The effect of coffee husks used as pellet bedding material on the intestinal barrier, immune-related gene expression and microbiota composition in the broiler chicken caecum.

Introduction: Using coffee husks as waste material for bedding contributes to sustainable development. A sustainable choice of bedding has also, however, to be a safe choice for poultry. The study analysed immune-related gene expression in the intestinal mucosa and indicator bacteria in caecal content collected from broiler chickens bedded on material with coffee husk addition. Material and Methods: One-day-old Ross 308 chickens were divided into four groups of 10 birds each in five replicates: C, the control group kept on wheat straw bedding; CH10, a group kept on bedding of 10% coffee husks and 90% wheat straw; CH25, a group kept on bedding of 25% husks and 75% straw; and CH50, a group kept on bedding of 50% husks and 50% straw. After 42 days, the birds were slaughtered, the caecal mucosae were removed for RNA isolation and the caecal content was collected for bacterial DNA isolation. The expression of genes involved in intestinal immune response and host organism defence and the relative abundance of indicator bacteria were analysed. Results: Upregulation of the expression of genes related to the immune response and intestinal tightness was correlated with an increase in the percentage of coffee husks in the pellet. Coffee husk pellets at 50% bedding content caused a significant numerical increase in Bifidobacterium and a statistically significant increase in Lactobacillus. A significant reduction in E. coli bacteria was also demonstrated in this group. Coffee husk pellets at all content percentages resulted in a statistically significant diminution of the level of Streptococcus bacteria. Conclusion: The addition of coffee husks to poultry litter effects beneficial changes in the expression of genes related to intestinal health and the caecal bacterial profile.

Oxygen-enriched carbon quantum dots from coffee waste: Extremely active organic photocatalyst for sustainable solar-to-H2O2 conversion.

Solar-driven artificial photosynthesis offers a promising avenue for hydrogen peroxide (H2O2) generation, an efficient and economical replacement for current methods. The efficiency and selectivity hurdles of the two-electron oxygen reduction reaction (ORR) in solar-to- H2O2 conversion are substantial barriers to large scale production. In this manuscript, a simple biomass-assisted synthesis was performed to produce oxygen-enriched carbon quantum dots (OE-CQDs) from spent coffee waste, acting as an efficient photocatalyst for solar-powered H2O2 production. OE-CQDs can stabilize and store light-generated electrons effectively, boosting charge separation and enhancing photocatalytic performance with longevity. The maximal photocatalytic H2O2 production was achieved viz the utilization of OE-CQDs with generation rate of 356.86 µmol g-1 h-1 by retaining 80% activity without any external sacrificial donors. The outstanding performance of synthesized OE-CQDs under light exposure at wavelength (λ) of 280 nm has been ensured by the quantum yield value of 9.4% upon H2O2 generation. The combinatorial benefits of OE-CQDs with their authentic crystalline structure and oxygen enrichment, is expected to be enhancing the ORR activity through accelerating charge transfer, and optimizing oxygen diffusion. Consequently, our eco-friendly method holds considerable promise for creating highly efficient, metal-free photocatalysts for artificial H2O2 production.

Whey protein concentrate and skimmed milk powder as encapsulation agents for coffee silverskin extracts processed by spray drying.

We tested the hypothesis that milk proteins, through microencapsulation, guarantee protection against bioactive substances in coffee silverskin extracts. Therefore, the aim of this study was to carry out technological, nutritional and physicochemical characterisation of a coffee silverskin extract microencapsulated using instant skim milk powder and whey protein concentrate as wall materials. The aqueous extract of coffee silverskin was spray-dried using 10% (w/v) skim milk powder and whey protein concentrate. The samples were characterised by determining the water content, water activity, particle size distribution, colour analysis and total phenolic compound content as well as antioxidant activity using 2,2-diphenyl-radical 1-picrylhydrazyl scavenging methods, nitric oxide radical inhibition and morphological analysis. The product showed water activity within a range that ensured greater stability, and the reduced degradation of the dried coffee silverskin extract with whey protein concentrate resulted in better rehydration ability. The luminosity parameter was higher and the browning index was lower for the encapsulated samples than for the pure coffee silverskin extract. The phenolic compound content (29.23 ± 8.39 and 34.00 ± 8.38 mg gallic acid equivalents/g for the coffee silverskin extract using skimmed milk powder and whey protein concentrate, respectively) and the antioxidant activity of the new product confirmed its potential as a natural source of antioxidant phenolic compounds. We conclude that the dairy matrices associated with spray drying preserved the bioactive and antioxidant activities of coffee silverskin extracts.

Production of biodiesel via esterification of coffee waste-derived bio-oil using sulfonated catalysts.

Catalytic esterification of acid-rich coffee waste-derived bio-oil was performed using sulfonated metal oxide catalysts (Al2O3, MgO, ZrO2, and TiO2) and ethanol to produce fatty acid alkyl esters. The potential of the sulfonated catalysts for esterification decreased in the following order: Ti-SO4 > Zr-SO4 > Al-SO4 > Mg-SO4. Particularly, Ti-SO4 and Zr-SO4 resulted in 91.2 % (peak area %) and 85.2 % esters, respectively. This is attributed to the contributions of well-dispersed Brønsted acid sites created by -SO3H functional groups, additional Lewis acid sites formed by Ti and Zr oxides, and their appropriate pore size. Compared with HCl and H3PO4, the use of H2SO4 for TiO2 treatment significantly enhanced ester formation. When using Ti-SO4, increasing the catalyst-to-feedstock ratio (1/2 âˆ¼ 1/10) significantly increased the esters' selectivity (38.7 %∼94.7 %). Ethanol utilization caused a superior selectivity for esters than methanol, while the increasing temperature favored ester production. This study proposes an eco-friendly and practical method for biodiesel generation.

Utilization of Spent Coffee Grounds for Bioelectricity Generation in Sediment Microbial Fuel Cells.

This study examined the utilization of spent coffee grounds with different aqueous extraction methods for the bioelectricity generation from coastal benthic sediment through a sediment microbial fuel cell (SMFC) system. Different methods for the aqueous extraction of SCGs were evaluated, including rinsing and drying of the SCG (SMFC-CRD), immersion, rinsing and drying (SMFC-CRID), drying alone (SMFC-CD), and untreated SCG (SMFC-C). The caffeine concentration in the SCG was significantly reduced using pretreatments, with SMFC-CRID achieving the lowest concentration of 0.021 ± 0.001 mg/g. SMFC-CRD contributed to the generation of the highest current density of 213.7 mA/m2 during closed-circuit operation and exhibited the highest power density of 96.9 mW/m2 in the polarization test, due to the suitable caffeine content of 0.275 ± 0.001 mg/g in the SCG. This study could provide a cost-effective method for reusing SCGs (i.e., 128 g) while generating bioelectricity as an alternative energy source. These results suggest that pretreatment with SCGs is essential for achieving optimal power density and reducing the caffeine concentration in the SMFC system.

Valorization of pectins from coffee wastes for the development of pectin-chitosan films.

Coffee wastes are underused materials, largely available in coffee producing regions, which can be used to obtain pectins for the development of films for packaging. Coffee residual water (CRW) provided a phenolic and protein rich-pectic fraction (CRWP), which has 49 % uronic acid. This pectic fraction was used for the development of films with chitosan (Chit). Additionally, pectins extracted from coffee pulp with acid, Coffea arabica pectin (CAP), hot water-soluble pectic fraction (HWSP), and chelating agent-soluble pectic fraction (CSP), were used to develop pectin-chitosan films. Flow and viscoelastic properties of film forming solutions were assessed, showing better characteristics for the pectins from the pulp over those from the residual water. The different composition of the pectin fractions allowed to relate film properties with their structural features and Fourier transform infrared (FTIR) spectroscopy showed interactions between pectin and chitosan in the films. Results showed that CAP-Chit and CSP-Chit films were transparent, hydrophobic, and had the best mechanical properties. These results demonstrate that coffee residual wastes have the potential to provide pectins that can be used for the development of films.

Evaluation of coffee husks in pellet bedding, performance characteristics, footpad dermatitis scoring, and meat quality of broiler ducks.

The study aimed to analyze the chemical composition of pellet bedding made of straw or coffee husks (10, 25, 50%) and the performance characteristics of broiler ducks and footpad dermatitis. During rearing, the properties of the bedding and utility features of ducks were analyzed, and the frequency of footpad dermatitis (FPD) in ducks was verified. There was a decrease in dry matter from the 28th day of rearing. The crude fiber, NDF, ADF, and nitrogen content decreased compared to fresh bedding, while phosphorus and potassium increased. The highest pH was found in the CH25 and CH50 groups in fresh bedding on day 42 and in CH50 on day 14. High adj. R2 was found due to rearing time and bedding material (0.817-0.985). The ducks' growth rate in the CH25 group was higher at week 6 than in the other groups. In CH10 and CH25 groups, higher carcass weight was found than in group C. In group CH10, a higher weight of pectoral muscles and lower wing proportion was found than in C. In CH25, a higher remains weight was shown than in C and CH50. In CH50, lower water-holding capacity in the pectoral muscles was found than in the other groups. Considering the bedding (the content of nitrogen, phosphorus, and potassium), carcass features, and meat quality (water-holding capacity, intramuscular fat, and water content), it is possible to use 10, 25 or 50% of coffee husks in straw pellets in the rearing of broiler ducks. Due to the FPD, the moisture should be lowered.

Utilization of coffee waste as a sustainable feedstock for high-yield lactic acid production through microbial fermentation.

Lactic acid is an important industrial precursor; however, high substrate costs are a major challenge in microbial fermentation-based lactic acid production. Coffee waste is a sustainable feedstock alternative for lactic acid production via microbial fermentation. Herein, the feasibility of coffee waste as a feedstock was explored by employing appropriate pretreatment methods and optimizing enzyme combinations. Coffee waste pretreatment with hydrogen peroxide and acetic acid along with a combination of Viscozyme L, Celluclast 1.5 L, and Pectinex Ultra SP-L achieved the 78.9 % sugar conversion rate at a substrate concentration of 4 % (w/v). Lactiplantibacillus plantarum WiKim0126-induced fermentation with a 4 % solid loading yielded a lactic acid concentration of 22.8 g/L (99.6 % of the theoretical maximum yield) and productivity of 0.95 g/L/h within 24 h. These findings highlight the viability of coffee waste as an eco-friendly resource for sustainable lactic acid production.

Use of coffee husks - comparison of pellet bedding quality, performance features, and some welfare indicators of broiler chickens.

BACKGROUND: The study aimed to evaluate the influence of wheat straw and different coffee husk (CHs) levels in pellet bedding on its quality, broiler chickens' performance, meat quality, and welfare indicators. In total, 200 Ross 308 chickens were divided into 4 groups: C - control with wheat straw pellet; CH10 - pellet with 10% CHs, CH25 - pellet with 25% CHs, and CH50 - pellet with 50% CHs. During 42 days of rearing, each bedding's physicochemical features were analyzed. The production results were controlled, and the footpad dermatitis, hock burns, and feather quality were assessed. From chosen birds, carcass composition was analyzed, as well as the qualitative features (color, water-holding capacity, drip loss) and breaking bone strength. RESULTS: The bedding material and rearing days influenced the content of dry matter, crude fiber, nitrogen, phosphorus, potassium, NDF, ADF, and pH. The results were inconclusive. The increasing trends in nitrogen, phosphorus, and potassium content were noticed at the end of rearing. Strong coefficient determination in bedding features was found (0.580 - 0.986). The pellet with CHs had no adverse effect on the growth performance of broilers. In the CH50 group, a lower fat percentage was found. A beneficial effect on water-holding capacity was noticed in leg muscles from CH10 and pectoral muscles from CH25. A significant decrease was found in footpad dermatitis incidence in groups CH25 and CH50. CONCLUSIONS: It can be concluded that CHs reuse in broilers as the pellet bedding material is possible due to the beneficial effect on some meat quality features and no adverse effect on the performance of broiler chickens. The positive impact on lower foot pad dermatitis incidence indicated the possibility of using CHs in pellet bedding.

Ginsentide-like Coffeetides Isolated from Coffee Waste Are Cell-Penetrating and Metal-Binding Microproteins.

Coffee processing generates a huge amount of waste that contains many natural products. Here, we report the discovery of a panel of novel cell-penetrating and metal ion-binding microproteins designated coffeetide cC1a-c and cL1-6 from the husk of two popular coffee plants, Coffea canephora and Coffea liberica, respectively. Combining sequence determination and a database search, we show that the prototypic coffeetide cC1a is a 37-residue, eight-cysteine microprotein with a hevein-like cysteine motif, but without a chitin-binding domain. NMR determination of cC1a reveals a compact structure that confers its resistance to heat and proteolytic degradation. Disulfide mapping together with chemical synthesis reveals that cC1a has a ginsentide-like, and not a hevein-like, disulfide connectivity. In addition, transcriptomic analysis showed that the 98-residue micrcoproten-like coffeetide precursor contains a three-domain arrangement, like ginsentide precursors. Molecular modeling, together with experimental validation, revealed a Mg2+ and Fe3+ binding pocket at the N-terminus formed by three glutamic acids. Importantly, cC1a is amphipathic with a continuous stretch of 19 apolar amino acids, which enables its cell penetration to target intracellular proteins, despite being highly negatively charged. Our findings suggest that coffee by-products could provide a source of ginsentide-like bioactive peptides that have the potential to target intracellular proteins.

Adsorptive removal of heavy metals and organic dyes by sodium alginate/coffee waste composite hydrogel.

Heavy metals and dyes used in technological applications have a detrimental influence on human health and the environment. The most used methods for removing pollutants depend on high-cost materials. Therefore, this research was conducted on cost-effective alternatives derived from natural resources and food waste. Herein, we designed a composite hydrogel based on sodium alginate/coffee waste (Alg/coffee) as adsorbent for the removal of organic and inorganic pollutants from aquatic solutions. The selectivity study displayed that Alg/coffee is more effective in adsorbing Pb(II) and acridine orange dye (AO). Adsorption of Pb(II) and AO was studied at concentration range of 0-170 mgL-1 and 0-40 mgL-1. Adsorption data of Pb(II) and AO reveals their fitting to Langmuir-isotherm and pseudo-second-order-kinetic models. The findings demonstrated that Alg/coffee hydrogel are more effective than coffee powder itself with an adsorption (%) approaching 98.44 % of Pb(II) and 80.53 % of AO. Real sample analysis reveals the efficiency of Alg/coffee hydrogel beads in Pb(II) adsorption. The adsorption cycle was examined four times providing high efficiency toward Pb(II) and AO. Desorption of Pb(II) and AO was easily performed using HCl eluent. Thus, Alg/coffee hydrogel beads could be promising adsorbent for the removal of organic and inorganic pollutants.

Improvement of Robusta coffee aroma by modulating flavor precursors in the green coffee bean with enzymatically treated spent coffee grounds: A circular approach.

Spent coffee grounds (SCG) are by-products obtained from the industrial process of instant coffee production or alternatively after brewing of coffee at the point of consumption. This solid residue represents one of the largest waste materials worldwide, making this fraction a rational target for valorization. The composition of SCG varies significantly depending on the brewing and extraction methods. However, this by-product is mainly composed of cellulose, hemicellulose polysaccharides and lipids. Here, we report on the enzymatic hydrolysis of industrial SCG by the use of a combination of specific carbohydrate active enzymes, enabling sugar extraction yield of 74.3 %. The generated sugar-rich extract, primarily composed of glucose (8.41 ± 1.00 % of total SCG mass) and mannose (2.88 ± 0.25 % of total SCG mass), is separated from hydrolyzed grounds and soaked with green coffee. After drying and roasting, the coffee soaked with SCG enzymatic extract displayed lower earthy, burnt and rubbery notes as well as smoother and more acidic notes in the flavor profile as compared to untreated reference. Aroma profiling performed by SPME-GC-MS corroborated the sensorial effect, with a 2-fold increase in the generation of sugar-derived molecules such as Strecker aldehydes and diketones after soaking and roasting and a 45 % and respectively 37 % reduction in phenolic compounds and pyrazines. This novel technology could represent an innovative in situ valorization stream for the coffee industry, coupled with sensory improvement of the final cup.

Phenanthrene sorption studies on coffee waste- and diatomaceous earth-based adsorbents, and adsorbent regeneration with cold atmospheric plasma.

Phenanthrene (PHE) is a polycyclic aromatic hydrocarbon categorized as a high priority organic pollutant being toxic for the ecosystem and human health, and its sorption on natural organic or inorganic substances seems a well-promising method for its removal from water streams. The goals of the present work are (i) to assess the capacity of low-cost adsorbents fabricated by treating coffee wastes and diatomaceous earth to remove PHE from water; (ii) to elucidate the role of the pore structure on PHE sorption dynamics; and (iii) to assess the potential to regenerate adsorbents loaded with PHE, by using the novel technology of cold atmospheric plasma (CAP). Diatomaceous earth (DE) and DE pre-treated with sodium hydroxide (NaOH) or phosphoric acid (H3PO4) were chosen as inorganic adsorbents. Coffee waste (CW) and activated carbons (AC) produced from its pyrolysis at 800 °C (CWAC), either untreated (CWAC-800) or pre-treated with NaOH (CWAC-NaOH-800) and H3PO4 (CWAC-H3PO4-800), were chosen as organic adsorbents. The adsorbents were characterized with nitrogen adsorption-desorption isotherms, attenuated total reflectance-Fourier transform infrared spectroscopy, Raman spectroscopy, scanning electron microscopy, and mercury intrusion porosimetry. Based on the PHE sorption capacity and pore structure/surface characteristics, the CWAC-NaOH-800 was chosen as the most efficient adsorbent for further equilibrium and kinetic sorption studies. The multi-compartment model was used to describe the PHE sorption dynamics in CWAC-NaOH-800 by accounting for the pore/surface diffusion and instantaneous sorption. The CWAC-NaOH-800 exhibited remarkable values for (i) the specific surface area (SBET = 676.5 m2/g) and meso- and micro-pore volume determined by nitrogen sorption (VLN2 = 0.415 cm3/g); (ii) the macro- and meso-pore volume determined by mercury intrusion porosimetry (VMIP = 3.134 cm3/g); and (iii) the maximum PHE sorption capacity (qmax = 142 mg/g). The percentage of adsorbent recovery after its regeneration with CAP was found to be ~ 35%. From the simulation of sorption dynamics, it was found that at early times, the sorption kinetics is governed by the film diffusion towards the external surface of grains, but at late times, most of the adsorbed mass is transferred primarily to meso-/macro-pores via diffusion, and secondarily to micro-porosity via surface diffusion. Based on the adsorbent characteristics, effect of pH on sorption efficiency, and numerical analysis of sorption dynamics, it was concluded that probably the dominant adsorption mechanism is the π-π interactions between hydrophobic PHE aromatic rings and CWAC-NaOH-800 graphene layers. The high PHE removal efficiency of CWAC-NaOH-800, the successful interpretation of sorption dynamics with the multi-compartment model, and the potential to regenerate PHE-loaded adsorbents with the green and economic technology of CAP motivate a strategy for testing CWACs towards the adsorption of other PAHs, application of adsorbents to real wastewaters, and scaling-up to pilot units.

Soil quality index as a tool to assess biochars soil quality improvement in a heavy metal-contaminated soil.

The assessment of soil quality improvement provided by biochars is complex and rarely examined. In this work, soil quality indices (SQIs) were produced to evaluate coffee industry feedstock biochars improvement on soil quality samples of a heavy metal-multicontaminated soil. Therefore, a 90-day incubation experiment was carried out with the following treatments: contaminated soil (CT), contaminated soil with pH raised to 7.0 (CaCO3), contaminated soil + 5% (m/m) coffee ground biochar, and contaminated soil + 5% (m/m) coffee parchment biochar (PCM). After incubation, chemical and biological attributes were analyzed, and the data were subjected to principal component analysis and Pearson correlation to obtain a minimum dataset (MDS), which explain the majority of the variance of the data. The MDS-selected attributes were dehydrogenase and protease activity, exchangeable Ca content, phytoavailable content of Cu, and organic carbon, which composed the SQI. The resulting SQI ranged from 0.50 to 0.56, with the highest SQI obtained for the PCM treatment and the lowest for the CT. The phytoavailable content Cu was the determining factor for differentiating PCM from the other treatments, which was a biochar original attribute and helped to improve soil quality based on the SQI evaluation, further than heavy metal immobilization due to the soil sample pH increase. Longer-term experiments may illustrate clearer advantages of using biochar to improve heavy metal-contaminated soil quality, as physical attributes may also respond, and more significant contributions to biological attributes could be obtained as biochar ages.

Value-Added Products from Coffee Waste: A Review.

Coffee waste is often viewed as a problem, but it can be converted into value-added products if managed with clean technologies and long-term waste management strategies. Several compounds, including lipids, lignin, cellulose and hemicelluloses, tannins, antioxidants, caffeine, polyphenols, carotenoids, flavonoids, and biofuel can be extracted or produced through recycling, recovery, or energy valorization. In this review, we will discuss the potential uses of by-products generated from the waste derived from coffee production, including coffee leaves and flowers from cultivation; coffee pulps, husks, and silverskin from coffee processing; and spent coffee grounds (SCGs) from post-consumption. The full utilization of these coffee by-products can be achieved by establishing suitable infrastructure and building networks between scientists, business organizations, and policymakers, thus reducing the economic and environmental burdens of coffee processing in a sustainable manner.

Valorization of coffee wastes as plant growth promoter in mulching film production: A contribution to a circular economy.

Food waste valorization, considered as energy and/or chemicals source, via biorefinery or biotechnology, gained great attention in recent years, because of the fast depletion of primary resources, increased waste generation and landfilling worldwide. Coffee by-products for example (i.e. coffee pulp, coffee husks, silver skin, spent coffee, etc.) have been investigated in different forms either as a source of antioxidant and valuable chemicals and as a filler in composites. A new valorization route for coffee silver skin (CSS), up to now just sent to damping, is here investigated: particulate bio-composites based on poly(butylene succinate-co-adipate) (PBSA), an aliphatic biodegradable polyester commercially available, have been formulated with up to a 30 wt% of CSS, in order to prepare mulching films for agriculture. The bacterial analysis of the filler indeed, has underlined the presence of potential Plant Growth-Promoting Bacteria species, mainly ascribed to the Bacillus genus, which can survive both the roasting and the compounding processes. The obtained composites have been characterized mechanically and thermally and their hydrophilic nature has been investigated by measuring their contact angle. Eventually, the bacteria release from the composite films has been examined by means of in-vitro tests. The plant growth promoting capability of the films was preliminarily evaluated in pot experiments using lettuce as a model crop. The composite films were able to release the endogenous bacteria in the soil and to stimulate plant and root growth of the assayed crop. The possibility to produce functionalized biodegradable mulching films by recycling agricultural wastes can thus be forecast, highlighting potential multiple advantages in terms of soil preservation/fertilization, decrease of polymeric materials in mulching products, exploitation of a waste.

Pyrolysis of tea and coffee wastes: effect of physicochemical properties on kinetic and thermodynamic characteristics.

Physicochemical properties, kinetic pyrolysis and thermodynamic study of spent green tea, pure spent coffee grounds, spent coffee grounds blended with 50% torrefied barley and coffee husk were experimentally investigated using thermogravimetric analysis under an inert atmosphere to evaluate their thermochemical application. Five isoconversional methods were applied to determine effective activation energy (E a) of the pyrolysis processes. All methods showed good agreement by determining fluctuating E a values (150-500 kJ mol-1). Complex E a profiles with conversion were divided into four stages corresponding to thermal degradation of main biomass constituents (extractives, hemicellulose, cellulose and lignin), indicating that extractives decomposition was the least demanding reaction while lignin decomposition was the most demanding. The kinetic process was verified by reconstruction according to the Friedman parameters. The thermodynamic parameters were evaluated to determine the energy demand and efficiency throughout the process. The values obtained for physicochemical properties such as volatile matter (> 68%) and higher heating value (> 17 MJ kg-1), average E a (223-319 kJ mol-1) and significant energy efficiency implied that these types of biomass waste have significant reactivity and consequently the highest potential for the production of bioenergy and a range of high-value chemicals and materials. Supplementary Information: The online version contains supplementary material available at 10.1007/s10973-022-11878-4.

Coffee Waste Macro-Particle Enhancement in Biopolymer Materials for Edible Packaging.

Plastic pollution has raised interest in biodegradable and sustainable plastic alternatives. For edible food packaging, seaweed biopolymers have been studied for their film-forming properties. In this study, packaging films were developed using the solvent casting technique from natural red seaweed (Kappaphycus alvarezii) and coffee waste product. The physico-chemical and thermal properties of seaweed/coffee biopolymer films was obtained using dynamic light scattering (DLS), scanning electron microscopy (SEM), Fourier transmission irradiation (FT-IR), water contact angle measurement (WCA) and thermogravimetric analysis (TGA). The characterization study was carried out to improve the film's morphological, thermal, and mechanical properties. The average particle size of coffee waste was found to be between 1.106 and 1.281 µm, with a zeta potential value of -27.0 mV indicating the compound's strong negative charge. The SEM analysis revealed that the coffee filler was evenly dispersed in the polymer matrix, improving the film's structural properties. The FT-IR result shows that coffee waste was successfully incorporated over the film matrix with the presence of a N-H bond. The hydrophobic property of the film was enhanced with the incorporation of coffee filler, indicating increased water contact angle compared to the neat film. The tensile properties of the biopolymer film were significantly improved at 4 wt% coffee powder with optimum tensile strength (35.47 MPa) with the addition of coffee waste powder. The incorporation of coffee waste into the seaweed matrix increased the functional properties of the fabricated biopolymer film. Thus, seaweed/coffee biopolymer film has the potential to be used in food packaging and other applications.

Humic-like crop stimulatory activities of coffee waste induced by incorporation of phytotoxic phenols in melanoidins during coffee roasting: Linking the Maillard reaction to humification.

Here we showed that the water-soluble components of fresh green coffee beans inhibit the growth of lettuce in hydroponic systems, whereas those of roasted coffee waste facilitate it. The growth enhancement was hardly related to hydroponic parameters (i.e., pH and electric conductivity) or the nitrogen contents of the extracts. Rather, the presence of chromogenic polymeric melanoidins in the coffee waste was found to be crucial for the crop growth acceleration. The quantitative comparison of low-molecular-weight organics including phytotoxic phenolics between the extracts suggested that Maillard reactions occurring during coffee roasting transform the phenolics into polymeric melanoidin products. The identification of humic-like molecular compositions in the roasted coffee waste and the restoration of crop-stimulating activity by the addition of a phenol oxidase to the fresh coffee bean extract also supported that the low-molecular-weight phenols are oxidatively coupled during the roasting, which was consistent with the bottom-up synthesis of crop-stimulatory humic substances.

Evaluation of Physico-Mechanical Properties on Oil Extracted Ground Coffee Waste Reinforced Polyethylene Composite.

The current work discusses ground coffee waste (GCW) reinforced high-density polyethylene (HDPE) composite. GCW underwent two types of treatment (oil extraction, and oil extraction followed by mercerization). The composites were prepared using stacking HDPE film and GCW, followed by hot compression molding with different GCW particle loadings (5%, 10%, 15% and 20%). Particle loadings of 5% and 10% of the treated GCW composites exhibited the optimum level for this particular type of composite, whereby their mechanical and thermal properties were improved compared to untreated GCW composite (UGC). SEM fracture analysis showed better adhesion between HDPE and treated GCW. The FTIR conducted proved the removal of unwanted impurities and reduction in water absorption after the treatment. Specific tensile modulus improved for OGC at 5 vol% particle loading. The highest impact energy absorbed was obtained by OGC with a 16% increment. This lightweight and environmentally friendly composite has potential in high-end packaging, internal automotive parts, lightweight furniture, and other composite engineering applications.