Antiglycative and carbonyl trapping properties of the water soluble fraction of coffee silverskin

Health Benefits of Olive Leaf: The Focus on Efficacy of Antiglycation Mechanisms

Olive leaves have been a therapeutic herbal agent for diseases for centuries. Olive leaves contain many health-beneficial nutrients and bioactive components. There is much evidence for the positive effects of the phenolic compounds they contain on health. The main active phenolic component in olive leaves is oleuropein, which can constitute 6%-9% of the leaf's dry matter and has been intensively studied for its promising results/effects on human health. In addition, olive leaf provides health benefits through bioactive components, such as secoiridoids, flavonoids, triterpenes, and lignans. The anti-inflammatory, antioxidant, anticancer, antidiabetic, and antihypertensive properties of bioactive components, especially oleuropein, are well known. In addition, various health benefits, such as neuroprotective effects and microbiota modulation, are also mentioned. In recent years, in vitro studies have shown that olive leaves and bioactive components from olive leaves may have antiglycation effects. Currently, it is thought that the components found in olive leaves have a direct or indirect antiglycation effect. It is thought that, their direct effects include reducing the interaction between sugars and amino acids, nucleic acids, and lipids and sequestering reactive dicarbonyl species, and their indirect effects include preventing the formation of advanced glycation end-products (AGEs) by reducing inflammation and oxidative stress. However, in vivo and clinical studies are needed to prove these mechanisms and understand how their metabolism works in the human body. This review examines the beneficial health effects of olive leaves and their potential antiglycation role.

Coffee leaf extract inhibits advanced glycation end products and their precursors: A mechanistic study

Excessive accumulation of advanced glycation end products (AGEs) in the body is associated with diabetes and its complications. In this study, we aimed to explore the potential and mechanism of coffee leaf extract (CLE) in inhibiting the generation of AGEs and their precursors in an in vitro glycation model using bovine serum albumin and glucose (BSA-Glu) for the first time. High-performance liquid chromatography analysis revealed that CLE prepared with ultrasound pretreatment (CLE-U) contained higher levels of trigonelline, mangiferin, 3,5-dicaffeoylquinic acid, and γ-aminobutyric acid than CLE without ultrasound pretreatment (CLE-NU). The concentrations of these components, along with caffeine and rutin, were dramatically decreased when CLE-U or CLE-NU was incubated with BSA-Glu reaction mixture. Both CLE-U and CLE-NU exhibited a dose-dependent inhibition of fluorescent AGEs, carboxymethyllysine, fructosamine, 5-hydroxymethylfurfural, 3-deoxyglucosone, glyoxal, as well as protein oxidation products. Notably, CLE-U exhibited a higher inhibitory capacity compared to CLE-NU. CLE-U effectively quenched fluorescence intensity and increased the α-helix structure of the BSA-Glu complex. Molecular docking results suggested that the key bioactive compounds present in CLE-U interacted with the arginine residues of BSA, thereby preventing its glycation. Overall, this research sheds light on the possible application of CLE as a functional ingredient in combating diabetes by inhibiting the generation of AGEs.

Effects of lotus seedpod oligomeric procyanidins on the inhibition of AGEs formation and sensory quality of tough biscuits

The advanced glycation end products (AGEs) are formed in baked products through the Maillard reaction (MR), which are thought to be a contributing factor to chronic diseases such as heart diseases and diabetes. Lotus seedpod oligomeric procyanidins (LSOPC) are natural antioxidants that have been added to tough biscuit to create functional foods that may lower the risk of chronic diseases. The effect of LSOPC on AGEs formation and the sensory quality of tough biscuit were examined in this study. With the addition of LSOPC, the AGEs scavenging rate and antioxidant capacity of LSOPC-added tough biscuits were dramatically improved. The chromatic aberration (ΔE) value of tough biscuits containing LSOPC increased significantly. Higher addition of LSOPC, on the other hand, could effectively substantially reduced the moisture content, water activity, and pH of LSOPC toughen biscuits. These findings imply that using LSOPC as additive not only lowers the generation of AGEs, but also improves sensory quality of tough biscuit.

Can coffee silverskin be a useful tool to fight metabolic syndrome?

Coffee is one of the most consumed products in the world, and its by-products are mainly discarded as waste. In order to solve this problem and in the context of a sustainable industrial attitude, coffee by-products have been studied concerning their chemical and nutritional features for a potential application in foodstuffs or dietary supplements. Under this perspective, coffee silverskin, the main by-product of coffee roasting, stands out as a noteworthy source of nutrients and remarkable bioactive compounds, such as chlorogenic acids, caffeine, and melanoidins, among others. Such compounds have been demonstrating beneficial health properties in the context of metabolic disorders. This mini-review compiles and discusses the potential health benefits of coffee silverskin and its main bioactive components on metabolic syndrome, highlighting the main biochemical mechanisms involved, namely their effects upon intestinal sugar uptake, glucose and lipids metabolism, oxidative stress, and gut microbiota. Even though additional research on this coffee by-product is needed, silverskin can be highlighted as an interesting source of compounds that could be used in the prevention or co-treatment of metabolic syndrome. Simultaneously, the valorization of this by-product also responds to the sustainability and circular economy needs of the coffee chain.

Modulation of 1,2-Dicarbonyl Compounds in Postprandial Responses Mediated by Food Bioactive Components and Mediterranean Diet

Glycoxidative stress with the consequent generation of advanced glycation end products has been implied in the etiology of numerous non-communicable chronic diseases. During the postprandial state, the levels of 1,2-dicarbonyl compounds can increase, depending on numerous factors, including characteristics of the subjects mainly related to glucose metabolism disorders and nutritional status, as well as properties related to the chemical composition of meals, including macronutrient composition and the presence of dietary bioactive molecules and macromolecules. In this review, we examine the chemical, biochemical, and physiological pathways that contribute to postprandial generation of 1,2-dicarbonyl compounds. The modulation of postprandial 1,2-dicarbonyl compounds is discussed in terms of biochemical pathways regulating the levels of these compounds, as well as the effect of phenolic compounds, dietary fiber, and dietary patterns, such as Mediterranean and Western diets.

Valorization of Coffee Silverskin through Subcritical Water Extraction: An Optimization Based on T-CQA Using Response Surface Methodology

Coffee silverskin (CS) is the only byproduct of the roasting process for coffee beans and is rich in phenolic compounds with various bioactivities. This study proposes a valorization option for bioactive compounds (T-CQA) based on a subcritical water extraction (SWE) technique, which is known for its high efficiency and feasibility for use on an industrial scale. The use of water as a sole solvent requires a minimum number of cleaning steps and renders the extract safe for further applications, such as in either the cosmetic or food industry. Response surface methodology with a Box–Behnken design is effectively used to optimize and explain the individual and interactive process variables (i.e., extraction temperature, extraction time, and solid–liquid ratio) on the T-CQA content obtained from coffee silverskin by the SWE technique. The final model exhibits a precise prediction of the experimental data obtained for the maximum T-CQA content. Under the optimum conditions, the CS extract is found to contain a higher content of T-CQA and TPC than that reported previously. For antioxidant activity, up to 26.12 ± 3.27 mg Trolox equivalent/g CS is obtained.

In vitro bioactivities of coffee brews fermented with the probiotics Lacticaseibacillus rhamnosus GG and Saccharomyces boulardii CNCM-I745

Previously, we demonstrated the production of bioactive metabolites (e.g., indole-3-lactate, 4-hydroxyphenyllactate, 3-phenyllactate, 2-isopropylmalate) by the probiotics Lacticaseibacillus rhamnosus GG and Saccharomyces boulardii CNCM-I745 during coffee brew fermentation. However, it remains unclear if in situ production of bioactive metabolites confers additional health benefits to coffee brews. Here, we aimed to investigate the in vitro bioactivities of freeze-dried cell-free coffee supernatants fermented with L. rhamnosus GG and/or S. boulardii CNCM-I745, compared to non-fermented coffee supernatants. In vitro bioactivity assays pertained to α-amylase and α-glucosidase inhibition, antiglycative activities, anti-proliferation against human cancer cell lines (MCF-7, HCT116, and HepG2), cellular antioxidant activities, and anti-inflammatory activities. We demonstrated that non-fermented coffee supernatants displayed weak starch hydrolase inhibition (IC₅₀ > 36.00 mg/mL), but otherwise displayed strong anti-glycative (IC₅₀ 0.71-0.74 mg/mL), anti-proliferative (IC₅₀ 0.45, 0.36, and < 0.5 mg/mL for MCF-7, HCT116, and HepG2 respectively), cellular antioxidant (85,844.22 µmol quercetin equivalents/100 g coffee supernatant), and anti-inflammatory activities (35.7% reduction in nitrite production at 0.13 mg/mL). In all the assays tested, probiotic fermented coffee supernatants exhibited very similar bioactivities compared to non-fermented coffee supernatants, and improvements were not observed. Overall, in vitro bioactivities of coffee brews were not improved via in situ metabolite production by L. rhamnosus GG and/or S. boulardii CNCM-I745. Therefore, bioactive metabolites produced during probiotic-induced food fermentations may not necessarily confer additional health benefits compared to non-fermented counterparts.

Halophytes as source of bioactive phenolic compounds and their potential applications

Halophytes are salt-tolerant plants that inhabit environments in which they are exposed to extreme stress, wherefore they exhibit conserved and divergent metabolic responses different from those of conventional plants. Thus, the synthesis and accumulation of metabolites, especially of those oxidative stress-related such as phenolic compounds, should be investigated. The potential of halophytes as a source of phenolics and their prospective industrial applications are evaluated based on a comprehensive review of the scientific literature on the phenolic compounds of more than forty halophytes and their biological activities. Additionally, an overview of the analytical methodologies adopted for phenolics determination in halophytes is provided. Finally, the prospective uses and beneficial effects of the phenolic preparations from these plants are discussed. Halophytes are complex matrices, exhibiting a wide variety of phenolics in their composition, wherefore the results can be greatly affected depending on the organ plant under analysis and the extraction methodology, especially the extraction solvent used. High-performance liquid chromatography, coupled with diode array detection (HPLC-DAD) or mass spectrometry (HPLC-MS), are the most used technique. Halophytes biosynthesize phenolics in concentrations that justify the remarkable antioxidant and antimicrobial activities shown, making them ideal sources of bioactive molecules to be employed in a multitude of sectors.

Coffee Silver Skin: Chemical Characterization with Special Consideration of Dietary Fiber and Heat-Induced Contaminants

Coffee silver skin is produced in large amounts as a by-product during the coffee roasting process. In this study, coffee silver skin of the species Coffea arabica L. and Coffea canephora Pierre ex A. Froehner as well as silver skin pellets produced in the coffee industry were characterized with respect to both nutritional value and potential heat-induced contaminants. Enzymatic-gravimetric/chromatographic determination of the dietary fiber content showed values ranging from 59 to 67 g/100 g with a comparably high portion of soluble fiber, whereas low molecular weight soluble fiber was not detected. Compositional and methylation analysis indicated the presence of cellulose and xylans in the insoluble dietary fiber fraction, whereas pectic polysaccharides dominate the soluble dietary fiber fraction. The protein content as determined by the Kjeldahl method was in the range of 18 to 22 g/100 g, and all essential amino acids were present in coffee silver skin; whereas fat contents were low, high ash contents were determined. Elemental analysis by inductively coupled plasma mass spectrometry (ICP-MS) showed the presence of macroelements in large amounts, whereas toxic mineral elements were only detected in trace amounts or being absent. Acrylamide was quantified with levels of 24–161 µg/kg. Although 5-hydroxymethylfurfural was detected, its concentration was below the limit of determination. Furfuryl alcohol was not detected.

Characterization of Coffee Silver Skin as Potential Food-Safe Ingredient

By-products from the coffee industry are produced in large amounts each year. Among other wastes, coffee silver skin (CSS) is highly available and more stable due to its lower content of water. This research aimed to characterize coffee silver skin composition and evidence its potentiality for use as a food-safe ingredient in new formulations. Results showed an average total dietary fiber content of 50% but with a higher ratio for insoluble than soluble fiber. A high content of total phenolic compounds, chlorogenic acid, caffeine, and caffeic acid was found and correlated with the high measured antioxidant capacity. Moreover, minerals (e.g., calcium, magnesium, phosphorous, potassium, copper, iron, manganese) important for human wellbeing were found at a high level in CSS, while toxic minerals (e.g., nickel) were found at low levels. In conclusion, coffee silver skin could have an advantageous role for the recovery of valuable compounds and as a potential food-safe ingredient.

Novel advances in inhibiting advanced glycation end product formation using natural compounds

Advanced glycation end products (AGEs) are a group of complex compounds generated by nonenzymatic interactions between proteins and reducing sugars or lipids. AGEs accumulate in vivo and activate various signaling pathways closely related to the occurrence of various chronic metabolic diseases. In this paper, we describe the process through which AGEs are formed, the classification of AGEs, and biological effects of AGEs on human health. Most importantly, we review recent progress in natural compound-based AGE formation inhibitors. Major classes of natural inhibitors, including polyphenols, polysaccharides, terpenoids, vitamins and alkaloids, have been described. Their mechanisms of action have been summarized as scavenging free radicals, chelating metal ions, capturing active carbonyl compounds, protecting protein glycation sites, and lowering blood glucose levels. Although these natural compounds have good antiglycation activity, to date, they are not widely used in the clinic, likely because of their low content levels. However, these natural compounds and their molecular frameworks will play a valuable role in inspiring drug discovery.

Potential applications of by-products from the coffee industry in polymer technology - Current state and perspectives

Coffee is one of the most popular beverages in the world, and its popularity is continuously growing, which can be expressed by almost doubling production over the last three decades. Cultivation, processing, roasting, and brewing coffee are known for many years. These processes generate significant amounts of by-products since coffee bean stands for around 50% of the coffee cherry. Therefore, considering the current pro-ecological trends, it is essential to develop the utilization methods for the other 50% of the coffee cherry. Among the possibilities, much attention is drawn to polymer chemistry and technology. This industry branch may efficiently consume different types of lignocellulosic materials to use them as fillers for polymer composites or as intermediate sources of particular chemical compounds. Moreover, due to their chemical composition, coffee industry by-products may be used as additives modifying the oxidation resistance, antimicrobial, or antifungal properties of polymeric materials. These issues should be considered especially important in the case of biodegradable polymers, whose popularity is growing over the last years. This paper summarizes the literature reports related to the generation and composition of the coffee industry by-products, as well as the attempts of their incorporation into polymer technology. Moreover, potential directions of research based on the possibilities offered by the coffee industry by-products are presented.

Attenuation of methylglyoxal-induced glycation and cellular dysfunction in wound healing by Centella cordifolia

Current pre-clinical evidences of Centella focus on its pharmacological effects on normal wound healing but there are limited studies on the bioactivity of Centella in cellular dysfunction associated with diabetic wounds. Hence we planned to examine the potential of Centella cordifolia in inhibiting methylglyoxal (MGO)-induced extracellular matrix (ECM) glycation and promoting the related cellular functions. A Cell-ECM adhesion assay examined the ECM glycation induced by MGO. Different cell types that contribute to the healing process (fibroblasts, keratinocytes and endothelial cells) were evaluated for their ability to adhere to the glycated ECM. Methanolic extract of Centella species was prepared and partitioned to yield different solvent fractions which were further analysed by high performance liquid chromatography equipped with photodiode array detector (HPLC-PDA) method. Based on the antioxidant [2,2-diphenyl-1-picrylhydrazyl (DPPH) assay] screening, anti-glycation activity and total phenolic content (TPC) of the different Centella species and fractions, the ethyl acetate fraction of C. cordifolia was selected for further investigating its ability to inhibit MGO-induced ECM glycation and promote cellular distribution and adhesion. Out of the three Centella species (C. asiatica, C. cordifolia and C. erecta), the methanolic extract of C. cordifolia showed maximum inhibition of Advanced glycation end products (AGE) fluorescence (20.20 ± 4.69 %, 25.00 ± 3.58 % and 16.18 ± 1.40 %, respectively). Its ethyl acetate fraction was enriched with phenolic compounds (3.91 ± 0.12 mg CAE/μg fraction) and showed strong antioxidant (59.95 ± 7.18 μM TE/μg fraction) and antiglycation activities. Improvement of cells spreading and adhesion of endothelial cells, fibroblasts and keratinocytes was observed for ethyl acetate treated MGO-glycated extracellular matrix. Significant reduction in attachment capacity of EA.hy926 cells seeded on MGO-glycated fibronectin (41.2%) and attachment reduction of NIH3t3 and HaCaT cells seeded on MGO-glycated collagen (33.7% and 24.1%, respectively) were observed. Our findings demonstrate that ethyl acetate fraction of C. cordifolia was effective in attenuating MGO-induced glycation and cellular dysfunction in the in-vitro wound healing models suggesting that C. cordifolia could be a potential candidate for diabetic wound healing. It could be subjected for further isolation of new phytoconstituents having potential diabetic wound healing properties.

Applications of Compounds from Coffee Processing By-Products

To obtain the coffee beverage, approximately 90% of the edible parts of the coffee cherry are discarded as agricultural waste or by-products (cascara or husk, parchment, mucilage, silverskin and spent coffee grounds). These by-products are a potential source of nutrients and non-nutrient health-promoting compounds, which can be used as a whole ingredient or as an enriched extract of a specific compound. The chemical composition of by-products also determines food safety of the novel ingredients. To ensure the food safety of coffee by-products to be used as novel ingredients for the general consumer population, pesticides, mycotoxins, acrylamide and gluten must be analyzed. According with the priorities proposed by the Food Agriculture Organization of the United Nations (FAO) to maximize the benefit for the environment, society and economy, food waste generation should be avoided in the first place. In this context, the valorization of food waste can be carried out through an integrated bio-refinery approach to produce nutrients and bioactive molecules for pharmaceutical, cosmetic, food and non-food applications. The present research is an updated literature review of the definition of coffee by-products, their composition, safety and those food applications which have been proposed or made commercially available to date based on their chemical composition.

Healthy eating recommendations: good for reducing dietary contribution to the body's advanced glycation/lipoxidation end products pool?

The present review aims to give dietary recommendations to reduce the occurrence of the Maillard reaction in foods and in vivo to reduce the body's advanced glycation/lipoxidation end products (AGE/ALE) pool. A healthy diet, food reformulation and good culinary practices may be feasible for achieving the goal. A varied diet rich in fresh vegetables and fruits, non-added sugar beverages containing inhibitors of the Maillard reaction, and foods prepared by steaming and poaching as culinary techniques is recommended. Intake of supplements and novel foods with low sugars, low fats, enriched in bioactive compounds from food and waste able to modulate carbohydrate metabolism and reduce body's AGE/ALE pool is also recommended. In conclusion, the recommendations made for healthy eating by the Spanish Society of Community Nutrition (SENC) and Harvard University seem to be adequate to reduce dietary AGE/ALE, the body's AGE/ALE pool and to achieve sustainable nutrition and health.

In Vitro Bioaccessibility and Antioxidant Activity of Coffee Silverskin Polyphenolic Extract and Characterization of Bioactive Compounds Using UHPLC-Q-Orbitrap HRMS

Coffee silverskin (CS), the main by-product in the coffee industry, contains a vast number of human health-related compounds, which may justify its exploitation as a functional food ingredient. This study aimed to provide a comprehensive analysis of the polyphenolic and alkaloid profile through UHPLC-Q-Orbitrap HRMS analysis. The bioaccessibility of total phenolic compounds and changes in the antioxidant activity during an in vitro gastrointestinal digestion were also evaluated through spectrophotometric tests (TPC by Folin-Ciocalteu, ABTS, DPPH, and FRAP), to elucidate their efficacy for future applications in the nutraceutical industry. Caffeoylquinic and feruloylquinic acids were the most representative polyphenols, with a mean concentration of 5.93 and 4.25 mg/g, respectively. Results showed a high content of caffeine in the analyzed CS extracts, with a mean value of 31.2 mg/g, meaning a two-fold increase when compared to coffee brews. Our findings highlighted that both the bioaccessibility and antioxidant activity of CS polyphenols significantly increased in each in vitro gastrointestinal digestion stage. In addition, the colon stage might constitute the main biological site of action of these antioxidant compounds. These results suggest that in vivo, the dietary polyphenols from CS might be metabolized by human colonic microflora, generating metabolites with a greater antioxidant activity, increasing their well-known beneficial effects.

Depigmentation and Anti-aging Treatment by Natural Molecules

Natural molecules are becoming more accepted choices as cosmetic agents, many products in the market today claim to include natural components. Plants include many substances that could be of a value in the whitening of the skin and working as anti-aging agents. A wide range of articles related to natural skin whitening and anti-aging agents have been reviewed. Many plant-derived and natural molecules have shown to affect melanin synthesis by different mechanisms, examples include Arbutin, Ramulus mori extract, Licorice extract, Glabridin, Liquiritin, Kojic acid, Methyl gentisate, Aloesin, Azelaic acid, Vitamin C, Thioctic acid, Soya bean extracts, Niacinamide, α and β-hydroxy acids, Lactic acid, Chamomile extract, and Ellagic acid. Some of the widely used natural anti-aging products as natural antioxidants, collagen, hyaluronic acid, and coenzyme Q can counteract the effects of reactive oxygen species in skin cells and have anti-aging properties on the skin. It was concluded that many natural products including antioxidants can prevent UV-induced skin damage and have whitening and anti-aging effects. It is very important to develop and stabilize appropriate methods for the evaluation of the whitening and anti-aging capacity of natural products and their exact mechanism of action to ensure real efficacy based on evidence-based studies. The attention should be oriented on the formulations and the development of an appropriate vehicle to ensure suitable absorption of these natural products in addition to evaluating the suitable concentration of these molecules required having the desired effects without causing harmful side effects.

Anti-glycation effect and the α-amylase, lipase, and α-glycosidase inhibition properties of a polyphenolic fraction derived from citrus wastes

The advanced glycation end products (AGEs) constitute a wide variety of substances synthesized from interactions between amino groups of proteins and reducing sugars, which excess induces pathogenesis of chronic diseases. Brazil is the major producer of citrus, a low-cost source of hesperidin, which is a polyphenol recognized for its capacity to inhibit AGEs formation. This is the first work to evaluate the effects of a polyphenolic fraction derived from citrus wastes on the antiglycation and on the inhibition properties of digestive enzymes on the possibility to process these wastes in high value-added products. At concentrations of 10, 15 and 20 mg/mL inhibition of AGEs was higher than 60%. The extracts were able to inhibit by 76% the activity of pancreatic lipase and by 98% the activity of α-glucosidase. For the α-amylase the inhibition capacity was lower than 50%. Strong correlation was obtained among anti-glycation with polyphenolic content and antioxidant capacity.

Coffee Silverskin Extract: Nutritional Value, Safety and Effect on Key Biological Functions

This study aimed to complete the scientific basis for the validation of a coffee silverskin extract (CSE) as a novel food ingredient according to European legislation. Nutritional value, safety, effects on biochemical biomarkers and excretion of short chain fatty acids (SCFAs) in vivo of CSE were assessed. Proteins, amino acids, fat, fatty acids, fiber, simple sugars and micronutrients were analyzed. For the first time, toxicological and physiological effects were evaluated in vivo by a repeated-dose study in healthy Wistar rats. Hormone secretion, antioxidant (enzymatic and no-enzymatic) and anti-inflammatory biomarkers, and dietary fiber fermentability of CSE (analysis of SCFAs in feces) were studied in biological samples. This unique research confirms the feasibility of CSE as a human dietary supplement with several nutrition claims: "source of proteins (16%), potassium, magnesium, calcium and vitamin C, low in fat (0.44%) and high in fiber (22%)". This is the first report demonstrating that its oral administration (1 g/kg) for 28 days is innocuous. Hormone secretion, antioxidant or anti-inflammatory biomarkers were not affected in heathy animals. Total SCFAs derived from CSE fiber fermentation were significantly higher (p < 0.05) in male treated rats compared to male control rats. All the new information pinpoints CSE as a natural, sustainable and safe food ingredient containing fermentable fiber able to produce SCFAs with beneficial effects on gut microbiota.

Melanoidins from Coffee, Cocoa, and Bread Are Able to Scavenge α-Dicarbonyl Compounds under Simulated Physiological Conditions

Free amino residues react with α-dicarbonyl compounds (DCs) contributing to the formation of advanced glycation end products (AGEs). Phenolic compounds can scavenge DCs, thus controlling the dietary carbonyl load. This study showed that high-molecular weight cocoa melanoidins (HMW-COM), HMW bread melanoidins (HMW-BM), and especially HMW coffee melanoidins (HMW-CM) are effective DC scavengers. HMW-CM (1 mg/mL) scavenged more than 40% DCs within 2 h under simulated physiological conditions, suggesting some physiological relevance. Partial acid hydrolysis of HMW-CM decreased the dicarbonyl trapping capacity, demonstrating that the ability to react with glyoxal, methylglyoxal (MGO), and diacetyl was mainly because of polyphenols bound to macromolecules. Caffeic acid (CA) and 3-caffeoylquinic acid showed a DC-scavenging kinetic profile similar to that of HMW-CM, while mass spectrometry data confirmed that hydroxyalkylation and aromatic substitution reactions led to the formation of a stable adduct between CA and MGO. These findings corroborated the idea that antioxidant-rich indigestible materials could limit carbonyl stress and AGE formation across the gastrointestinal tract.

Inhibition of the Maillard Reaction by Phytochemicals Composing an Aqueous Coffee Silverskin Extract via a Mixed Mechanism of Action

This work aimed to evaluate the contribution of isoflavones and melatonin to the aqueous extract obtained from the coffee silverskin (CSE) antiglycative properties, which has not been previously studied. To achieve this goal, two model systems constituted by bovine serum albumin (BSA) and reactive carbonyls (glucose or methylglyoxal) in the presence or absence of pure phytochemicals (chlorogenic acid (CGA), genistein, and melatonin) and CSE were employed. Glucose was used to evaluate the effect on the formation of glycation products formed mainly in the early stage of the reaction, while methylglyoxal was employed for looking at the formation of advanced products of the reaction, also called methylglyoxal-derivative advanced glycation end products (AGE) or glycoxidation products. CGA inhibited the formation of fructosamine, while genistein and melatonin inhibited the formation of advanced glycation end products and protein glycoxidation. It was also observed that phenolic compounds from CSE inhibited protein glycation and glycoxidation by forming BSA-phytochemical complexes. CSE showed a significant antiglycative effect (p < 0.05). Variations in the UV-Vis spectrum and the antioxidant capacity of protein fractions suggested the formation of protein-phytochemical complexes. Fluorescence quenching and in silico analysis supported the formation of antioxidant-protein complexes. For the first time, we illustrate that isoflavones and melatonin may contribute to the antiglycative/antiglycoxidative properties associated with CSE. CGA, isoflavones, and melatonin composing CSE seem to act simultaneously by different mechanisms of action.

Effect of Coffee Silver Skin and Brewers' Spent Grain in the Control of Root-knot Nematodes

Plant parasitic nematodes (PPN) are important pests of numerous agricultural crops especially vegetables, able to cause remarkable yield losses correlated to soil nematode population densities at sowing or transplant. The concern on environmental risks, stemming from the use of chemical pesticides acting as nematicides, compels to their replacement with more sustainable pest control strategies. To verify the effect of aqueous extracts of the agro-industry waste coffee silverskin (CS) and brewers’ spent grain (BSG) on the widespread root-knot nematode Meloidogyne incognita, and on the physiology of tomato plants, a pot experiment was carried out in a glasshouse at 25 ± 2 °C. The possible phytotoxicity of CS and BSG extracts was assessed on garden cress seeds. Tomato plants (landrace of Apulia Region) were transplanted in an artificial nematode infested soil with an initial population density of 3.17 eggs and juveniles/mL soil. CS and BSG were applied at rates of 50 and 100 % (1L/pot). Untreated and Fenamiphos EC 240 (nematicide) (0.01 μL a.i./mL soil) treated plants were used as controls. Reactive oxygen species (ROS) and chlorophyll content of tomato plants were estimated during the experiment. CS extract, at both doses, significantly reduced nematode population in comparison to the untreated control, although it was less effective than Fenamiphos. BSG extract did not reduce final nematode population compared to the control. Ten days after the first treatment, CS 100 %, BSG 50 % and BSG 100% elicited the highest ROS values, which considerably affected the growth of tomato plants in comparison to the untreated plants. The control of these pests is meeting with difficulties because of the current national and international regulations in force, which are limiting the use of synthetic nematicides. Therefore, CS extracts could assume economic relevance, as alternative products to be used in sustainable strategies for nematode management.

An Assessment of the Bioactivity of Coffee Silverskin Melanoidins

Melanoidins present in coffee silverskin, the only by-product of the roasting process, are formed via the Maillard reaction. The exact structure, biological properties, and mechanism of action of coffee silverskin melanoidins, remain unknown. This research work aimed to contribute to this novel knowledge. To achieve this goal, melanoidins were obtained from an aqueous extract of Arabica coffee silverskin (WO2013004873A1) and was isolated through ultrafiltration (>10 kDa). The isolation protocol was optimized and the chemical composition of the high molecular weight fraction (>10 kDa) was evaluated, by analyzing the content of protein, caffeine, chlorogenic acid, and the total dietary fiber. In addition, the structural analysis was performed by infrared spectroscopy. Antioxidant properties were studied in vitro and the fiber effect was studied in vivo, in healthy male Wistar rats. Melanoidins were administered to animals in the drinking water at a dose of 1 g/kg. At the fourth week of treatment, gastrointestinal motility was evaluated through non-invasive radiographic means. In conclusion, the isolation process was effective in obtaining a high molecular weight fraction, composed mainly of dietary fiber, including melanoidins, with in vitro antioxidant capacity and in vivo dietary fiber effects.

Coffea canephora silverskin from different geographical origins: A comparative study

Coffee silverskin is the major by-product of coffee roasting. Among all the coffee by-products, it is a relatively stable product due to its low moisture content. Currently, silverskin is used as direct fuel (e.g. firelighters), for composting and soil fertilization. As it is a natural source of several bioactive compounds that can be extracted and further used for food or dermocosmetic purposes, the valorization of this by-product is of utmost importance, having in view the sustainability and circular economy principles. The aim of this work was to evaluate, for the first time, the influence of different geographical origins (Brazil, Uganda, Vietnam, Cameroon, Indonesia, and India) on the chemical composition of silverskin obtained from Coffea canephora beans. Different parameters were analysed, including ashes, protein, soluble and insoluble fiber, and total lipid amounts; vitamin E, fatty acid and phenolics profiles (by HPLC-DAD-FLD, GC-FID, and HPLC-DAD, respectively); caffeine, 5‑caffeoylquinic acid and hydroxymethyfurfural contents (by HPLC-DAD); and antioxidant profile (total phenolics and flavonoids contents, DPPH inhibition, and Ferric Reducing Antioxidant Power). Significant differences (p < 0.05) were found between the samples, especially regarding the fatty acid profile and the antioxidant composition. For instance, the Brazilian silverskin was the richest in total lipids and vitamin E, while the Indian silverskin was the poorest in phenolics and antioxidant activity, and presented a higher relative percentage of saturated fatty acids. A Principal Component Analysis allowed to group the studied samples according to their geographical proximity.

Characterization of MK₈(H₂) from Rhodococcus sp. B7740 and Its Potential Antiglycation Capacity Measurements

Menaquinone (MK) has an important role in human metabolism as an essential vitamin (VK₂), which is mainly produced through the fermentation of microorganisms. MK₈(H₂) was identified to be the main menaquinone from Rhodococcus sp. B7740, a bacterium isolated from the arctic ocean. In this work, MK₈(H₂) (purity: 99.75%) was collected through a convenient and economic extraction process followed by high-speed countercurrent chromatography (HSCCC) purification. Additionally, high-resolution mass spectrometry (HRMS) was performed for further identification and the hydrogenation position of MK₈(H₂) (terminal unit) was determined using nuclear magnetic resonance (NMR) for the first time. MK₈(H₂) showed a superior antioxidant effect and antiglycation capacity compared with ubiquinone Q10 and MK₄. High-performance liquid chromatography–mass spectrometer (HPLC-MS/MS) and molecular docking showed the fine interaction between MK₈(H₂) with methylglyoxal (MGO) and bull serum albumin (BSA), respectively. These properties make MK₈(H₂) a promising natural active ingredient with future food and medicine applications.

Coffee Silverskin: A Review on Potential Cosmetic Applications

Coffee silverskin, the major coffee-roasting by-product, is currently used as fuel and for soil fertilization. However, there are several studies reporting silverskin as a good source of bioactive compounds that can be extracted and further used by cosmetic industry. Its high antioxidant potential may be due to the synergistic interaction of chlorogenic acids (1–6%), caffeine (0.8–1.25%), and melanoidins (17–23%), among other antioxidant compounds. The bioactive compounds of silverskin can answer to the new fields of cosmetic industry on natural active ingredient resources that improve health skin appearance, counteract skin aging and related diseases, in an environmentally friendly approach. Skin aging is a complex process associated with oxidative metabolism and reactive oxygen species (ROS) generation. ROS production increase matrix metalloproteinases (MMPs), as well as pro-inflammatory mediators, resulting in consequent skin damage and aging. To counteract this process, cosmetic industry is looking for compounds able to increase MMP inhibitory activities, hyaluronidase inhibitory activity, expression of collagen and elastase inhibitory activity, as potential bioactive ingredients with anti-aging purposes. This review focuses on skin aging factors and the potential anti-aging, anti-inflammatory, antimicrobial, anti-cellulite and anti-hair loss activity, as well as protection against UV damage, of coffee silverskin and their bioactive compounds.

Carboxymethyl-lysine: thirty years of investigation in the field of AGE formation

In 1985 carboxymethyl-lysine (CML), the first glycoxidation product, was discovered by Dr Ahmed while trying to identify the major products formed in reactions of glucose with lysine under physiological conditions. From that moment, a significant number of researchers have joined efforts to study its formation routes both in foods and in living beings, and the possibility of the existence of an additive action between food-occurring and in vivo produced CML and to explore all the implications associated with its appearance in the biological systems, regardless of its origin. This review presents interesting information on the latest advances in the research on CML sources, mitigation strategies, intake, metabolism and body fluid and tissue delivery, its possible in vivo synergy with highly modified advanced glycation end products-protein, and the physio-pathological implications derived from the presence of this compound in body fluids and tissues.

Effect of hydroxytyrosol and olive leaf extract on 1,2-dicarbonyl compounds, hydroxymethylfurfural and advanced glycation endproducts in a biscuit model

The antiglycative activity of hydroxytyrosol (HT) and olive leaf extract (OLE) was investigated in wheat-flour biscuits. Quercetin (QE) and gallic acid (GA) were used as reference of antiglycative activity of phenolic compounds. HT, OLE, QE and GA were added in the range of 0.25-0.75% (w/w). Samples were compared against a control recipe baked at 180°C/20min. HT biscuit was able to inhibit efficiently the formation of hydroxymethylfurfural (HMF) and 3-deoxyglucosone (3-DG), as well as reduced the formation of overall free fluorescent AGEs and pentosidine. The inhibition of the 3-DG and HMF formation was directly and significantly correlated under controlled baking conditions. However, samples formulated with OLE exerted similar antiglycative capacity against pentosidine and Nε-carboxyethyl-lysine, although the amount of HT in the biscuit was 100-fold lower than the biscuit formulated with HT. Methylglyoxal, 3-DG, and glyoxal were the predominant 1,2-dicarbonyl compounds after baking but only 3-DG was significantly reduced by HT.

Coffee Silverskin Extract Protects against Accelerated Aging Caused by Oxidative Agents

Nowadays, coffee beans are almost exclusively used for the preparation of the beverage. The sustainability of coffee production can be achieved introducing new applications for the valorization of coffee by-products. Coffee silverskin is the by-product generated during roasting, and because of its powerful antioxidant capacity, coffee silverskin aqueous extract (CSE) may be used for other applications, such as antiaging cosmetics and dermaceutics. This study aims to contribute to the coffee sector’s sustainability through the application of CSE to preserve skin health. Preclinical data regarding the antiaging properties of CSE employing human keratinocytes and Caenorhabditis elegans are collected during the present study. Accelerated aging was induced by tert-butyl hydroperoxide (t-BOOH) in HaCaT cells and by ultraviolet radiation C (UVC) in C. elegans. Results suggest that the tested concentrations of coffee extracts were not cytotoxic, and CSE 1 mg/mL gave resistance to skin cells when oxidative damage was induced by t-BOOH. On the other hand, nematodes treated with CSE (1 mg/mL) showed a significant increased longevity compared to those cultured on a standard diet. In conclusion, our results support the antiaging properties of the CSE and its great potential for improving skin health due to its antioxidant character associated with phenols among other bioactive compounds present in the botanical material.

Effect of theanine and polyphenols enriched fractions from decaffeinated tea dust on the formation of Maillard reaction products and sensory attributes of breads

The antiglycoxidative properties of theanine (TEF) and polyphenols enriched fractions (PEF) prepared from tea dust were tested in a model system composed of bovine serum albumin (BSA) and methylglyoxal (MGO). PEF caused a decrease in available free amino groups of BSA in presence and absence of MGO, suggesting the simultaneous occurrence of glycoxidation reaction and phenols-protein interaction. The presence of PEF and TEF inhibited formation of fluorescent advanced glycation end-products (AGEs). Moreover, theanine (TB) and polyphenol-enriched bread (PB) were formulated. A significant increase in free amino groups was observed in TBs with a dose-response effect, while addition of PEF in bread produced a significant decrease (p<0.05). PEF efficiently reduced fluorescent AGE formation in breads compared with TEF. The results are in line with the simplified model systems. PEF used as food ingredient allows obtaining a tasty food possessing health promoting properties and lower content of potential harmful compounds (AGEs).