Optimization of the Extraction from Spent Coffee Grounds Using the Desirability Approach

In-Vitro and In-Silico Investigation for the Spent-Coffee Bioactive Phenolics as a Promising Aflatoxins Production Inhibitor

Aflatoxin, is a naturally occurring polyketide generated by Aspergillus flavus via biosynthetic pathways, including polyketide synthase (PKS) and non-ribosomal enzymes. The in vitro analysis supported by molecular dynamics (MD) techniques was used to examine the antifungal and anti-aflatoxigenic activity of spent coffee grounds (SCGs) methanol extract. The High-Performance Liquid Chromatography results revealed the presence of 15 phenolic acids and five flavonoids. (R)-(+)-Rosmarinic acid (176.43 ± 2.41 µg/g) was the predominant of the detected acids, followed by gallic acid (34.83 ± 1.05 µg/g). At the same time, apigenin-7-glucoside is the dominant flavonoid in the SCGs extract by 1717.05 ± 5.76 µg/g, and naringin (97.27 ± 1.97 µg/g) comes next. The antifungal and anti-aflatoxigenic activity of the SCGs extracts was 380 µL/mL and 460 µL/mL, respectively. The SGGs’ effect of inhibiting five Aspergillus strains’ growth on the agar media ranged between 12.81 ± 1.71 to 15.64 ± 1.08 mm by two diffusion assays. Molecular docking results confirmed the inhibitory action of different phenolics and flavonoids on the PKS and NPS key enzymes of the aflatoxin biosynthetic mechanism. The SCGs extract components with the highest free binding energy, naringin (−9.1 kcal/mL) and apigenin 7-glucoside (−9.1 kcal/mol), were subjected to an MD simulation study. The computational results infer the stabilizing effects on the enzymes upon ligand binding led to the impairment in its functionality. The current study represents a novel attempt to assess the anti aflatoxins mechanism of phenolics and flavonoids targeting PKS and NPS via computational approaches compared to in-vitro assays.

Agri-Food Wastes as Natural Source of Bioactive Antioxidants

Nowadays, the health of the ecosystem and quality of life are jeopardized by the growing quantities of waste that are released into the environment [...].

Mechanisms Underlying Neurodegenerative Disorders and Potential Neuroprotective Activity of Agrifood By-Products

Neurodegenerative diseases, characterized by progressive loss in selected areas of the nervous system, are becoming increasingly prevalent worldwide due to an aging population. Despite their diverse clinical manifestations, neurodegenerative diseases are multifactorial disorders with standard features and mechanisms such as abnormal protein aggregation, mitochondrial dysfunction, oxidative stress and inflammation. As there are no effective treatments to counteract neurodegenerative diseases, increasing interest has been directed to the potential neuroprotective activities of plant-derived compounds found abundantly in food and in agrifood by-products. Food waste has an extremely negative impact on the environment, and recycling is needed to promote their disposal and overcome this problem. Many studies have been carried out to develop green and effective strategies to extract bioactive compounds from food by-products, such as peel, leaves, seeds, bran, kernel, pomace, and oil cake, and to investigate their biological activity. In this review, we focused on the potential neuroprotective activity of agrifood wastes obtained by common products widely produced and consumed in Italy, such as grapes, coffee, tomatoes, olives, chestnuts, onions, apples, and pomegranates.

Spent Coffee Grounds Valorization as Bioactive Phenolic Source Acquired Antifungal, Anti-Mycotoxigenic, and Anti-Cytotoxic Activities

Spent coffee grounds (SCGs), which constitute 75% of original coffee beans, represent an integral part of sustainability. Contamination by toxigenic fungi and their mycotoxins is a hazard that threatens food production. This investigation aimed to examine SCGs extract as antimycotic and anti-ochratoxigenic material. The SCGs were extracted in an eco-friendly way using isopropanol. Bioactive molecules of the extract were determined using the UPLC apparatus. The cytotoxicity on liver cancer cells (Hep-G2) showed moderate activity with selectivity compared with human healthy oral epithelial (OEC) cell lines but still lower than the positive control (Cisplatin). The antibacterial properties were examined against pathogenic strains, and the antifungal was examined against toxigenic fungi using two diffusion assays. Extract potency was investigated by two simulated models, a liquid medium and a food model. The results of the extract showed 15 phenolic acids and 8 flavonoids. Rosmarinic and syringic acids were the most abundant phenolic acids, while apigenin-7-glucoside, naringin, epicatechin, and catechin were the predominant flavonoids in the SCGs extract. The results reflected the degradation efficiency of the extract against the growth of Aspergillus strains. The SCGs recorded detoxification in liquid media for aflatoxins (AFs) and ochratoxin A (OCA). The incubation time of the extract within dough spiked with OCA was affected up to 2 h, where cooking was not affected. Therefore, SCGs in food products could be applied to reduce the mycotoxin contamination of raw materials to the acceptable regulated limits.

Microwave-Assisted Extraction of Phenolic Compounds from Spent Coffee Grounds. Process Optimization Applying Design of Experiments

In this study, sustainable technology microwave-assisted extraction (MAE) in association with green solvents was applied to recover phenolic compounds from spent coffee grounds (SCGs). A design of experiments (DOE) was used for process optimization. Initially, a 2⁴⁻¹ two level Fractional Factorial Design was used and ratios “solvent to solute” and “ethanol to water” were identified as the significant experimental factors. Consequently, Central Composite Design (CCD) was applied to analyze the effects of the significant variables on the response yield, total polyphenols content (TPC), and antioxidant activity (AA) by the DPPH assay method, and quadratic surfaces to optimize those responses were generated. The values of the significant factors of 16.7 (solvent/solute) and 68.9% (ethanol/water) were optimized simultaneously the yield (%) at 6.98 ± 0.27, TPC (mg GAE/g) at 117.7 ± 6.1, and AA (µmol TE/g) at 143.8 ± 8.6 and were in excellent agreement with those predicted from the CCD model. The variations of the compositions of the lipids, caffeine, pentacyclic diterpenes, and FAME as a function of the dominant factor % ethanol in the solvent mixture were analyzed by applying NMR and GC-FID, and the results obtained confirmed their determinative significance.

New Antioxidant Ingredients from Brewery By-Products for Cosmetic Formulations

The purpose of this work was to evaluate the total phenol content and antioxidant activity of different types of handcrafted beers (Ego, Alter, Fiat Lux, Triplo Malto, Ubi, and Maior), as well as the starting materials (malts, hops, and yeast), the intermediate products, and the waste products (spent malts, hops, and yeast), in view of their use in innovative cosmetic formulations. Extractions from starting and spent samples were taken from water or 70° alcohol. The total phenol content (Folin Ciocalteau Essay) of all the brewing products depended on the specific product under investigation. The highest values were found in starting hops (ranging from approximately 93 to 155 mg GAE/g, according to the extraction solvent), intermediate ones in starting malt and starting yeast, and the lowest values in wort. The total phenol content in the final beers originates from the phenols that were extracted from the different ingredients, namely the starting malts, hops and yeast, but non-negligible values were still observed in spent products. The method used for the evaluation of the antioxidant activity, trolox equivalent antioxidant capacity (DPPH), ferric-ion reducing antioxidant parameter (FRAP), and radical cation scavenging activity and reducing power (ABTS) strongly influenced the results. In general, the results reflected the trend observed for the total phenol content: that beers are progressively enriched by phenols originating from all the starting ingredients, and that spent products still possess non-negligible antioxidant activity. It is interesting to note that waste yeast frequently showed higher values than those of the starting material; it can be inferred that yeast is able to absorb phenols from the beer during brewing. By considering the interest in exploiting waste derived from processing foods, the biological activity of waste Alter brewery products has been evaluated on a cell culture of keratinocytes (spent products of malt, hop, and yeast). Preliminary in vitro assays in keratinocyte HaCaT cells were carried out to assess the potential bioactivity of spent extracts. Among the spent extracts, the spent hop and yeast extracts showed the ability to improve the mitochondrial activity and prevent oxidative stress in HaCaT cells, two features in skin ageing. In conclusion, this study offers evidence that waste from handcrafted beers can be an interesting source of phenols for the preparation of skin anti-aging cosmetics.

Valorization of Spent Coffee by Caffeine Extraction Using Aqueous Solutions of Cholinium-Based Ionic Liquids

Spent coffee grounds (SCGs) are a waste product with no relevant commercial value. However, SCGs are rich in extractable compounds with biological activity. To add value to this coffee byproduct, water and aqueous solutions of cholinium-based ionic liquids (ILs) were studied to extract caffeine from SCGs. In general, all IL aqueous solutions lead to higher extraction efficiencies of caffeine than pure water, with aqueous solutions of cholinium bicarbonate being the most efficient. A factorial planning was applied to optimize operational conditions. Aqueous solutions of cholinium bicarbonate, at a temperature of 80 °C for 30 min of extraction, a biomass–solvent weight ratio of 0.05 and at an IL concentration of 1.5 M, made it possible to extract 3.29 wt% of caffeine (against 1.50 wt% obtained at the best conditions obtained with pure water). Furthermore, to improve the sustainability of the process, the same IL aqueous solution was consecutively applied to extract caffeine from six samples of fresh biomass, where an increase in the extraction yield from 3.29 to 13.10 wt% was achieved. Finally, the cholinium bicarbonate was converted to cholinium chloride by titration with hydrochloric acid envisioning the direct application of the IL-caffeine extract in food, cosmetic and nutraceutical products. The results obtained prove that aqueous solutions of cholinium-based ILs are improved solvents for the extraction of caffeine from SCGs, paving the way for their use in the valorization of other waste rich in high-value compounds.

Antioxidant and Anti-Inflammatory Profiles of Spent Coffee Ground Extracts for the Treatment of Neurodegeneration

Spent coffee grounds (SCGs), waste products of coffee beverage production, are rich in organic compounds such as phenols. Different studies have demonstrated phenol beneficial effects in counteracting neurodegenerative diseases. These diseases are associated with oxidative stress and neuroinflammation, which initiates the degeneration of neurons by overactivating microglia. Unfortunately, to date, there are no pharmacological therapies to treat these pathologies. The aim of this study was to evaluate the phenolic content of 4 different SCG extracts and their ability to counteract oxidative stress and neuroinflammation. Caffeine and 5-O-caffeoylquinic acid were the most abundant compounds in all extracts, followed by 3-O-caffeoylquinic acid and 3,5-O-dicaffeoylquinic acid. The four extracts demonstrated a different ability to counteract oxidative stress and neuroinflammation in vitro. In particular, the methanol extract was the most effective in protecting neuron-like SH-SY5Y cells against H₂O₂-induced oxidative stress by upregulating endogenous antioxidant enzymes such as thioredoxin reductase, heme oxygenase 1, NADPH quinone oxidoreductase, and glutathione reductase. The water extract was the most effective in counteracting lipopolysaccharide-induced neuroinflammation in microglial BV-2 cells by strongly reducing the expression of proinflammatory mediators through the modulation of the TLR4/NF-κB pathway. On these bases, SCG extracts could represent valuable nutraceutical sources for the treatment of neurodegeneration.