328 Journal homepage: www.fia.usv.ro/fiajournal Journal of Faculty of Food Engineering, Ştefan cel Mare University of Suceava, Romania Volume XII, Issue 4 – 2013, pag. 328 - 331 POLY PHEN OL CON TEN T AN D ANT IO XIDANT A CTI V IT Y O F COM MERC IA L BEER S FROM THE ROMAN IAN M A RKE T *Mircea OROIAN1, Cristina DAMIAN1, Ana LEAHU1, Oana GHERASIM1 1 Faculty of Food Engineering, Stefan cel Mare University of Suceava, Romania m.oroian@fia.usv.ro * Corresponding author Received November 7th 2013, accepted December 5th 2013 Abstract: The aim of this study is to evaluate the polyphenol content and antioxidant activity of 10 different samples from the Romanian market. The samples were purchased from the local market of Suceava town, Suceava county. Polyphenolic compounds are ubiquitous in all plant organs and are, therefore, an integral part of the human diet. They are synthesised by the phenylpropanoid biosynthetic pathway, which produces the large variety of plant phenols. The polyphenol content of the beer samples was measured using the Folin Ciocalteau method. The antioxidant activity of beer samples were measured using the DPPH assay. The two method were applied using a UV-VIS spectrometer. The 10 beer samples analyzed showed considerable differences between them among total polyphenol content, ranging between 61.40 mg GAE/l for Landbier beer to 361.40 mg GAE/l for Skol beer. All the beer samples showed strong activities of the DPPH radical at the concentration test. The values of PI% are rangind between 10.24 and 33.68%. Tuborg beer showed the highest antioxidant activity, while Landbier showed the smallest one. Keywords:polyphenol, antioxidant activity, beer 1. Introduction Beer is a natural beverage, with no fat and low caloric content, with organic acids and vitamins, proteins, hop and water. Beer has a higher nutritional value than other alcoholic beveragesm because of its mineral value and essential nutrients such as potassium, magnesium, calcium and sodium. The use of cereals and malt to produce beer may also contribute for the ingestion of naturally occuraing antioxidant compounds, such as polyphenols [1]. Polyphenolic compounds are ubiquitous in all plant organs and are, therefore, an integral part of the human diet. They are synthesised by the phenylpropanoid biosynthetic pathway, which produces the large variety of plant phenols. In the last decades, the interest of polyphenolic compounds was related to the ability of them to bind and precipitate marcomolecules (dietary protein, carbohydrate, digestive enzymes), but in the last part of XX century, the interest in food phenolics has increased due to the antioxidant and free radical-scavenging Food and Environment Safety - Journal of Faculty of Food Engineering, Ştefan cel Mare University - Suceava Volume XII, Issue 4 – 2013 Mircea OROIAN, Cristina DAMIAN, Ana LEAHU, Polyphenol content and antioxidant activity of commercial beers from the romanian market, Volume XII, Issue 4 – 2013, pag. 328 - 331 329 abilities [2]. Polyphenols may exert an indirect antioxidant effect, by protecting endogenous antioxidant enzymes in the human body [3, 4]. Stevenson & Hurst [3] suggest in their review that it appears that polyphenols can provide significant protection from oxidative stress in vitro at concentrations much lower than would be required for chemical antioxidant protection [5]. The antioxidant properties of phenolics is mainly because of their redox properties, which allow them to act as reducing agents, hydro-gen donators and singlet oxygen quenchers [6]. A polyphenol substance can be defined as an antioxidant only if it fulfills two conditions, firstly, when present in low concentration relative to the substrate to be oxidized it can delay, retard or prevent the oxidation or free radical mediated oxidation of a substrate and secondly that the resulting radicals formed after scavenging must be stable [7]. The aim of this study is to evaluate the polyphenol content and antioxidant activity of 10 different samples from the Romanian market. 2. Materials and methods 2.1. Materials For this study were purchased 10 different commercial beers from the Romanian Market. 2.2. Polyphenols content FolinCiocalteau reagent preparation Reagents: 7.5% Na2CO3 solution, Foli Ciocalteau solution 1:10, methanol. 100 g of Na2WO42H2O and 25 g of Na2MoO42H2O are dissoved into 700 mL of warmed bidistilled water. 50 mL of 85% o-phoshoric acid and 100 mL of 37% clorhidric acid are mixed with the previous substances. The mix is boilled for 10 h. 150 of Li2SO4H2O and some goats of Br are added, and the boilling is continued for 15 min. The mix is puted into 1 L flask and filled up with bidistilled water. The reagent is kept in dark. Beer polyphenol determination 0.2 ml of beer are added into a tube, 2 ml of Folin Ciocalteau 1:10 and 1.8 ml of 7.5 % Na2CO3 are added. The mixture is agitated and the absorbance in measured at 750 nm using the Ocean Optics HR4000 spetrometer. Polyphenol calibration curve is made using a known polyphenol (gallic acid) of 1, 2, 3, 4 and 5 mg/L concentration, respectively. The calibration curve is presented into figure 1. Fig.1. Polyphenol calibration curve 2.3. Antioxidant activity The antioxidant activiy was determined using the DPPH assay. The antiradical power determination is made by y = 0,114x R² = 0,984 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0 2 4 A bs or ba nc e Acid galic mg/L Food and Environment Safety - Journal of Faculty of Food Engineering, Ştefan cel Mare University - Suceava Volume XII, Issue 4 – 2013 Mircea OROIAN, Cristina DAMIAN, Ana LEAHU, Polyphenol content and antioxidant activity of commercial beers from the romanian market, Volume XII, Issue 4 – 2013, pag. 328 - 331 330 comparing with a stable radical, 1,1- difenil-2–picrilhidrazil, DPPH. Fig.2 DPPH chemical structure 5 μl of beer sample are added into a spectrohotometer cuvette and after it 3 ml of DPPH solution (25 mg/L methanol) are added. The sample is left for 5 min and the absorbance is measured at 517 nm using a Ocean Optics HR4000 UV-VIS spectrometer. The inhibition power of free radical (PI %) is measured by comparing the DPPH absorbance with the sample absorbance using the equation: PI % = [1 – (Asample/ Ablank)] × 100. The absorbance for the samples Asample were measured at 517 nm, and for Ablank for the DPPH solution. 2.4.Statistical analysis The statistical analysis was made using the next software packs: Excel 2007. The variables were weighted with the inverse of the standard deviation of all objects in order to compensate for the different scales of the variables. 3. Results and discussions The polyphenol content of the 10 beer samples were examined using the Folin Ciocalteau method, and the results are presented in table 1. The 10 beer samples analyzed showed considerable differences between them among total polyphenol content, ranging between 61.40 mg GAE/l for Landbier beer to 361.40 mg GAE/l for Skol beer. Guinness, Gauloise and Suceava beers showed a high content of polyphenol (>100 mg GAE/l). The polyphenols play a critical role into the flavor stability and for the colloidal stability too. Table 1. Polyphenol content of beer samples No. Commercial name Acid galic mg/L 1 Skol 361,40 2 Suceava 107,01 3 Ursus 96,49 4 Timişoareana 94,74 5 Tuborg 68,42 6 Silva brună 78,95 7 Ursus brună 70,18 8 Gauloise 115,79 9 Guinness 131,58 10 Landbier 61,40 The antioxidant activity of the 10 beer samples are presented into the table 2. All the beer samples showed strong activities of the DPPH radical at the concentration test. The values of PI% are rangind between 10.24 and 33.68%. Tuborg beer showed the highest antioxidant activity, while Landbier showed the smallest one. All the results showed that the raw materials and the brewering process have significant influence on the DPPH radical activity of beer samples. Food and Environment Safety - Journal of Faculty of Food Engineering, Ştefan cel Mare University - Suceava Volume XII, Issue 4 – 2013 Mircea OROIAN, Cristina DAMIAN, Ana LEAHU, Polyphenol content and antioxidant activity of commercial beers from the romanian market, Volume XII, Issue 4 – 2013, pag. 328 - 331 331 Table 2. Antioxidant activity No. Commercial name PI % 1 Skol 11.29 2 Suceava 13.12 3 Ursus 12.06 4 Timişoareana 17.79 5 Tuborg 33.68 6 Silva brună 13.12 7 Ursus brună 12.61 8 Gauloise 11.16 9 Guinness 21.57 10 Landbier 10.24 4. Conclusions Phenolic compounds play a critical role into arome stability and in the coloidal stability of beer. The phenolic compounds are considered, in general, the most important source of antioxidants in beer. Even the individuals phenolics responsible for the antioxidant activity of the beer were not determined the general contribution of the phenolic compounds at the antioxidant activity of the beer ranged between 10.24 and 33.68%. The results obtained showed that the raw materials and the brewing process can influence significantly the antioxidant activity. The polyphenol content ranged between 61.40 mg GAE/l for Landbier beer to 361.40 mg GAE/l for Skol beer. 5. References [1] TAFULO. P. A. R., Quieros. R. B.. DELERUE-MATOS. C. M.., SALES. M. G. F., Control and comparison of the antioxidant capacity of beers. Food research International. 43. 1702-1709. (2010) [2] BRAVO. L.. Polyphenols: Chemistry. Dietary Sources. Metabolism. and Nutritional Significance. Nutrition Reviews. 50 (11). 317- 333.. (1998). [3] STEVENSON. D.E.. HURST. R.D.. Polyphenolic phytochemicals – just antioxidants or much more? Cellular & Molecular Life Sciences. 64: 2900–2916. (2007). [4] ARON. P.M.. KENNEDY. J.A. Flavan-3-ols: nature. occurrence and biological activity. Molecular Nutrition & Food Research 52: 79– 104. (2008). [5] WEICHSELBAUM. E.. BUTTRISS. J. L.. Polyphenols in the diet. Nutrition Bulletin. 33. 157-164. (2010). [6] RICE-EVANS. C. A.. MILLER. N. J.. & PAGANGA. G. Structure-antioxidant activity relationships of flavonoids and phenolic acids. Free Radical Biology and Medicine. 20(7). 933–956. (1996). [7] KAUR. C.. KAPOOR. H.C.. Antioxidants in fruit and vegetables - the millenium’s health. International Journal of Food Science and Technology. 36. 703-725. (2001)