IJFS#1510_bozza Ital. J. Food Sci., vol. 31, 2019 - 617 PAPER ANTIOXIDANT ACTIVITY AS WELL AS VITAMIN C AND POLYPHENOL CONTENT IN THE DIET FOR ATHLETES B. FRĄCZEK*1, M. MORAWSKA2, M. GACEK3 and K. POGOŃ4 1Department of Sports Medicine and Human Nutrition, University School of Physical Education in Cracow, Al. Jana Pawla II 78, 31-571 Cracow, Poland 2Department of Sports Medicine and Human Nutrition, University School of Physical Education in Cracow, Al. Jana Pawla II 78, 31-571 Cracow, Poland 3Department of Sports Medicine and Human Nutrition, University School of Physical Education in Cracow, Al. Jana Pawla II 78, 31-571 Cracow, Poland 4Department of Fruit, Vegetable and Mushroom Technology, University of Agriculture in Cracow, Poland *Corresponding author: Tel.: +48 126831002; Fax: +48 126831223 E-mail address: barbara.fraczek@awf.krakow.pl ABSTRACT The aim of the study was to analytically evaluate the total content of vitamin C and polyphenols as well as the antioxidant potential of daily food rations planned for athletes. Chemical analyses showed that an average food ration for women (2,120.1 kcal, 90.8 g protein, 53.1 g fat and 354.0 g carbohydrates) contained 5.5±2.6 mg vitamin C and 20.1±4.1 mg polyphenols in 100 g fresh mass. An average food ration for men (2,648.8 kcal, 112.5 g protein, 63.1 g fat and 447.4 g carbohydrates) contained 5.6±1.4 mg vitamin C and 22.9±8.1 mg polyphenols in 100 g fresh mass. The antioxidant potential of an average ration for women expressed as reducing power (FRAP index) in 100 g fresh mass was 8.2±0.7 mmol Fe+2, and for men, 8.9 ±0.9 mmol Fe+2. The antioxidant potential of an average ration prepared for women and men expressed as antiradical activity against DPPH in 100 g fresh mass was respectively: 2.7±02 mmol and 2.7±0.4 mmol Trolox equivalent. Balanced food rations rich in products with high nutrient density can ensure the appropriate intake of vitamin C and polyphenols and high antioxidant potential of the diet. Keywords: vitamin C, polyphenols, antioxidant potential, diet, athletes, chemical analyses Ital. J. Food Sci., vol. 31, 2019 - 618 1. INTRODUCTION The situation of intensive physical exercise leads to the disruption of body homeostasis, also in terms of prooxidant-antioxidant equilibrium (oxidative stress) as a result of intense metabolic processes and the influence of psychological and environmental factors. Intensive physical exercise induces the overproduction of reactive oxygen species, which cause oxidative damage to tissues as a result of peroxidation of lipids, proteins and DNA. By reducing the skeletal muscle contraction strength, speeding up fatigue and lowering immunity, they reduce athletes' performance (SUNG et al., 2016; YAVARI et al., 2015). High oxidative stress occurring in athletes generates increased demand for antioxidant vitamins and polyphenols (HEATON et al., 2017; MORILLAS-RUIZ et al., 2006; ORLANDO et al., 2018; SCHNEIDER et al., 2018; YAVARI et al., 2015). A rich source of dietary antioxidants is fruit and vegetables with high contents of bioactive substances, including vitamin C, carotenoids and polyphenols (phenolic acids and flavonoids with anthocyans) (NADERI et al., 2018; SIKORA et al., 2008). The Swiss food pyramid for athletes recommends daily consumption of 5 portions of fruit and vegetables in all colors, ensuring a wide range of bioactive substances (WALTER et al., 2007). In this context, planning balanced food rations, rich in products with high nutrient density, such as fruit and vegetables and other products with high nutrient density, is of special importance in athletes' diet (YAVARI et al., 2015). Literature review shows that many works present the nutritional value, including the content of antioxidant substances and antioxidant activity of selected products and dishes, such as e.g., honey (CIANCIOSI et al., 2018), fruit (AIRES et al., 2017; NADERI et al., 2018; SHIN et al., 2018; ZENTENO-RRAMÍREZ et al., 2018), vegetables (JAISWAL et al., 2012; SOTIROUDIS et al., 2010), legumes (DURAZZO et al., 2013), whole grains (DURAZZO et al. 2015), several varieties of wheat and black barley (SIEBENHANDL et al., 2007), different cereal grain species (VAN HUNG, 2016), sour cherry juice (FERRETTI et al., 2010; MCCORMICK et al., 2015), sprouts (HOTNOG et al., 2017), as well as grilled chicken salad and spaghetti with tomatoes and parmesan cheese (FRĄCZEK and GACEK, 2013; GACEK et al. 2012). Fewer works describe the nutritional value and antioxidant properties of daily food rations (ALIAKBARLU et al., 2014; BEDOGNI et al., 1999; KORÉISSI-DEMBÉLÉ et al., 2017; MARCONI et al., 2018; ZLOCH et al., 2018). Evaluation of antioxidant potential of different products and dishes is one aspect of the innovative approach to research on food (DURAZZO, 2017). Therefore, this study focused on vitamin C and polyphenol content as well as antioxidant properties of complete daily food rations planned for athletes with consideration of products and dishes they prefer, in accordance with qualitative and quantitative recommendations. The study aimed to answer the question whether it is possible to prepare food rations that meet the qualitative and quantitative recommendations for athletes (balanced in terms of energy and macroelements intake) and at the same time are rich in dietary antioxidants and have high antioxidant properties. The innovative approach to the issue is the verification through chemical analyses of the nutritional value of food rations based on theoretical databases. In this context, the aim of the study was to analytically evaluate the total content of vitamin C and polyphenols as well as the antioxidant properties of daily food rations planned for athletes (women and men) of disciplines that require them to maintain low body mass. Ital. J. Food Sci., vol. 31, 2019 - 619 2. MATERIALS AND METHODS 2.1. Material Daily food rations were prepared on the basis of dietary databases for Polish athletes (women and men) professionally doing disciplines that require them to maintain low body mass, with consideration of their dietary preferences. The criterion for the open selection of participants was doing the sport professionally for at least 3 years. The explored group of athletes for whom the menus were prepared included people aged 18- 30 (22±3.8), representing the following disciplines: long-distance running, middle-distance running, triple jump, race walking, ballet, artistic gymnastics, rhythmic gymnastics, ski jumping, Nordic combined, synchronised swimming and dancing. The age and somatic indices of the participating athletes are presented in Table 1. Body composition (total fat mass TBF and total body water TBW) was measured using bio- impedance testing method (Body Comp MF from Akern). Table 1. Statistical characteristics of anthropometric indices of the study subjects. Group Statistics Age (years) Body weight (kg) Body height (cm) TBF (%) TBW (%) BMI (kg/ m2) Overall Mean 22.0 58.4 171.5 11.7 64.6 19.8 SD 3.8 6.9 7.1 4.6 3.4 1.6 Men Mean 21.3 62.6 175.3 9.1 66.5 20.0 SD 3.7 5.3 6.4 3.3 2.4 1.5 Women Mean 22.9 53.2 166.8 15.1 62.2 19.1 SD 3.8 4.9 4.7 3.8 2.9 1.4 The athletes' dietary preferences were determined for 185 products and dishes using a 5- point hedonic scale (5 – like very much, 4 – like, 3 – neither like nor dislike, 2 – dislike, 1 – dislike very much). The proposed menus included products and dishes for which a high level of preference was obtained (mean values in the 4.64-4.00 range for 41 products, such as vegetables, fruit, cereal products, flour products, poultry, eggs and egg dishes). Products that were disliked were excluded from the diet (mean preference indices in the 2.50-2.99 range, such as pumpernickel, soy products, margarines, fish in cream sauce and in oil). Based on the analysis of dietary preferences, two weekly menus were prepared – 14 daily food rations (7 for women: W1-W7 and 7 for men: M1-M7). The menus were prepared in accordance with qualitative (WALTER et al., 2007) and quantitative recommendations for athletes (KREIDER et al., 2010; POTGIETER, 2013) on the basis of data concerning products' and dishes' nutritional value in Polish “Tables of food ingredients and nutritional value” (KUNACHOWICZ et al., 2005). The quantitative assumptions for the planned food rations are presented in Table 2. The nutritional value of dishes was calculated on the basis of the adopted recipes, taking into consideration raw products (and values for edible parts). Ital. J. Food Sci., vol. 31, 2019 - 620 Table 2. Detailed assumptions for intended diet plans for women and men (CRP – daily food serving). Energy/nutrient Women Men Energy (kcal) 2162.0 2779.0 Protein (g/kg b.w.) 1.7 1.7 Protein (g) 90.4 106.4 Protein (% of energy) 16.7 15.3 Fat (g/kg b.w.) 1.0 1.0 Fat (g) 53.2 62.6 Fat (% of energy) 22.1 20.3 Carbohydrates (g/kg b.w.) 6.5 7.4 Total carbohydrates (g) 350.4 470 Indigestible carbohydrates (g) 315.4 430 Carbohydrates (% of energy) 61.2 64.4 Dietary fiber (g) 25-40 25-40 The planned daily food rations were prepared in a food laboratory and then sent for chemical analyses to the Malopolska Centre of Food Monitoring at the University of Agriculture in Krakow. Each food ration was prepared and analyzed twice in 2 samples (each ration was evaluated in 4 iterations). Tables 3 and 4 present the basic list of products and dishes in the weekly menus for athletes (women and men). Table 3. Weekly menu prepared for women (the list of products/dishes). Breakfast Lunch Dinner Supper W1 Strawberry porridge Chocolate pudding and a nectarine Tomato soup with pasta, grilled chicken breast with rice and grilled vegetables Rye bread with fish spread and vegetable salad W2 Rye bread with honey, white cheese and vegetables Banana shake (with buttermilk) Tomato cream soup, beef chops with barley groats, raw salad (carrot, apple) Vegetable salad with toasts W3 Muesli with natural yoghurt, rye bread with white cheese and vegetables Fruit salad with natural yoghurt Cucumber soup with rice, tagliatelle with shrimp Layer salad (vegetables, boiled eggs) with yoghurt sauce and white rye bread W4 Scrambled eggs with rye bread, an orange Steamed dumplings with shake (buttermilk, strawberries) Vegetable soup with potatoes, spaghetti Bolognese Rye bread with, white cheese and vegetables, fruit yoghurt W5 Porridge with natural yoghurt, rye bread with chicken ham and vegetables Yoghurt ice-cream Zucchini cream soup, cod fillet with rice and boiled vegetables Pancakes with strawberry jam, rye bread with cheese and tomato W6 Rye bread with egg spread, natural yoghurt, lettuce, a nectarine Pancakes with roasted apple Beetroot soup with potatoes, farfalle with chicken and broccoli Rye bread with white cheese spread and tomatoes W7 Rye bread with strawberry jam and mozarella, tomato, natural yoghurt White rice with strawberry mousse Tomato cream cheese, beef steak with pearl barley and lettuce Lecsó with white rye bread Ital. J. Food Sci., vol. 31, 2019 - 621 Table 4. Weekly menu prepared for men (the list of products/dishes). Breakfast Lunch Dinner Supper M1 Scrambled eggs with rye bread, an orange Steamed dumplings with strawberry shake (with buttermilk) Vegetable soup, spaghetti Bolognese Rye bread with, white cheese and vegetables, fruit yoghurt M2 Porridge with natural yoghurt, rye bread with chicken ham and vegetables Yoghurt ice-cream, sponge cake Zucchini cream soup, roasted cod fillet with potatoes and vegetables Pancakes with strawberry jam, rye bread with cheese and tomato M3 Rye bread with egg spread and lettuce, a nectarine Pancakes with roasted apple Beetroot soup with potatoes, farfalle with chicken and broccoli Rye bread with white cheese spread and tomato, cherry yoghurt with muesli M4 Porridge with raspberry, a roll with strawberry jam Banana shake (with buttermilk) Tomato soup with pasta, chicken breast with rice and cabbage salad Nice-style salad with rye bread M5 Muesli with natural yoghurt, rye bread with Gouda cheese and vegetables, a banana Strawberry dumplings Tomato cream soup with toasts, risotto with vegetables Rye bread with fish spread and vegetable salad M6 Muesli with natural yoghurt, rye bread with white cheese, vegetables and strawberry jam, an apple Yoghurt ice-cream, sponge cake Leek cream soup with a baguette, beef steak with rice and rocket and tomato salad Rye bread with chicken ham, egg and vegetables M7 Muesli with natural yoghurt, rye bread with mozarella cheese and tomato Fruit salad with fruit yoghurt Cucumber soup with rice, chicken pizza Rye bread with white cheese spread and smoked salmon with vegetables The mean mass of complete food rations for women was: 2,108.5 g (W1), 2,046.5 g (W2), 2,266.5 g (W3), 2,073.0 g (W4), 2,034.0 g (W5), 2,014.0 g (W6) and 2,085.5 g (W7), and for men: 2,359.5 g (M1), 2,572.5 g (M2), 2,454.5 g (M3), 2,824.0 g (M4), 2,566.5 g (M5), 2,507.0 g (M6) and 2,349.5 g (M7). The mean mass of an average food ration prepared for women (W1-W7) was: 2,090.42±92.29 g, and for men (M1-M7): 2,519.07±161.56 g. 2.2. Preparation of materials The rations were homogenized and air-frozen using a freezing chamber (Feutron-type 3626-51, Germany) within 90 minutes in order to reach a temperature of -30°C in the thermal centre. The frozen material was then dried. Drying parameters: initial product temperature: -30°C, condenser temperature: -52°C, shelf temperature: 20°C; drying: 6 hours of total drying time at shelf temperature of 30°C. Drying was carried out for 24 hours. 2.3. Chemical analyses Homogenates were used to determine dry mass content, and lyophilized samples were used to test the other indices. Dry mass content was determined in accordance with the AOAC procedure (2005, no. 930.04) with the weighing method, by drying up to solid mass at a temperature of 105 °C. Total nitrogen was determined in accordance with the AOAC Ital. J. Food Sci., vol. 31, 2019 - 622 procedure (2005, no 978.04) with the Kjeldahl method using Distillation Unit B-324 (Büchi, Switzerland). Protein content was determined using the 6.25 rate of conversion, and fat content in accordance with the AOAC procedure (2005, no. 920.39) with the Soxhlet method using diethyl ether-based extraction. Total ash content was determined in accordance with the AOAC procedure (2005, no. 920.05) by incinetaring the material at 485°C, and dietary fiber content in accordance with the AOAC procedure (2005, no. 991.43) enzymatic fermentation and drying the remnants at 105 °C. Total carbohydrates content and the energy value of the rations were determined in accordance with the guidelines of FAO (2003). The vitamin C content in food rations was tested via the HPLC method according to EN 14130 (2003). The analysis was performed on a Thermo Scientific DIONEX ULTIMATE 3000 UPLC chromatograph with a DAD detector. The extract was injected onto an Onyx Monolithic C 18 column (100 x 4.6 mm). Elution was carried out using 0.1 M metaphoric acid at a flow rate of 1 ml/min. Absorbance measurement was carried out at a wavelength of λ = 254 nm. The sum of L-ascorbic acid and dehydroascorbic acid was determined after reduction with L-cysteine according to EN 14130 (2003). To determine antioxidant properties, 80% methanol extracts were made from lyophilized food rations using sonification. The total polyphenol content was determined using the method described by SINGLETON et al. (1999). The appropriate amount of extracts from lyophilized food rations was collected and a reaction was carried out with the Folin-Ciocalteu reagent in the presence of Na2CO3. After 60 minutes, absorbance was read on a Hitachi UV-VIS spectrometer, type U-2900 (Hitachi, Japan) compared to the blind sample at λ = 675 nm. The results were read on the basis of a standard curve prepared for gallic acid. Antioxidant activity against DPPH radical (1,1-diphenyl-2-pictyhydrazole) was determined using the method described by PEKKARINEN et al. (1999). Extracts from lyophilized food rations were mixed with a DPPH radical solution, and after 10 minutes of reaction, the absorbance was measured on a Hitachi UV-VIS U-2900 (Hitachi, Japan) UV- VIS spectrophotometer at a wavelength of λ = 516 nm. The percentage of radical scavenging level (% RSA) was determined by referring the absorbance of extracts from lyophilized food rations to the absorbance of the blind sample. The value of antioxidant activity against DPPH radical is expressed in Trolox millimoles (water-soluble α- tocopherol analogue – 2-carboxyl-6-hydroxyl-2,5,7,8-tetramethylchromate). Antioxidant activity using the FRAP method was determined according to the procedure described by BENZIE and STRAIN (1996). Extracts from lyophilized food rations were mixed with a TPTZ solution (2,4,6-Tripyridyl-S-triazine) and FeCl3 in an acetate buffer. After 10 minutes of incubation at 37°C, absorbance was measured on a Hitachi UV-VIS U- 2900 (Hitachi, Japan) UV-VIS spectrophotometer at a wavelength of λ = 595 nm against a blind sample. The value of antioxidant activity determined by the FRAP method was expressed in millimoles of Fe2+ ions. 3. RESULTS The analyses showed that an average food ration prepared for women contained: 2,120.1 kcal, 90.8 g protein, 53.1 g fat and 354.0 g carbohydrates, and for men: 2,648.8 kcal, 112.5 g protein, 63.1 g fat and 447.4 g carbohydrates (Tables 5 and 6). Ital. J. Food Sci., vol. 31, 2019 - 623 Table 5. Nutritional value of food rations planned for women (M±SD). W1 W2 W3 W4 W5 W6 W7 W1-W7 Energy value (kcal) 2066.0 2228.8 1969.8 2121.2 2135.0 2117.2 2203.0 2120.1±86.1 Protein (g) 86.8 88.5 84.7 93.3 92.0 95.3 94.9 90.8±4.1 Fat (g) 51.1 58.4 44.4 52.9 52.9 54.0 58.0 53.1±4.7 SFAs (g) 12.1 18.0 12.6 13.5 14.6 13.5 19.2 14.8±2.7 MUFAs (g) 27.5 29.1 22.6 27.6 28.1 28.9 27.2 27.3±2.2 PUFAs (g) 11.4 11.3 9.1 11.8 10.1 11.7 11.6 11±1.0 Carbohydrates (g) 346.6 380.9 336.7 349.3 351.4 349.2 363.8 354±14.3 Dietary fiber (g) 31.9 43.7 28.8 31.3 28.6 36.8 38.5 34.2±5.6 Table 6. Nutritional value of food rations planned for men (M±SD). M1 M2 M3 M4 M5 M6 M7 M1-M7 Energy value (kcal) 2585.7 2754.9 2578.9 2683.6 2714.8 2667.2 2556.2 2648.8±76.0 Protein (g) 116.7 114.4 114.5 100.4 110.7 112.5 118.7 112.5±6.0 Fat (g) 65.5 68.7 62.0 60.7 63.7 61.4 59.7 63.1±3.1 SFAs (g) 15.2 18.4 15.6 15.1 21.0 19.4 21.2 18±2.7 MUFAs (g) 34.9 38.2 32.7 32.9 28.0 29.5 30.1 32.3±3.5 PUFAs (g) 15.4 12.1 13.7 12.7 14.6 12.5 8.3 12.8±2.3 Carbohydrates (g) 420.7 460.0 426.9 484.3 466.5 452.9 420.4 447.4±25.1 Dietary fiber (g) 38.3 40.2 36.2 50.4 41.7 36.9 34.4 39.7±5.3 W1/M1 - first daily food serving, W2/M2 - second daily food serving, W3/M3 - third daily food serving, W4/M4 - fourth daily food serving, W5/M5 - fifth daily food serving, W6/M6 - sixth daily food serving, W7/M7 - seventh daily food serving The chemical analyses showed that 100 g fresh mass of an average food ration prepared for women contained: 5.5±2.6 mg vitamin C and 20.1±4.1 mg polyphenols, and for men, respectively: 5.6±1.4 mg and 22.9±8.1 mg. The antioxidant properties of an average ration for women expressed as reducing power (FRAP index) in 100 g fresh mass was found to be 8.2±0.7 mmol Fe+2, and for men 8.9±0.9 mmol Fe+2. The antioxidant properties of an average ration developed for women and men expressed as antiradical activity against DPPH in 100 g fresh mass was respectively: 2.7±02 mmol and 2.7±0.4 mmol Trolox equivalent. The respective values for dry mass were higher (Tables 7 and 8). Ital. J. Food Sci., vol. 31, 2019 - 624 Table 7. Vitamin C and polyphenol content as well as antioxidant potential of food rations planned for women (per 100 g fresh and dry mass) (M±SD). Evaluated indices W1 W2 W3 W4 W5 W6 W7 W1-W7 100g fm Vitamin C (mg) 5.0±0.3 3.5±0.2 5.3±0.2 3.6±0.2 5.0±0.2 11.1±0.4 5.0±0.2 5.5±2.6 Polyphenols as gallic acid (mg) 16.4±5.4 23.1±3.4 23.2±2.0 21.2±5.6 12.60.9 21.6±1.2 22.9±0.8 20.1±4.1 Reducing activity (the FRAP method) (mmol Fe+2) 7.5±0.4 9.2±0.4 7.6±0.4 7.9±0.2 7.9±0.8 7.9±0.4 9.1±0.8 8.2±0.7 Antioxidant activity against DPPH (mmol Te – Trolox equivalent) 2.3±0.6 2.8±0.2 2.8±0.1 3.0±0.4 2.7±0.2 2.8±0.2 2.8±0.3 2.7±0.2 100g dm Vitamin C (mg) 21.0±1.0 13.2±0.6 24.3±1.2 14.3±0.7 19.8±0.9 43.3±2.1 19.6±0.9 22.2±10.1 Polyphenols (mg) as gallic acid 68.3±21.5 86.1±13.9 106.8±9.3 84.0±21.9 49.6±4.2 83.9±6.5 88.9±2.8 81.1±17.9 Reducing activity (the FRAP method) (mmol Fe+2) 31.3±1.1 34.4±1.4 35.1±2.1 31.6±0.6 31.1±3.8 31.0±1.8 35.5±3.7 32.9±2.0 Antioxidant activity against DPPH (mmol Te – Trolox equivalent) 9.4±2.3 10.5±0.6 12.9±0.4 12.0±1.5 10.5±0.8 10.9±0.8 10.9±1.1 11.0±1.1 Antioxidant activity against DPPH (%RSA for extract: 20 mg lyophilized food ration/g) 13.1±3.1 14.4±0.9 17.8±0.5 16.6±2.0 14.5±1.2 15.0±1.1 15.1±1.5 15.2±1.6 Table 8. Vitamin C and polyphenol content as well as antioxidant potential of food rations planned for men (per 100 g fresh and dry mass) (M±SD). Evaluated indices M1 M2 M3 M4 M5 M6 M7 M1-M7 100g fm Vitamin C (mg) 4.9±0.3 5.9±0.3 4.2±0.3 4.8±0.3 5.1±0.3 8.6±0.5 5.8±0.3 5.6±1.4 Polyphenols (mg) as gallic acid 26.2±1.0 19.4±0.8 20.1±0.2 18.7±1.3 16.9±2.8 19.4±1.7 40.2±6.2 22.9±8.1 Reducing activity (the FRAP method) (mmol Fe+2) 9.1±0.1 7.4±0.2 8.5±0.4 8.2±0.4 9.0±0.5 9.6±0.7 10.4±0.2 8.9±0.9 Antioxidant activity against DPPH (mmol Te – Trolox equivalent) 2.8±0.1 2.4±0.2 2.5±0.2 2.6±0.1 2.8±0.9 2.3±1.2 3.6±0.3 2.7±0.4 Ital. J. Food Sci., vol. 31, 2019 - 625 100g dm Vitamin C (mg) 18.4±1.2 22.8±1.4 16.4±1.0 20.2±1.3 19.8±1.2 33.1±2.1 21.8±1.4 21.8±5.4 Polyphenols (mg) as gallic acid 97.7±3.4 74.8±3.5 78.8±1.9 78.8±5.7 65.2±11.1 75.1±8.2 151.4±25.2 88.8±29.2 Reducing activity (the FRAP method) (mmol Fe+2) 33.8±0.3 28.4±0.7 33.3±1.2 34.8±1.8 34.7±2.1 37.2±2.8 39.1±1.1 34.5±3.4 Antioxidant activity against DPPH (mmol Te – Trolox equivalent) 10.3±0.1 9.4±0.8 9.7±0.9 11.0±0.5 10.8±3.8 8.9±4.7 13.6±1.5 10.5±1.6 Antioxidant activity against DPPH (%RSA for extract: 20 mg lyophilized food ration/g) 14.2±0.2 13.0±1.0 13.4±1.3 15.2±0.6 15.0±5.2 12.3±6.4 18.8±2.1 14.6±2.1 4. DISCUSSION Different groups of sports disciplines have different dietary requirements, connected with the kind of exercise and the dominant energy pathways, development of specific motor properties and the rigor of maintaining body mass and composition. One of special groups is athletes who train disciplines that require maintaining low body mass and low fat content, which is connected with planning a balanced diet with relatively lower energy intake but high nutrient density (rich in i.a., vegetables, fruit, wholegrain cereal products, legumes, fish and nuts) (THOMAS et al., 2016). The presented original study showed that food rations prepared for athletes (women and men) of disciplines that require maintaining low body mass, in accordance with qualitative and quantitative recommendations, balanced in terms of energy and basic nutrients intake, rich in fruit and vegetables and other products with high nutrient value and with high content of dietary antioxidants, including vitamin C and polyphenols, ensuring high antioxidant properties (with the energy intake of 2,120 kcal in female and 2,649 kcal in male athletes). High vitamin C and polyphenol content results from including in the prepared food rations an appropriate number of portions of products being natural sources of dietary antioxidants (i.a., fruit and/or vegetables in each meal). The mean content of vitamin C found in the prepared food rations, i.e., 5.5 mg/100 g fresh mass (women) and 5.6 mg/100 g fresh mass (men), with the assumption of their average weight of 2,090.42 g for women and 2,519.07 g for men, corresponds to vitamin C content of 114.97 mg (women) and 141.07 mg (men). Comparing the content of vitamin C in an average (within a week) food ration to the norms of physiological demand for vitamin C (RDA: 75 mg/day for women and 90 mg/day for men) (KREIDER et al., 2010), additionally increased in athletes (POTGIETER, 2013), shows that this diet can ensure its normative intake and the demand can be covered, also in the conditions of physical exercise. The described mean content of vitamin C in an average food ration corresponds to satisfying the RDA demand of 153.29% (in women) and 156.74% (in men). High vitamin C content in the prepared food rations results from high vitamin C content in products and dishes included in them, such as raw fruit and vegetables (KUNACHOWICZ et al., 2005). Extremely high content of vitamin C occurs in red peppers, but it is also high in tomatoes and lettuce (KUNACHOWICZ et al., 2005), which are the ingredients of many salads and (cream) soups planned in the analyzed food rations for athletes. Ital. J. Food Sci., vol. 31, 2019 - 626 The total content of polyphenols in the analyzed food rations is also the product of their high content in the ingredients. The mean content of polyphenols found in the prepared food rations, i.e., 20.1 mg/100 g fresh mass (women) and 22.9 mg/100 g fresh mass (men), with the assumption of their average weight of 2,090.42 g for women and 2,519.07 g for men, corresponds to polyphenol content of 420.17 mg (women) and 576.87 mg (men). The recommended intake of polyphenols, promoting good functioning of the body, is estimated at 250-500 mg/day (SIKORA et al., 2008). An average food ration, supplying this amount of polyphenols, covers the recommended intake. A study aimed to estimate the intake of phenolic compounds with the diet showed that a statistical Pole consumes approx. 440 mg polyphenols/day, and important sources of these antioxidants are vegetables (31%) and fruit (23%) (SIKORA et al., 2008). It is estimated that Western societies consume on average 50-800 mg, and Eastern up to 2 g flavonoids/day. An average Mediterranean diet provides 100-1000 mg flavonoids/day (SIKORA et al., 2008). In the Czech population the average intake of plant polyphenols was 426.6 mg/day (less than in other European as well as non-European, countries, including Spain, France, Ireland, Brazil etc.) (ZLOCH et al., 2018). A population of elderly Japanese (mostly men) consumed 1492 mg/day of polyphenols on average, and coffee and green tea were the largest sources of polyphenols in their daily life (TAGUCHI et al., 2015). Total polyphenol content in fruit and vegetables varies. In vegetables the content is the highest in: broccoli (290 mg/100 g), carrots (156 mg/100 g) and onions (150 mg/100 g) (CIEŚLIK et al., 2006). In apples, peaches and mandarines the content of extracted polyphenols was between 18.8 and 28.0 mg/100 g fresh fruit (ARRANZ et al., 2009). Out of the vegetables used to prepare the dishes in the analyzed food rations, the richest in polyphenols are red peppers (68.50 mg/100 g), onions (45.81 mg/100 g) and garlic (36.10 mg/100 g) (CIEŚLIK et al., 2006). Foods' antioxidant properties are correlated with the content of substances with antioxidant properties, including vitamin C and polyphenols. The antioxidant potential of an average food ration determined in this study, expressed as reducing power (FRAP index) was: 8.2 mmol Fe+2/100 g ration fresh mass (for women) and 8.9 mmol Fe+2/100 g ration (for men), and expressed as antiradical activity against DPPH was: 2.7 mmol/100 g ration fresh mass (for women and men). Antioxidant properties of food rations prepared for athletes is the product of content of bioactive substances with antioxidant properties and antioxidant potential of individual products/dishes and results from including the recommended number of portions of fruit and vegetables with high antioxidant activity, including honey and wholegrain cereal products. It is worth pointing out that antioxidant capacity of vegetables is usually lower than that of fruit, especially berries, and higher than that of cereal products. Antioxidant activity of fruit varies from 1.02 (pears) to 3.91 mmol/100 g (strawberries), and of vegetables, mushrooms and legumes from 0.27 (cucumbers) to 6.91 mmol/100 g (beans). High potential (>2 mmol/100 g) also occurs in peas, dill, dock, red cabbage and beetroot. Especially high antioxidant potential expressed as DPPH scavenging activity has been described for Brussels sprouts and red peppers (EC50 7.8 mg and 11.9 mg, respectively) (CIEŚLIK et al., 2006; SIKORA et al., 2008). Significant antioxidant properties of fruit and vegetable snacks have also been reported (GRAMZA-MICHAŁOWSKA and CZŁAPKA-MATYASIK, 2011). With reference to antioxidant properties of wholegrain cereal products, studies have shown that the antioxidant potential of boiled wholegrain pasta (expressed as FRAP index) is from 3.26±0.08 to 19.52±1.28 μmol/g dry mass (DURAZZO et al., 2014). Another study concerning dishes preferred by athletes showed high antioxidant properties of chicken salad (0.29 mmol/100 g) and tomato spaghetti (0.35 mmol/100 g) (GACEK et al., 2012). Ital. J. Food Sci., vol. 31, 2019 - 627 Antioxidant activity of the prepared and analyzed food rations, being the product of content of antioxidant substances, including vitamin C and polyphenols, proves they are useful in a rational diet, also for people engaging in intensive physical exercise, who need more antioxidants. Exogenous antioxidants have an impact on the total antioxidant capacity and physical fitness in athletes (MORILLAS-RUIZ et al., 2006; SCHNEIDER et al., 2018), so an important aspect of a rational diet is the appropriate intake of vegetable bioactive substances. Research has confirmed the importance of diet with high antioxidant properties for the restoration of athletes' antioxidant status. In this respect, it has been shown that antioxidant-rich diet improved the redox status of triathlon athletes (Schneider et al., 2018), and high consumption of flavones from cocoa improved the total antioxidant capacity during workout and regeneration in professional cyclists (DECROIX et al., 2017). It has been confirmed beyond doubt that satisfying higher nutritional demand, also in terms of vitamin C and other antioxidants, promotes the implementation of dietary strategies connected with muscle regeneration, glycogen replenishment, preventing fatigue, the improvement of immunity and preparation for further training and contests (HEATON et al., 2017; MYBURGH, 2014). It is recommended to apply dietary strategies that improve diet antioxidant potential (so-called antioxidant food ration) (YAVARI et al., 2015). When discussing the importance of antioxidants in the diet of physically active people, we may refer to a study that showed a positive influence of 6-week Nordic walking training on the improvement of blood antioxidant protection system in women over age 55 (CEBULA et al., 2017). Due to some cases of nutritional deficiencies and because of the importance of antioxidants for increasing antioxidant activity and protecting skeletal muscles from oxidation damage caused by physical exercise, researchers attempt to study the supplementation of athletes' diet with antioxidant substances, including melatonin (LEONARDO-MENDONCA et al., 2017), coenzyme Q (ORLANDO et al., 2018), vitamin C (YAVARI et al., 2015), and L-carnitine (SUNG et al., 2016) and whey protein (XU et al., 2011). Some studies have also shown the risk of negative impact of supplementing high doses of vitamin C (1g/day) and E (≥260 IU/day) on disorders in skeletal muscles adjusted to long training sessions (MASON et al., 2016). Functional drinks based on almonds and olive oil enriched with α-tocopherol and docosahexaenoic acid (DHA) can also be used to modulate oxidative stress and improve effort tolerance of athletes. They also help improve blood polyphenol concentration in older athletes and increase the expression of antioxidant enzyme genes in peripheral blood cells after exercise in young athletes (CAPO et al., 2016). Supplementation with purple grape juice displayed ergogenic activity (by delaying exhaustion) and led to increasing antioxidant activity and decreasing the concentration of inflammation markers in recreational runners (TOSCANO et al., 2015). Literature also includes other examples of supplementing athletes' diet with antioxidant substances (YAVARI et al., 2015). The presented results can be useful in planning diet and dietary strategies improving the antioxidant properties of the diet of people with high physical activity and increased nutritional needs. Regular consumption of fresh fruit and vegetables, whole grains, legumes and beans, sprouts and seeds is an effective and safe way to cover the antioxidant needs of physically active people. Ital. J. Food Sci., vol. 31, 2019 - 628 5. CONCLUSIONS Balanced food rations prepared for athletes (with the mean energy value of approx. 2,120 kcal for women and approx. 2,649 kcal for men included the normative amount of vitamin C (114.97 mg – women and 141.07 mg – men) and polyphenols (420.17 mg – women and 576.87 mg – men). Balanced food rations for athletes, including fruit and/or vegetables in each meal and the normative amount of vitamin C and polyphenols, have high antioxidant properties. Preparing balanced food rations for athletes, providing not only appropriate amounts of energy and macroelements but also bioactive substances (vitamin C and polyphenols) as well as high antioxidant properties is possible, though not easy. Chemical analyses confirmed the nutritional value of food rations planned on the basis of tables of products' and dishes' nutritional value. RESERCH FUNDING The study was supported from the European Union funds within the framework of the European Social Fund “Doctus - Lesser Poland Fund for Grants for PhD Students”. REFERENCES Aires A., Carvalho R., Matos M., Carnide V., Silva A.P. and Goncalves B. 2017. Variation of chemical constituents, antioxidant activity, and endogenous plant hormones throughout different ripening stages of highbush blueberry (Vaccinium corymbosum L.) cultivars produced in centre of Portugal. Journal of Food Biochemistry 41:416. Aliakbarlu J., Shadieh M. and Khalili S. 2014. A Study on Antioxidant Potency and Antibacterial Activity of Water Extracts of Some Spices Widely consumed in Iranian Diet. Journal of Food Biochemistry 38:159-166. AOAC. Official Methods of Analysis of AOAC International (18thed.), Maryland, USA, ISBN: 0-935584-77-3, 2005. Arranz S., Saura-Calixto F., Shaha S. and Kroon P.A. 2009. High contents of non-extractable polyphenols in fruits suggest that polyphenol contents of plant foods have been underestimated. Journal of Agricultural and Food Chemistry 57:7298- 7303. Bedogni G., Bernini C.E., Gatti G., Severi S., Poli M., Ferrari F. and Battistini N. 1999. Comparison of food composition tables and direct chemical analysis for the assessment of macronutrient intake in a military community. International Journal of Food Science and Nutrition 50:73-79. Benzie I.F.F. and Strain J.J. 1996. The ferric reducing ability of plasma (FRAP) as a measure of "antioxidant power": the FRAP assay. Analytical Biochemistry 239:70-76. Capó X., Martorell M., Busquets-Cortés C., Sureda A., Riera J., Drobnic F., Tur J.A. and Pons A. 2016. Effects of dietary almond- and olive oil-based docosahexaenoic acid- and vitamin E-enriched beverage supplementation on athletic performance and oxidative stress markers. Food & Function 7:4920-4934. Cebula A., Tyka A.K., Pilch W., Szyguła Z., Pałka T., Sztafa-Cabała K., Frączek B. and Tyka A. 2017. Effects of 6-week Nordic walking training on body composition and antioxidant status for women > 55 Years of Age. International Journal of Occupational Medicine and Environmental Health 30:1-10. Cianciosi D., Forbes-Hernández T.Y., Afrin S., Gasparrini M., Reboredo-Rodriguez P., Manna P.P., Zhang J., Lamas L.B., Martínez Flórez S., Toyos P.A., Quiles J.L., Giampieri F. and Battino M. 2018. Phenolic compounds in honey and their associated health benefits: A review. Molecules 23:1-20.10. Cieślik E., Gręda A. and Adamus W. 2006. Contents of Polyphenols in Fruit and Vegetables. Food Chemistry 94:135-142. Decroix L., Tonoli C., Soares D.D., Descat A., Drittij-Reijnders M.J., Weseler A.R., Bast A., Stahl W., Heyman E. and Meeusen R. 2017. Acute cocoa flavanols intake has minimal effects on exercise-induced oxidative stress and nitric oxide production in healthy cyclists: a randomized controlled trial. Journal International Society of Sports Nutrition 14:28. Durazzo A. 2017. Study approach of antioxidant properties in foods: Update and considerations. Foods 6:17. Ital. J. Food Sci., vol. 31, 2019 - 629 Durazzo A., Casale G., Melini V., Maiani G. and Acquistucci R. 2015. Evaluation of antioxidant properties in cereals: Study of some traditional Italian wheats. Foods 4:391-399. Durazzo A., Turfani V., Azzini E., Maiani G. and Carcea M. 2014. Antioxidant properties of experimental pastas made with different wholegrain cereals. Journal of Food Research 3:4. Durazzo A., Turfani V., Azzini E., Maiani G. and Carcea M. 2013. Phenols, lignans and antioxidant properties of legume and sweet chestnut flours. Food Chemistry 140:666-671. EN14130. Food Products. Determining the content of vitamin C using the HPLC Method, Brussels, Belgium, 2003. FAO. Food energy - methods of analysis and conversion factors. FAO Food and Nutrition Paper 77, Rome, ISBN: 92-5- 105014-7, 2003. Ferretti G., Bacchetti T., Belleggia A. and Neri D. 2010. Cherry antioxidants: From farm to table. Molecules 15:6993-7005. Frączek B. and Gacek M. 2013. Assessment of the nutritive value of dishes designed for athletes- grilled chicken salad and spaghetti with tomatoes and parmesan cheese. Polish Journal of Food and Nutrition Sciences 63:261-266. Gacek M., Frączek B. and Morawska M. 2012. Vitamin C and polyphenol content as well as antioxidant activity of foods designed for physically active people: grilled chicken salad and spaghetti with tomatoes and parmezan cheese. Bromatologia i Chemia Toksykologiczna 45:930-935. (in Polish, Abstract in English) Gramza-Michałowska A. and Człapka-Matyasik M. 2011. Evaluation of the antiradical potential of fruit and vegetable snacks. Acta Scientiarum Polonorum Technologia Alimentaria 10:61-72. Heaton L., Davis J., Rawson E., Nuccio R., Witard O., Stein K., Baar K., Carter J. and Baker L. 2017. Selected in-season nutritional strategies to enhance recovery for team sport athletes: A Practical Overview. Sports Medicine 47:2201-2218. Hotnog A.D., Miklos A., Tero-Vescan A. and Filip C. 2017. The advantages of vegetal sprouts consumption in the modern diet. Acta Medica Marisiensis 63:57-57. Jaiswal A.K., Rajauria G., Abu-Ghannam N. and Gupta S. 2012. Effect of different solvents on polyphenolic content, Antioxidant capacity and antibacterial activity of Irish York cabbage. Journal of Food Biochemistry 36:344-358. Koréissi-Dembélé Y., Doets E.L., Fanou-Fogny N., Hulshof P.J.M., Moretti D. and Brouwer I.D. 2017. Comparing intake estimations based on food composition data with chemical analysis in Malian women. Public Health Nutrition 20:1351- 1361. Kreider R.B., Wilborn C.D., Taylor L., Campbell B., Almada A.L., Collins R., Cooke M., Earnest C.P., Greenwood M., Kalman D.S., Kerksick C.M., Kleiner S.M., Leutholtz B., Lopez H., Lowery L.M., Mendel R., Smith A., Spano M., Wildman R., Willoughby D.S., Ziegenfuss T.N. and Antonio J. 2010. ISSN exercise & sport nutrition review: research & recommendations. Journal International Society of Sports Nutrition 7:7. Kunachowicz H., Nadolna I., Przygoda B. and Iwanow K. 2005. Food composition and nutrition tables. PZWL, Warszawa. (in Polish) Leonardo-Mendonca R.C., Ocaña-Wilhelmi J., De Harto T., De Teresa-Galván C., Guerra-Hernández E., Rusanova I., Fernández-Ortiz M., Sayed Ramy K.A., Escames G. and Acuña-Castroviejo D. 2017. The benefit of a supplement with the antioxidant melatonin on redox status and muscle damage in resistance-trained athletes. Applied Physiology, Nutrition and Metabolism 42:700-707. Marconi S., Durazzo A., Camilli E., Lisciani S., Gabrielli P., Aguzzi A., Gambelli L., Lucarini M. and Marletta L. 2018. Food composition databases: Considerations about complex food matrices. Foods 7:2. Mason S.A., Morrison D., McConell G.K. and Wadley G.D. 2016. Muscle redox signalling pathways in exercise. Role of antioxidants. Free Radical Biology and Medicine 98:29-45. McCormick R., Peeling P., Binnie M., Dawson B. and Sim M. 2106. Effect of tart cherry juice on recovery and next day performance in well-trained Water Polo players. Journal International Society of Sports Nutrition 14:1550-2783. Morillas-Ruiz J.M., Villegas Garcia J.A., Lopez F.J., Vidal-Guevara M.L. and Zafrilla P. 2006. Effects of polyphenolic antioxidants on exercise-induced oxidative stress. Clinical Nutrition 25:444-453. Myburgh K. 2104. Polyphenol Supplementation: Benefits for Exercise Performance or Oxidative Stress? Sports Medicine 44: 57-70. Ital. J. Food Sci., vol. 31, 2019 - 630 Naderi A., Adel M., Conrad P.E., Kyle L. and Sajjad R. 2018. Fruit for sport. Trends in Food Science and Technology 74:85-98. Orlando P., Silvestri S., Galeazzi R., Antonicelli R., Marcheggiani F., Cirilli I., Bacchetti T. and Tiano L. 2018. Effect of ubiquinol supplementation on biochemical and oxidative stress indexes after intense exercise in young athletes. Redox Report 23:136-145. Pekkarinen S.S., Heinonen I.M. and Hopia A.I. 1999. Flavonoids quercetin, myricetin, kaemferol and (+) catechin and antioxidants in methyl linoleate. Journal of the Science of Food and Agriculture 79:499-506. Potgieter S. 2013. Sport nutrition: A review of the latest guidelines for exercise and sport nutrition from the American College of Sport Nutrition, the International Olympic Committee and the International Society for Sports Nutrition. South African Journal of Clinical Nutrition 26:6-16. Schneider C.D., Bock P.M., Becker G.F., Moreira J.C.F., Bello-Klein A. and Oliveira A.R. 2018. Comparison of the effects of two antioxidant diets on oxidative stress markers in triathletes. Biology of Sport 35:181. Shin D., Chae K.S., Choi H.R., Lee S.J., Gim S.W., Kwon G.T., Lee H.T., Song Y.C., Kim K.J., Kong H.S. and Kwon J.W. 2018. Bioactive and pharmacokinetic characteristics of pre-matured black raspberry, Rubus Occidentalis. Italian Journal of Food Science 30:428-439. Siebenhandl S., Grausgruber H., Pellegrini N., Del Rio D., Fogliano V., Pernice R. and Berghofer E. 2007. Phytochemical profile of main antioxidants in different fractions of purple and blue wheat, and black barley. Journal Agricultural Food Chemistry 55:8541-8547. Sikora E., Cieślik E. and Topolska K. 2008. The sources of natural antioxidants. Acta Scientiarum Polonorum Technologia Alimentaria 7:5-7. Singleton V.L., Orthofer R. and Lamuela-Raventós R.M. 1999. Analysis of total phenols and other oxidation substrates and antioxidants by means of Folin-Ciocalteu reagent. Methods in Enzymology 299:152-178. Sotiroudis G., Melliou E., Sotiroudis T. and Chinou J. 2010. Chemical analysis, antioxidant and antimicrobial activity of three Greek cucumber (Cucumis Sativus) cultivars. Journal of Food Biochemistry 34:61-78. Sung D.J., Kim S., Kim J., An H.S. and So W-Y. 2016. Role of L-carnitine in sports performance: Focus on ergogenic aid and antioxidant. Science & Sports 31:177-188. Taguchi C., Fukushima Y., Kishimoto Y., Suzuki-Sugihara N., Saita E., Takahashi Y. and Kondo K. 2015. Estimated dietary polyphenol intake and major food and beverage sources among elderly Japanese. Nutrients 7:10269-10281. Thomas D.T., Erdmann K.A. and Burke L.M. 2016. Position of the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine: Nutrition and Athletic Performance. Journal of the Academy of Nutrition and Dietetics 116:501-528. Toscano L.T., Tavares R.L., Toscano L.T., Silva C.S.O., Almeida A.E.M., Biasoto A.C.T., Goncalves M.C.R. and Silva A.S. 2015. Potential ergogenic activity of grape juice in runners. Applied Physiology, Nutrition and Metabolism 40:899. Walter P., Infanger E. and Muhlemann P. 2007. Food pyramid of the Swiss Society for Nutrition. Annals of Nutrition and Metabolism 51:15-20. Van Hung P. 2016. Phenolic compounds of cereals and their antioxidant capacity. Critical Reviews in Food Science and Nutrition 56:25-35. Xu R., Liu N., Xu X. and Kong B. 2011. Antioxidative effects of whey protein on peroxide-induced cytotoxicity. Journal of Dairy Science 94:3739-3746. Yavari A., Javadi M., Mirmiran P. and Bahadoran Z. 2015. Exercise-induced oxidative stress and dietary antioxidants. Asian Journal of Sports Medicine 6:e24898. Zenteno-Rramírez G., Juárez-Flores B.I., Aguirre-Rivera J.R., Monreal-Montes M., Mérida García J., Pérez Serratosa M., Varo Santos M.Á., Ortiz Pérez M.D. and Rendón-Huerta J.A. 2018. Juices of prickly pear fruits (Opuntia spp.) as functional foods. Italian Journal of Food Science 30:614-627. Zloch Z., Sedláček P., Langmajerová J. and Müllerová D. 2018. Intake and profile of plant polyphenols in the diet of the Czech population. Polish Journal of Food and Nutrition Sciences 68:57-62. Paper Received January 30, 2018 Accepted April 15, 2019