Phenolic Compounds In Foods Research Articles

Machine Learning-Based Nanozyme Sensor Array as an Electronic Tongue for the Discrimination of Endogenous Phenolic Compounds in Food.

The detection of endogenous phenolic compounds (EPs) in food is of great significance in elucidating their bioactivity and health effects. Here, a novel bifunctional vanillic acid-Cu (VA-Cu) nanozyme with peroxidase-like and laccase-like activities was successfully prepared. The peroxidase mimic behavior of VA-Cu nanozyme can catalyze 3,3',5,5'-tetramethylbenzidine (TMB) to generate oxidized TMB (oxTMB). Owing to the high reducing power of EPs, this process can be inhibited, and the degree of inhibition increases with the increase of reaction time. Additionally, owing to the outstanding laccase mimic behavior of the VA-Cu, it can facilitate the oxidation of various EPs, resulting in the formation of colored quinone imines, and the degree of catalysis increases with the increase of reaction time. Based on the interesting experimental phenomena mentioned above, a six-channel nanozyme sensor array (2 enzyme-mimic activities × 3 time points = 6 sensing channels) was constructed, successfully achieving discriminant analysis of nine EPs. In addition, the combination of artificial neural network (ANN) algorithms and sensor arrays has successfully achieved accurate identification and prediction of nine EPs in black tea, honey, and grape juice. Finally, a portable method for identifying EPs in food has been proposed by combining it with a smartphone.

A robust method for quantifying 42 phenolic compounds by RP-HPLC/DAD: Columns performance and characterization of Brazilian Citrus peels

Reliable analytical methods are the basis for the elucidation of phenolic compounds in foods. This study aimed to optimize and validate a method for determining 42 phenolics using reverse-phase (RP) high-performance liquid chromatography (HPLC) coupled to diode-array-detector-DAD. The performance of two RP columns was evaluated. The 150x4.6 mm 3-μm column showed superior separation quality, whereas 35 of the 42 phenolics showed a separation resolution ≥1.5. The method's linearity, precision (coefficient variation< 3.09%), recovery (87.5-103.2%), specificity, limits of detection (0.04-0.25 mg/L), and quantification (0.06-0.25 mg/L) had acceptable ranges. Thirty phenolics were quantified in Citrus peels, mainly flavanones, flavanols, flavonols, and phenolic acids, highlighting the high values of hesperidin (535-35070 mg/kg) and naringin (26-36466 mg/kg). Lemon peels named 'Lisboa,' 'Thaiti,' 'Thaiti-2000', and 'Thaiti-2001' presented the main phenolics associated with antioxidant capacity. The presented method was robust for determining 42 phenolic compounds, offering a new approach for bioactive compound quantification in food matrices.

Soluble and hydrolyzable phenolic compounds in date fruits (Phoenix dactylifera L.) by UPLC-QTOF-MS/MS and UPLC-DAD

Phenolic compounds in plant foods exist in soluble, hydrolyzable, and insoluble forms. This study is the first to analyze both soluble (extracted using 80 % methanol) and hydrolyzable (extracted using ethyl acetate after alkaline hydrolysis) phenolics in 18 date cultivars. The phenolic compounds were identified and quantified using ultra-high-performance liquid chromatography with quadrupole time-of-flight mass spectrometry and diode array detectors. A total of 59 peaks were detected, of which 45 were identified while 14 remained unidentified. The concentrations of the soluble and hydrolyzable phenolics ranged from 27.5–54.0 and 24–78.5 mg/100 g fresh weight, respectively. Gallic acid and ferulic acid predominated in the soluble and hydrolyzable fractions, quercetin and taxifolin were predominant in the soluble fraction, while caffeic acid and chlorogenic acid were abundant in the hydrolyzable fraction. The hydrolyzable phenolics were found to contribute significantly to the total phenolic content of date fruits pointing to the need to include them in the analysis of total phenolic compounds in foods.

Stability and preservation of phenolic compounds and related antioxidant capacity from agro-food matrix: Effect of pH and atmosphere

Phenolic compounds are major bioactive chemicals in plant-based food products with proven health benefits. However, alkaline pH processing promotes phenolic compounds auto-oxidation, leading to a loss in food products and by-products. A phenolic-rich brewery effluent, representative of plant-based food matrices, was subdued to aging tests to investigate phenolic compounds stability in different conditions. Three conditions were tested: pH 2 in atmospheric air, pH 13.5 in atmospheric air and under N2 flow. Studied phenolic compounds remained stable in acid pH and alkaline pH under N2 but decreased sharply in alkaline pH. Interestingly, global antioxidant capacity was either stable or degraded according to antioxidant assay performed. Phenolic compounds and their corresponding antioxidant capacity study with coupled HPLC-antioxidant capacity showed that their chemical structure drove their stability. Flavan-3-ols were the main compounds prone to auto-oxidation, followed by catechol acids. Monohydroxy phenolic acids were resistant to major auto-oxidation. This study highlights food phenolic compounds behavior with consequences on antioxidant capacity in a real agro-food system in extreme alkaline condition.

Complexation and conjugation between phenolic compounds and proteins: mechanisms, characterisation and applications as novel encapsulants

Food phenolic compounds (PCs) and proteins interact and react via non-covalent and covalent routes to form phenolic compound–protein (PCP) complexes and conjugates.

Impact of fermentation on the structure and antioxidant activity of selective phenolic compounds

The impact of fermentation on the structure and antioxidant potential of phenolic compounds in foods have received wide attention. In this study, five common phenolic compounds (ferulic acid, polydatin, cyanidin-3-O-glucoside, rutin, tannic acid) were fermented by Aspergillus oryzae, Lactobacillus plantarum and Saccharomyces cerevisiae respectively. The qualitative and quantitative analyses of the fermentation products were separately performed by HPLC-DAD-ESI-QTOF-MS/MS and HPLC-DAD, and the antioxidant properties (assessed by DPPH and ABTS assays) were also estimated. The results demonstrated that the glycosidic bonds in the phenolic compounds were hydrolyzed during fermentation, which led to the formation of additional phenolic metabolites such as gallic acid, protocatechuic acid and quercetin, as evidenced by the identification of 15 phenolic compounds in the fermented samples. The contents of these phenolics were considerably decreased (p < 0.05) to 1.72%–97.99% during fermentation, while the phenolic metabolites were detected in certain amounts (0.44–15.53 mg/L). The antioxidant activities of these phenolics also varied among different fermenting microorganisms. This study provides direct evidence of the metabolites and antioxidant properties of these common food phenolic compounds after fermentation.

Pectin conformation influences the bioaccessibility of cherry laurel polyphenols and gut microbiota distribution following in vitro gastrointestinal digestion and fermentation

Interactions between dietary fiber and phenolic compounds in foods can influence their gastrointestinal fate. This study aimed to examine the effect of four types of pectin on the polyphenols of cherry laurel puree and human gut microbiota during a simulated in vitro gastrointestinal digestion and large intestine fermentation. Results revealed that the combined addition of different pectins and pectinase to cherry laurel puree significantly affected the content and bioaccessibility of phenolics. The addition of pectins and pectinase distinctively impacted the phenolic subclasses in both raw and post-digested/fermented cherry laurel puree, suggesting differential interactions due to structural features. Both pectins and pectinase modulated the composition of fecal microbiota after in vitro fermentation, increasing bacterial diversity following pectinase treatment. The combined addition of pectins followed by pectinase had differential impacts on polyphenol bioaccessibility and gut microbiome diversity, hence having a potential outcome in terms of human health.

Targeted UHPLC-QTOF-IMS based metabolite profiling for bioactive compounds in Rosa webbiana wallich ex royle: An unexploited native from western himalayas

The current study focused on the tissues of wild Rosa webbiana from different altitudes of Indian Western Himalayas for vitamin C content, total phenolics, flavonoids, total sugars, and antioxidant potential. To date, there are very few studies on underutilized tissues viz. fruits, leaves and stem of Rosa webbiana growing in the higher altitudes. The targeted UHPLC-QTOF-IMS illustrated the phenolics fingerprinting of tissue extracts. Twelve bioactive compounds were detected with quercetin, kaempferol, and their derivatives dominantly in stem and leaves. The results have revealed that fruits possessed the highest vitamin C, and sugar contents (960, and 191.6 mg/100 g, respectively). Compared to other tissues, leaves showed the highest total phenolics as well as best results in vitro assays employed to assess antioxidant potential. The antioxidant activity showed a positive correlation with total phenolics. A significant variation in total phenolics, total flavonoids, and antioxidant potential was mainly attributed to oxidative stress on plants due to altitude difference, and secondary metabolite production. Taken together, the underutilized tissues of Rosa webbiana could be exploited as a promising, low-cost resource of phenolic compounds in food, cosmetic, and pharmaceutical industries. Our study will pave the way to developing food products from Rosa webbiana, a natural source for health-conscious people.

Extraction Systems and Analytical Techniques for Food Phenolic Compounds: A Review.

Phenolic compounds are highly valuable food components due to their potential utilisation as natural bioactive and antioxidant molecules for the food, cosmetic, chemical, and pharmaceutical industries. For this purpose, the development and optimisation of efficient extraction methods is crucial to obtain phenolic-rich extracts and, for some applications, free of interfering compounds. It should be accompanied with robust analytical tools that enable the standardisation of phenolic-rich extracts for industrial applications. New methodologies based on both novel extraction and/or analysis are also implemented to characterise and elucidate novel chemical structures and to face safety, pharmacology, and toxicity issues related to phenolic compounds at the molecular level. Moreover, in combination with multivariate analysis, the extraction and analysis of phenolic compounds offer tools for plant chemotyping, food traceability and marker selection in omics studies. Therefore, this study reviews extraction techniques applied to recover phenolic compounds from foods and agri-food by-products, including liquid-liquid extraction, solid-liquid extraction assisted by intensification technologies, solid-phase extraction, and combined methods. It also provides an overview of the characterisation techniques, including UV-Vis, infra-red, nuclear magnetic resonance, mass spectrometry and others used in minor applications such as Raman spectroscopy and ion mobility spectrometry, coupled or not to chromatography. Overall, a wide range of methodologies are now available, which can be applied individually and combined to provide complementary results in the roadmap around the study of phenolic compounds.

Analysis of Phenolic Compounds in Buckwheat (Fagopyrum esculentum Moench) Sprouts Modified with Probiotic Yeast.

Buckwheat sprouts are a source of various nutrients, e.g., antioxidant flavonoids, which have a positive effect on human health. This study analyzed the content of phenolic compounds and assessed their impact on the antioxidant and anti-inflammatory properties and dietary fiber in modified buckwheat sprouts. For this purpose, the buckwheat seeds were modified by adding Saccharomyces cerevisiae var. boulardii. The modified buckwheat sprouts showed a higher content of total phenol compounds (1526 µg/g d.w.) than the control sprouts (951 µg/g d.w.) and seeds (672 µg/g d.w.). As a consequence, a higher antioxidant activity and anti-inflammatory effect were noted. Probiotic-rich sprouts also had the highest content of total dietary fiber and its soluble fraction. A correlation between phenolic compounds and the antioxidant and anti-inflammatory effects, as well as dietary fiber, was shown. The interaction between dietary fiber and phenolic compounds affects the bioaccessibility, bioavailability, and bioactivity of phenolic compounds in food. The introduction of probiotic yeast into the sprouts had a positive effect on increasing their nutritional value, as well as their antioxidant and anti-inflammatory activity. As a consequence, the nutraceutical potential of the raw material changed, opening a new direction for the use of buckwheat sprouts, e.g., in industry.

Rheology of individual chitosan and polyphenol/chitosan microparticles for food engineering

Encapsulation of perishable bioactive molecules has become a standard process in the food industry. Beads in the millimeter size range may offer technological advantage over smaller particles and nano-structured materials for encapsulation purposes because of higher volume to surface ratios, but their size might seriously affect the sensory properties of the final edible products. We investigated the rheological properties of individual beads composed of chitosan (CTS) cross-linked with sodium tripolyphosphate (TTP). We produced the beads by the external gelation method using different combinations of CTS and TTP concentrations. Analysis of raw data showed that CTS and TTP affected both the morphology and the response of the particles to mechanical load in a non proportional way. The data indicated that the mechanical properties of the beads could not be explained with the aid of standard linear viscoelastic models. We therefore exploited a recently-developed nonlinear model to analyse mechanical data collected during the stress phase and estimate viscoelastic parameters. We found a clear synergic effect of CTS and TTP concentrations on particles’ stiffness and a crossover effect on their viscosity. Two representative bioactive food phenolic compounds, i.e. chlorogenic acid and catechin, were then encapsulated into the beads. Encapsulation of chlorogenic acid and catechin dramatically altered the viscoelastic behaviour of the particles in a similar way. The particles became less stiff and viscous and more fluid-like compared to empty beads with the same CTS and TTP composition. Our results pave the way for a more accurate evaluation of sensory characteristics of novel functional foods incorporating particle carriers for bioactive molecules.

Recovery of Polyphenols Using Pressurized Hot Water Extraction (PHWE) from Black Rosehip Followed by Encapsulation for Increased Bioaccessibility and Antioxidant Activity.

In this work, pressurized hot water extraction (PHWE) of hydrophilic polyphenols from black rosehip fruit was maximized using response surface methodology for simultaneous optimization in terms of extraction yield, total antioxidant capacity, total (poly)phenols, catechin, total monomeric anthocyanins, and cyanidin-3-O-glucoside. Extraction parameters, including temperature (X1: 40–80 °C) and the solvent-to-solid ratio (X2: 10–40 mL/g), were investigated as independent variables. Experimentally obtained values were fitted to a second-order polynomial model, and optimal conditions were determined using multiple regression analysis and analysis of variance. The black rosehip extract (BRE) obtained at optimized PHWE conditions was further encapsulated in biopolymer-coated liposomes and spray dried to enhance its processing and digestive stability. After reconstitution, the fabricated particles had an average size of 247–380 nm and a zeta-potential of 15–45 mV. Moreover, encapsulation provided remarkable protection of the phenolics under in vitro gastrointestinal digestion conditions, resulting in up to a 5.6-fold more phenolics in the bioaccessible fraction, which also had 2.9–8.6-fold higher antioxidant activity compared to the nonencapsulated BRE. In conclusion, PHWE in combination with a biopolymer coating is a potent method for the production of stable and safe edible natural extracts for the delivery of (poly)phenolic compounds in food and dietary supplements.

Analysis of Phenolic Compounds in Food by Coulometric Array Detector: A Review.

Phenolic compounds are an important group of organic molecules with high radical scavenging, antimicrobial, anti-inflammatory, and antioxidant properties. The emerging interest in phenolic compounds in food products has led to the development of various analytical techniques for their detection and characterization. Among them, the coulometric array detector is a sensitive, selective, and precise method for the analysis of polyphenols. This review discusses the principle of this method and recent advances in its development, as well as trends in its application for the analysis of phenolic compounds in food products, such as fruits, cereals, beverages, herbs, and spices.

Variability in the Beneficial Effects of Phenolic Compounds: A Review.

When analysing the beneficial effects of phenolic compounds, several factors that exert a clear influence should be taken into account. The content of phenolic compounds in foods is highly variable, directly affecting individual dietary intake. Once ingested, these compounds have a greater or lesser bioaccessibility, defined as the amount available for absorption in the intestine after digestion, and a certain bioavailability, defined as the proportion of the molecule that is available after digestion, absorption and metabolism. Among the external factors that modify the content of phenolic compounds in food are the variety, the cultivation technique and the climate. Regarding functional foods, it is important to take into account the role of the selected food matrix, such as dairy matrices, liquid or solid matrices. It is also essential to consider the interactions between phenolic compounds as well as the interplay that occurs between these and several other components of the diet (macro- and micronutrients) at absorption, metabolism and mechanism of action levels. Furthermore, there is a great inter-individual variability in terms of phase II metabolism of these compounds, composition of the microbiota, and metabolic state or metabotype to which the subject belongs. All these factors introduce variability in the responses observed after ingestion of foods or nutraceuticals containing phenolic compounds.

High Hydrostatic Pressure to Increase the Biosynthesis and Extraction of Phenolic Compounds in Food: A Review.

Phenolic compounds from fruits and vegetables have shown antioxidant, anticancer, anti-inflammatory, among other beneficial properties for human health. All these benefits have motivated multiple studies about preserving, extracting, and even increasing the concentration of these compounds in foods. A diverse group of vegetable products treated with High Hydrostatic Pressure (HHP) at different pressure and time have shown higher phenolic content than their untreated counterparts. The increments have been associated with an improvement in their extraction from cellular tissues and even with the activation of the biosynthetic pathway for their production. The application of HHP from 500 to 600 MPa, has been shown to cause cell wall disruption facilitating the release of phenolic compounds from cell compartments. HPP treatments ranging from 15 to 100 MPa during 10–20 min at room temperature have produced changes in phenolic biosynthesis with increments up to 155%. This review analyzes the use of HHP as a method to increase the phenolic content in vegetable systems. Phenolic content changes are associated with either an immediate stress response, with a consequent improvement in their extraction from cellular tissues, or a late stress response that activates the biosynthetic pathways of phenolics in plants.

Phenolic Substances in Foods and Anticarcinogenic Properties: A Public Health Perspective.

The interest in polyphenols from vegetable sources has been progressively increased because of the demonstrated correlation between their abundance in certain foods or food preparations of traditional importance and heritage, and the answer of anti-inflammatory strategies in hospitalized patients in the presence of polypehnol-rich foods (as a complementary therapy). Consequently, research involving the accessory role of polyphenols as anti-tumoral aids have been carried out with the aim of finding new additional strategies. The purpose of this paper to evaluate the role of phenolic compounds in foods with reference to health effects for human beings. The importance of these molecules has been evaluated by the health and safety perspectives in terms of: fight to cardiovascular diseases; prevention of chronic-degenerative disorders; general antioxidant properties; and anticarcinogenic features. Moreover, the role of polyphenols-rich foods as anticancer agents has been discussed with relation to two distinct "action plans" on the public hygiene level: the promotion of human health on the one side (for non-hospitalized and normal subjects), and reliable contrasting strategies in cancer patients.

Bioavailability of Phenolic Compounds in Food and their Properties in Cellular Protection

Bioavailability of Phenolic Compounds in Food and their Properties in Cellular Protection

Sensitive Detection of Caffeic Acid and Rutin via the Enhanced Anodic Electrochemiluminescence Signal of Luminol.

The electrooxidation of phenolic groups of caffeic acid and rutin promote anodic electrochemiluminescence (ECL) luminol substantially. A sensitive, and cost-effective ECL method has thus been developed to detect caffeic acid, ranging from 0.1 to 5.0 μM, with a detection limit of 0.1 μM and rutin ranging from 0.2 to 25 μM with a detection limit of 0.12 μM. Contrarily, phenolic compounds quench the weak cathodic ECL of luminol. Both of anodic and cathodic ECL mechanisms of luminol in the presence of phenolic compounds are analyzed. The method based on the boomed anodic ECL of luminol is comparable to those based on Ru(bpy)32+ and S2O82-/O2 systems. A lower onset potential and price than the other ECL reagents would realize its widely applications in the detection of phenolic compounds in food and medicine.

Analysis of Major Phenolic Compounds in Foods and Their Health Effects

Analysis of Major Phenolic Compounds in Foods and Their Health Effects

Analysis of Main and Healthy Phenolic Compounds in Foods

Abstract Background: In the last few decades, the media has been overwhelming the consumer with various dietary requirements that some of which lead to no avail. On the other hand, the Mediterranean diet, which stems from a very ancient lore, stands as one of the most effective diets whose conspicuous and positive results are still impacting the lives of many Mediterranean locals. The “Mediterranean Diet” is an umbrella term that is used to denote a plethora of natural ingredients used in the culinary tradition of the region, and which comprises but is not limited to olive oil, cereals, wine, fruits, dried fruits, and spices. MD components are known for being rich in antioxidant compounds. Polyphenols belong to the category of antioxidants that occur in the above-mentioned Mediterranean foods. Objective: The current review aims at presenting main classes of phenols from plant foods, their role as dietary components, and an overview on analytical methods for their extraction from food matrices, their separation, detection and quantification. Conclusions: The discrimination of phenols is not an easy matter, and several methods are described in the literature, mainly chromatographic methods, which are herein reviewed. In short, phenols are mainly found in vegetable foods in which the Mediterranean Diet is rich. The health effects of some phenols and analytical methods are herein revised. Highlights: Phenols or Phenolics is a designation corresponding to compounds that have one or more hydroxyl groups attached to a 6-carbon aromatic ring. Phenols in foods occur mainly as secondary metabolites of vegetables, often found in polymeric forms (polyphenols). Phenols from foods are mainly simple phenols (e.g., caffeic acid), flavonoids, the most varied and ubiquitous class (e.g., catechin, quercetin), stilbenes (resveratrol), lignans, and tannins. In addition to the wide range of polyphenols present in foods, the compounds are quantitatively and qualitatively distributed in a heterogenous way in the different compartments of the food matrix. This structural and compartmental diversity leads to an important variability of the physicochemical properties impacting otherwise the extraction of phenols. Total phenols are determined by the Folin Cioucalteau method, as described in European Pharmacopeaea.