Shela Gorinstein

Comparison of some biochemical characteristics of different citrus fruits

The goal of this investigation was to evaluate the antioxidant properties of some citrus fruits. The contents of dietary fibre, total polyphenols, essential phenolics, ascorbic acid and some trace elements of lemons, oranges and grapefruits were determined and compared with their total radical-trapping antioxidative potential (TRAP). There were no significant differences in the contents of total, soluble and insoluble dietary fibre in the studied peeled fruits or their peels. The contents of total, soluble and insoluble dietary fibre in peels were significantly higher than in peeled fruits (P < 0.05 in all cases). The peeled lemons, oranges and grapefruits contain 164 10.3; 154 10.2 and 135 10.1 and their peels 190 10.6; 179 10.5 and 155 10.3 mg/100 g of total polyphenols, respectively. The content of total polyphenols in peeled lemons and their peels was significantly higher than in peeled oranges and grapefruits and their peels, respectively. The content of total polyphenols in the peels was significantly higher than in peeled fruits (P < 0.05 in all cases). The same results were obtained in the investigation of essential phenolics and ascorbic acid. The content of Fe in peeled lemons and their peels was significantly higher than in peeled oranges and grapefruits and their peels, respectively. Also the TRAP was significantly higher in peeled lemons and their peels than in peeled oranges and grapefruits and their peels, respectively. In all three fruits, the TRAP was significantly higher in peels than in peeled fruits (P< 0.05). In conclusion, lemons possess the highest antioxidant potential among the studied citrus fruits and are preferable for dietary prevention of cardiovascular and other diseases. The peels of all citrus fruits are rich in dietary fibres and phenolic compounds and suitable for industrial processing. # 2001 Published by Elsevier Science Ltd. All rights reserved.

Methods of measurement and evaluation of natural antioxidant capacity/activity (IUPAC Technical Report)*

The chemical diversity of natural antioxidants (AOXs) makes it difficult to separate, detect, and quantify individual antioxidants from a complex food/biological matrix. Moreover, the total antioxidant power is often more meaningful to evaluate health beneficial effects because of the cooperative action of individual antioxidant species. Currently, there is no single antioxidant assay for food labeling because of the lack of standard quantification methods. Antioxidant assays may be broadly classified as the electron transfer (ET)- and hydrogen atom transfer (HAT)-based assays. The results obtained are hardly comparable because of the different mechanisms, redox potentials, pH and solvent dependencies, etc. of various assays. This project will aid the identification and quantification of properties and mutual effects of antioxidants, bring a more rational basis to the classification of antioxidant assays with their constraints and challenges, and make the results more comparable and understandable. In this regard, the task group members convey their own experiences in various methods of antioxidants measurement.

Comparative content of some bioactive compounds in apples, peaches and pears and their influence on lipids and antioxidant capacity in rats

The aim of this study was to compare some bioactive compounds in apples, peaches and pears and their influence on lipids and antioxidant capacity in rats. The content of total polyphenols (g/100g) was 0.23 +/- 0.03; 0.22 +/- 0.03 and 0.68 +/- 0.1 in peeled fruits and 0.48 +/- 0.04, 0.47 +/- 0.04 and 1.2 +/- 0.12 in peels of peaches, pears and apples, respectively. Caffeic, p-coumaric and ferulic acids and the total radical-trapping antioxidative potential (TRAP) values in peeled apples and their peels were significantly higher than in peaches and pears, respectively. Contrarary, no significant differences in the content of dietary fiber among the studied fruits were found. The content of all studied indices in peels was significantly higher than peeled fruits (p < 0.05 ). A good correlation between the total polyphenols and the TRAP values was found in all fruits. Diets supplemented with apples and to a less extent with peaches and pears have improved lipid metabolism and increased the plasma antioxidant potential especially in rats fed with added cholesterol. The highest content of biologically active compounds and the best results in the experiment on rats makes apple preferable for dietary prevention of atherosclerosis and other diseases.

Comparison of the contents of the main biochemical compounds and the antioxidant activity of some Spanish olive oils as determined by four different radical scavenging tests.

The aim of this study was to compare the contents of the main biochemical compounds and the antioxidant capacity of five Spanish olive oils by four different antioxidant tests and to find out the most valuable oil for disease preventing diets. Fatty acids, sterols and individual antioxidant compounds in Arbequina, Hojiblanca, Extra Virgin, Picual and Lampante Spanish olive oils were determined. Antioxidant activities were done as well using different radical scavenging activities: total radical-trapping antioxidative potential by ABAP (TRAP-ABAP), radical scavenging activity by DPPH (RSA-DPPH), antioxidant assay by beta-carotene-linoleate model system (AA-beta-carotene) and total antioxidant status by ABTS (TAA-ABTS). The highest content of all studied antioxidant compounds (353; 329; 4.6 and 2.7 mg/kg for tocopherols, tocotrienols, polyphenols and o-diphenols, respectively) was found in Extra Virgin oil. Also the highest antioxidant capacity was observed in Extra Virgin oil (668 nM/ml; 29.4%; 40.4% and 2.64 mM TE/kg for TRAP-ABAP, RSA-DPPH, AA- beta-carotene and TAA-ABTS, respectively). The correlation between total phenols and antioxidant capacities measured by four methods was very high, but the highest for the beta-carotene (R = 0.9958). In conclusion, the best method for determination of the antioxidant capacity of olive oils is the beta-carotene test. Extra Virgin olive oil has high organoleptic properties and the highest antioxidant activity. The above-mentioned makes this oil a preferable choice for diseases preventing diets.

Characterisation of peach dietary fibre concentrate as a food ingredient

Abstract Insoluble and soluble dietary fibre (DF) fractions of peach DF concentrate, obtained by an enzymatic-chemical method, were analysed for neutral sugars, uronic acids and Klason lignin. Proximate composition, energy value, colour and water- and oil-holding capacities were also determined. Total DF constituted 31–36% dry matter (DM) of the concentrate and insoluble DF was its major fraction (20–24% DM). The high proportion of soluble fraction (11–12% DM) in the peach DF concentrate, in comparison with cereal brans, was noticeable. Insoluble and total dietary fibre contents significantly decreased throughout the harvest time of the original fresh fruit. Results suggested that peach DF concentrate may be not only an excellent DF source but an ingredient in the food industry because it showed a high affinity for water (9.12–12.09 g water/g fibre) and low energy (3.723–3.494 kcal/g). However, the use of this material could affect the colour and pH of the final product.

Comparative content of total polyphenols and dietary fiber in tropical fruits and persimmon.

Recent studies have shown that dietary fiber and polyphenols of vegetables and fruits improve lipid metabolism and prevent the oxidation of low density lipoprotein cholesterol (LDL-C), which hinder the development of atherosclerosis. The goal of this study was to measure the total polyphenol and dietary fiber contents of some tropical fruits (i.e., pineapple, wax apple, rambutan, lichi, guava, and mango) and compare the results to the content of these substances in the better characterized persimmon. It was found that lichi, guava, and ripe mango (cv. Keaw) have 3.35, 4.95, and 6.25 mg of total polyphenols in 100 g fresh fruit, respectively. This is significantly higher than in persimmon, pineapple, wax apple, mature green mango, and rambutan [P < 0.0005 for pineapple (Smooth Cayene variant), wax apple, persimmon, rambutan, mature green mango (cv. Keaw); the value of P < 0.001 is found only for pineapple (Phuket, Queen variant)]. The same relationship was observed for the contents of gallic acid and of dietary fiber. It can be supposed that among the studied fruit, lichi, guava, and ripe mango may be preferable for dietary prevention of atherosclerosis.

Characterization of antioxidant compounds in Jaffa sweeties and white grapefruits

Antioxidant compounds and the antioxidative activities of new Israeli citrus fruit sweetie [(Oroblanco, pummelo-grapefruit hybrid (Citrus grandis×C. paradisi)] were compared with the better-known white grapefruit. Total and free phenols were determined with the Folin–Ciocalteu reagent, phenolic acids (free, esters and glycosides) by HPLC analysis and anthocyanins spectrophotometrically. The antioxidant activities were estimated with two scavenging radicals: 2, 2′-azinobis (3-ethylbenzothiazoline-6-sulfonate)- (ABTS) and nitric oxide (NO). Free radical scavenging properties of sweetie and grapefruit were evaluated by β-carotene bleaching (β-carotene). The results of kinetic reactions showed that both fruits differed in their capacities to quench these radicals and sweetie showed more antioxidative activity than grapefruit. Trans-hydroxycinnamic acids (caffeic, p-coumaric, ferulic, and sinapic) were more abundant in grapefruits than in sweeties. High correlation was observed between antioxidative activities and phenols (R2=0.94). Both fruits have high concentrations of natural antioxidants with high antioxidative activities. Phenol content and the antioxidative potential are significantly higher in sweetie than in grapefruit. The higher antioxidant capacity of sweetie could make these new kinds of citrus fruits preferable for diets. In summary, the studied citrus fruit has high total phenolics and high antioxidant activities in vitro. Consumption of this fruit may contribute to an adequate intake of antioxidant phytochemicals.

Comparison of the Main Bioactive Compounds and Antioxidant Activities in Garlic and White and Red Onions after Treatment Protocols

Polish garlic and white and red onions were subjected to blanching, boiling, frying, and microwaving for different periods of time, and then their bioactive compounds (polyphenols, flavonoids, flavanols, anthocyanins, tannins, and ascorbic acid) and antioxidant activities were determined. It was found that blanching and frying and then microwaving of garlic and onions did not decrease significantly the amounts of their bioactive compounds and the level of antioxidant activities ( P > 0.05). The HPLC profiles of free and soluble ester- and glycoside-bound phenolic acids showed that trans-hydroxycinnamic acids (caffeic, p-coumaric, ferulic, and sinapic) were as much as twice higher in garlic than in onions. Quercetin quantity was the highest in red onion among the studied vegetables. The electrophoretic separation of nonreduced garlic and onion proteins after boiling demonstrated their degradation in the range from 50 to 112 kDa.

Moderate beer consumption and the blood coagulation in patients with coronary artery disease

Objectives. To evaluate the influence of a short period of moderate beer consumption on the status of the thrombolitic activity in patients with coronary artery disease (CAD).

The Influence of Persimmon Peel and Persimmon Pulp on the Lipid Metabolism and Antioxidant Activity of Rats Fed Cholesterol

Abstract The aim of this study was to compare the hypocholesterolemic and antioxidant effects of two diets supplemented with dry persimmon in rats fed cholesterol (C). Three groups of male Wistar rats each of 13 animals during 4 weeks were fed different diets: the control group (CG)—semipurified diet with 1% of C and two experimental groups (EG1) and (EG2)—the same diet fortified with 7% of dry persimmon peel and dry persimmon pulp, respectively. In animals of all three groups before and after the 4-week trial period total cholesterol (TC), LDL-C, HDL-C, triglycerides (TG), and lipid peroxides (LP) were examined. After the completion of the experiment a statistically significant increase in plasma TC and LDL-C in all three groups was found. In the animals of EG1 this increase was statistically less significant than in CG (P The present results demonstrate that persimmon fruit exercises a hypocholesterolemic and antioxidant effects and therefore is considered for an antiatherosclerotic diet. A diet fortified with dry persimmon peel is more efficient than the same diet fortified with dry persimmon pulp. Therefore the persimmon peel showing the effectiveness of its antioxidant activity can be used by individual consumers and in industrial processing.