Effect of processing on bioaccessibility and bioavailability of bioactive compounds in coffee beans

2-Methyloxolane as an effective bio-based solvent for the removal of βN-alkanoyl-5-hydroxytryptamines from Arabica green coffee beans

βN-alkanoyl-5-hydroxytryptamines (Cn-5HTs) are the main constituents of coffee wax and may be responsible for the increased severity of gastric disorders in sensitive consumers. Their removal from green coffee beans can result in a "stomach-friendly" brew. This work presents a green approach to Cn-5HTs extraction using the bio-based solvent 2-methyloxolane (2-MeOx). HPLC/DAD analyses on Arabica Brazil samples show that mild conditions (30 min at 50 °C) extract about 90% of the wax, without affecting the caffeine content of the beans, whereas almost complete removal is achieved in 60 min at reflux. 2-MeOx forms an azeotrope with water, its possible re-use has been demonstrated using aqueous 2-MeOx (95.5%) as the solvent. These preliminary results make 2-MeOx a possible candidate for the replacement of dichloromethane (DCM) in coffee dewaxing. The importance of fermentation in reducing Cn-5HTs by about 36% has been demonstrated in an analysis of green beans subjected to different post-harvest treatments.

Investigation of Chemical Composition, Antioxidant Properties, and Molecular Docking in Different Roasting Stages of Coffee Beans

This study investigates the chemical composition and antioxidant properties of coffee beans at different roasting stages, namely green coffee, filter-roasted coffee, and espresso-roasted coffee. Using a Golden Roaster machine, specific roasting profiles were developed to achieve distinct flavor characteristics: an intense flavor and balanced acidity for espresso, and a balanced, complex taste for filter coffee. Results indicate that filter-roasted coffee exhibits the highest radical scavenging activity, as evidenced by its lowest IC50 value for 2,2-diphenyl-1-picrylhydrazyl (DPPH) inhibition. Green coffee demonstrates superior iron chelation activity, while filter-roasted coffee contains the highest flavonol content and espresso-roasted coffee has the highest flavonoid content. Bacterial sensitivity tests show that both filter-roasted and espresso-roasted coffee are effective against certain strains, including Klebsiella pneumoniae ATCC 13883. Gas chromatography-mass spectrometry (GC–MS) analysis identifies key compounds such as caffeine and 4,4-dimethyl-3-(3-methylbut-3-enylidene)-2-methylenebicyclo [4.1.0] heptane in filter-roasted coffee, and 2-(2-hydroxyphenyl) buta-1,3-diene in espresso-roasted coffee. Molecular docking and in silico molecule’s absorption, distribution, metabolism, excretion, and toxicity (ADME) studies suggest potential pharmaceutical applications for coffee compounds. These findings provide valuable insights into coffee’s complex chemistry and its health-related properties. Additionally, the importance of coffee profiling in bioprocesses is highlighted by the need to carefully analyze the profiling process to optimize the biological effects and health benefits of these compounds. Coffee profiling not only enhances consumer taste experiences but also contributes to a better understanding of coffee’s potential health benefits by effectively identifying biomolecules and nutrients for use in bioprocesses.

Graphical Abstract

Lipophilic and Hydrophilic Metabolites as Descriptors of Different Coffee Beverages

Coffee is a widely consumed beverage rich in bioactive phytochemicals. This study investigated the effect of brewing method on the profile of potential bioactive compounds in different coffee beverages using metabolomics and lipidomics based on UHPLC-MS/QTOF. The oil contents of the espresso coffee (EC), pot coffee (PC), instant coffee (IC), and filter coffee (FC) beverages studied were 0.13% ± 0.002, 0.12% ± 0.001, 0.04% ± 0.002, and 0.03% ± 0.003, respectively. Univariate analysis indicated significant differences (P < 0.001) in oil content when EC and PC beverages were compared with IC and FC beverages. Principal component analysis revealed similarities in the lipid profiles of FC and EC beverages and the hydrophilic profiles of PC and FC beverages. The EC beverage had the highest intensity of hydrophilic compounds such as adenine, theobromine, chlorogenic acid, and caffeine. The PC beverage was the most abundant in triglycerides, phosphatidylcholine, and diterpenes. Cafestol and kahweol esters, but not their free forms, were the most abundant diterpenes in the PC beverage. This work provides information on the differences in the profile of potentially bioactive compounds in four commonly consumed coffee beverage types and, thus, on the possible differences in the health effects of these coffee beverage types.

Bioaccessibility of Phenolic Compounds, Resistant Starch, and Dietary Fibers from Australian Green Banana during In Vitro Digestion and Colonic Fermentation

Green bananas contain a substantial amount of resistant starch (RS), dietary fiber (DF), and phytochemicals, which exhibit potent antioxidant capabilities, primarily attributable to the abundance of polyphenols. The objective of this study was to assess the variations in the contents and bioaccessibility of RS, DF, and phenolic compounds in three types of Australian green bananas (Cavendish "Musa acuminata", Ladyfinger "Musa paradisiaca L.", and Ducasse "Musa balbisiana"), along with their antioxidant capacities, and the production of short-chain fatty acids (SCFAs) following in vitro simulated gastrointestinal digestion and colonic fermentation. The studied cultivars exhibited significant levels of RS, with Ladyfinger showing the greatest (49%). However, Ducasse bananas had the greatest DF concentration (38.73%). Greater TPC levels for Ladyfinger (2.32 mg GAE/g), as well as TFC and TTC (0.06 mg QE/g and 3.2 mg CE/g, respectively) in Cavendish, together with strong antioxidant capacities (DPPH, 0.89 mg TE/g in Cavendish), have been detected after both intestinal phase and colonic fermentation at 12 and 24 h. The bioaccessibility of most phenolic compounds from bananas was high after gastric and small intestinal digestion. Nevertheless, a significant proportion of kaempferol (31% in Cavendish) remained detectable in the residue after colonic fermentation. The greatest production of SCFAs in all banana cultivars was observed after 24 h of fermentation, except valeric acid, which exhibited the greatest output after 12 h of fermentation. In conclusion, the consumption of whole green bananas may have an advantageous effect on bowel health and offer antioxidant characteristics.

The Perfect Cup? Coffee-Derived Polyphenols and Their Roles in Mitigating Factors Affecting Type 2 Diabetes Pathogenesis

Type 2 diabetes (T2D) is a growing health concern with an estimated 462 million people having been diagnosed worldwide. T2D is characterized by chronically elevated blood glucose and insulin resistance, which culminate in a diminished function of the β-cell mass in its later stages. This can be perpetuated by and result in inflammation, excess reactive oxygen species production, obesity, and the dysregulation of multiple cellular pathways. Many naturally occurring small molecules have been investigated in terms of their roles in modulating glucose homeostasis and β-cell function. Many of these compounds can be found in commonly used sources of food and drink. Interestingly, a correlation has been observed between coffee consumption and T2D incidence. However, the specific compounds responsible for this correlation and their mechanisms are still somewhat undetermined. This paper reviews recent research findings on the effects of several polyphenols that are either found in coffee or are metabolites of compounds found in coffee (enterodiol, enterolactone, matairesinol, secoisolariciresinol, kaempferol, quercetin, and chlorogenic acid) on glucose homeostasis and health complications associated with glucose dysregulation, with a special emphasis on their potential anti-diabetic effects. The factors that affect polyphenol content in coffee are also addressed.

Variables Affecting the Extraction of Antioxidants in Cold and Hot Brew Coffee: A Review

Coffee beans are a readily available, abundant source of antioxidants used worldwide. With the increasing interest in and consumption of coffee beverages globally, research into the production, preparation, and chemical profile of coffee has also increased in recent years. A wide range of variables such as roasting temperature, coffee grind size, brewing temperature, and brewing duration can have a significant impact on the extractable antioxidant content of coffee products. While there is no single standard method for measuring all of the antioxidants found in coffee, multiple methods which introduce the coffee product to a target molecule or reagent can be used to deduce the overall radical scavenging capacity. In this article, we profile the effect that many of these variables have on the quantifiable concentration of antioxidants found in both cold and hot brew coffee samples. Most protocols for cold brew coffee involve an immersion or steeping method where the coffee grounds are in contact with water at or below room temperature for several hours. Generally, a higher brewing temperature or longer brewing time yielded greater antioxidant activity. Most studies also found that a lower degree of coffee bean roast yielded greater antioxidant activity.

Coffee fermentation process: A review

In recent years, the importance of controlling coffee fermentation in the final quality of the beverage has been recognized. The literature review was conducted in the Science Direct and Springer databases, considering studies published in the last ten years, 74 references were selected. Several studies have been developed to evaluate and propose fermentation conditions that result in sensory improvements in coffee. So, this review aims to describe detailed the different protocols for conducting the coffee fermentation step and how they could influence the sensory quality of coffee based on the Specialty Coffee Association protocol. We propose a new way to identify coffee post-harvest processing not based on the already known wet, dry and semi-dry processing. The new identification is focused on considering fermentation as a step influenced by the coffee fruit treatment, availability of oxygen, water addition, and starter culture utilization. The findings of this survey showed that each type of coffee fermentation protocol can influence the microbiota development and consequently the coffee beverage. There is a migration from the use of processes in open environments to closed environments with controlled anaerobic conditions. However, it is not possible yet to define a single process capable of increasing coffee quality or developing a specific sensory pattern in any environmental condition. The use of starter cultures plays an important role in the sensory differentiation of coffee and can be influenced by the fermentation protocol applied. The application of fermentation protocols well defined is essential in order to have a good product also in terms of food safety. More research is needed to develop and implement environmental control conditions, such as temperature and aeration, to guarantee the reproducibility of the results.

Coffee bean processing: Emerging methods and their effects on chemical, biological and sensory properties

Emerging processing methods have been applied in coffee bean processing for improved sensory quality. The processes focus on optimizing the fermentation process of the coffee cherries and beans. This involves various pathways, including the formation of volatiles, flavor precursors and organic acids and the reduction in the concentrations of bioactive compounds. Comprehensive information regarding the effect of these emerging processes on the chemical, biological and sensory properties of the coffee beans is summarized. Emerging processes affected the coffee bean to various degrees depending on the raw material and the method used. The emerging methods promoted the reduction of bioactives such as caffeine and phenolics in coffee beans. Substantial improvement of these processes is needed to obtain coffee beans with improved biological activities. Effort to simplify the methods and optimize the post-fermentation process is crucial for the methods to be easily accessible by the producers and to produce defect-free coffee beans.

Quality Evaluation of Hainan Robusta Coffee Bean Oil Produced by Ultrasound Coupled with Coconut Oil Extraction

This study investigates the treatment of coconut oil using thermosonic treatment in combination with green coffee beans. Under a defined ratio of coconut oil to green coffee beans, the effect of different thermosonic time on the quality parameters, active substance content, antioxidant capacity, and thermal oxidative stability of coconut oil were investigated as a strategy to potentially improve the quality of oil. Results showed that the β-sitosterol content of CCO (coconut coffee oil) treated with the thermal method combined with green coffee bean treatment reached up to 393.80 ± 11.13 mg/kg without affecting the lipid structure. In addition, DPPH clearance equivalents increased from 5.31 ± 1.30 mg EGCG/g to 71.34 ± 0.98 mg EGCG/g, and the ABTS clearance equivalent was 45.38 ± 0.87 mg EGCG/g versus 0 for the untreated sample. The improvement in thermal oxidation stability of treated coconut oil is also significant. The TG (Thermogravimetry) onset temperature was elevated from 277.97 °C to 335.08 °C and the induction time was elevated up to 24.73 ± 0.41 h from 5.17 ± 0.21 h. Thermosonic treatment in combination with green coffee beans is an ideal option to improve the quality of coconut oil. The results of this article provide new ideas for the development of plant-blended oil products and the new utilization of coconut oil and coffee beans.

Risk Assessment of Trigonelline in Coffee and Coffee By-Products

Trigonelline is a bioactive pyridine alkaloid that occurs naturally in high concentrations in coffee (up to 7.2 g/kg) and coffee by-products (up to 62.6 g/kg) such as coffee leaves, flowers, cherry husks or pulp, parchment, silver skin, and spent grounds. In the past, coffee by-products were mostly considered waste and discarded. In recent years, however, the use of coffee by-products as food has attracted interest because of their economic and nutritional value and the environmental benefits of sustainable resource use. Their authorization as so-called novel foods in the European Union may lead to increased oral exposure of the general population to trigonelline. Therefore, the aim of this review was to assess the risk to human health of acute and chronic exposure to trigonelline from coffee and coffee by-products. An electronic literature search was performed. Current toxicological knowledge is limited, with few human data available and a lack of epidemiological and clinical studies. There was no evidence of adverse effects after acute exposure. No conclusion can be drawn on chronic exposure to isolated trigonelline due to the lack of data. However, trigonelline ingested as a component of coffee and coffee by-products appears to be safe for human health, based on the safe traditional use of these products.

Changes of polyphenols and antioxidants of arabica coffee varieties during roasting

Coffee is the most consumed beverage in the world after water. Multiple benefits are attributed to it in human health due to the presence of antioxidant compounds, whose content depends, among other factors, on the processing conditions of the coffee bean. The objective of this study was to determine the kinetics of polyphenols and antioxidants during the roasting of three varieties of arabica coffee. For this, we worked with varieties of coffee, Catimor, Caturra, and Bourbon, from the province of La Convencion, Cuzco, Peru. The samples were roasted in an automatic induction roaster, and 12 samples were taken during roasting (at 0, 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, and 21 min of roasting) in triplicate. For green coffee beans, titratable acidity, total soluble solids, moisture and apparent density were determined. The change in polyphenol content was determined using the Folin-Ciocalteu method, and antioxidant activity was determined using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2-azino-bis- (3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS⁺) free radical capture technique during roasting. Polyphenol and antioxidant contents increased until minute 5 of roasting and then decreased until minute 20, and in some cases, there were slight increases in the last minute. The model that best described the changes in these bioactive compounds was the cubic model (R ² 0.634 and 0.921), and the best fits were found for the Bourbon variety, whose green grain had more homogeneous characteristics. The changes in the relative abundances of nine phenolic compounds were determined using high-performance liquid chromatography (HPLC). In conclusion, roasting modifies phenolic compounds and antioxidants differently in the coffee varieties studied. The content of some phenols increases, and in other cases, it decreases as the roasting time increases. The roasting process negatively affects the bioactive compounds and increases the fracturability of Arabica coffee beans, elements that should be taken into account at the moment of developing roasting models in the industry.

Chlorogenic Acids and Caffeine from Coffee By-Products: A Review on Skincare Applications

Upcycling is a modern trend in the cosmetic sector, focusing on by-products reuse and waste reduction. Consumers are more aware of the origin of cosmetic products and their environmental impact, promoting the upcycling phenomenon. Converting these raw materials into products of higher quality or value contributes to the final product’s sustainability. In fact, several agri-food by-products that are typically discarded have generated great interest, due to their value-added compounds with high functionality and/or bioactivity. Coffee is well known as a cosmetic ingredient, particularly due to the presence of phenolic compounds, such as chlorogenic acids, and caffeine. Caffeine is widely used in cosmetic formulations due to its photoprotector and anti-aging properties, as well as lipolytic action in cellulitis, and hair regrowth. Chlorogenic acids are powerful antioxidants and exhibit anti-aging and photoprotector abilities. Coffee by-products, such as coffee beans, possess these bioactive compounds and other chemical characteristics that can provide functional properties in cosmetic formulations. Coffee silverskin and spent coffee grounds are high-volume by-products of the coffee industry. Their use has been explored in different cosmetic formulations demonstrating safety, stability, acceptability as well as skin improvement, thus supporting their valorization as natural and sustainable new ingredients in skincare products.

Nutritional Composition of Tonka Bean (Dipteryx odorata) and Its Application as an Elder-Friendly Food with Gelling Agent

(1) Background: The purpose of this study was to compare the nutritional characteristics of Tonka beans according to the cooking method and to prove the feasibility of application as an elder-friendly food. (2) Methods: After analyzing the nutritive components, antioxidant activity, and anti-diabetic activity of raw, boiled, and roasted Tonka beans, custards, to which roasted Tonka beans were added, were prepared using a gelling agent to meet the KS viscosity standards (≤1500 mPa.s). (3) Results: The cooking methods decreased the nutritive factors in Tonka beans. However, while boiling caused significant losses, roasting led to minor losses. However, because the elderly should avoid eating uncooked foods for safety reasons, semi-solid elder-friendly food was manufactured with roasted Tonka beans, which caused minor losses compared to boiling. The concentration of each gelling agent satisfying the KS viscosity was less than 0.745% of locust bean gum, 0.734% of κ-carrageenan, and 1.094% of agar. (4) Conclusions: Roasted Tonka beans are suitable for use as an elder-friendly food for the health and safety of the elderly, and it will be possible to promote balanced food intake through the use of gelling agents for the elderly who have difficulty swallowing.

Bioaccessibility and bioactivities of phenolic compounds from roasted coffee beans during in vitro digestion and colonic fermentation

Bioaccessibility and bioactivity of phenolic compounds in coffee beans relate to roasting and digestion process. This study aimed to estimate phenolic content, antioxidant potential, bioaccessibility, and changes in short chain fatty acids (SCFAs) production during in vitro digestion and colonic fermentation of commercial roasted (light, medium and dark) coffee beans. There was no significant difference found among all three different roasting levels. TPC and DPPH were enhanced 15 mg GAE/g and 60 mg TE/g during gastrointestinal digestion, respectively. For colonic fermentation, the highest TPC and FRAP of all coffee beans was found at 2 and 4 h, respectively. The gastric bioaccessibility of most of the phenolic compounds were relatively higher due to thermal phenolic degradation. Total SCFAs production was only up to 0.02 mM because of thermal polysaccharide decomposition. Light roasted beans exhibited relatively higher phenolic bioaccessibility, antioxidant activities and SCFAs production, which would be more beneficial to gut health.

The Effect of Pre-Treatment of Arabica Coffee Beans with Cold Atmospheric Plasma, Microwave Radiation, Slow and Fast Freezing on Antioxidant Activity of Aqueous Coffee Extract

Thermal and non-thermal technologies used in food processing should be not only effective in terms of decontamination and preservation but also minimize undesirable losses of natural bioactive compounds. Arabica (Coffea arabica) is the most cultivated variety of coffee, making it a valuable source of phytonutrients, including antioxidants. In the present study, green and roasted Arabica coffee beans were treated with slow freezing (SF), fast freezing (FF), microwave radiation (MWR) and cold atmospheric plasma (CAP). Moisture content (MC) of coffee beans and antioxidant activity (AOA) of aqueous extracts were measured. Green coffee showed a decrease in MC after MWR treatment, and roasted coffee showed an increase in MC after freezing. After SF and FF at −19 °C for 24 h, all extract samples showed an increase in AOA by 4.1–17.2%. MWR treatment at 800 W for 60 s was accompanied by an increase in the AOA of green coffee extracts by 5.7%, while the changes in the AOA of roasted coffee extracts were insignificant. Sequential combined treatments of SF + MWR and FF + MWR resulted in an additive/synergistic increase in the AOA of green/roasted coffee extracts, up to +23.0%. After CAP treatment with dielectric barrier discharge (DBD) parameters of 1 μs, 15 kV and 200 Hz for 5 and 15 min, green coffee showed a decrease in the extract AOA by 3.8% and 9.7%, respectively, while the changes in the AOA of roasted coffee extracts were insignificant. A high positive correlation (r = 0.89, p < 0.001) between AOA and MC was revealed. The results obtained indicate that SF, FF, MWR and combined treatments may be applied at the pre-extraction stage of coffee bean preparation in order to increase the yield of antioxidant extractives.

Activating Effects of the Bioactive Compounds From Coffee By-Products on FGF21 Signaling Modulate Hepatic Mitochondrial Bioenergetics and Energy Metabolism in vitro

Coffee by-products contain bioactive compounds that have been shown to have the capacity to modulate human metabolism. The goal of this study was to investigate the effects of the main bioactive compounds in coffee by-products and two aqueous extracts from the coffee husk and silverskin on the activation of fibroblast growth factor 21 (FGF21) signaling and the subsequent regulation of mitochondrial bioenergetics and lipid and glucose metabolism. HepG2 cells treated with palmitic acid (PA) were used in a non-alcoholic fatty liver disease (NAFLD) cell model. The bioactive compounds from coffee by-products (50 μmol L⁻¹) and the aqueous extracts from the coffee silverskin and coffee husk (100 μg mL⁻¹) increased ERK1/2 phosphorylation and the secretion of FGF21 (1.3 to 1.9-fold). Coffee by-products' bioactive compounds counteracted inflammation and PA-triggered lipotoxicity. Oxidative stress markers (ROS, mitochondrial superoxide, and NADPH oxidase) and the activity of antioxidant enzymes (superoxide dismutase and catalase) were modulated through the activation of Nrf2 signaling. Mitochondrial bioenergetics were regulated by enhancing respiration and ATP production via PGC-1α, and the expression of oxidative phosphorylation complexes increased. Coffee by-products' bioactive compounds decreased lipid accumulation (23–41%) and fatty acid synthase activity (32–65%) and triggered carnitine palmitoyltransferase-1 activity (1.3 to 1.7-fold) by activating AMPK and SREBP-1c pathways. The GLUT2 expression and glucose uptake were increased (58–111%), followed by a promoted glucokinase activity (55–122%), while glucose production and phosphoenolpyruvate carboxykinase activity were reduced due to IRS-1/Akt1 regulation. The bioactive compounds from coffee by-products, primarily chlorogenic and protocatechuic acids, could regulate hepatic mitochondrial function and lipid and glucose metabolism by activating FGF21 and related signaling cascades.

Interactome of millet-based food matrices: A review

Millets are recently being recognized as emerging food ingredients with multifaceted applications. Whole grain flours made from millets, exhibit diverse chemical compositions, starch digestibility and physicochemical properties. A food matrix can be viewed as a section of food microstructure, commonly coinciding with a physical spatial domain that interacts or imparts specific functionalities to a particular food constituent. The complex millet-based food matrices can help individuals to attain nutritional benefits due to the intricate and unique digestive properties of these foods. This review helps to fundamentally understand the binary and ternary interactions of millet-based foods. Nutritional bioavailability and bioaccessibility are also discussed based on additive, synergistic, masking, the antagonistic or neutralizing effect of different food matrix components on each other and the surrounding medium. The molecular basis of these interactions and their effect on important functional attributes like starch retrogradation, gelling, pasting, water, and oil holding capacity is also discussed.

Effect of the Post-Harvest Processing on Protein Modification in Green Coffee Beans by Phenolic Compounds

The protein fraction, important for coffee cup quality, is modified during post-harvest treatment prior to roasting. Proteins may interact with phenolic compounds, which constitute the major metabolites of coffee, where the processing affects these interactions. This allows the hypothesis that the proteins are denatured and modified via enzymatic and/or redox activation steps. The present study was initiated to encompass changes in the protein fraction. The investigations were limited to major storage protein of green coffee beans. Fourteen Coffea arabica samples from various processing methods and countries were used. Different extraction protocols were compared to maintain the status quo of the protein modification. The extracts contained about 4–8 µg of chlorogenic acid derivatives per mg of extracted protein. High-resolution chromatography with multiple reaction monitoring was used to detect lysine modifications in the coffee protein. Marker peptides were allocated for the storage protein of the coffee beans. Among these, the modified peptides K.FFLANGPQQGGK.E and R.LGGK.T of the α-chain and R.ITTVNSQK.I and K.VFDDEVK.Q of β-chain were detected. Results showed a significant increase (p < 0.05) of modified peptides from wet processed green beans as compared to the dry ones. The present study contributes to a better understanding of the influence of the different processing methods on protein quality and its role in the scope of coffee cup quality and aroma.