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Fruit processing industries produce by-products that are good sources of natural antioxidants. These residuals are non-toxic and available in large quantities. A central composite design (CCD) and response surface methodology (RSM) were used to optimize experimental conditions. The processing variables were solvent type, solvent to solid ratio, ethanol concentration, temperature, and time. The responses were total phenolic content (TPC), scavenging activity of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, and yield. The optimal conditions were 70% ethanol— water mixture as a food grade solvent, temperature of 35 °C and extraction time 60 min for obtaining extracts with maximum of total phenolic content. Predicted values for total phenolic content in pear, apricot, and peach were 24.7, 19.3, and 10.4 mg gallic acid equivalents per 100 g fruit residual, respectively.

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group of polyphenolic natural antioxidants present in large numbers in fruit, vegetables, spices, seeds, red wine, chocolate, etc. ( 18 , 19 , 34 ). Quercetin (Que) is an essential flavonoid known to be a multifunctional agent due to its antioxidant

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by preventing oxidative stress related diseases. Recently, there is a growing demand for natural antioxidants due to both consumers' preference and side effects linked with the use of synthetic antioxidants. On the other hand, the emergence of

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Research justified that natural antioxidants and bioactive agents related to antioxidant effects could act on signal transduction pathways and/or phase II enzyme activities directly and/or indirectly. These molecules can also influence the apoptotic genes. In the case of plant extracts, which contain several active compounds, one might consider it is impossible to discover the single mechanism of action. This problem becomes even more complicated, when we bring the obtained data of in vitro and in vivo experiments into consideration. Therefore the multifactorial actions must be analyzed in long-term in vivo studies on redox homeostasis. The questions are: can the absorbed compounds of natural extracts from the gastrointestinal tract influence the changed cellular redox states and how can these molecules act on the redox homeostasis of blood in IBD patients? Our aim was to present the protective effect of a natural product made from Raphanus sativus niger squeezed juice (0.2 g/die Raphacol bile granule) in a twelve-month clinical study in patients suffering from IBD. Raphacol treatment did not influence the activity of IBD. Beside beneficial subjective judgement, bile acid level was elevated continuously and the values of redox parameters were decreased in the plasma during treatment. The granule diminished the erythrocyte chemiluminescence significantly and the HbA 1c -level moderately until the beginning of the ninth month. After this, the trend has changed until the end. Data showed that antioxidant and isothiocyanate-rich granule could influence the redox homeostasis of IBD patients even at low dose.

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Abstract

This work presents a study of the thermal degradation of ultra-high molecular mass polyethylene (UHMWPE) stabilized with natural (α-tocopherol and carvacrol) and synthetic antioxidants. Thermogravimetric analysis in dynamic mode was used to determine the apparent activation energies of different samples. The stabilization of UHMWPE with low concentrations (around 0.3%) of α-tocopherol is enough to obtain an efficient thermal performance of the polymer. Carvacrol is also a good stabilizer for UHMWPE, but at higher concentration than in the case of α-tocopherol. The comparison of apparent activation energy between samples with natural and synthetic antioxidants in similar concentration shows that α-tocopherol is a better stabilizer in terms of their thermal performance.

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.O.A.C. AMR, S.A. (1991): Effectiveness of synthetic and potential natural antioxidants in improving the stability of sheep's anhydrous butter fat during long-term storage. J. Sci. Fd Agric., 55 , 75-85. Effectiveness of synthetic

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Acta Alimentaria
Authors: S. Dragoev, D. Balev, G. Ivanov, B. Nikolova-Damyanova, T. Grozdeva, E. Filizov, and K. Vassilev

Lipid oxidation is one of the main factors responsible for the quality loss in refrigerated and frozen stored fish products. The aim of the study was to evaluate the effect of superficial treatment of Atlantic salmon (Salmo salar) with dihydroquercetin (DHQ) solutions on the hydrolytic and oxidative changes in fish lipids during refrigerated storage. It was found that treatment with DHQ solution (1.0 g l−1) reduced approximately twice the free fatty acids content of chilled stored salmon. After 11 days of storage at 1 °С, the contents of hydroperoxides (HPO) and 2-thiobarbituric acid reactive substances (TBARS) of these samples decreased with 45.00 and 0.91 mg MDA/kg, respectively. The share of saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), and polyunsaturated fatty acids (PUFA) in control and experimental samples did not differ significantly (P>0.05). Results obtained show that the superficial treatment of salmon with DHQ solution (1.0 g l−1) delayed the hydrolytic and oxidative changes in fish lipids significantly, thus preserving the salmon freshness up to 11 days of storage at 1 °С.

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Acta Alimentaria
Authors: S.M. Silveira, A. Cunha Jr., M. Maraschin, S. Verruck, F.L. Secchi, G. Scheuermann, E.S. Prudencio, N. Fronza, and C.R.W. Vieira

The antioxidant and antimicrobial activities of extracts of 12 plant species growing in Brazil were determined. Antimicrobial activity against 12 food-related bacterial species was studied using the disc-diffusion, MIC, and MBC methods. Campomanesia eugenioides extract was the most active against the tested Gram-positive bacteria, whereas Parapiptadenia rigida bark extract presented the highest activity against the evaluated Gram-negative bacteria (MIC and MBC of 0.075 and 0.62 mg ml−1, respectively, against Pseudomonas aeruginosa). Those two extracts also presented high phenolic content and high DPPH and ABTS radical scavenging ability. C. eugenioides extract presented high Fe2+ chelating capacity. The results of the present study demonstrate that, among the evaluated extracts, P. rigida bark and C. eugenioides, both Brazilian native species, presented the highest potential of application as natural antimicrobial and antioxidant agents.

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In in vitro studies it was detected that the juice from the choleretic black radish root had hydrogen donating and d-field element-chelating abilities. The juice exhibited strong reducing power property and radical scavenging effect in H2O2/∙OH luminol system.

With the help of short term animal experiment we examined the in vivo effect of Raphanus sativus root juice on hyperlipidemia in rats.

A chemiluminescent study was applied to determine the total scavenger activity (TSC) of erythrocytes and plasma of untreated and treated animals. We also determined the different liver enzyme activities: alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) and metabolite concentrations (cholesterol, triacylglycerols, total bilirubin, glucose) by spectrophotometry in the sera.

In our study, using experimental hyperlipidemic condition, it has been detected that black radish root juice could moderate the injurious effect of lipid rich diet in rats in vivo.

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: Shahidi, F. (Ed) Natural antioxidants. Chemistry, health effects and application. AOCS Press, Champaign, IL, pp. 182-203. Natural antioxidants. Chemistry, health effects and application

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