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Phenol Content (phenol + content)
Kinds of Phenol Content Selected AbstractsSUPERHEATED STEAM-DRYING OF MATE LEAVES AND EFFECT OF DRYING CONDITIONS ON THE PHENOL CONTENTJOURNAL OF FOOD PROCESS ENGINEERING, Issue 3 2006EVERTON FERNANDO ZANOELO ABSTRACT Four drying experiments of mate leaves (Ilex paraguariensis St. Hilaire) were carried out in a packed bed superheated steam dryer by varying outlet steam temperature from 120 to 140C and equivalent particle diameter from 4.7 × 10,3 to 6.95 × 10,3 m. The influence of these variables on the drying coefficient calculated by assuming a simplified drying kinetic model was investigated. A classical statistical approach revealed the significant effect of both factors on this parameter. Two additional drying runs were performed at identical conditions with conventional hot air and low pressure superheated steam, respectively. The influence of drying atmosphere on the total content of phenols was evaluated. A conventional process of extraction by using an aqueous methanol solution was adopted. Analyses for total phenols were performed by spectrophotometry at 715 nm by applying Folin-Denis assay. The leaves dried with superheated steam had approximately 47% higher retention of these compounds. [source] Effect of location on virgin olive oils of the two main Tunisian olive cultivarsEUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY, Issue 9 2009Mokhtar Guerfel Abstract The olive oil content in phenolic compounds depends on the variety of the fruit used for its extraction as well as on the predominant climate conditions in the tree cultivation area. Here, we report on the characterization of virgin olive oil samples obtained from fruits of the main Tunisian olive cultivars Chemlali and Chétoui, grown in three different Tunisian locations, Zaghouan (North), Sousse (Center) and Sfax (South). Chétoui olive oil samples obtained from fruits of olive trees cultivated in Zaghouan and Chemlali olive oil samples obtained from fruits of olive trees cultivated in Sousse were found to have a higher mean total phenol content (1004 and 330,mg/kg, respectively). Olive oil samples obtained from fruits of both cultivars had different phenolic profiles and a higher content in 3,4-DHPEA-EDA when the olive trees were cultivated in Zaghouan. Both olive cultivars were found to have different responses to environmental conditions. Chétoui olive oil showed decreased oxidative stability when the fruits were obtained from olive trees cultivated in the center of Tunisia (34.8,h) and in Sfax (16.17,h). Furthermore, statistical data showed that the phenolic composition and oxidative stability of Chétoui olive oil varied more by location than those of Chemlali olive oils. [source] DISTRIBUTION AND ANTIOXIDANT ACTIVITY OF POLYPHENOLS IN RIPE AND UNRIPE TREE PEPPER (CAPSICUM PUBESCENS)JOURNAL OF FOOD BIOCHEMISTRY, Issue 4 2007G. OBOH ABSTRACT Capsicum pubescens, commonly known as tree pepper with its distinctive thick-fleshed pungent fruit (ripe and unripe), is used as a vegetable condiment or made into a sauce. The present study sought to determine the distribution of polyphenols and antioxidant activity in its thick flesh and seeds. Free, bound and total phenol content of each extract was subsequently determined, while reducing power, Fe (II)-chelating ability, OH radical-scavenging ability and ability of the extracts to inhibit lipid peroxidation in basal and Fe (II)-induced lipid peroxidation in brain was used for antioxidant capacity. Unripe pepper had higher total phenol content than ripe pepper; however, there was no significant difference ( P > 0.05) in the total phenol content of flesh for both peppers (unripe [110 mg/100g], ripe [95 mg/100 g]) and the seed (unripe [110.0 mg/100 g ], ripe [90 mg/100 g]). Nevertheless, the free polyphenols in flesh and seed of the peppers were significantly higher ( P < 0.05) than the bound polyphenols. All the extracts inhibited lipid peroxidation in a dose-dependent manner, although free polyphenols from the flesh of ripe pepper caused the highest inhibition in malondialdehyde production in rat's brain. Free and bound polyphenols from the flesh of unripe pepper had the highest Fe (II)-chelating and OH radical-scavenging ability. While the free polyphenols from the flesh of ripe pepper had the highest reducing power, this may have accounted for its ability to reduce Fe (II)-induced lipid peroxidation. Therefore, by removing the seed from pepper, a 50% loss in the total phenol content would result, which will substantially reduce antioxidant activity. PRACTICAL APPLICATIONS Because many degenerative human diseases have been recognized as being a consequence of free radical damage, there have been many studies undertaken on how to delay or prevent the onset of these diseases. The most likely and practical way to fight against degenerative diseases is to improve body antioxidant status, which could be achieved by higher consumption of vegetables and fruits. Foods from plant origin usually contain natural antioxidants that can scavenge free radical. The inclusion of either ripe or unripe pepper in a diet is a common practice in Africa and some other parts of the world; our recent findings on the antioxidant properties of Capsicum pubescens clearly indicate that its inclusion in the diet will contribute greatly in the prevention of neuro-degenerative diseases associated with oxidative stress, by inhibiting lipid peroxidation. Moreover, removing the seeds of this pepper during food processing will reduce the total phenol content by 50%, and consequently reduce the antioxidant activity. [source] STABILITY OF ANTHOCYANINS, PHENOLS AND FREE RADICAL SCAVENGING ACTIVITY THROUGH SUGAR ADDITION DURING FROZEN STORAGE OF BLACKBERRIESJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 2009MIRELA KOPJAR ABSTRACT Influence of sugar and mixtures of sugar on color retention of two varieties of blackberries, Thornfree and Cacanska bestrna, were investigated during storage at ,18C for 12 months. After harvest, blackberries were coated with sugars (sucrose, fructose and glucose) and different sugar (sucrose + fructose + glucose, fructose + glucose, fructose + sucrose) mixtures. Anthocynin content, total phenol content and free radical scavenging activity of prepared samples were evaluated. Ratio of fruit : sugar was 1:1. The highest anthocyanin retention was in blackberry samples with glucose addition and the lowest in samples with sucrose addition, in both cultivars. Blackberry samples with sucrose addition had even lower retention than samples without sugar addition. Samples with an addition of other sugars had higher retention of anthocyanin than samples stored without sugars. PRACTICAL APPLICATION Possibility of phenols retention of blackberries due to sugar addition, during cold storage was investigated. Results showed that glucose had the most positive effect on anthocyanins retention as well as total phenolic compounds content. For that reason, certain amount of sucrose in fruit preserves can be replaced by addition of glucose, and for that reason retention of phenolic compounds can be higher and, as could be expected, more effective against oxidative stress in human body due to intake of product formulation with glucose. [source] EFFECT OF OXYGEN CONCENTRATION ON THE BIOCHEMICAL AND CHEMICAL CHANGES OF STORED LONGAN FRUITJOURNAL OF FOOD QUALITY, Issue 1 2009G. CHENG ABSTRACT Longan fruits were stored for 6 days in atmosphere of 5, 21 (air) or 60% O2 (balance N2) at 28C and 90,95% relative humidity to examine effects of low and high O2 concentration on enzymatic browning and quality attributes of the fruit. Changes in pericarp browning, pulp breakdown, disease development, total phenol content, activities of phenol metabolism-associated enzymes, relative leakage rate, ,,, -diphenyl- , -picrylhydrazy (DPPH) radical scavenging activity, and contents of total soluble solids, titratable acidity and ascorbic acid were evaluated. Storage of fruit in a 5% O2 atmosphere markedly delayed pericarp browning in association with maintenance of high total phenolic content and reduced activities of polyphenol oxidase (PPO), peroxidase (POD) and phenylalanine ammonia lyase. Moreover, the fruit stored in a 5% O2 atmosphere exhibited a lower relative leakage rate and higher DPPH radical scavenging activity than fruit stored in air. This presumably was beneficial in maintaining compartmentation of enzymes and substrates, and thus, reducing pericarp browning. Pulp breakdown and disease development were also reduced by exposure to a 5% oxygenatmosphere. On the contrary, exposure of longan fruit to a 60% O2 atmosphere accelerated pericarp browning, pulp breakdown and decay development. PPO and POD activities and relative leakage rate were similar for control and 60% O2 -treated fruit after 4 and 6 days of storage. Furthermore, treatment with 60% O2 significantly decreased the phenolic content and DPPH scavenging activity of fruit. In addition, exposure to 5 or 60% O2 resulted in a higher level of total soluble solids, but a lower level of ascorbic acid of longan fruit flesh. In conclusion, exposure to a 5% O2 atmosphere showed great potential to reduce pericarp browning and extend shelf life of longan fruit. PRACTICAL APPLICATIONS Pericarp browning and pulp breakdown are the major causes of deterioration in postharvest longan. Conventional controlled atmosphere with low O2 and high CO2 is effective in maintaining quality and extending shelf life of fruits and vegetables, including inhibition of tissue browning. In this study, 5%-controlled atmosphere reduced significantly pericarp browning, pulp breakdown and rot development. It could potentially be useful as a postharvest technology of longan fruit for reducing or replacing the use of chemicals such as SO2 and fungicides, but it requires further investigation. [source] Changes on Enological Parameters of White Wine Packaged in Bag-in-Box during Secondary Shelf LifeJOURNAL OF FOOD SCIENCE, Issue 8 2009Y. Fu ABSTRACT:, This study investigated the effects of temperature (22, 35, and 45 °C), storage time (48, 30, and 15 d), and packaging type on the quality of white wine in bag-in-box (BIB) during the secondary shelf life. Several enological parameters (color and contents of free and total SO2, total aldehyde, and total phenol) were monitored and correlated with oxygen transmission rate (OTR) and Fourier transform infrared (FTIR) spectral data. Time and temperature had significant effects on color development and SO2 depletion during storage. The increased absorbance at 420 nm was correlated with decreases of free SO2 and total SO2. Overall, total phenol content correlated negatively with total aldehyde content. The variance of the enological parameters can be correlated with the OTR data, indicating the barrier properties for the tested packages were different. FTIR,ATR spectra of the wine were analyzed chemometrically using PLS algorithm. The resulting models were able to predict the,A420, free SO2, total SO2, total phenol, total aldehyde, and storage time of the wines. This technique can potentially be used as an efficient tool to evaluate the quality of wine. [source] Antioxidative Ability, Dioscorin Stability, and the Quality of Yam Chips from Various Yam Species as Affected by Processing MethodJOURNAL OF FOOD SCIENCE, Issue 2 2009Y.-M. Liu ABSTRACT:, The antioxidative ability, stability of storage protein dioscorin, and the quality of fried yam chips from different cultivars of Chinese yams influenced by various processing treatments were investigated. Total phenolic content and DPPH free radical scavenging effect were found to be the highest in Mingchien (MC) and the lowest in Keelung (KL) yam. Following processing, freeze-dried yams of all varieties showed the least decrease in total phenolic compounds and DPPH radical scavenging effect, while boiling caused the greatest decrease in both. Fresh yams of all varieties contained the highest dioscorin contents comparing with their counterparts. Boiling and deep-frying caused severe protein denaturation resulting in loss of dioscorin solubility after purification. Freeze-drying resulted in increase in protein surface hydrophobicity (So); nonetheless, it attained higher total phenol content, antioxidative capacity, and dioscorin stability of yams compared with other processing treatments. The peroxide values of all yam chips increased during the initial stage, then declined with advanced storage. Fracturability of all yam chips gradually decreased, due to the absorption of moisture, with increasing storage time. [source] Localized and Systemic Increase of Phenols in Tomato Roots Induced by Glomus versiforme Inhibits Ralstonia solanacearumJOURNAL OF PHYTOPATHOLOGY, Issue 10 2004H. H. Zhu Abstract Ralstonia solanacearum is an important plant pathogen in tropical and subtropical countries. Here, we describe the inhibition of R. solanacearum as a result of increased phenols induced locally or systemically by an arbuscular mycorrhizal (AM) fungus. In pot cultures, R. solanacearum populations in the rhizosphere, on root surfaces and in the xylem were decreased by 26.7, 79.3 and 81.7%, respectively, following inoculation of tomato plants (Lycopersicon esculentum Mill.) with Glomus versiforme Berch. Colonization of the plants by both R. solanacearum and G. versiforme increased the contents of soluble phenols and cell-wall bound phenols in root tissue, but with different patterns. Whereas R. solanacearum preferably promoted the cell-wall bound phenol content, G. versiforme preferably enhanced the soluble phenol content. Split root experiments revealed that R. Solanacearum was inhibited by G. versiforme, and that G. versiforme also increased the phenol content systemically, but to a lesser extent than locally. [source] Phenolic compounds in the brown seaweed Ascophyllum nodosum: distribution and radical-scavenging activitiesPHYTOCHEMICAL ANALYSIS, Issue 5 2010Laetitia Audibert Abstract Introduction , Phenolic compounds are metabolites exhibited at high levels in Phaeophyceae. Although several studies have been conducted on total phenol contents, no one to our knowledge has dealt with the contents of phenolic compounds and antioxidant activities on purified fractions. Objective , The purpose of this study was the extraction and purification of phenolic compounds from the brown seaweed Ascophylllum nodosum, to determine both their distribution and their radical-scavenging activities, and to obtain a sufficiently purified oligophenolic fraction to perform an RP-HPLC analysis on molecules with a molecular weight (MW) < 2,kDa. Methodology , Phenolic compounds were separated and purified by liquid,liquid extraction, tangential ultrafiltration and dialysis. Then, the contents of both phenolic compounds and radical-scavenging activities were measured by the Folin,Ciocalteu reagent, and DPPH and ABTS assays. NMR analysis was performed to validate the process. RP-HPLC with a C18 column was performed on the oligophenolic fraction, using a novel method developed in this study. Results , Seven fractions were obtained as a function of polarity and molecular weight. Among them, the fraction containing phenolic compounds with a MW , 50,kDa appeared to be the most active, correlated with the content of phenolic compounds. Conclusion , This work constitutes a step forward in the separation and purification of bioactive phlorotannins and represents a prerequisite for further investigations into their structural characterisation and distribution in A. nodosum. [source] | |||||||||||||