Antioxidant Activity Of Phenolic Compounds Research Articles

Exploring the Correlation Between the Molecular Structure and Biological Activities of Metal-Phenolic Compound Complexes: Research and Description of the Role of Metal Ions in Improving the Antioxidant Activities of Phenolic Compounds.

We discussed and summarized the latest data from the global literature on the action of polyphenolic antioxidants and their metal complexes. The review also includes a summary of the outcomes of theoretical computations and our many years of experimental experience. We employed various methods, including spectroscopy (FT-IR, FT-Raman, NMR, UV/Vis), X-ray diffraction, thermal analysis, quantum calculations, and biological assays (DPPH, ABTS, FRAP, cytotoxicity, and genotoxicity tests). According to our research, the number and position of hydroxyl groups in aromatic rings, as well as the delocalization of electron charge and conjugated double bonds, have a major impact on the antioxidant effectiveness of the studied compounds. Another important factor is metal complexation, whereby high ionic potential metals (e.g., Fe(III), Cr(III), Cu(II)) enhance antioxidant properties by stabilizing electron charge, while the low ionic potential metals (e.g., Ag(I), Hg(II), Pb(II)) reduce efficacy by disrupting electron distribution. However, we observed no simple correlation between ionic potential and antioxidant capacity. This paper gives insights that will aid in identifying new, effective antioxidants, which are vital for nutrition and the prevention of neurodegenerative illnesses. Our results outline the connections between biological activity and molecular structure, offering a foundation for the methodical design of antioxidants. Our review also shows in detail how we use various complementary methods to assess the impact of metals on the electronic systems of ligands. This approach moves beyond the traditional "trial and error" method, allowing for the more efficient and rational development of future antioxidants.

Nanoparticles based on biopolymers improved antioxidant activity of phenolic compounds from jambolan (Syzygium cumini (L.) skeels)

Jambolan (Syzygium cumini L.) is an underutilized fruit rich in bioactive phenolic compounds, specially anthocyanins, but the low stability of these substances and interaction with other compounds in the food matrix limit their application as food additives; nanoencapsulation is the best strategy to overcome these limitations. This study aimed to nanoencapsulate a phenolic-rich jambolan extract using whey proteins and pectin by nanoprecipitation in different antisolvent compositions. Two formulations were synthesized (7.33 % extract, 1.67 % pectin, and 5 % concentrated or isolated whey protein) precipitated in different acetone concentrations (50, 70, and 100 % v/v). SEM showed particles with spherical shape and smooth surface. DLS pointed diameters between 82 nm and 116 nm. FTIR indicated chemical interactions between the materials. Encapsulation efficiency showed high phenolic compounds entrapment in all systems [73.81–84.65 %, p > 0.05]. However, particles precipitated in 50 and 100 % acetone (v/v) showed greater anthocyanins retention [56.89–35.24 %, p < 0.05]. Nanoencapsulation potentiated the antioxidant activity up to 110 % more than the crude extract (p < 0.05). These results show the potential of nanoprecipitation as an effective encapsulation process and the biopolymers combination to produce nanoparticles containing jambolan phenolic compounds to promote their application in foods and health products.

Digested galactoglucomannan mitigates oxidative stress in human cells, restores gut bacterial diversity, and provides chemopreventive protection against colon cancer in rats

Galactoglucomannan (GGM) is the predominant hemicellulose in coniferous trees, such as Norway spruce, and has been used as a multipurpose emulsifier in the food industry. In vitro digestion with a cellular antioxidant activity assay was performed to determine the bioaccessibility and antioxidant activity of phenolic compounds, and the behaviour of GGM on in vivo experimental assay against induced colon cancer. The results showed that digestion decreased the bioaccessibility and antioxidant capacity of phenolic compounds. Cellular analysis did not support these findings once an antioxidant effect was observed in human cell lines. GGM attenuated the initiation and progression of colon cancer, by reducing the foci of aberrant crypts in rats, and modified the intestinal bacterial microbiota (disrupting the balance between Firmicutes and Bacteroidetes phyla). Thus, GGM provided chemopreventive protection against the development of colon cancer and acted as an intracellular antioxidant agent.

Effect of GABA combined with ultrasound stress germination treatment on phenolic content and antioxidant activity of highland barley.

This study investigated the effects of γ-aminobutyric acid (GABA) combined with ultrasonic stress germination (AUG) treatment on the phenolic content and antioxidant activity of highland barley (HB). Key variables, including germination times (ranging from 0 to 96 h), ultrasonic power (200-500 W), and GABA concentration (5-20 mmol/L), were optimized using response surface methodology (RSM) to enhance the enrichment of phenolic compounds. Furthermore, the study assessed the content, composition, and antioxidant activities of phenolic compounds in HB under various treatment conditions such as germination alone (G), ultrasonic stress germination (UG), and AUG treatment. The study identified optimal conditions for the phenolic enrichment of HB, which included a germination time of 60 h, an ultrasound power of 300 W, and a GABA concentration of 15 mmol L-1. Under these conditions, the total phenolic content (TPC) in HB was measured at 7.73 milligrams of gallic acid equivalents per gram dry weight (mg GAE/g DW), representing a 34.96% enhancement compared to untreated HB. Notably, all treatment modalities - G, UG, and AUG - significantly increased the phenolic content and antioxidant activity in HB, with the AUG treatment proving to be the most effective. These obtained results suggest that AUG treatment is a promising processing method for enriching phenolic compounds and improving antioxidant activity in HB. Subsequently, the AUG-treated HB can be used to develop phenolic-rich germinated functional foods to further broaden the application of HB. © 2024 Society of Chemical Industry.

Evaluation of the solvent effect on the extraction and antioxidant activity of phenolic compounds from the nettle (Urtica dioica L.) seeds: application of PCA and regression analyses

Evaluation of the solvent effect on the extraction and antioxidant activity of phenolic compounds from the nettle (Urtica dioica L.) seeds: application of PCA and regression analyses

Characterization, Bioaccesibility and Antioxidant Activities of Phenolic Compounds Recovered from Yellow pea (Pisum sativum) Flour and Protein Isolate.

This study focused on studying the bioaccesible phenolic compounds (PCs) from yellow pea flour (F) and protein isolate (I). Total phenolic contents (TPC), PCs composition and antioxidant activities were analysed in ethanol 60% extracts obtained by applying ultrasound assisted extraction (UAE, 15min/40% amplitude). The preparation of I under alkaline conditions and the elimination of some soluble components at lower pH produced a change of PCs profile and antioxidant activity. After simulated gastrointestinal digestion (SGID) of both ingredients to obtain the digests FD and ID, notable changes in the PCs concentration and profiles could be demonstrated. FD presented a higher ORAC activity than ID (IC50 = 0.022 and 0.039mg GAE/g dm, respectively), but lower ABTS•+ activity (IC50 = 0.8 and 0.3mg GAE/g dm, respectively). After treatment with cholestyramine of extracts from FD and ID in order to eliminate bile salts and obtain the bioaccesible fractions FDb and IDb, ROS scavenging in H2O2-induced Caco2-TC7 cells was evaluated, registering a greater activity for ID respect to FD (IC50 = 0.042 and 0.017mg GAE/mL, respectively). These activities could be attributed to the major bioaccesible PCs: OH-tyrosol, polydatin, trans-resveratrol, rutin, (-)-epicatechin and (-)-gallocatechin gallate for FD; syringic (the most concentrated) and ellagic acids, trans-resveratrol, and (-)-gallocatechin gallate for ID, but probably other compounds such as peptides or amino acids can also contribute.

Effects of natural deep eutectic solvent on the extraction efficiency and antioxidant activities of Toona sinensis seed polyphenols: Composition and mechanism

This study was designed to investigate the effects of natural deep eutectic solvents (NADESs) on extraction efficiency and antioxidant activities of phenolic compounds from Toona sinensis seeds (TSSs) compared with ethanol and water extraction methods. The single factor experiment was employed to optimize the extraction conditions of TSSs phenolic compounds on NADESs. Results indicate that the NADES of choline chloride-oxalic acid (CC-OA) with a molar ratio of 2:1 (solid/liquid ratio: 1:90 (m/v), extraction time: 30 min) showed the highest total phenolic content (32.58 mg GAE/g DW) and antioxidant activities (DPPH radical scavenging activity: 95.94%) compared with ethanol or water extraction. In addition, 15 main phenolic compounds were identified in the extracts of CC-OA solvent, while only 9 and 6 main compounds were identified in the extracts of ethanol and water solvents, respectively. The molecular dynamic simulation result illustrates that the high extraction efficiency of the NADES mainly attributing to their high compatibility as well as hydrogen interaction between ellagic acid (the main polyphenol in TSSs) and CC-OA solvent. In summary, the NADES (CC-OA at the ratio of 2:1) showed superior extraction efficiency on TSSs phenolic compound compared with ethanol or water extraction which could be an environmentally friendly method for the high-value utilization of TSSs.

Extraction of polyphenols associated with pectin from olive waste (alperujo) with choline chloride.

The main by-product from olive oil extraction (alperujo) was extracted with hot water, citric acid, natural deep eutectic solvent (choline chloride: citric acid), and only choline chloride. The purified extracts were composed of macromolecular complexes constituting polyphenols associated with pectin. The extracts were structurally characterized by FT-IR and solid-NMR spectroscopy and an in vitro test revealed distinct antioxidant and antiproliferative activity, depending on the extracting agents. The choline chloride-extracted complex contained the highest amount of polyphenols among the examined agents, which exhibited a strong antioxidant activity and significant antiproliferative capacity. However, the complex extracted by hot water showed the highest antiproliferative capacity in vitro against the colon carcinoma Caco-2 cell line. In this finding, choline chloride could be used as a novel, green and promising alternative to the conventional extracting agent for the production of complexes that combine the antioxidant activity of phenolic compounds and the physiological effects of pectic polysaccharides.

Myrtaceae leaves grown in Agroforestry: a sustainable alternative to producing natural antioxidants extracts

Myrtaceae species such as uvaia, grumixama, and feijoa have been used in Brazil’s Agroforestry Systems (AFS). In AFS, frequent pruning occurs, and leaves are discarded. However, the leaves contain specific phenolic compounds (PC) that, when appropriately extracted, produce extracts with antioxidant activity (AA). These extracts meet the demand for natural and sustainable food ingredients. Therefore, the drying study (40, 50, and 60 °C) of uvaia, grumixama, and feijoa leaves obtained from AFS was carried out, and the effect of drying on the PC profile (LC-ESI-MS/MS) and AA were evaluated. In the uvaia extracts, the major compounds were EGCG, gallic acid, and isoquercitin, accounting for 94% of their PC, and leaves dried at 50 °C promoted a better phenolic extraction. The gallic acid, 2.5 DHBA and isoqueticitrin represent 79% of the relative composition of PC in grumixama extracts, and leaves dried at 60 °C were the condition that allowed a greater extraction. While, epicatechin, catechin, gallic acid and isoquercitrin correspond to 66% of the PC composition of feijoa leaves. Grumixama had the highest values for AA by the FCRC and DPPH while feijoa had significant values for FRAP in all treatments. Dried leaves at 50 °C showed higher AA for all methods, except for grumixama which showed this behavior at 60 °C. These results indicate that these matrices proved promising sustainable sources of various phenolic compounds. The drying process of the leaves at 50 and 60 °C had a greater extraction of compounds with antioxidant activity, with potential industrial applications.

Antioxidant system of garden cress sprouts for using in bio-monitor of cadmium and lead contamination

Based on garden cress significantly used for phytoremediation, the antioxidant system included antioxidant-phenolic compounds and antioxidant-enzymes of 6-day-garden cress sprouts (GCS) were assessed as potential bio-indicators for cadmium (Cd) and lead (Pb) contamination. Total phenolic and flavonoid contents of GCS germinated under Cd and Pb treatments (25–150 mg kg−1) gradually increased with increasing concentration of metals and peaked by 2.0, 2.6, and 2.5, 2.3 folds at 150 mg kg−1, respectively. By using DPPH, ABTS, and PMC antioxidant assays, the total antioxidant activity of phenolic compounds of GCS increased 6.1, 13.0, and 5.8-fold for Cd and 5.9, 14.6, and 8.2-fold for Pb at 150 mg kg−1, respectively. The antioxidant enzymes of GCS (POD, CAT, GR, and GST) were significantly activated in response to Cd and Pb stress, and two new electrophoretic POD bands were detected. GCS was absorbed 19.0% and 21.3% of Cd and Pb at 150 mg metal kg−1, respectively. In conclusion, the approaches of the antioxidant defense system of GSC could potentially be used as bio-indicator for monitoring Cd and Pb contamination in a short time of germination process.

Nutritional composition, antioxidant activity and gossypol level of Nazilli glandless cottonseed, cottonseed kernel and their cold-pressed meal

BackgroundThe study was conducted to determine the nutrient composition and gossypol levels of glandless cottonseed (GCS), glandless cottonseed kernel (GCSK) glandless cottonseed meal (GCSM) and cottonseed kernel meal (GCSKM) obtained by cold pressing of cotton seeds and kernels (Glandless Nazilli variety) as a raw material of compound feed industry.ResultFeed and dry matter (DM)-based nutrient analyses showed significant differences (p < 0.05) in DM, OM (organic matter), CP (crude protein), EE (ether extract), ash and NFE (nitrogen-free extract) contents between GCS and GCSK. The DM-based K, P, S, Mg, Ca, Na, Fe, Cu, Zn and Al contents were significantly different (p < 0.05) between GCS and GCSK. The concentrations of nonessential heavy metals (Cd, Pb, Ni and Al) in GCS, GCSK, GCSM and GCSKM samples were below the permissible limits. The linoleic acid (C18:2; ω6) was the main component (55.55%) among the 20 fatty acids identified in GCS oil. The level of unsaturated fatty acids (70.78%) was higher than that of saturated fatty acids (29.22%). Total phenolics concentrations of GCS, GCSK, GCSM and GCSKM samples were 7.87, 2.18, 5.86 and 1.91 mg gallic acid equivalents (GAE)/g, respectively. Free and total gossypol levels of GCS and GCSK were 294 and 440, and 521 and 706 mg/kg, respectively.ConclusionThe results revealed that nutritional properties of Nazilli GCS with low gossypol and high linoleic acid content were relatively higher compared to the other meals investigated. The antioxidant activity of phenolic compounds, albeit at low levels in Nazilli GCS and GCSM, may contribute to animal health and production efficiency when used in animal rations.

Gastrointestinal digestion assays for evaluating the bioaccessibility of phenolic compounds in fruits and their derivates: an overview

Fruits and their derivatives are sources of phenolic compounds, which contribute to the maintenance of health benefits. In order to exert such properties, these compounds must be exposed to gastrointestinal conditions during digestion. In vitro methods of gastrointestinal digestion have been developed to simulate and evaluate the changes that compounds undergo after being exposed to various conditions. We present, in this review, the major in vitro methods for evaluating the effects of gastrointestinal digestion of phenolic compounds in fruits and their derivatives. We discuss the concept of bioaccessibility, bioactivity, and bioavailability, as well as the conceptual differences and calculations among studies. Finally, the main changes caused by in vitro gastrointestinal digestion in phenolic compounds are also discussed. The significant variation of parameters and concepts observed hinders a better evaluation of the real effects on the antioxidant activity of phenolic compounds, thus, the use of standardized methods in research would contribute for a better understanding of these changes.

Dietary Phenolic Compounds: Their Health Benefits and Association with the Gut Microbiota.

Oxidative stress causes various diseases, such as type II diabetes and dyslipidemia, while antioxidants in foods may prevent a number of diseases and delay aging by exerting their effects in vivo. Phenolic compounds are phytochemicals such as flavonoids which consist of flavonols, flavones, flavanonols, flavanones, anthocyanidins, isoflavones, lignans, stilbenoids, curcuminoids, phenolic acids, and tannins. They have phenolic hydroxyl groups in their molecular structures. These compounds are present in most plants, are abundant in nature, and contribute to the bitterness and color of various foods. Dietary phenolic compounds, such as quercetin in onions and sesamin in sesame, exhibit antioxidant activity and help prevent cell aging and diseases. In addition, other kinds of compounds, such as tannins, have larger molecular weights, and many unexplained aspects still exist. The antioxidant activities of phenolic compounds may be beneficial for human health. On the other hand, metabolism by intestinal bacteria changes the structures of these compounds with antioxidant properties, and the resulting metabolites exert their effects in vivo. In recent years, it has become possible to analyze the composition of the intestinal microbiota. The augmentation of the intestinal microbiota by the intake of phenolic compounds has been implicated in disease prevention and symptom recovery. Furthermore, the "brain-gut axis", which is a communication system between the gut microbiome and brain, is attracting increasing attention, and research has revealed that the gut microbiota and dietary phenolic compounds affect brain homeostasis. In this review, we discuss the usefulness of dietary phenolic compounds with antioxidant activities against some diseases, their biotransformation by the gut microbiota, the augmentation of the intestinal microflora, and their effects on the brain-gut axis.

The Effect of Probiotic on Antioxidant Activity of Phenolic Compounds in Functional Yogurt Fortified by Plum Juice

The Effect of Probiotic on Antioxidant Activity of Phenolic Compounds in Functional Yogurt Fortified by Plum Juice

Chemoinformatic modelling of the antioxidant activity of phenolic compounds.

Antioxidants are chemicals used to protect foods from deterioration by neutralizing free radicals and inhibiting the oxidative process. One approach to investigate the antioxidant activity is to develop quantitative structure-activity relationships (QSARs). A curated database of 165 structurally heterogenous phenolic compounds with the Trolox equivalent antioxidant capacity (TEAC) was developed. Molecular geometries were optimized by means of the GFN2-xTB semiempirical method and diverse molecular descriptors were obtained afterwards. For model development, V-WSP unsupervised variable reduction was used before performing the genetic algorithms-variable subset selection (GAs-VSS) to construct the best five-descriptor multiple linear regression model. The coefficient of determination and the root-mean-square error were used to measure the performance in calibration (R2 = 0.789 and RMSEC = 0.381), and test set prediction (Q2 = 0.748 and RMSEP = 0.416), along several cross-validation criteria. To thoroughly understand the TEAC prediction, a fully explained mechanism of action of the descriptors is provided. In addition, the applicability domain of the model defined a theoretical chemical space for reliable predictions of new phenolic compounds. This in silico model conforms to the five principles stated by the Organization for Economic Co-operation and Development (OECD). The model may be useful for virtual screening of the antioxidant chemical space, and for identifying the most potent molecules related to an experimental measurement of TEAC activity. In addition, the model could assist chemists working on computer-aided drug design (CADD) for the synthesis of new targets with improved activity and potential uses in food science. This article is protected by copyright. All rights reserved.

Molecular Geometry, Homo-Lumo Analysis and Mulliken Charge Distribution of 2,6-Dichloro-4-Fluoro Phenol Using DFT and HF Method

&#x0D; Phenolic compounds are used in human diet, commonly present in plants. Foremost polyphenolic compounds found in plants are flavanols, flavonoids, flavonones, iso-flavones, phenolic acids, flavonoids, chalcones, lignans etc. These compounds possess antimicrobial, antiviral and anti-inflammatory properties along with high antioxidative activity. The antioxidative activity of phenolic compounds depends on their structure. The polyphenols are very useful for the treatment of inflammation, cancer, anti-ageing purposes in cosmetic formulations, and nutraceutical applications. This article focused on substituted phenol, taking into concern their potential health benefits. The recent rise in machine-learning methods has engendered many advances in the molecular sciences. Using desired level of electronic structure theory from density functional theory, we can calculate the properties (electronic structure, force field, energy) of atomistic systems. The full electron density carries with it a considerable computational cost. While the DFT calculation loses accuracy when the molecule is either extended or compressed, Δ-DFT corrects these errors. Here, molecular point group symmetries are used to obtain chemical accuracy. The optimal 2,6-dichloro-4-fluoro phenol molecular geometry was derived using the 6-311+G (d, p) basis set and DFT/B3LYP (density functional theory) and Hartree-Fock (HF) techniques. A detailed interpretation of Homo-Lumo analysis of 2,6-dichloro-4-fluoro phenol is also listed. Using the 6-311+G (d, p) basis set and the Hartree-Fock (HF) method, the Mulliken charge distribution of this molecule has also been computed.

Stability and antioxidant activity of phenolic compounds during in vitro digestion.

The impact of phenolic compounds on the human body depended on the type, content, bioavailability, and antioxidant activity. After digestion, different phenolic compounds had different changes of bioavailability and antioxidant activity, which needed to be considered in the application. In this experiment, the structural stability and antioxidant activity of 27 phenolic compounds (phenolic acids, flavonols, flavonoids, and flavanones) were investigated during the in vitro simulated digestion. This experiment eliminated the influence of food matrix, provide a basis for regularity for the changes of phenolic substances in different materials. Results showed that the bioaccessibility of phenolic compounds with different structures varied, and there was a conformational relationship between the structure and stability. After oral digestion, most of the phenolic compounds underwent degradation and the cellular antioxidant activity (CAA) values decreased to a large extent (p<0.05). After gastric digestion, the content (p>0.05) and CAA values (p<0.05) of most phenolic compounds increased. However, after intestinal digestion, the phenolic compounds were degraded to a greater extent, and different structures of phenolic compounds had different changes in CAA values (p<0.05). In general, the CAA values of most phenolic compounds after in vitro digestion were lower than the initial value. The 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azino-bis (3-ehylbenzthiazoline-6-sulfonic acid) (ABTS), and ferric reducing antioxidant power (FRAP) values of phenolic acids and flavonols decreased after in vitro simulated digestion (p<0.05), while the values of DPPH, ABTS, and FRAP of most flavonoids (p<0.05) increased. The increased oxygen radical absorption capacity (ORAC) values were found in most phenolic acids, flavonols, and flavonoids (p<0.05), and most flavanones showed unremarkable changes in ORAC values (p>0.05). In general, the changing trend of chemical-based antioxidant activity was consistent with the content of phenolic compounds.

Metabolomic Profiling and Assessment of Phenolic Compounds Derived from Vitis davidii Foex Cane and Stem Extracts

Phenolic extracts from berry seeds have been extensively studied for their health benefits. However, few studies have been conducted on the effects of phenolic extracts from Vitis L. canes and berry stems. The Chinese spine grape (V. davidii Foex) is an important and widely distributed wild species of Vitis L. The present study explored the metabolomic profile and evaluated the antioxidant activity of phenolic compounds in extracts from V. davidii Foex. canes and stems, with a focus on their role in preventing DNA damage caused by free radicals and inhibiting the growth of breast (MCF-7) and cervical (HeLa) cancer cells. Total phenolic compounds in the dried berry stems of spine grapes were higher than that in vine canes. Analysis of the extracts showed that proanthocyanins, epicatechin, catechin, and phenolic acid were the main phenolic compounds in V. davidii Foex, but in higher quantities in berry stems than in vine canes. However, trans-resveratrol and kaempferol 3-O-glucoside were present in the vine canes but not in the berry stems. Antioxidant analysis by FRAP and ABTS showed that extracts from berry stems and vine canes had a higher antioxidant activity than thinned young fruit shoots before flowering, leaves, peel, pulp, and seeds in V. davidii Foex. Moreover, the antioxidant activity of extracts from berry stems was higher than that in other grape species, except for muscadine. In vitro analyses further showed that the extracts significantly increased H2O2 scavenging ability and conferred a protective effect against DNA damage. Furthermore, a low concentration of phenolic compounds in extracts from the vine canes and berry stems of spine grapes inhibited the proliferation of the MCF-7 and Hela cancer cells. These research results provided some important useful information for the exploitation of V. davidii Foex canes and berry stems and indicated that canes and stems of V. davidii Foex had good antioxidant properties, anticancer activity and prevented DNA damage, providing evidence for medical utilization of V. davidii Foex.

Phenolic features and anthocyanin profiles in winemaking pomace and fresh berries of grapes with different pedigrees.

The total contents and antioxidant activities of phenolic compounds as well as anthocyanin profiles were analyzed and compared in fresh berries and fermented pomace of three grape cultivars with different pedigrees. The phenolic contents and antioxidant activities decreased significantly in skins (p < 0.05), while relatively large amounts of them were retained in seeds after fermentative maceration. Fermentative maceration also had a significant impact on the anthocyanin compositions. The proportions of anthocyanins with more stable structures, such as malvidin derivatives, methylated, diglucosides and nonacylated anthocyanins, increased significantly in the pomace skins (p < 0.05). There were obvious differences in phenolic features and anthocyanin profiles among the three cultivars. 'NW196', a wine hybrid of Vitis vinifera and V. quinquangularis, was characterized by the highest total anthocyanin contents and degree of diglucosylation. The results obtained in this study could contribute to the primary data for the development and utilization of winemaking pomace, especially from local non-Vitis vinifera grapes.

In Vitro Bioaccessibility and Antioxidant Activity of Phenolic Compounds in Coffee-Fortified Yogurt.

Yogurt is considered one of the most popular and healthy dairy products, and has been exploited as a delivery matrix for phenolic compounds. In this study, coffee powder was added to yogurt as a functional ingredient to produce coffee-fortified yogurt. Total phenolic compounds, antioxidant activity and individual hydroxycinnamic acids have been identified and quantified through mass spectrometry. The results from coffee-fortified yogurt were compared with fermented coffee and plain yogurt. Coffee-fortified yogurt had higher total phenolic content and antioxidant activity compared to plain yogurt. However, the total phenolic compounds found in coffee-fortified yogurt represented only 38.9% of the original content in coffee. Caffeoylquinic acids were the most abundant phenolic compounds in coffee. Fermented coffee and coffee-fortified yogurt displayed lower amounts of individual phenolic compounds with respect to coffee (69.8% and 52.4% of recovery, respectively). A protective effect of the yogurt matrix on total and individual coffee phenolic compounds has been observed after in vitro digestion, resulting in a higher bioaccessibility in comparison with digested fermented coffee. Moreover, coffee-fortified yogurt showed the highest antioxidant values after digestion. These findings clearly demonstrate that coffee-fortified yogurt can be considered a significant source of bioaccessible hydroxycinnamic acids, besides its health benefits as a fermented dairy product.