findings indicate that Konacha STL is a suitable medium for biovalorisation by wine yeasts or LAB via the generation of commercially useful volatile and non-volatile compounds. Future optimizations could further render fermentation an economically viable strategy for the upcycling of STL.

Effect of three milling processes (cyclone-, bead- and stone-millings) on the quality of matcha: Physical properties, taste and aroma

Analysis of three matcha (cyclone-, bead- and stone-milled) revealed differences in their sizes and surface morphologies. Using liquid chromatography, 4 sugars, 6 organic acids, 18 amino acids and 9 polyphenols were detected in all matcha samples and shown to present in different amount. Moreover, 108 volatile compounds were detected and 30 potential flavour-contributing compounds were quantified by gas chromatography time-of-flight mass spectrometry using headspace-stir bar sorptive extraction-thin-film solid-phase microextraction (HS-SBSE-TFSPME). Sensory evaluation by a trained panel found that the matcha samples possess different notes (cyclone-milled: leafy; bead-milled: fishy; and stone-milled: roasty) which is supported by the volatile compound analysis. Finally, the three matcha were differentiated based on non-volatile and volatile components using principal component analysis, and the correlation between chemical composition and sensory evaluation data was carried out using partial least square regression. In conclusion, milling processes clearly affected the physical, chemical and sensory qualities of matcha.

Coffee by-products as the source of antioxidants: a systematic review

Background: Solid waste from coffee depulping process threatens the organism in environment as it produces organic pollutants. Evidence suggested that coffee by-product could valorize owing to its potential as antioxidant sources. The aim of this systematic review was to evaluate antioxidant activity of coffee by-products obtained from different coffee variants (arabica and robusta) and processing methods. Methods: The systematic review was conducted as of May 29, 2021 for records published within the last ten years (2011-2021) using seven databases: Embase, Medline, BMJ, Web of Science, Science Direct, Cochrane, and PubMed. Data on type of specimen, processing methods, and antioxidant activities were collected based on PRISMA guidelines. Results: Our data suggested that aqueous extract was found to be the most common processing method used to obtain the antioxidant from various coffee by-products, followed by methanol and ethanol extract. A variety of antioxidant properties ranging from strong to low activity was found depending on the variety, type of coffee by-products (cascara, pulp, husk, silverskin, and parchment), and processing technique. Fermentation employing proper bacteria was found effective in improving the yield of bioactive compounds resulting in higher antioxidant capacity. Applications in feedstuffs, foods, beverages, and topical formulation are among the potential utilization of coffee by-products. Conclusion: Coffee by-products contain bioactive compounds possessing antioxidant properties which could be used as additives in foods, beverages, and cosmetics. In particular, their benefits in skin care products require further investigation.

Coffee By-Products as Sustainable Novel Foods: Report of the 2nd International Electronic Conference on Foods-"Future Foods and Food Technologies for a Sustainable World"

The coffee plant Coffea spp. offers much more than the well-known drink made from the roasted coffee bean. During its cultivation and production, a wide variety of by-products are accrued, most of which are currently unused, thermally recycled, or used as fertilizer or animal feed. Modern, ecologically oriented society attaches great importance to sustainability and waste reduction, so it makes sense to not dispose of the by-products of coffee production but to bring them into the value chain, most prominently as foods for human nutrition. There is certainly huge potential for all of these products, especially on markets not currently accessible due to restrictions, such as the novel food regulation in the European Union. The by-products could help mitigate the socioeconomic burden of coffee farmers caused by globally low coffee prices and increasing challenges due to climate change. The purpose of the conference session summarized in this article was to bring together international experts on coffee by-products and share the current scientific knowledge on all plant parts, including leaf, cherry, parchment and silverskin, covering aspects from food chemistry and technology, nutrition, but also food safety and toxicology. The topic raised a huge interest from the audience and this article also contains a Q&A section with more than 20 answered questions.

A Narrative Review of the Current Knowledge on Fruit Active Aroma Using Gas Chromatography-Olfactometry (GC-O) Analysis

Fruit aroma, a mixture of chemical compounds with odor, is a strong attractant derived from a complex mixture of different amounts and intensities (threshold) of chemical compounds found in fruits. The odor-producing compounds of fruit aroma are derived from carbohydrates, lipids, phenolic compounds, and mono- and sesquiterpenes, among others. The identification of compounds responsible for fruit aroma is usually conducted using gas chromatography coupled with olfactometry (GC-O). This technique separates the chemical compounds from the aroma of foods using a chromatographic column and divides the resultant outflow between the physical detector and a testing outlet (sniffing port). Trained judges describe the perceived odor in terms of the intensity of the odor zones perceived according to their training method. Moreover, the use of GC-O coupled with a mass detector (GC-MS-O) allows for the retrieval of chemical information such as identification and quantification of compounds, which can be correlated to sensory information. This review aimed to demonstrate the application of GC-MS-O in the identification of precursor compounds in fruit aroma, considering important factors for the application, main results, and most recent advances in this field.

Aroma-Active Compounds in Robusta Coffee Pulp Puree-Evaluation of Physicochemical and Sensory Properties

Wet coffee processing generates a large amount of coffee pulp waste that is mostly disposed of in the processing units. To reduce this waste and the associated environmental burden, an alternative strategy would be to exploit the coffee pulp to produce a durable and stable consumable product. Accordingly, a puree produced from Robusta coffee pulp was investigated in relation to its physicochemical and sensory properties. After thermal and chemical stabilization, the obtained puree (pH 3.6) was found to exhibit a multimodal particle size distribution, shear-thinning behavior, and lower discoloration, as well as an antioxidant capacity of 87.9 µmol_TE/g_DM. The flavor of the puree was examined by sensory evaluation and the corresponding analyses of aroma-active volatile compounds, as determined using aroma extract dilution analyses (AEDA) and gas chromatography-mass spectrometry/olfactometry (GC-MS/O). The puree was characterized by dominant fruity (4.4), floral (3.4), citrusy (3.3) and hay-like (3.3) odor impressions. The aroma-active compounds were predominantly aldehydes, acids, and lactones, whereby (E)-β-damascenone, geraniol, 4-methylphenol, 3-hydroxy-4,5-dimethylfuran-2(5H)-one, and 4-hydroxy-3-methoxybenzaldehyde exhibited the highest flavor dilution (FD) factor (1024), thereby indicating their high impact on the overall aroma of the puree. This study demonstrates an approach to stabilize coffee pulp to produce a sweet, fruity puree with comparable physical properties to other fruit purees and that can be used as a new and versatile flavoring ingredient for various food applications.