Showing papers in "Journal of Agricultural and Food Chemistry in 2009"
TL;DR: A significant relationship between antioxidant capacity and total phenolic content was found, indicating that phenolic compounds are the major contributors to the antioxidant properties of these plants.
Abstract: Aqueous extracts of 30 plants were investigated for their antioxidant properties using DPPH and ABTS radical scavenging capacity assay, oxygen radical absorbance capacity (ORAC) assay, superoxide dismutase (SOD) assay, and ferric reducing antioxidant potential (FRAP) assay. Total phenolic content was also determined by the Folin−Ciocalteu method. Antioxidant properties and total phenolic content differed significantly among selected plants. It was found that oak (Quercus robur), pine (Pinus maritima), and cinnamon (Cinnamomum zeylanicum) aqueous extracts possessed the highest antioxidant capacities in most of the methods used, and thus could be potential rich sources of natural antioxidants. These extracts presented the highest phenolic content (300−400 mg GAE/g). Mate (Ilex paraguariensis) and clove (Eugenia caryophyllus clovis) aqueous extracts also showed strong antioxidant properties and a high phenolic content (about 200 mg GAE/g). A significant relationship between antioxidant capacity and total phe...
1,358 citations
TL;DR: The aim of this review was to discuss the current information about the microbial degradation metabolites obtained from different phenolics and their formation pathways, identifying their differences and similarities and the modulation of gut microbial population by phenolics.
Abstract: Dietary phenolic compounds are often transformed before absorption. This transformation modulates their biological activity. Different studies have been carried out to understand gut microbiota transformations of particular polyphenol types and identify the responsible microorganisms. Although there are potentially thousands of different phenolic compounds in the diet, they are typically transformed to a much smaller number of metabolites. The aim of this review was to discuss the current information about the microbial degradation metabolites obtained from different phenolics and their formation pathways, identifying their differences and similarities. The modulation of gut microbial population by phenolics was also reviewed in order to understand the two-way phenolic-microbiota interaction. Clostridium and Eubacterium genera, which are phylogenetically associated, are other common elements involved in the metabolism of many phenolics. The health benefits from phenolic consumption should be attributed to their bioactive metabolites and also to the modulation of the intestinal bacterial population.
1,048 citations
TL;DR: In this review, assays used recently were selected for extended discussion, including discussion of the mechanisms underlying each assay and its application to various plants and foods.
Abstract: Recently, research on natural antioxidants has become increasingly active in various fields. Accordingly, numerous articles on natural antioxidants, including polyphenols, flavonoids, vitamins, and volatile chemicals, have been published. Assays developed to evaluate the antioxidant activity of plants and food constituents vary. Therefore, to investigate the antioxidant activity of chemical(s), choosing an adequate assay based on the chemical(s) of interest is critical. There are two general types of assays widely used for different antioxidant studies. One is an assay associated with lipid peroxidations, including the thiobarbituric acid assay (TBA), malonaldehyde/high-performance liquid chromatography (MA/HPLC) assay, malonaldehyde/gas chromatography (MA/GC) assay, β-carotene bleaching assay, and conjugated diene assay. Other assays are associated with electron or radical scavenging, including the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) as...
798 citations
TL;DR: In this review, antimicrobials from a range of plant, animal, and microbial sources are reviewed along with their potential applications in food systems and factors influencing the antimicrobial activity of such agents are discussed including extraction methods, molecular weight, and agent origin.
Abstract: In this review, antimicrobials from a range of plant, animal, and microbial sources are reviewed along with their potential applications in food systems. Chemical and biochemical antimicrobial compounds derived from these natural sources and their activity against a range of pathogenic and spoilage microorganisms pertinent to food, together with their effects on food organoleptic properties, are outlined. Factors influencing the antimicrobial activity of such agents are discussed including extraction methods, molecular weight, and agent origin. These issues are considered in conjunction with the latest developments in the quantification of the minimum inhibitory (and noninhibitory) concentration of antimicrobials and/or their components. Natural antimicrobials can be used alone or in combination with other novel preservation technologies to facilitate the replacement of traditional approaches. Research priorities and future trends focusing on the impact of product formulation, intrinsic product parameters, and extrinsic storage parameters on the design of efficient food preservation systems are also presented.
713 citations
TL;DR: The control efficacy against adult T. castaneum remained over 80% after five months, presumably due to the slow and persistent release of the active components from the nanoparticles, and indicates that it is feasible to use the PEG coating nanoparticles loaded with garlic essential oil to control the store-product pests.
Abstract: The aim of this work was to characterize polyethylene glycol (PEG) coated nanoparticles loaded with garlic essential oil and to evaluate their insecticidal activity against adult Tribolium castaneum. Preparation of nanoparticles was carried out using the melt-dispersion method, a very simple, convenient, and low-cost technique. The oil-loading efficiency could reach 80% at the optimal ratio of essential oil to PEG (10%). The morphology results and nanoparticle size showed that the nanoparticles had a round appearance and good dispersion, <240 nm in the average diameter, characterized by transmission electron microscope and dynamic light scattering, respectively. The abundance and percentage content of the major components did not show any significant difference between free and nanoencapsulated oil when analyzed by gas chromatography−mass spectrometry. The control efficacy against adult T. castaneum remained over 80% after five months, presumably due to the slow and persistent release of the active compon...
417 citations
TL;DR: The results indicated that Que, Iso and Rut could bind alpha-glucosidase to form a new complex, which exhibited a strong static fluorescence quenching via nonradiation energy transfer, and an obvious blue shift of maximum fluorescence, which would be significant for the development of more powerful antidiabetes drugs and efficacious utilization of tartary buckwheat.
Abstract: Three flavonoids from tartary buckwheat bran, namely, quercetin (Que), isoquercetin (Iso) and rutin (Rut), have been evaluated as alpha-glucosidase inhibitors by fluorescence spectroscopy and enzymatic kinetics and have also been compared with the market diabetes healer, acarbose The results indicated that Que, Iso and Rut could bind alpha-glucosidase to form a new complex, which exhibited a strong static fluorescence quenching via nonradiation energy transfer, and an obvious blue shift of maximum fluorescence The sequence of binding constants (K(A)) was Que > Iso > Rut, and the number of binding sites was one for all of the three cases The thermodynamic parameters were obtained by calculations based on data of binding constants They revealed that the main driving force of the above-mentioned interaction was hydrophobic Enzymatic kinetics measurements showed that all of the three compounds were effective inhibitors against alpha-glucosidase Inhibitory modes all belonged to a mixed type of noncompetitive and anticompetitive The sequence of affinity (1/K(i)) was in accordance with the results of binding constants (K(A)) The concentrations which gave 50% inhibition (IC(50)) were 0017 mmol*L(-1), 0185 mmol*L(-1) and 0196 mmol*L(-1), compared with acarbose's IC(50) (0091 mmol*L(-1)); the dose of acarbose was almost five times of that of Que and half of that of Iso and Rut Our results explained why the inhibition on alpha-glucosidase of tartary buckwheat bran extractive substance (mainly Rut) was much weaker than that of its hydrolysis product (a mixture of Que, Iso and Rut) This work would be significant for the development of more powerful antidiabetes drugs and efficacious utilization of tartary buckwheat, which has been proved as an acknowledged food in the diet of diabetic patients
409 citations
TL;DR: In this contribution, an exhaustive revision is presented involving the research for innovative functional food ingredients from microalgae including new species composition and bioactivity and new processing and extraction methods.
Abstract: Nowadays, a wide variety of compounds such as polyphenols, polyunsaturated fatty acids (PUFA), or phytosterols obtained, for example, from wine, fish byproducts, or plants are employed to prepare new functional foods. However, unexplored natural sources of bioactive ingredients are gaining much attention since they can lead to the discovery of new compounds or bioactivities. Microalgae have been proposed as an interesting, almost unlimited, natural source in the search for novel natural functional ingredients, and several works have shown the possibility to find bioactive compounds in these organisms. Some advantages can be associated with the study of microalgae such as their huge diversity, the possibility of being used as natural reactors at controlled conditions, and their ability to produce active secondary metabolites to defend themselves from adverse or extreme conditions. In this contribution, an exhaustive revision is presented involving the research for innovative functional food ingredients from microalgae. The most interesting results in this promising field are discussed including new species composition and bioactivity and new processing and extraction methods. Moreover, the future research trends are critically commented.
408 citations
TL;DR: The physicochemical and antimicrobial properties of starch-chitosan films incorporated with oregano essential oil (OEO) and the presence of OEO led to the formation of more flexible films and TGA analysis demonstrated that the addition of chitOSan and OEO did not affect the thermal stability of the films.
Abstract: The physicochemical and antimicrobial properties of starch−chitosan films incorporated with oregano essential oil (OEO) have been investigated. The antimicrobial effects of starch−chitosan−OEO films against Bacillus cereus, Escherichia coli, Salmonella enteritidis, and Staphylococcus aureus were determined by the disk inhibition zone method. The film mechanical properties, water vapor permeability (WVP), Fourier transform infrared spectra (FTIR), and thermograms (TGA) were also determined. Films added with OEO effectively inhibited the four microorganisms tested and demonstrated improved barrier properties. The presence of OEO in starch−chitosan films led to the formation of more flexible films. Chitosan was not effective against the tested organisms, but it decreased film rigidity and WVP. TGA analysis demonstrated that the addition of chitosan and OEO did not affect the thermal stability of the films.
405 citations
TL;DR: The best possible combinations of ethanol concentration, extraction temperature, and extraction time with the application of ultrasound were obtained for the maximum extraction of phenolic compounds, antioxidant activities, and anthocyanins from grape seed by using response surface methodology (RSM).
Abstract: Important functional components from Campbell Early grape seed were extracted by ultrasound-assisted extraction (UAE) technology. The experiments were carried out according to a five level, three variable central composite rotatable design (CCRD). The best possible combinations of ethanol concentration, extraction temperature, and extraction time with the application of ultrasound were obtained for the maximum extraction of phenolic compounds, antioxidant activities, and anthocyanins from grape seed by using response surface methodology (RSM). Process variables had significant effect on the extraction of functional components with extraction time being highly significant for the extraction of phenolics and antioxidants. The optimal conditions obtained by RSM for UAE from grape seed include 53.15% ethanol, 56.03 degrees C temperature, and 29.03 min time for the maximum total phenolic compounds (5.44 mg GAE/100 mL); 53.06% ethanol, 60.65 degrees C temperature, and 30.58 min time for the maximum antioxidant activity (12.31 mg/mL); and 52.35% ethanol, 55.13 degrees C temperature, and 29.49 min time for the maximum total anthocyanins (2.28 mg/mL). Under the above-mentioned conditions, the experimental total phenolics were 5.41 mg GAE/100 mL, antioxidant activity was 12.28 mg/mL, and total anthocyanins were 2.29 mg/mL of the grape seed extract, which is well matched with the predicted values.
386 citations
TL;DR: After the pH-shifting processes, soy protein adopted a molten globule-like conformation that largely maintained the original secondary structure and overall compactness but lost some tertiary structure, which led to markedly improved emulsifying activity of SPI as well as the emulsion stability.
Abstract: Structural unfolding of soy protein isolate (SPI) as induced by holding (0, 0.5, 1, 2, and 4 h) in acidic (pH 1.5−3.5) and alkaline (pH 10.0−12.0) pH solutions, followed by refolding (1 h) at pH 7.0, was analyzed. Changes in emulsifying properties of treated SPI were then examined. The pH-shifting treatments resulted in a substantial increase in protein surface hydrophobicity, intrinsic tryptophan fluorescence intensity, and disulfide-mediated aggregation, along with the exposure of tyrosine. After the pH-shifting processes, soy protein adopted a molten globule-like conformation that largely maintained the original secondary structure and overall compactness but lost some tertiary structure. These structural modifications, consequently, led to markedly improved emulsifying activity of SPI as well as the emulsion stability.
351 citations
TL;DR: Although the biosynthesis of benzoxazinoid hydroxamic acids has been elucidated, the genes and mechanisms controlling their differential expression in different plant tissues and along plant ontogeny remain to be unraveled.
Abstract: Many cereals accumulate hydroxamic acids derived from 2-hydroxy-2H-1,4-benzoxazin-3(4H)-one. These benzoxazinoid hydroxamic acids are involved in defense of maize against various lepidopteran pests, most notably the European corn borer, in defense of cereals against various aphid species, and in allelopathy affecting the growth of weeds associated with rye and wheat crops. The role of benzoxazinoid hydroxamic acids in defense against fungal infection is less clear and seems to depend on the nature of the interactions at the plant-fungus interface. Efficient use of benzoxazinoid hydroxamic acids as resistance factors has been limited by the inability to selectively increase their levels at the plant growth stage and the plant tissues where they are mostly needed for a given pest. Although the biosynthesis of benzoxazinoid hydroxamic acids has been elucidated, the genes and mechanisms controlling their differential expression in different plant tissues and along plant ontogeny remain to be unraveled.
TL;DR: Results indicated that curcumin enhanced the gastrointestinal absorption by liposomes encapsulation, and the available information strongly suggests that liposome encapsulation of ingredients such asCurcumin may be used as a novel nutrient delivery system.
Abstract: To enhance the curcumin absorption by oral administration, liposome-encapsulated curcumin (LEC) was prepared from commercially available lecithins (SLP-WHITE and SLP-PC70) and examined for its inte...
TL;DR: The results showed that the sequential treatments and graded precipitations were very effective on the fractionation of hemicelluloses from bagasse and noticeable differences in the chemical composition and molecular weights were observed among the graded hemICEllulosic subfractions from the water-soluble and alkali- soluble hemiceLLuloses.
Abstract: The sequential treatment of dewaxed sugarcane bagasse with H(2)O and 1 and 3% NaOH at a solid to liquid ratio of 1:25 (g mL(-1)) at 50 degrees C for 3 h yielded 74.9% of the original hemicelluloses. Each of the hemicellulosic fractions was successively subfractionated by graded precipitation at ethanol concentrations of 15, 30, and 60% (v/v). Chemical composition, physicochemical properties, and structures of eight precipitated hemicellulosic fractions were elucidated by a combination of sugar analysis, nitrobenzene oxidation of bound lignin, molecular determination, Fourier transform infrared (FT-IR), (1)H and (13)C nuclear magnetic spectroscopies, and thermal analysis. The results showed that the sequential treatments and graded precipitations were very effective on the fractionation of hemicelluloses from bagasse. Comparison of these hemicelluloses indicated that the smaller sized and more branched hemicelluloses were extracted by the hot water treatment; they are rich in glucose, probably originating from alpha-glucan and pectic polysaccharides. The larger molecular size and more linear hemicelluloses were dissolved by the alkali treatment; they are rich in xylose, principally resulting from l-arabino-(4-O-methylglucurono)-d-xylans. In addition, noticeable differences in the chemical composition and molecular weights were observed among the graded hemicellulosic subfractions from the water-soluble and alkali-soluble hemicelluloses. The Ara/Xyl ratio increased with the increment of ethanol concentration from 15 to 60%, and the arabinoxylans with higher Ara/Xyl ratios had higher molecular weights. There were no significant differences in the structural features of the precipitated hemicellulosic subfractions, which are mainly constituted of l-arabino-(4-O-methyl-d-glucurono)xylan, whereas the difference may occur in the distribution of branches along the xylan backbone.
TL;DR: The results suggested that the antidiabetic effect of oleuropein and hydroxytyrosol might be due to their antioxidant activities restraining the oxidative stress which is widely associated with diabetes pathologies and complications.
Abstract: This study was designed to test the antidiabetic and antioxidative activities of olive leaf oleuropein and hydroxytyrosol. Diabetes in Wistar rats was induced by intraperitoneal injections of alloxan. The serum glucose and cholesterol, hepatic glycogen, the thiobarbituric acid-reactive substances (TBARS), and the components of hepatic and serum antioxidant system were examined. Diabetic rats showed hyperglycemia, hypercholesterolemia, increased lipid peroxidation, and depletion in the antioxidant enzymes activities. The administration, for 4 weeks, of oleuropein and hydroxytyrosol rich extracts, leading to 8 and 16 mg/kg body weight of each compound, significantly decreased the serum glucose and cholesterols levels and restored the antioxidant perturbations. These results suggested that the antidiabetic effect of oleuropein and hydroxytyrosol might be due to their antioxidant activities restraining the oxidative stress which is widely associated with diabetes pathologies and complications.
TL;DR: The good antioxidant activity shown by functionalized materials proved the efficiency of the reaction method and the formation of covalent bonds between antioxidant and biopolymer was verified.
Abstract: In this work, the synthesis of gallic acid-chitosan and catechin-chitosan conjugates was carried out by adopting a free radical-induced grafting procedure. For this purpose, an ascorbic acid/hydrogen peroxide redox pair was employed as radical initiator. The formation of covalent bonds between antioxidant and biopolymer was verified by performing UV, FT-IR, and DSC analyses, whereas the antioxidant properties of chitosan conjugates were compared with that of a blank chitosan, treated in the same conditions but in the absence of antioxidant molecules. The good antioxidant activity shown by functionalized materials proved the efficiency of the reaction method.
TL;DR: The polyphenol chemistry of tea and coffee, specifically their stability, and scavenging ability of reactive oxygen species (ROS) and reactive carbonyl species (RCS) are reviewed.
Abstract: Tea and coffee, the most popular beverages in the world, have been consumed for thousands of years for their alluring flavors and health benefits. Polyphenols, particularly flavonoids and phenolic acids, are of great abundance in tea and coffee and contribute a lot to their flavor and health properties. This paper reviews the polyphenol chemistry of tea and coffee, specifically their stability, and scavenging ability of reactive oxygen species (ROS) and reactive carbonyl species (RCS). During the manufacturing and brewing process, green tea and black tea polyphenols undergo epimerization and oxidation, respectively. Meanwhile, the lactonization and the polymerization of chlorogenic acid are the major causes for the degradation of polyphenols in coffee. Tea catechins, besides having antioxidant properties, have the novel characteristic of trapping reactive carbonyl species. The A ring of the catechins is the binding site for RCS trapping, whereas the B ring is the preferred site for antioxidation.
TL;DR: It is demonstrated that vacuum-microwave drying, especially at 240 W, can produce high-quality products, with the additional advantage of reduced processing times, compared to other processes such as freeze-drying.
Abstract: The objective of this study was to evaluate the application of vacuum-microwave drying (240, 360, and 480 W) in the production process of dehydrated strawberry and to compare and contrast the quality of these dehydrated strawberries in terms of their polyphenol compounds, concentration of some heat liable components, and color to that of freeze-dried, convective, and vacuum-dried strawberry. Thus, the effect of vacuum-microwave drying and other drying methods on the antioxidant activity of berries was evaluated. Whole fresh and dried fruits were assessed for phenolics (anthocyanins, flavanols, hydroxycinnamic acids, and flavonols), ascorbic acid, and antioxidant activity (all parameters were calculated on a dry matter basis). Analysis of data shows that ellagic acid and flavanol changes were affected by drying techniques and cultivar. Drying destroyed anthocyanins, flavanols, and ascorbic acid, and there was a significant decrease in antioxidant activity. The most striking result was that conventional and vacuum drying decreased antioxidant activity in both cultivars, whereas contradictory results were found for vacuum-microwave processed strawberry. This study has demonstrated that vacuum-microwave drying, especially at 240 W, can produce high-quality products, with the additional advantage of reduced processing times, compared to other processes such as freeze-drying.
TL;DR: An analytical approach based on HPLC with ELSD that quantifies the major FODMAPs in 45 vegetables and 41 fruits is described, finding that apple, pear, mango, clingstone peach, and watermelon all contained fructose in excess of glucose.
Abstract: Fermentable oligo-, di-, and monosaccharides and polyols (FODMAPs) are short-chain carbohydrates that can be poorly absorbed by the small intestine and may have a wide range of effects on gastrointestinal processes. FODMAPs include lactose, fructose in excess of glucose, fructans and fructooligosaccharides (FOS, nystose, kestose), galactooligosaccharides (GOS, raffinose, stachyose), and sugar polyols (sorbitol, mannitol). This paper describes an analytical approach based on HPLC with ELSD that quantifies the major FODMAPs in 45 vegetables and 41 fruits. Sorbitol and/or mannitol were measured in 18 vegetables (range = 0.09-2.96 g/100 g of fw), raffinose and/or stachyose in 7 vegetables (0.08-0.68 g/100 g of fw), and nystose and/or kestose in 19 vegetables (0.02-0.71 g/100 g of fw). Apple, pear, mango, clingstone peach, and watermelon all contained fructose in excess of glucose. Sorbitol was measured in 15 fruits (0.53-5.99 g/100 g of fw), mannitol was found in 2 fruits, and nystose or kestose was measured in 8 fruits. Understanding the importance of dietary FODMAPs will be greatly assisted by comprehensive food composition data.
TL;DR: The results show silver nanoparticle incorporated sodium alginate coated vegetables and fruits are suitable for preservation and shows good antibacterial activity against test strains.
Abstract: Biosynthesis of silver nanoparticles using Trichoderma viride and their incorporation into sodium alginate for vegetable and fruit preservation has been demonstrated in this study. Aqueous silver (Ag(+)) ions when exposed to the filtrate of T. viride are reduced in solution. These extremely stable silver nanoparticles were characterized by means of UV-vis spectrophotometer, FTIR, TEM, and EDS. The nanoparticles exhibit maximum absorbance at 421 nm in the UV spectrum. The presence of proteins was identified by FTIR. TEM micrograph revealed the formation of polydispersed nanoparticles, and the presence of elemental silver was confirmed by EDS analysis. The silver nanoparticle incorporated sodium alginate thin film shows good antibacterial activity against test strains. This film increases the shelf life of carrot and pear when compared to control with respect to weight loss and soluble protein content. These results show silver nanoparticle incorporated sodium alginate coated vegetables and fruits are suitable for preservation.
TL;DR: The concept of resveratrol as a dietary beneficial compound in intestinal inflammation at doses possibly attainable with resver atrol-enriched nutraceuticals is reinforced.
Abstract: The naturally occurring polyphenol resveratrol has been acknowledged with health-beneficial properties. Most of the studies dealing with its in vivo effects assay huge doses, not representative from a dietary point of view. Our aim was to ascertain whether resveratrol can exert anti-inflammatory activity in vivo at an attainable dietary dose. Rats were fed with 1 mg of resveratrol/kg/day (a human equivalent dose) for 25 days, and in the last 5 days, 5% dextran sulfate sodium (DSS) was administered to induce colitis. Effects on colon tissue damage, gut microbiota, reactive oxygen species, inflammatory markers and nitric oxide production as well as gene expression profile with microarrays were evaluated. Resveratrol increased lactobacilli and bifidobacteria as well as diminished the increase of enterobacteria upon DSS treatment. Resveratrol significantly protected the colonic mucosa architecture, reduced body weight loss, diminished the induced anemia and reduced systemic inflammation markers, colonic mucosa prostaglandin E(2), cycloxygenase-2, prostaglandin E synthase and nitric oxide levels. In addition, the expression of 2,655 genes in distal colon mucosa related to important pathways was varied. These results reinforce the concept of resveratrol as a dietary beneficial compound in intestinal inflammation at doses possibly attainable with resveratrol-enriched nutraceuticals.
TL;DR: Factorization analysis of spectra was able to differentiate unadulterated infant formula powder from samples containing 1 ppm melamine with no misclassifications, a confidence level of 99.99%, and selectivity > 2.99%.
Abstract: Near- and mid-infrared spectroscopy methods (NIR, FTIR-ATR, FTIR-DRIFT) were evaluated for the detection and quantification of melamine in infant formula powder. Partial least-squares (PLS) models were established for correlating spectral data to melamine concentration: R(2) > 0.99, RMSECV ≤ 0.9, and RPD ≥ 12. Factorization analysis of spectra was able to differentiate unadulterated infant formula powder from samples containing 1 ppm melamine with no misclassifications, a confidence level of 99.99%, and selectivity > 2. These nondestructive methods require little or no sample preparation. The NIR method has an assay time of 1 min, and a 2 min total time to detection. The FTIR methods require up to 5 min for melamine detection. Therefore, NIR and FTIR methods enable rapid detection of 1 ppm melamine in infant formula powder.
TL;DR: In vitro fermentation of purified PC dimers with human microbiota revealed two main metabolites, which were responsible for the health effects of chocolate and wine and a degradation pathway, partly different from that of monomeric flavan-3-ols, is proposed.
Abstract: Procyanidins (PCs) are highly abundant phenolic compounds in the human diet and might be responsible for the health effects of chocolate and wine. Due to low absorption of intact PCs, microbial metabolism might play an important role. So far, only a few studies, with crude extracts rich in PCs but also containing a multitude of other phenolic compounds, have been performed to reveal human microbial PC metabolites. Therefore, the origin of the metabolites remains questionable. This study included in vitro fermentation of purified PC dimers with human microbiota. The main metabolites identified were 2-(3,4-dihydroxyphenyl)acetic acid and 5-(3,4-dihydroxyphenyl)-γ-valerolactone. Other metabolites detected were 3-hydroxyphenylacetic acid, 4-hydroxyphenylacetic acid, 3-hydroxyphenylpropionic acid, phenylvaleric acids, monohydroxylated phenylvalerolactone, and 1-(3′,4′-dihydroxyphenyl)-3-(2′′,4′′,6′′-trihydroxyphenyl)propan-2-ol. Metabolites that could be quantified accounted for at least 12 mol % of the dimers...
TL;DR: The data indicate that the free radical scavenging assays tested have limited value in predicting the antioxidant activity in complex foods.
Abstract: Numerous attempts have been made to relate the free radical scavenging capacity of compounds to their antioxidant activity in foods even though antioxidant activity is dependent on both physical and chemical properties. The objective of this study was to compare the free radical scavenging activity of various compounds to their ability to inhibit lipid oxidation in foods. The order of free radical scavenging activity of polar compounds was ferulic acid > coumaric acid > propyl gallate > gallic acid > ascorbic acid as determined by a modified oxygen radical absorbance capacity, while the order of nonpolar compounds was rosmarinic acid > butylated hydroxytoluene ≥ tert-butylhydroquinone (TBHQ) > α-tocopherol as determined by the 2,2-diphenyl-1-picrylhydrazyl assay. Of these compounds, only propyl gallate and TBHQ were found to inhibit lipid oxidation in cooked ground beef as determiend by thiobarbituric acid reactive substances, while only propyl gallate, TBHQ, gallic acid, and rosmarinic acid inhibited lip...
TL;DR: Investigation of boiling and steaming processes at atmospheric and high pressures on the phenolic components and antioxidant properties of pinto and black beans found anthocyanins, flavan-3-ols, and flavonols may play important roles on the overall antioxidant activities of black beans.
Abstract: The effects of boiling and steaming processes at atmospheric and high pressures on the phenolic components and antioxidant properties of pinto and black beans were investigated. In comparison to the original raw beans, all processing methods caused significant (p < 0.05) decreases in total phenolic content (TPC), total flavonoid content (TFC), condensed tannin content (CTC), monomeric anthocyanin content (MAC), DPPH free-radical scavenging activity (DPPH), ferric-reducing antioxidant power (FRAP), and oxygen radical absorbing capacity (ORAC) values in both pinto and black beans. Steaming processing resulted in a greater retention of TPC, DPPH, FRAP, and ORAC values than the boiling processes in both pinto and black beans. To further investigate how thermal processing affected phenolic compositions and to elucidate the contribution of individual phenolic compounds to antioxidant properties, phenolic acids, anthocyanins, flavan-3-ols, and flavonols were quantitatively analyzed by high-performance liquid chromatography (HPLC). All thermal processing significantly (p < 0.05) affected individual phenolic acids, anthocyanins, flavan-3-ols, and flavonols, significantly (p < 0.05) reduced total phenolic acid contents in both pinto and black beans and total flavonol contents in pinto beans, and dramatically reduced anthocyanin contents in black beans. Phenolic acids and flavonols may play important roles on the overall antioxidant activities of pinto beans, while anthocyanins, flavan-3-ols, and flavonols may play important roles on the overall antioxidant activities of black beans.
TL;DR: The polar paradox appeared to be the particular case of a far more global nonlinear effect that was observed here and the proposal of a new scenario of the behavior of phenolic compounds in emulsified systems with special emphasis on the micellization process is made.
Abstract: Twenty years ago, Porter et al. (J. Agric. Food Chem. 1989, 37, 615−624) put forward the polar paradox stating among others that apolar antioxidants are more active in emulsified media than their polar homologues. However, some recent results showing that not all antioxidants behave in the manner proposed by this hypothesis led us to investigate the relationship between antioxidant property and hydrophobicity. With a complete homologous series of chlorogenic acid esters (methyl, butyl, octyl, dodecyl, hexadecyl, octadecyl, and eicosyl), we observed in emulsified medium that antioxidant capacity increases as the alkyl chain is lengthened, with a threshold for the dodecyl chain, after which further chain extension leads to a drastic decrease in antioxidant capacity. The antioxidant capacity evaluation in emulsion was possible using a newly developed conjugated autoxidizable triene (CAT) assay, which allows the assessment of both hydrophilic and lipophilic antioxidants. The nonlinear behavior was mainly expl...
TL;DR: The dependence of the stage of berry development on the accumulation of the products of alcohol dehydrogenase, alcohol acetyl transferase, and enal isomerase enzyme activity from the lipoxygenase pathway raises possibilities for the manipulation of aroma profiles in grapes and wines.
Abstract: The evolution of volatile compounds was explored in grape berries at fortnightly intervals from fruit-set to late ripening to identify when biosynthetic pathways may be targeted for enhancement of grape and wine aroma. Stepwise linear discriminant analysis (SLDA) fully recognized patterns in berry physiological developmental stages with most of the variance (>99.0%) explained. The preveraison berry developmental stage was identified as a transition stage for volatile compound biosynthesis when most compounds were potentially sequestered to nonvolatile conjugates and berries lost their potential to synthesize esters and terpenes. Terpenes (predominantly eucalyptol, β-caryophyllene, and α-humulene) characterized early berry development, whereas benzene derivatives (2-phenylethanol and 2-phenylethanal) appeared toward late ripening. Furthermore, C6 volatile compounds changed from acetate esters to aldehydes and finally to alcohols during early, middle, and late berry developmental stages, respectively. The d...
TL;DR: The bioactive compounds discussed in this review are flavonoids, carotenoids, curcumin, ascorbic acid, and citrus limonoids.
Abstract: Mom's conventional wisdom of eating fruits and vegetables to lead a healthy life has evolved with scientific, fact-finding research during the past four decades due to advances in science of "Foods for Health". Epidemiological and prospective studies have demonstrated the vital role of fruits, vegetables, and nuts in reducing the risk of cancer and cardiovascular diseases. In recent years, several meta-analyses strongly suggested that by adding one serving of fruits and vegetables to daily diet, the risk of cardiovascular diseases will be decreased up to 7%. The multidisciplinary and partnership efforts of agriculture and medical scientists across the globe stimulated interest in establishing certain interdisciplinary centers and institutes focusing on "Foods for Health". While the consumption of various healthy foods continues, several questions about toxicity, bioavailability, and food-drug interactions of bioactive compounds are yet to be fully understood on the basis of scientific evidence. Recent research on elucidation of the molecular mechanisms to understand the "proof of the concept" will provide the perfect answer when consumers are ready for a "consumer-to-farm" rather than the current "farm-to-consumer" approach. The multidisciplinary research and educational efforts will address the role of healthy foods to improve eye, brain, and heart health while reducing the risk of cancer. Through this connection, this review is an attempt to provide insight and historical perspectives on some of the bioactive compounds from the day of discovery to their current status. The bioactive compounds discussed in this review are flavonoids, carotenoids, curcumin, ascorbic acid, and citrus limonoids.
TL;DR: Current knowledge on natural bioactive compounds that act through the signaling pathways and modulate inflammatory gene expressions are summarized, thus providing evidence for these substances in cancer chemopreventive action.
Abstract: Several epidemiologic studies have shown that chronic inflammation predisposes individuals to various types of cancer. Many cancers arise from sites of infection, chronic irritation, and inflammation. Conversely, an oncogenic change induces an inflammatory microenvironment that promotes the development of tumors. Natural bioactive compounds in dietary plant products including fruits, vegetables, grains, legumes, tea, and wine are claimed to help prevent cancer, degenerative diseases, and chronic and acute inflammation. Modern methods in cell and molecular biology allow us to understand the interactions of different natural bioactive compounds with basic mechanisms of inflammatory response. The molecular pathways of this cancer-related inflammation are now unraveled. Natural bioactive compounds exert anti-inflammatory activity by modulating pro-inflammatory gene expressions have shown promising chemopreventive activity. This review summarizes current knowledge on natural bioactive compounds that act through the signaling pathways and modulate inflammatory gene expressions, thus providing evidence for these substances in cancer chemopreventive action.
TL;DR: B Bran bioprocessing increases the bioaccessibility of phenolic compounds as well as the colonic end metabolite 3-phenylpropionic acid.
Abstract: Ferulic acid (FA) is the most abundant phenolic compound in wheat grain, mainly located in the bran. However, its bioaccessibility from the bran matrix is extremely low. Different bioprocessing techniques involving fermentation or enzymatic and fermentation treatments of wheat bran were developed aiming at improving the bioaccessibility of phenolic compounds in bran-containing breads. The bioaccessibility of ferulic acid, p-coumaric acid, and sinapic acid was assessed with an in vitro model of upper gastrointestinal tract (TIM-1). Colonic metabolism of the phenolic compounds in the nonbioaccessible fraction of the breads was studied with an in vitro model of human colon (TIM-2). The most effective treatment was the combination of enzymes and fermentation that increased the bioaccessibility of FA from 1.1% to 5.5%. The major colonic metabolites were 3-(3-hydroxyphenyl)propionic acid and 3-phenylpropionic acid. Bran bioprocessing increases the bioaccessibility of phenolic compounds as well as the colonic end metabolite 3-phenylpropionic acid.
TL;DR: Results suggest that phlorofucofuroeckol A has a potential for functional foods with antioxidant and anti-inflammatory activities.
Abstract: Bioactivity-guided fractionation of Ecklonia stolonifera was used to determine the chemical identity of bioactive constituents, with potent antioxidant activities. The structures of the phlorotannins were determined on the basis of spectroscopic analysis, including NMR and mass spectrometry analysis. The antioxidant activities of the isolated compounds were evaluated by free radical scavenging activities in both in vitro and cellular systems. The anti-inflammatory effects of the isolated compounds were evaluated by determining their inhibitory effects on the production of nitric oxide (NO) and prostaglandin E(2) (PGE(2)) in lipopolysaccharide (LPS)-induced RAW 264.7 murine macrophage cells. The results indicated that phlorofucofuroeckol A, dieckol, and dioxinodehydroeckol showed potential radical scavenging activities against 2,2-diphenyl-1-picrylhydrazyl. Among them, phlorofucofuroeckol A and dieckol significantly suppressed the intracellular reactive oxygen species level assayed by 2',7'-dichlorofluorescein diacetate assay in LPS-induced RAW 264.7 cells. Phlorofucofuroeckol A significantly inhibited the LPS-induced production of NO and PGE(2) through the down-regulation of inducible nitric oxide synthase and cyclooxygenase 2 protein expressions. In conclusion, these results suggest that phlorofucofuroeckol A has a potential for functional foods with antioxidant and anti-inflammatory activities.