Variety and shelf-life of coffee packaged in capsules

Exploring accurate mass measurements in pixel-based chemometrics: Advancing coffee classification with GC-HRMS-A proof of concept study

This paper presents a study that assesses the application of chemometrics for classifying coffee samples in a quality control context. High-resolution and accurate mass measurements were utilized as input for pixel-based orthogonal partial least squares discriminant analysis (OPLS-DA) models. The compositional data were acquired through a fully automated workflow combining headspace solid-phase microextraction and gas chromatography-high-resolution mass spectrometry (GC-HRMS) using an FT-Orbitrap® mass analyzer. A workflow centered on accurate mass measurements was successfully utilized for group-type analysis, offering an alternative to methods relying solely on MS similarity searches. The predictive models underwent thorough evaluation, demonstrating robust multivariate classification performance. Five key coffee attributes, bitterness, acidity, body, intensity, and roasting level were successfully predicted using GC-HRMS data. The results revealed strong predictive accuracy across all models, ranging from 88.9 % (bitterness) to 94.4 % (roasting level). This study represents a significant advancement in automating methods for coffee quality control, notably increasing the predictive ability of the models compared to existing literature.

Application of ATR-FTIR for Green Arabica Bean Shelf-Life Determination in Accelerated Storage

Coffee bean oxidation is associated with enzymatic and non-enzymatic browning, the degradation of desirable aromatic compounds, the development of undesirable flavors, increased susceptibility to microbial spoilage, and volatile compound losses. This study investigated natural dry process (DP) and honey process (HP) green coffee beans stored in GrainPro® bags for 0, 5, 10, and 20 days under accelerated storage conditions at 30 °C, 40 °C, and 50 °C with relative humidity of 50%. A kinetic model was used to estimate the shelf life of the green coffee beans. DP recorded durability of 45.67, 29.9, and 24.92 days at 30 °C, 40 °C, and 50 °C, respectively, with HP 60.34, 38.07, and 19.22 days. Partial least squares (PLS) analysis was performed to build the models in order to predict the shelf life of coffee based on peroxide (PV) and thiobarbituric acid reactive substances (TBARS) values. In terms of prediction with leave-one-out cross-validation (LOOCV), PLS provided a higher accuracy for TBARS (R2 = 0.801), while PV was lower (R2 = 0.469). However, the auto-prediction showed good agreement among the observed and predicted values in both PV (R2 = 0.802) and TBARS (R2 = 0.932). Based on the variable importance of projection (VIP) scores, the ATR-FTIR peaks as 3000-2825, 2154-2150, 1780-1712, 1487-2483, 1186-1126, 1107-1097, and 1012-949 cm-1 were identified to be the most related to PV and TBARS on green coffee beans shelf life. ATR-FITR showed potential as a fast and accurate technique to evaluate the oxidation reaction that related to the loss of coffee quality during storage.

The Lipidic and Volatile Components of Coffee Pods and Capsules Packaged in an Alternative Multilayer Film

Coffee pods and capsules require packaging that guarantees the optimal coffee preservation. The chemical composition of coffee can undergo quality decay phenomena during storage, especially in terms of lipidic and volatile components. Amongst coffee packaging, aluminum multilayer materials are particularly widely diffused. However, aluminum is a negative component because it is not recoverable in a mixed plastic structure and its specific weight gives significant weight to packaging. In this study, a multilayer film with a reduced content of aluminum was used to package coffe pods and capsules and compared to a standard film with an aluminum layer. Their influence on the peroxides and volatile organic compounds of two coffee blends, 100% Coffea arabica L., 50% Coffea arabica L., and 50% Coffea canephora var. robusta L., were studied during their 180-day shelf life. The predominant volatile organic compounds detected belonged to the class of furans and pyrazines. Both packaging materials used for both coffee blends in the pods and capsules showed no significant differences during storage. Thus, the alternative packaging with less aluminum had the same performance as the standard with the advantage of being more sustainable, reducing the packaging weight, with benefits for transportation, and preserving the coffee aroma during the shelf life.

Exploring different high-capacity tools and extraction modes to characterize the aroma of brewed coffee

In the present work, the potential benefit of using multi-cumulative trapping headspace extraction was explored by comparing the results using solid-phase microextraction (SPME) coated with divinylbenzene/carboxen/polydimethylsiloxane and a probe-like tool coated with polydimethylsiloxane. The efficiency of a single 30-min extraction, already explored in previous work, was compared with that of multiple shorter extractions. We evaluated three different conditions, i.e., three repeated extractions for 10 min each from different sample vials (for both the probe-like tool and SPME) or from the same vial (for SPME) containing brewed coffee. The entire study was performed using comprehensive two-dimensional gas chromatography coupled with mass spectrometry. The two-dimensional plots were aligned and integrated using a tile-sum approach before any statistical analysis. A detailed comparison of all the tested conditions was performed on a set of 25 targeted compounds. Although a single 30-min extraction using the probe-like tool provided a significantly higher compound intensity than SPME single extraction, the use of multiple shorter extractions with SPME showed similar results. However, multiple extractions with the probe-like tool showed a greater increase in the number of extracted compounds. Furthermore, an untargeted cross-sample comparison was performed to evaluate the ability of the two tested tools and the different extraction procedures in differentiating between espresso-brewed coffee samples obtained from capsules made of different packaging materials (i.e., compostable capsules, aluminum capsules, aluminum multilayer pack). The highest explained variance was obtained using the probe-like tool and multiple extractions (91.6% compared to 83.9% of the single extraction); nevertheless, SPME multiple extractions showed similar results with 88.3% of variance explained.

Storage Stability of Spray- and Freeze-Dried Chitosan-Based Pickering Emulsions Containing Roasted Coffee Oil: Color Evaluation, Lipid Oxidation, and Volatile Compounds

Drying Pickering o/w emulsions has been considered as a promising strategy to produce oil microcapsules, as long as their quality parameters can be preserved over storage. In this sense, it is shown as an interesting alternative to preserve the quality of roasted coffee oil, a valuable agroindustrial byproduct. Thus, freeze- and spray-dried chitosan-based Pickering emulsions of roasted coffee oil were evaluated over 30 days of storage at 25 °C together with the non-encapsulated oil as a control. Water sorption isotherms were determined, whereas color, oxidative stability (peroxide value and conjugated dienes) and volatile compounds were assessed over the storage period. Type II isotherms and Guggenheim–Anderson–Boer (GAB) model parameters showed that water binding was impaired by the surface oil in freeze-dried samples. Oxidation was maintained under acceptable values over the storage for all samples, with slightly higher protection also observed for volatile compounds in the spray-dried particles. The powdered emulsions were able to suitably preserve the oil’s quality over 30 days of storage, enabling its commercialization and application as a food ingredient and potential flavoring.

Sustainability issues along the coffee chain: From the field to the cup

The coffee industry is one of the most important commercial value chains worldwide. Nonetheless, it is also associated to several social, economic, and environmental concerns that impair its sustainability. The present review is focused on these main sustainability concerns from the field to the coffee cup, as well as on the strategies that are being developed and/or implemented to attain sustainability and circular economy principles in the different chain segments. In this context, distinct approaches have been applied, such as sustainable certifications (e.g., voluntary sustainability standards), corporate sustainability initiatives, direct trade, relationship coffee concepts, geographical indication, legislations, waste management, and byproducts valorization, among others. These strategies are addressed and discussed throughout this review, as well as their recognized advantages and limitations. Overall, there is still a long way to go to attain the much-desired sustainability in the coffee chain, being essential to join the efforts of all actors and entities directly or indirectly involved, namely, producers, retailers, roasters, governments, educational institutions (such as universities and scientific research institutes), and organizations.

Potential Aroma Chemical Fingerprint of Oxidised Coffee Note by HS-SPME-GC-MS and Machine Learning

This study examines the volatilome of good and oxidised coffee samples from two commercial coffee species (i.e., Coffea arabica (arabica) and Coffea canephora (robusta)) in different packagings (i.e., standard with aluminium barrier and Eco-caps) to define a fingerprint potentially describing their oxidised note, independently of origin and packaging. The study was carried out using HS-SPME-GC-MS/FPD in conjunction with a machine learning data processing. PCA and PLS-DA were used to extrapolate 25 volatiles (out of 147) indicative of oxidised coffees, and their behaviour was compared with literature data and critically discussed. An increase in four volatiles was observed in all oxidised samples tested, albeit to varying degrees depending on the blend and packaging: acetic and propionic acids (pungent, acidic, rancid), 1-H-pyrrole-2-carboxaldehyde (musty), and 5-(hydroxymethyl)-dihydro-2(3H)-furanone.

Innovative Process for Dried Caper (Capparis spinosa L.) Powder Production

This research aimed to develop a new time, energy, and cost-saving production process for obtaining dried powder from Capparis spinosa floral buds. Four different trials, including dry salting with 40% NaCl (for 10 days and 40 days) and brine salting with 18% NaCl (at room temperature for 3 days and at 60 °C for 6 h), were carried out, and two different air-drying temperatures (40 and 50 °C) were used. The effects on chemical and sensory characteristics were investigated and compared with traditional undried caper samples. Spectroscopy and chromatographic techniques such as UV-VIS, GC-MS, and FTIR were used for chlorophylls, carotenoids, polyphenols, flavonoids, and volatile aroma compounds' analyses. Moreover, a sensory descriptive analysis and acceptability were applied to individuate the product most appreciated by the consumers. Among the different trials, brine salting at 60 °C and drying at 50 °C constituted the fastest process that yielded an appreciated powder by consumers; the chemical analyses demonstrated that this process did not lead to the formation of extraneous aroma compounds that could influence the typical sensory properties of capers and maintained high levels of chlorophylls, carotenoids, and polyphenols. Altogether, the results could be of great significance to industrial production and potentiate positive impacts on the economy of production areas.

Volatile Compound Characterization of Coffee (Coffea arabica) Processed at Different Fermentation Times Using SPME-GC-MS

Coffee is a beverage that is consumed due to its flavor and fragrance. In this investigation, we demonstrated the relations between different dry fermentation processes of coffee (aerobic, anaerobic, and atmosphere modified with CO2) and fermentation times (0, 24, 48, 72, and 96 h), with pH, acidity, and seven volatile marker compounds of coffee. Volatile compounds were extracted by solid phase microextraction (SPME) and an analysis was performed by gas chromatography−mass spectrometry (GC−MS). A significant effect (p < 0.05) between the fermentation time and a decrease in pH was demonstrated, as well as between the fermentation time and increasing acidity (p < 0.05). Acetic acid was positively correlated with the fermentation time, unlike 2-methylpyrazine, 2-furanmethanol, 2,6-dimethylpyrazine, and 5-methylfurfural, which were negatively correlated with the fermentation time. The aerobic and anaerobic fermentation treatments obtained high affinity with the seven volatile marker compounds analyzed due to the optimal environment for the development of the microorganisms that acted in this process. In contrast, in the fermentation process in an atmosphere modified with CO2, a negative affinity with the seven volatile compounds was evidenced, because this gas inactivated the development of microorganisms and inhibited their activity in the fermentation process.

Insights on Single-Dose Espresso Coffee Capsules' Volatile Profile: From Ground Powder Volatiles to Prediction of Espresso Brew Aroma Properties

Single-dose coffee capsules have revolutionized the coffee market, fueling espresso coffee popularity and offering access to a wide selection of coffee blends. Nevertheless, scarce information related to coffee powder and brew’s combined volatile characterization is available. In this study, it is hypothesized that coffee brew aroma characteristics can be predicted based on coffee powder’s volatile composition. For this, headspace solid-phase microextraction (HS-SPME) combined with comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry detection (GC × GC-ToFMS) was used. The data were combined via chemometric tools to characterize in depth the volatile composition of eight blends of capsule-coffee powder and respective espresso brews, simulating the consumer’s perception. A total of 390 volatile compounds were putatively identified, 100 reported for the first time in roasted coffee or brews. Although the same chemical families were determined among the coffee powders and espresso brews, a different volatile profile was determined for each matrix. The Pearson correlation of coffee powders and respective brews allowed to identify 15 volatile compounds, mainly terpenic and esters recognized by their pleasant notes, with a strong relationship between the amounts present in both matrices. These compounds can be key markers to predict the volatile aroma potential of an espresso brew when analyzing the coffee powder.

Sugars Replacement as a Strategy to Control the Formation of α-Dicarbonyl and Furanic Compounds during Cookie Processing

In the last decade, several preventive strategies were considered to mitigate the chemical hazard accumulation in food products. This work aimed to study the effect of different sugars on the development of the main chemical hazard in cookies. For this purpose, model biscuits prepared using sucrose, fructose, and glucose were baked at different temperatures (150, 170, and 190 °C) and for different times (from 5 to 45 min), and the levels of α-dicarbonyl compounds, such as 3-deoxyglucosone (3-DG), glyoxal (GO) and methylglyoxal (MGO), 5-hydroxymethylfurfural (HMF), and furanic aromatic compounds were monitored. The replacement of sucrose in the cookie recipes with monosaccharides had as a consequence the highest accumulation of 3-DG (200-600 times higher), MGO, HMF, and furanic volatile compounds, while the use of sucrose allowed for maintaining the 3-DG, MGO, and HMF levels at less than 10 mg/kg dry matter in cookies for the estimated optimal baking time. Moreover, cookies with sucrose were characterised in terms of volatile compounds, mainly in terms of lipid oxidation products, while cookies with fructose or glucose baked at the highest temperature were characterised almost exclusively by Maillard reaction products, confirming a faster development of this reaction during baking at the studied temperatures.