Effect of Roasting Level on the Development of Key Aroma-Active Compounds in Coffee.

Coffee roasting is considered the most critical process in the development of sensory characteristics. During this stage, a substantial number of compounds are generated. Nevertheless, only a limited number of these compounds are responsible for the aroma, referred to as key aroma-active compounds. This study aimed to assess the impact of roasting levels on the formation of these compounds. Coffee was roasted at four different levels: very light (RL85), light (RL75), medium (RL55), and extremely dark (RL25), according to the Specialty Coffee Association (SCA) guidelines. The extraction, olfactory evaluation, and identification of compounds were performed using solid-phase microextraction (SPME), gas chromatography-olfactometry (GC-O), and gas chromatography-mass spectrometry (GC-MS), respectively. A total of 74 compounds were successfully identified, of which 25 were classified as aroma-active compounds. RL75 and RL85 displayed similar aromatic profiles. RL55 was characterized by pleasant notes such as sweet, toasted hazelnut, and caramel. In contrast, RL25 was marked by undesirable odors including burnt notes, putrid, and sulfurous scents. This study is the first to identify key odorant compounds in coffee based on SCA roasting standards.

Microwave-Assisted Extraction Optimization and Effect of Drying Temperature on Catechins, Procyanidins and Theobromine in Cocoa Beans.

Cocoa beans (Theobroma cacao L.) are an important source of polyphenols. Nevertheless, the content of these compounds is influenced by post-harvest processes. In this sense, the concentration of polyphenols can decrease by more than 50% during drying. In this study, the process of procyanidins extraction was optimized and the stability of catechins, procyanidins, and theobromine to different drying temperatures was evaluated. First, the effectiveness of methanol, ethanol, acetone, and water as extract solvents was determined. A Box-Behnken design and response surface methodology were used to optimize the Microwave-Assisted Extraction (MAE) process. The ratios of methanol-water, time, and temperature of extraction were selected as independent variables, whereas the concentration of procyanidins was used as a response variable. Concerning the drying, the samples were dried using five temperatures, and a sample freeze-dried was used as a control. The quantitative analyses were carried out by HPLC-DAD-ESI-IT-MS. The optimal MAE conditions were 67 °C, 56 min, and 73% methanol. Regarding the drying, the maximum contents of procyanidins were obtained at 40 °C. To our knowledge, this is the first time that the stability of dimers, trimers, and tetramers of procyanidins on drying temperature was evaluated. In conclusion, drying at 40 °C presented better results than the freeze-drying method.

A Validated HPLC-UV-ESI-IT-MS Method for the Quantification of Carnosol in Lepechinia mutica, a Medicinal Plant Endemic to Ecuador.

The diphenolic diterpene carnosol was isolated from several species of the family Lamiaceae, including Lepechinia mutica, a medicinal plant endemic to Ecuador. The compound has exhibited high antioxidant, anti-inflammatory, antimicrobial, neuroprotective, and antifungal properties, as well as promising cytotoxicity against prostate, breast, skin, leukemia, and human colon cancer cell lines. In this paper, we developed and validated a simple, accurate, and reliable analytical HPLC-UV-ESI-IT-MS method, carried out on a C18 column, which is potentially suitable to quantify carnosol in plant extracts. The procedure complied with the established ICH validation parameters of analytical range (linearity in the range of 0.19-5.64 µg/g dried leaves; REAVERGE = 4.9%; R2 = 0.99907), analysis repeatability (RSD = 2.8-3.6%), intermediate precision (RSD = 1.9-3.6%), accuracy (estimated as % carnosol recovery in the range of 81 to 108%), and robustness. Finally, the LOD (0.04 µg/mg) and LOQ (0.19 µg/mg) values of carnosol/dried leaves were determined. Using this validated method, the content of carnosol in L. mutica was estimated to be 0.81 ± 0.04 mg/g of dried leaves (0.081%).

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.

Optimization of drying process and pressurized liquid extraction for recovery of bioactive compounds from avocado peel by-product.

The aim of the present study was to optimize the extraction of phenolic compounds in avocado peel using pressurized liquid extraction (PLE) with GRAS solvents. Response surface methodology (RSM) based on Central Composite Design 22 model was used in order to optimize PLE conditions. Moreover, the effect of air drying temperature on the total polyphenol content (TPC) and individual phenolic compounds concentration were evaluated. The quantification of individual compounds was performed by HPLC-DAD-ESI-TOF-MS. The optimized extraction conditions were 200°C as extraction temperature and 1:1 v/v as ethanol/water ratio. Regarding to the effect of drying, the highest TPC was obtained with a drying temperature of 85°C. Forty seven phenolic compounds were quantified in the obtained extracts, showing that phenolic acids found to be the more stables compounds to drying process, while procyanidins were the more thermolabiles analytes. To our knowledge, this is the first available study in which phenolic compounds extraction was optimized using PLE and such amount of phenolic compounds was quantified in avocado peel. These results confirm that PLE represents a powerful tool to obtain avocado peel extracts with high concentration in bioactive compounds suitable for its use in the food, cosmetic or pharmaceutical sector.

Exploring the Antioxidant Potential of Tragia volubilis L.: Mitigating Chemotherapeutic Effects of Doxorubicin on Tumor Cells.

Several plants of the genus Tragia L. have shown antibacterial, fungicidal, and antiproliferative activity, among other types of activities; however, most species of the genus have not been investigated. Tragia volubilis L. is native to tropical America and Africa, and although it has been reported as medicinal in the literature, it has not been thoroughly investigated. In this study, the phytochemical screening, isolation, and identification of compounds and the determination of the antioxidant activity of the aqueous extract of Tragia volubilis L. and its partitions were carried out. Ethyl acetate and n-butanol partitions of the extract present high antioxidant activity according to the Antioxidant Activity Index. Due to their activity, these partitions were tested on RKO cells as a representative model, both individually and in combination with Doxorubicin. It was found that the partitions significantly reduced the effect of Doxorubicin, as well as the expression of proteins involved in DNA damage and cell death. While the reduction of the chemotherapeutic effect of Doxorubicin on tumor cells may not be a desired outcome in therapeutic settings, the findings of the study are valuable in revealing the antioxidant potential of Tragia volubilis L. and its partitions. This highlights the importance of carefully regulating the application of antioxidants, especially in the context of cancer chemotherapy.

Functional ingredient from avocado peel: Microwave-assisted extraction, characterization and potential applications for the food industry.

Avocado peel is a by-product obtained in high amounts in the food industry with no further applications despite its richness in bioactive compounds. In this context, an efficient "green" microwave assisted extraction (MAE) was optimized to maximize the extraction of bioactive polyphenols. Moreover, the phenolic composition of the developed green avocado extract was characterized by HPLC coupled to MS analysers and the potential applications for the food industry were studied assaying different bioactivities. Thus, the matrix metalloproteinases inhibition, the antioxidant capacity and the antimicrobial activity against gram-positive and gram-negative bacteria, yeast and mold were tested. The results pointed out both, high matrix metalloproteinases inhibitory capacity and antioxidant activity of avocado peel MAE extract. These findings suggest the potential food industry applications of this extract as natural food preservative, functional food ingredient or nutraceuticals with antioxidant and anti-aging activities.

Comprehensive characterization of phenolic and other polar compounds in the seed and seed coat of avocado by HPLC-DAD-ESI-QTOF-MS.

Avocado seed and seed coat are important by-products from avocado industrialization, with important functional properties. The aim of the present study was to determine the phenolic profile and other polar compounds of avocado seed and seed coat using accelerated solvent extraction (ASE) and liquid chromatography coupled to Ultra-High-Definition Accurate-Mass Q-TOF. In this research 84 compounds were identified, within eight subclass group, among these 45 phenolic compounds were identified for first time in avocado seed. Condensed tannins, phenolic acids and flavonoids were the most representative groups in both samples. As far as we are concerned, this is the first time that avocado seed coat has been studied regarding its phenolic compounds using such a powerful instrumental technique. In addition, the radical-scavenging activities were analysed in order to estimate the antioxidant potential of extracts. These results point out that avocado seed and seed coat constitute a source of bioactive ingredients for its use in the food, cosmetic or pharmaceutical sector.

Comprehensive identification of bioactive compounds of avocado peel by liquid chromatography coupled to ultra-high-definition accurate-mass Q-TOF.

Industrially the avocado pulp is exploited principally as oil and paste, generating a huge quantity of peel and seed as by-products. Avocado peel is a promising inexpensive candidate for recovery phenolic compounds. The aim of this work was to identify the bioactive compounds present in an extract of avocado peel obtained by a green extraction technique. Accelerated solvent extraction was performed using water and ethanol as extraction solvents. Liquid chromatography coupled to ultra-high-definition accurate-mass spectrometry was used in order to identify the bioactive compounds. A total of sixty-one compounds belonging to eleven families were identified. Procyanidins, flavonols, hydroxybenzoic and hydroxycinnamic acids were the most common compounds. A sum of thirty-five compounds has been identified here for the first time in avocado peel. These results confirm the potential of avocado peel as a source of bioactive ingredients for its use in the food, cosmetic or pharmaceutical sector.

Diversity for chemical composition in a collection of different varietal types of tree tomato (Solanum betaceum Cav.), an Andean exotic fruit.

We evaluated 23 tree tomato (Solanum betaceum) accessions from five cultivar groups and one wild relative (Solanum cajanumense) for 26 composition traits. For all traits we found highly significant differences (P<0.001) among the materials studied. The high diversity found within S. betaceum for composition traits was matched by a high diversity within each of the cultivar groups. We found that sucrose and citric acid were the most important soluble sugar and organic acid, respectively, in tree tomato. Fruit in the anthocyanin pigmented (purple) group had a carotenoid content similar to that in the yellow-orange cultivar groups. Total phenolic content was significantly correlated (r=0.8607) with antioxidant activity. Analyses of mineral content showed that tree tomato is a good source of K, Mg, and Cu. Multivariate principal components analysis (PCA) confirmed that an important diversity exists within each cultivar group. The results we have obtained indicate that the high diversity found within the tree tomato could be exploited for selection and breeding for developing the tree tomato as a commercial crop.

Chemical, technological and in vitro antioxidant properties of mango, guava, pineapple and passion fruit dietary fibre concentrate.

The aim of this work was to determine the chemical, technological and in vitro antioxidant properties of co-products from the industrialisation of some tropical exotic fruits, such as mango, pineapple, guava and passion fruit, and to evaluate their potential use as dietary fibre sources for food enrichment. Proximate compositions were determined, as well as the total, insoluble and soluble fibre contents. The water holding, oil holding and swelling capacities were also determined. For the antioxidant activity, three different test systems were used (ABTS, DPPH and FRAP). The dietary fibre content of the co-products varied in a range between 69.1 and 81.5g/100g on a dry matter basis with a good balanced ratio between insoluble dietary fibre and soluble dietary fibre. Phenol recovery was dependent on the fruit type and the solvent system used. Methanol:acetone was a more efficient solvent for extracting phenols than ethanol. There was a good correlation between total phenol content and antioxidant capacity of the fruit extracts. All samples analysed had good antioxidant capacity. The results of this study indicate that exotic fruit fibres obtained as co-products in the process to obtain juice may be considered a good source of natural compounds with significant antioxidant activity.