Phenolic compounds and antioxidant activity of hydroalcoholic extracts of wild and cultivated murtilla (Ugni molinae Turcz.)

Over the last decade a considerable increase in the number of studies addressing the use of antioxidants from natural sources has led to the identification and understanding of the potential mechanisms of biologically active components. This results from the fact that they can be used to replace synthetic antioxidants commonly used in food. Murtilla (Ugni molinae Turcz) is a native berry grown in Chile, and in the present study, the phenolic composition and antioxidant activity of its fruits were studied. Hydroalcoholic extracts of dehydrated fruits from two genotypes of murtilla (Ugni molinae Turcz.) were produced. Extracts of wild murtilla and 14-4 genotype fruits had 19.35 and 40.28mg GAE/g for Total Phenolic Compounds, 76.48, and 134.35μmol TEAC/g for DPPH, and 157.04 and 293.99 μmol TEAC/g for ABTS, respectively. Components such as quercetin, epicatechin, and gallic, benzoic and hydrocaffeic acids were identified by CG/MS analysis. All of them showed antioxidant activity. Therefore, it is possible to say that the hydroalcoholic extracts of murtilla have antioxidant potential to be used in lipidic food.

Influence of agro-ecological production areas on antioxidant activity, reducing sugar content, and selected phytonutrients of orange-fleshed sweet potato cultivars

Sweet potato is an important staple, and it is mainly known for its contribution of β-carotene in human diet. The effects of cultivar and habitat on this pigment and other nutritional characteristics of the crop still require investigation. In this study, three locally bred cultivars of sweet potato, two of which are orange-fleshed, were grown in three different agro-ecological areas to determine soluble sugar content, β-carotene, and total antioxidants of roots. In addition antioxidant activity, total carotenoids, and chlorophyll content were determined in edible leaves. Reducing sugars, β-carotene, total antioxidants capacity, total carotenoids, and chlorophyll content were significantly affected by environmental conditions. The location at lower altitude and closer to the coastline showed high evapotranspiration, thus reducing sugar content, antioxidant activity, and phytonutrients in both storage roots and leaves. Absence of water stress in agro-ecological locations further inland and at higher altitudes was associated with an increase in these compounds. Free radical scavenging activity of DPPH was higher in the storage roots (610.49 µmoles TE/100g) than in the leaves (426.06 µmoles TE/100g); nevertheless, opposite results were found for the ferric ion reducing activity (FRAP). The deep orange-fleshed cultivar A45 contained high β-carotene (15 mg/100g), which is enough to meet RDA for vitamin A. There is evidence of agro-ecological effect on sweet potato nutritional value.

Peroxidase activity and sensory quality of ready to cook mixed vegetables for soup: combined effect of biopreservatives and refrigerated storage

Enzymatic senescence processes and browning of fresh cut vegetables negatively affect their sensory properties and nutritional value and finally result in the rejection of affected products by consumers. In order to prevent quality decay, the combined effects of natural antioxidants and storage temperature on peroxidase activity and sensory attributes (overall visual quality, browning and odor) of individual and mixed vegetables for soup (butternut squash, leek and celery) were evaluated. Fresh cut vegetables were treated with antioxidant solutions as tea tree essential oil (15 μl/mL), propolis extract (15 μl/mL) and gallic acid (2 mg/mL) and stored at optimal (5 °C) and abusive (15 °C) temperature for a maximum of 14 days. The application of natural preservatives, plus optimal storage conditions, exerted significant inhibitory effects in peroxidase activity of squash, celery and mixed vegetables throughout the storage. Furthermore, propolis treatment applied on mixed vegetables retarded browning appearance and preserved the visual quality for a longer period when compared to untreated product.

Nutritional quality and bioactive compounds of partially defatted baru almond flour

This study aimed to investigate the nutritional quality and bioactive potential of partially defatted baru (Dipteryx alataVog.) almond flour (BAF). The flour’s proximate and mineral compositions, total phenolic, tocopherols and carotenoids contents, antioxidant capacity, trypsin inhibitor and amino acid analyses were performed. An experiment was conducted with 24 male Wistar rats in order to evaluate the flour’s protein quality. BAF has high protein, fiber and mineral contents (iron, zinc, magnesium and copper), and it is a source of calcium. BAF presented relevant amounts of total phenolics (625 mg/100g) and good antioxidant capacity (130 µmol/Trolox eq). Autoclaved BAF showed essential amino acids profile, digestibility and protein quality better than in natura BAF. Autoclaved BAF might be used for human consumption as a source of quality protein and bioactive compounds, in healthy diets and processed foods.

Optimization of the extraction process of polyphenols from cashew apple agro-industrial residues

The goal of this study was to determine the chemical composition of cashew apples agro-industrial residue and optimize the process of polyphenols extraction in this residue. The extraction process conditions were defined using a 24-1 fractional factorial experimental design using acetone and methanol as solvents. The independent variables were: time (30 to 90 min), temperature (30 to 50 °C), solvent concentrations (50% to 90%), agitation speed (100 to 300 rpm); the dependent variables were: total phenolic content and DPPH scavenging capacity. The optimized process was carried out by applying the Central Composite Rotational Design (CCRD) considering the results obtained with the 24-1 fractional factorial experimental design. The residue presented bioactive compounds in its composition, with emphasis on the content of total phenolic compounds (1975.64 mg/ 100 g). The extraction process was not affected by methanol; however, acetone affected the amounts of extracted phytochemicals. Extracts with high levels of polyphenols and strong DPPH scavenging capacity (> 80%) were obtained using 55% acetone, 30 minutes, 30 °C, and 150 rpm. The results showed that cashew apple residue is a potential natural source of bioactive compounds with strong antioxidant capacity. These compounds could be used partially or totally to replace synthetic antioxidants.

Quality changes during frozen storage of blue shrimp (Litopenaeus stylirostris) with antioxidant, α-tocopherol, under different conditions

Fresh blue shrimp (Litopenaeus stylirostris) muscle was stored with antioxidants under different conditions: ANTIOX 2%, packed in bilayer film of polyamide-low density polyethylene film (PA-LDPE) with 2% α-tocopherol; ANTIOX 4%, packed in PA-LDPE film with 4% α-tocopherol; and ANTIOX-GLAZED, samples stored glazed with 2% α-tocopherol. Shrimps packed in PA-LDPE without α-tocopherol were used as CONTROL. All samples were stored at –20 °C for 120 days. As compared to the CONTROL, the shrimp stored with the antioxidant showed lower lipid oxidation (0.10-0.14 vs 1.58 mgMA/kg of muscle), lost less firmness and astaxanthin content. ANTIOX 2% and ANTIOX-GLAZED showed the lowest concentrations of formaldehyde (0.081-0.083 μM/g). There were no significant differences in color and sensory properties, but differences in the integrity of the muscle fibers were observed. The treatments with α-tocopherol maintained the shrimp muscle quality during frozen storage. However, no significant differences were found between these treatments.

Effects of orange winemaking variables on antioxidant activity and bioactive compounds

AbstractAscorbic acid, carotenoids and polyphenols stand out among the orange juice natural antioxidants. The winemaking process affects their bioavailability and bioactivity. Antioxidant activities (AA) were estimated in different process conditions to asses those properties. The AA and their correlation with ascorbic acid, total phenolics and carotenoids content were calculated. The variables and levels analyzed were: pasteurized and natural must (PJ and NJ), pH 3.5 and 4.0 and fermentation temperatures at 10°C and 20°C. Statistically significant differences (α=0.05) were found among bioactive compounds concentrations. Antioxidant compounds concentration was higher in raw material than in orange wine. Juice pasteurization caused the major losses while subsequent vinification affects them to a lesser extent. Highest antioxidants retention was measured in wines from JN fermented at pH 3.5 and 10 °C (JN-3.5-10) followed by wines from JP and fermented at the same conditions (JP-3.5-10). AA determined by DPPH showed a positive and close correlation with FRAP, while ABTS showed a low correlation with former assays. Juice pasteurization process and fermentation temperature influenced bioactive compound reduction which correlates with the AA variation.

The influence of extraction methods on composition and antioxidant properties of rice bran oil

AbstractThe current study was employed to assess the influence of the different extraction methods on total tocols, γ-oryzanol content, and antioxidant properties of Chiang Mai Black rice, Mali Red rice, and Suphanburi-1 Brown rice bran oil. Rice bran oil (RBO) was extracted by Hexane, Hot pressed, Cold pressed, and Supercritical Fluid Extraction (SFe) methods. High yield of RBO was extracted by hexane and SFe methods. Total and subgroups of tocols, and γ-oryzanol content were determined by HPLC. The hexane extracted sample accounts for high content of γ-oryzanol and tocols. Besides, all of RBO extracts contain a significantly high amount of γ-tocotrienol. In vitro antioxidant assay results indicated that superior quality of oil was recovered by hexane extraction. The temperature in the extraction process also affects the value of the oil. Superior quality of oil was recovered by hexane extraction, in terms of phytochemical contents and antioxidant properties compared to other tested extraction methods. Further, thorough study of factors compromising the quality and quantity of RBO recovery is required for the development of enhanced functional foods and other related products.

Genetic variability for synthesis of bioactive compounds in peppers (Capsicum annuum) from Brazil

AbstractThe objective of this study was to evaluate the genetic variability for synthesis of bioactive compounds in pepper (Capsicum annuum, Solanaceae). Total phenolics, anthocyanins, carotenoids and antioxidant activity were evaluated in 14 accessions of Capsicum annuum from the Capsicum Genebank of Embrapa Temperate Agriculture (Pelotas – RS, Brazil). Thirty plants of each accession were cultivated in the field during spring and summer. The experimental design was a complete randomized block with 14 treatments (accessions) and three replications. The laboratory evaluations followed the same experimental design to field, but with two repetitions more. Seeds were discarded and opposite longitudinal portions of fruits were manually prepared for chemical analyzes. The data obtained showed high genetic variability for phenolics, anthocyanins, carotenoids and antioxidant activity. The P39, P77, P119, P143 and P302 accessions exhibited the highest levels of antioxidants, which are strongly indicated to be used in breeding programs of Capsicum peppers.

Effects of orange by-product fiber incorporation on the functional and technological properties of pasta

AbstractThe incorporation of fiber into products consumed every day by the general population is important and viable. The aim of the present work was to evaluate the impact of incorporating orange juice industry dietary fiber byproducts in fettuccini of fresh pasta. Three different fiber concentrations were added to fresh pastas (25 g/kg, 50 g/kg and 75 g/kg). The results showed a significant increase in solid loss content when the incorporation of orange fiber was greater than 50 g/kg. This difference did not occur regarding weight increase values and color parameters. The pasta with 75 g/kg orange fiber can be considered a “high fiber” product, with the total dietary fiber content of the pasta increasing by 99% compared to control pasta. The carotenoid and phenolic contents of pasta increased significantly with the incorporation of fiber at 75 g/kg, but only the pasta formulation with 25 g/kg of orange fiber did not differ from control pasta in relation to all of the sensory attributes and presented an acceptance greater than 75%. The addition of orange fiber byproducts to pastas is an interesting alternative because fiber has a high nutritional value and an abundance of antioxidants.

Effects of whole-wheat flour and bordeaux grape pomace (Vitis labrusca L.) on the sensory, physicochemical and functional properties of cookies

Abstract Grape pomace, which is derived from the skin and seeds, is the residue from the production of grape juice and wine. It corresponds to up to 20% of the total volume and it contains a high level of dietary fibers and bioactive compounds. In the Brazilian market, there is no product containing grape pomace as a replacement for conventional wheat flour. Thus, this study aimed to assess the effects of whole-wheat flour and organic Bordeaux grape pomace (Vitis labrusca L.) on the sensory, physicochemical and functional properties of cookies using response surface methodology (RSM). The regression models indicated that the addition of whole-wheat and organic grape pomace decreased (p < 0.0001) the water activity and significantly increased the content of fibers, hardness, brittleness, antioxidant activity and total phenolic content of the cookies. The RSM models presented suitable R2 and R2adj values (> 65% of explained data variability), except for brittleness. The sensory evaluation results revealed that no significant differences (p > 0.05) were observed for the cookie samples, implying that the addition of grape pomace and whole-wheat flour did not negatively affect the preference of cookies.

In vitro and in vivo antioxidant activity of the pulp of Jatobá-do-cerrado

Abstract Oxygen metabolism in cells causes the production of free radicals, which produce damage, including changes in cell structure and function. Antioxidants are substances that, at low concentrations, slow down or prevent oxidation. Fruits and vegetables contribute to the dietary supply of these compounds. The flora of the Cerrado in Brazil has shown to have high levels of bioactive compounds. This study aimed to characterize the antioxidant activity of the pulp of jatobá-do-cerrado in vitro and in vivo.In vitro antioxidant activity of the aqueous, ethanol and aqueous acetone extracts was evaluated by the DPPH method. We determined total phenols by the Folin-Ciocalteu assay and tannins by the Folin-Denis method.In vivo antioxidant potential of the aqueous acetone extract was evaluated by the TBARS technique. The aqueous acetone extract had the highest antioxidant capacity, followed by the aqueous and ethanol extracts. The same pattern occurred in the extraction of phenols and in the extraction of tannins. In vivo administration of the aqueous acetone extract inhibited lipid peroxidation compared to the control group. The inhibition of peroxidation has increased by elevating the dosage concentration of the extracts, demonstrating a significant antioxidant potential in vivo as well as in vitro.

Investigations towards the synthesis of isotope labelled analogues of tocopherols and tocotrienols /

Vitamin E is considered as the most effective lipophilic chain breaking antioxidant. a-Tocopherol and its analogues have been studied thoroughly with regards to its biokinetics and bioavailabily. Deuterated tocopherols have been synthesized and utilized in such studies. Tocotrienols are arousing more and more interest because of their high efficiency as antioxidants. However, to date, there is no effective synthetic method reported for deuterated tocotrienols. This thesis is focused on the investigation of the synthetic methods of deuterated tocotrienols and their analogues: 5-trideuteromethyl-a-tocotrienol, 5- trideuteromethyl-p-tocotrienol, tocotrienol acetate, silyl tocotrienol ether, etc. Several synthetic procedures for the preparation of poly-deuterated tocopherols are known. Mainly the deuterium is introduced by use of labelled formaldehyde and deuterated hydrogen chloride under Lewis acid catalysis. However, these methods are not effective in tocotrienols due to exchange of protons for deuterium at other sites under the acidic conditions. We developed several different approaches to generate polydeuterated tocotrienols by using both morpholinomethylation followed by reduction with NaCNBDs as deuterated reducing reagents and transmetalation strategy. The 5-trideuteromethyl-a-tocotrienol was finally obtained in a satisfactory yield of 60%. In addition, this thesis also discussed the study of structural comparison and the chemical property difference of tocopherols and tocotrienols, which provides hints to explain the reactivity difference of them towards oxidation at the C3-C4 positions.Furthermore, the methodology of halogenation and dehydrohalogenation of tocotrienol was explored to prepare a hexaene tocotrienol derivative as a florescent reporter of tocopherol.

Biological effects of resveratrol on skeletal muscle cells

Resveratrol, a polyphenol found in red wine, has been reported to have antithrombotic, antiatherogenic, and anticancer properties both in vitro and III VIVO. However, possible antidiabetic properties of resveratrol have not been examined. The objective of this study was to investigate the direct effects of resveratrol on basal and insulin-stimulated glucose uptake and to elucidate its mechanism of action in skeletal muscle cells. In addition, the effects of resveratrol on basal and insulin- stimulated amino acid transport and mitogenesis were also examined. Fully differentiated L6 rat skeletal muscle cells were incubated with resveratrol concentrations ranging from 1 to 250 IlM for 15 to 120 min. Maximum stimulation, 201 ± 8.90% of untreated control, (p<0.001), of2eH] deoxy- D- glucose (2DG) uptake was seen with 100 IlM resveratrol after 120 min. Acute, 30 min, exposure of the cells to 100 nM insulin stimulated 2DG uptake to 226 ± 12.52% of untreated control (p<0.001). This appears to be a specific property of resveratrol that is not shared by structurally similar antioxidants such as quercetin and rutin, both of which did not have any stimulatory effect. Resveratrol increased the response of the cells to submaximal insulin concentrations but did not alter the maximum insulin response. Resveratrol action did not require insulin and was not blocked by the protein synthesis inhibitor cycloheximide. L Y294002 and wortmannin, inhibitors of PI3K, abolished both insulin and resveratrolstimulated glucose uptake while phosphorylation of AktlPKB, ERK1I2, JNK1I2, and p38 MAPK were not increased by resveratrol. Resveratrol did not stimulate GLUT4 transporter translocation in GLUT4cmyc overexpressing cells, in contrast to the significant translocation observed with insulin. Furthermore, resveratrol- stimulated glucose transport was not blocked by the presence of the protein kinase C (PKC) inhibitors BIMI and G06983. Despite that, resveratrol- induced glucose transport required an intact actin network, similar to insulin. In contrast to the stimulatory effect seen with resveratrol for glucose transport, e4C]methylaminoisobutyric acid (MeAIB) transport was inhibited. Significant reduction of MeAIB uptake was seen only with 100uM resveratrol (74.2 ± 6.55% of untreated control, p<0.05), which appeared to be maximum. In parallel experiments, insulin (100 nM, 30 min) increased MeAIB transport by 147 ± 5.77% (p<0.00l) compared to untreated control. In addition, resveratrol (100 JlM, 120 min) completely abolished insulin- stimulated amino acid transport (103 ± 7.35% of untreated control,p>0.05). Resveratrol also inhibited cell proliferation in L6 myoblasts with maximal inhibition of eH]thymidine incorporation observed with resveratrol at 50 J.LM after 24 hours (8 ± 1.59% of untreated control, p

Elucidation of the components involved in the antioxidant activity of honey

Canadian honeys were analyzed for sugar concentration, honey colour, total phenolic content, the level of brown pigments, and antioxidant activity in order to elucidate the main components involved in the antioxidant activity of honey. By employing size-exclusion chromatography in combination with activity-guided fractionation, it was demonstrated that the antioxidant components are of high molecular weight (HMW), brown in colour and absorb at both 280nm and 450nm. The presence of brown HMW antioxidant components prompted an investigation on the influence of heattreatment on the Maillard reaction and the formation of melanoid ins. Heat-treatment of honey resulted in an increase in the level of phenolics in the melanoidin fractions which correlated with an increase in antioxidant activity. The preliminary results of this study suggest for the first time that honey melanoidins underlie the antioxidant activity of unheated and heat-treated honey, and that phenolic constituents are involved in the melanoidin structure and are likely incorporated by covalent or non-covalent interaction.