RESUMO
Plant foods, their products and processing by-products are well recognized as important sources of phenolic compounds. Recent studies in this field have demonstrated that food processing by-products are often richer sources of bioactive compounds as compared with their original feedstock. However, their final application as a source of nutraceuticals and bioactives requires addressing certain hurdles and challenges. This review discusses recent knowledge advances in the use of plant food processing by-products as sources of phenolic compounds with special attention to the role of genetics on the distribution and biosynthesis of plant phenolics, as well as their profiling and screening, potential health benefits, and safety issues. The potentialities in health improvement from food phenolics in animal models and in humans is well substantiated, however, considering the emerging market of plant food by-products as potential sources of phenolic bioactives, more research in humans is deemed necessary.
Assuntos
Manipulação de Alimentos , Valor Nutritivo , Fenóis/química , Plantas/química , Opinião Pública , Vias Biossintéticas/genética , Descontaminação , Contaminação de Alimentos , Inocuidade dos Alimentos , Humanos , Plantas/genética , Plantas/metabolismoRESUMO
Peanut skin (PS) and meal from dry-blanched peanuts (MDBP) were evaluated as sources of phenolic compounds. PS rendered the highest total phenolic content, antioxidant capacity towards ABTS radical cation, DPPH and hydroxyl radicals as well as reducing power. Phenolic acids were present in PS and MDBP whereas proanthocyanidins and monomeric flavonoids were found only in PS as identified by HPLC-DAD-ESI-MSn. Procyanidin-rich extracts prevented oxidation in non-irradiated and gamma-irradiated fish model system. Both extracts inhibited the growth of gram-positive (Bacillus cereus, Staphylococcus aureus, Listeria monocytogenes, Geobacillus stearothermophilus) and gram-negative bacteria (Pseudomonas aeruginosa, Pseudomonas fluorescens, Salmonella Enteritidis, Salmonella Typhimurium, Escherichia coli). Regardless of the strain, phenolic acid-rich extracts showed the lowest minimum inhibitory capacity (MIC); therefore presenting higher antibacterial effect. The MIC of phenolic acid-rich extracts (24-49µgphenolics/mL) was higher but comparable to Ampicillin (10µg/mL). Thus, phenolics in PS and MDBP may serve as antioxidants and antimicrobial compounds.
Assuntos
Anti-Infecciosos/farmacologia , Antioxidantes/farmacologia , Arachis , Flavonoides/farmacologia , Hidroxibenzoatos/farmacologia , Animais , Fenóis , Extratos Vegetais , Staphylococcus aureusRESUMO
Phenolics in food and agricultural processing by-products exist in the soluble and insoluble-bound forms. The ability of selected enzymes in improving the extraction of insoluble-bound phenolics from the starting material (experiment I) or the residues containing insoluble-bound phenolics (experiment II) were evaluated. Pronase and Viscozyme improved the extraction of insoluble-bound phenolics as evaluated by total phenolic content, antioxidant potential as determined by ABTS and DPPH assays, and hydroxyl radical scavenging capacity, reducing power as well as evaluation of inhibition of alpha-glucosidase and lipase activities. Viscozyme released higher amounts of gallic acid, catechin, and prodelphinidin dimer A compared to Pronase treatment. Furthermore, p-coumaric and caffeic acids, as well as procyanidin dimer B, were extracted with Viscozyme but not with Pronase treatment. Solubility plays an important role in the bioavailability of phenolic compounds, hence this study may assist in better exploitation of phenolics from winemaking by-products as functional food ingredients and/or supplements.
Assuntos
Antioxidantes/farmacologia , Inibidores Enzimáticos/farmacologia , Lipase/antagonistas & inibidores , Complexos Multienzimáticos/metabolismo , Fenóis/farmacologia , Extratos Vegetais/farmacologia , Pronase/metabolismo , alfa-Glucosidases/química , Antioxidantes/química , Inibidores Enzimáticos/química , Radical Hidroxila/química , Fenóis/química , Extratos Vegetais/química , SolubilidadeRESUMO
Background: The properties of plants with food preservation potential are well known since the antiquity.In recent years, the use of herbs and spices to improve the sensory characteristics and to extendthe shelf-life of foods has been growing. Objectives: To compare oregano (Origanum vulgare L.) and sage(Salvia officinalis L.) as a natural antioxidant in balls of chicken breast and added 0.50% salt. Methods:Samples of chicken meatballs were pre-cooked for 8 minutes in a water bath at 80o C, and packaged inpolyethylene bags with three layers, specific for vacuum cooking and high temperatures. The sampleswere separated into three groups: control (just salt), 0.10% oregano (dry plant) and sage 0.10% (dry plant),stored at -20o C for 144 hours. The tests to verify the formation of hexanal in samples were performedin the period of 0, 48, 96 and 144 hours of refrigerated storage. The determination of hexanal, extractedby micro-extraction (headspace solid phase micro-extraction - HS-SPME), was used as an indicator ofthe lipid oxidation of the samples. The analysis was conducted by a gas chromatograph coupled witha mass detector (GC-MS). The method was evaluated according to the validation parameters such aslinearity, repeatability and detection limit. The extraction was conducted at 70o C using a fiber (DVD/ CAR / PDMS) exposed for 20 minutes in the headspace after 5 minutes of equilibrium between thesample and the headspace. Results: Samples added 0.10% oregano or sage had effective protection in thedevelopment of hexanal, compared to control samples. The development of hexanal was significantlyhigher in the control samples, 34 Êg of hexanal/100 g of sample at the beginning and 280 Êg/100 g sampleat the end of refrigerated storage...
Assuntos
Origanum , SalviaRESUMO
Peanut samples were irradiated (0.0, 5.2, 7.2 or 10.0 kGy), stored for a year (room temperature) and examined every three months. Mycotoxic fungi (MF) were detected in non-irradiated blanched peanuts. A dose of 5.2 kGy was found suitable to prevent MF growth in blanched samples. No MF was detected in in-shell peanuts, with or without irradiation. The colors of the control in-shell and blanched samples were, respectively, 44.72 and 60.21 (L *); 25.20 and 20.38 (Chroma); 53.05 and 86.46 (°Hue). The water activities (Aw) were 0.673 and 0.425. The corresponding fatty acids were 13.33% and 12.14% (C16:0), 44.94% and 44.92% (C18:1, ω9) and 37.10% and 37.63% (C18:2, ω6). The total phenolics (TP) were 4.62 and 2.52 mg GAE/g, with antioxidant activities (AA) of 16.97 and 10.36 µmol TEAC/g. Storage time negatively correlated with Aw (in-shell peanuts) or L *, linoleic acid, TP and AA (in-shell and blanched peanuts) but positively correlated with Aw (blanched peanuts), and with oleic acid (in-shell and blanched peanuts). Irradiation positively correlated with antioxidant activity (blanched peanuts). No correlation was found between irradiation and AA (in-shell samples) or fatty acids and TP (in-shell and blanched peanuts). Irradiation protected against MF and retained both the polyunsaturated fatty acids and polyphenols in the samples.
Assuntos
Arachis/microbiologia , Arachis/efeitos da radiação , Irradiação de Alimentos/métodos , Fungos/isolamento & purificação , Fungos/efeitos da radiação , Antioxidantes/análise , Arachis/química , Ácidos Graxos/análise , Raios gama , Micotoxicose/prevenção & controle , Fenóis/análiseRESUMO
In-shell, peeled and blanched peanut samples were characterized in relation to proximate composition and fatty acid profile. No difference was found in relation to its proximate composition. The three major fatty acids were palmitic acid, oleic acid, and linoleic acid. In order to investigate irradiation and storage effects, peanut samples were submitted to doses of 0.0, 5.0, 7.5 or 10.0 kGy, stored for six months at room temperature and monitored every three months. Peanuts responded differently to irradiation, particularly with regards to tocopherol contents, primary and secondary oxidation products and oil stability index. Induction periods and tocopherol contents were negatively correlated with irradiation doses and decreased moderately during storage. α-Tocopherol was the most gamma radiation sensitive and peeled samples were the most affected. A positive correlation was found among tocopherol contents and the induction period of the oils extracted from irradiated samples. Gamma radiation and storage time increased oxidation compounds production. If gamma radiation is considered an alternative for industrial scale peanut conservation, in-shell samples are the best feedstock. For the best of our knowledge this is the first article with such results; this way it may be helpful as basis for future studies on gamma radiation of in-shell crops.
Assuntos
Arachis/química , Arachis/efeitos da radiação , Raios gama , Tocoferóis/análise , Absorção de Radiação/efeitos da radiação , Ácidos Graxos/análise , Oxirredução/efeitos da radiação , Óleos de Plantas/química , Fatores de Tempo , Raios UltravioletaRESUMO
Peanut skin, which is removed in the peanut blanching process, is rich in bioactive compounds with antioxidant properties. The aims of this study were to measure bioactive compounds in peanut skins and evaluate the effect of gamma radiation on their antioxidant activity. Peanut skin samples were treated with 0.0, 5.0, 7.5, or 10.0 kGy gamma rays. Total phenolics, condensed tannins, total flavonoids, and antioxidant activity were evaluated. Extracts obtained from the peanut skins were added to refined-bleached-deodorized (RBD) soybean oil. The oxidative stability of the oil samples was determined using the Oil Stability Index method and compared to a control and synthetic antioxidants (100 mg/kg BHT and 200 mg/kg TBHQ). Gamma radiation changed total phenolic content, total condensed tannins, total flavonoid content, and the antioxidant activity. All extracts, gamma irradiated or not, presented increasing induction period (h), measured by the Oil Stability Index method, when compared with the control. Antioxidant activity of the peanut skins was higher than BHT. The present study confirmed that gamma radiation did not affect the peanut skin extracts' antioxidative properties when added to soybean oil.