ANTIOXIDANT AND ANTIRADICAL ACTIVITY OF RAW AND EXTRUDED COMMON BEANS

Jarosław Korus¹, Dorota Gumul¹, Maria Fołta², Henryk Bartoń^2
1 Department of Carbohydrates Technology, Agricultural University of Cracow, Poland
² Department of Food Chemistry and Nutrition, Jagiellonian University, Medical College, Cracow, Poland

ABSTRACT

The study examined the effects of extrusion parameters on the phenolic content and the antioxidant and antiradical potential of five cultivars of common bean (Phaseolus vulgaris L.). The phenolic content of extrudates was found to be 22% to 37% lower than that of raw seeds. The antioxidant activity as measured by the FRAP method decreased due to extrusion by 11% to 32% on average, depending on cultivar. The antiradical activity against DPPH fell by 4% to 10%, and against ABTS, by 5% to 27%. Extrusion performed at 20% moisture of the raw material and a temperature of 120°C of the process had the least adverse effect on both phenolic content and antioxidant and antiradical potential.

Key words: bean, extrusion, antioxidant activity, antiradical activity.

INTRODUCTION

It is commonly known that an adequate diet is a major health-promoting factor. A balanced diet should comprise pulses, among them common bean (Phaseolus vulgaris L.). Dry seeds of that plant are eaten all over the world due to their high nutritive value resulting i.e. from a relatively high levels of protein, carbohydrates, group B vitamins, and mineral constituents [13,19]. A low incidence of cardiovascular diseases among the Asians may be attributed to the fact that they consume quite big amounts of pulses, ca 110 g per person daily [11]. The consumption of beans plays also a role in reducing the risk of diabetes, heart diseases, colon cancer, etc. [16].

Dry beans constitute an important source of antioxidants, mainly phenolics. These include hydroxybenzoic acids, hydroxycinnamic acids, flavonoids and tannins (procyanidins). Such components have a beneficial influence on human health through scavenging free radicals, chelating oxidation-catalysing metals, and activating antioxidant enzymes [3,9,16,18). Some factors (e.g. relatively long duration of culinary processing: soaking and cooking), however, limit the consumption of pulses. With the aim of overcoming this problem, efforts are made to produce convenience foods by using technologies such as extrusion [14,19]. Since the antioxidants contained in food products undergo changes in the course of processing, the antioxidant potential of the processed products may increase or decrease relative to the raw material [15]. Therefore, the present studies set out to determine the effects of extrusion conducted in varying conditions on the phenolic content and antioxidant activity of dry seeds of Phaseolus vulgaris L.

MATERIAL AND METHODS

The studies used dry seeds of five cultivars of Phaseolus vulgaris L. differing in the colour of the seed coat: Augusta and Rawela (red), Nigeria and Tip-Top (black), and Toffi (cream).

The seeds were ground in a mill Pulverisette 14 (Fritsch, Germany) and moistened to a 14 or 20% moisture content. Extrusion was performed in a single-screw extruder 20DN (Brabender, Germany). Two temperature profiles, 80/100/120°C and 120/160/180°C (temperature in the individual sections of the extruder), were applied, hereafter referred to as a temperature of 120 or 180°C, respectively.

Preparation of extracts
Two-stage, methanol-acetone, extraction was performed. First, 1 g of the powdered sample was extracted with 40 cm³ of HCl (0.16 mol·dm^-3) in 80% methanol for 2 h, gently stirring the sample in a water bath with a shaking device at a temperature of 20°C ± 2°C. Then the samples were centrifuged (4000 g) and the supernatant was collected. The residue was re-extracted with 40 cm³ of 70% acetone in the same conditions, and centrifuged as above. The both extracts were combined and stored at temperature -20°C.

Total phenolic content
The total phenolic contents of raw beans and extrudates were determined by the method of Singleton et al. [20] as modified by Dewanto et al. [7] (after Heimler et al. [9]). To 0.125 cm³ of extract, 0.5 cm³ of deionised water and 0.125 cm³ of the Folin-Ciocalteu reagent (Fluka) were added, and after 6 min, 1.25 cm³ of aqueous solution of Na₂CO₃ (7 g/100 cm³) and 1 cm³ of deionised water were added. After 90 min, absorbance at 760 nm was measured against water as a reference. The results were expressed as gallic acid equivalents (GAE), in milligrams of gallic acid per gram of the dry matter of sample, on the basis of the calibration curve (r² = 0.999).

Antioxidant activity (FRAP method)
The FRAP (Ferric Reducing Ability of Plasma) assay was performed according to Benzie and Strain [4]. To 10 cm³ test-tubes, 3.300 cm³ of acetate buffer (pH 3.6), 0.330 cm³ of FeCl₃ · 6 H₂O) (20 mmol·dm^-3) and 0.330 cm³ of tripyridyltriazine (TPTZ) (10 mmol·dm^-3 TPTZ in 40 mmol·dm^-3 HCl) were added and heated in a water bath at a temperature of 37°C for 5 min. Then, 0.330 cm³ of the methanol-acetone extracts of beans were added. Absorbance at 593 nm was measured after 15 min. The blank determination was performed in the same way with a mixture of extraction solvents (70% acetone and 0.16 M HCl in 80% methanol) in the ratio 1:1. The calibration curve was drawn by using FeSO₄ as a calibration solution (r² = 0.999).

Antiradical activity (DPPH method)
The DPPH radical-scavenging ability was determined following Brand-Williams et al. [5]. The extract (appropriately diluted with methanol so that the radical-scavenging degree would not exceed 70%) in an amount of 1.5 cm³ was treated with 3 cm³ of a solution of DPPH (2,2-diphenyl-1-picrylhydrazyl, Sigma) 4 mg/100 cm³ in 99% methanol and left in the dark at room temperature. After 15 min, absorbance at 515 nm was measured against methanol as a reference. The results were expressed as equivalents of Trolox (6-Hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid, Aldrich) TEAC in mmol per kilogram of the dry matter of sample (calibration curve r² = 0.995).

Antiradical activity (ABTS method)
The assay was performed by the method of Re et al. [17] as modified by Bartoń et al. [2]. An aqueous solution of ABTS (2,2’-azino-bis(3-ethylbenzotialozline-6-sulfonic acid), Sigma) of 7 mmol·dm^-3 was mixed with aqueous solution of potassium persulfate (2.45 mmol·dm^-3) (both heated to 30°C ± 0.5°C) and left for the night to produce the ABTS^●+ cation-radical. The ABTS^●+ solution was diluted with the PBS buffer (phosphate buffered saline, Sigma) to obtain a working solution of 1.05 ± 0.05 absorbance in such a way that the initial absorbance of the test solution with the extract added would be 0.7. Then, 2 cm³ of the working solution of ABTS^●+ was mixed either with 1 cm³ of PBS (blank) or with the extract appropriately diluted with PBS (so that the radical-scavenging degree would not exceed 60%), and after 15 min, absorbance at 734 nm was measured. Based on the calibration curve (r² = 0.996), the results were expressed as TEAC in millimoles of Trolox per kilogram of the dry matter of sample.

Statistical analysis
The results were statistically analysed using F-Snedecor’s and t-Student’s tests. The least significant difference (LSD) was calculated at p = 0.01. All analyses were performed in at least three replications.

RESULTS AND DISCUSSION

Before extrusion, the seeds of various common bean cultivars contained from 7.87 mg (Rawela) to 10.55 mg (Toffi) of total phenolics (Gallic Acid Equivalents; Table 1). Because of the differences in the methods of extraction and determination, and in the ways of expressing results between various authors, it is difficult to compare our data with those from literature. For example, Cardador-Martínez et al. [6] have found the total phenolic content of bean cv. Flor de Mayo to be 2.09 mg of catechin equivalents per gram of seeds. The same set of authors in another publication have reported the concentrations of phenolic compounds in six bean cultivars in the range 3.28-16.61 mg of catechin equivalents per gram of seeds [16]. The levels established by Vinson et al. [21] using the Folin-Ciocalteu method have been 35.9 µmol and 31.9 µmol of catechin per gram of seeds for kidney bean and pinto bean, respectively. Wu et al. [22] employing the latter method have determined from 2.23 to 12.47 mg of phenolics (GAE) per gram of seeds in various bean cultivars. Yet another authors, Marzo et al. [14], who have determined the total phenolic content of bean cv. Pinto by a method based on the Folin-Denis reagent, have obtained the value of 0.44 mg of phenolics per gram of seeds. The phenolic contents of twelve Italian cultivars of bean investigated by Heimler et al. [9] have ranged between 1.17 and 4.40 mg GAE per gram of seeds. As mentioned before, besides the determination method itself, also the way of phenolic compound extraction from the study material is of great importance. For example, Amarowicz et al. [1] have determined from 0.292 to 0.721 g of phenolic compounds per 100 g of lentil seeds in the sample, depending on the kind of the extraction solution. The highest yield of extraction has been reached when using a mixture of acetone with water in a ratio of 8:2. In our preliminary studies (data not shown) the yield of extraction was the highest with a mixture of acetone with water in a ratio of 7:3 (32% higher than with the above mixture in a ratio of 8:2, and ca 13 times higher than with methanol). The results of the present studies are close to those reported by Wu et al. [22] who have used a two-stage (but different from ours) extraction (hexane/dichloromethane 1:1, acetone/water/acetic acid 70:29.5:0.5).

Table 1. Total phenolic content of beans and extrudates

Extrusion parameters (moisture content in percent/temperature in DC)
Cultivar	Raw seeds	14/120		20/120		14/180		20/180		Mean after extrusion		LSD** p = 0.01
	GAE*	GAE	change relative to raw seeds %	GAE	change relative to raw seeds %	GAE	change relative to raw seeds %	GAE	change relative to raw seeds %	GAE	change relative to raw seeds %
Augusta	10.12	6.27	-38	7.75	-23	6.62	-34	6.55	-35	6.80	-33	I – 0.169 II – 0.169 I×II – 0.379
Nigeria	8.61	6.63	-23	6.66	-23	5.88	-32	6.24	-27	6.35	-26
Rawela	7.87	5.39	-31	5.99	-24	4.86	-38	5.26	-33	5.38	-32
Tip-Top	9.39	8.21	-12	7.59	-19	7.01	-25	6.28	-33	7.27	-22
Toffi	10.55	5.91	-44	7.56	-28	6.26	-41	6.84	-35	6.64	-37
Mean	9.31	6.48	-30	7.11	-23	6.13	-34	6.23	-33	X	X

* Gallic Acid Equivalent, mg/g d.m. of material ** LSD for: factor I – cultivar, factor II – extrusion parameters, factor III – interaction (I×II)

After extrusion, the phenolic content of beans decreased for all cultivars, from 22% (Tip-Top) to 37% (Toffi) relative to the raw material (Table 1). In contrast, Marzo et al. [14] have observed a fall reaching 50%. In our studies, the loss of phenolics was slightly greater for beans extruded at a higher temperature (33% on average for temperature 180°C vs. 27% for 120°C). Within the same temperature profile, the losses were smaller when the material had a higher initial moisture content. With the extrusion temperature of 120°C, the total phenolic content of samples moistened to 14% decreased by 30%, while of those moistened to 20%, by 24%. When extrusion was performed at 180°C, the respective values were 34 and 33%. The decrease in the phenolic content of beans averaged (for the two temperatures) 32% for the raw material moistened to 14%, and 28% for that with a higher, 20%, moisture content. This clearly demonstrates that a lower temperature of the extrusion process and a higher moisture content of the material to be extruded are advantageous for the phenolic content of extrudates. Such results correspond with those obtained by Ismail and Zahran [10] who have defined the best conditions of extrusion for soya bean and chick pea in terms of preserving nutritive components: these were 20% moisture and 160°C temperature, i.e. a relatively high moisture content of the raw material and a relatively low temperature of the process. A study by Korus et al. [12], examining the effects of extrusion parameters on the nutritive value of dry seeds of Phaseolus vulgaris L., has also shown that a higher moisture of the raw material and a lower temperature of extrusion make it possible to retain a bigger amount of chemical constituents. The various authors, however, differ about the effect of the two extrusion parameters on the retention of individual components of extruded foods.

The antioxidant activity determined by the FRAP method was the highest for the raw seeds of Toffi (99.50 mM Fe²⁺/kg) which contained also the greatest amount of phenolics among all the bean cultivars studied (Tables 1 and 2). Tip-Top showed a slightly lower activity (96.25 mM Fe²⁺/kg), and Rawela was the poorest in this respect (57.49 mM Fe²⁺/kg); the latter cultivar had the smallest phenolic content. Augusta, that contained the second highest amount of phenolics, displayed a medium antioxidant activity. Such results may be attributed to the differences in the composition of phenolic compounds between the bean cultivars because antioxidant activity varies among individual polyphenols. According to Gadow et al. [8], the antioxidant activity of the phenolic acids and flavonoids they have studied decreases in the following order: luteolin > quercetin > vanillic acid > ferulic acid > p-coumaric acid > rutin > caffeic acid. Except Augusta, the phenolic content of beans was well correlated with their antioxidant activity (r = 0.906, compared to 0.580 with Augusta taken into account).

Table 2. Antioxidant activity of beans and extrudates as determined by the FRAP method, in mmol Fe2+/kg d.m. of material

Extrusion parameters (moisture content in percent/temperature in DC)
Cultivar	Raw seeds	14/120		20/120		14/180		20/180		Mean after extrusion		LSD* p = 0.01
	mmol Fe2+	mmol Fe2+	change relative to raw seeds %	mmol Fe2+	change relative to raw seeds %	mmol Fe2+	change relative to raw seeds %	mmol Fe2+	change relative to raw seeds %	mmol Fe2+	change relative to raw seeds %
Augusta	67.17	58.62	-13	59.69	-11	57.15	-15	54.63	-19	57.52	-15	I – 3.234 II – 3.234 I×II – 7.231
Nigeria	82.16	60.48	-26	62.69	-24	59.90	-27	55.86	-32	59.73	-27
Rawela	57.49	51.06	-11	54.28	-5	50.34	-12	48.08	-16	50.94	-11
Tip-Top	96.25	77.60	-19	78.16	-19	76.43	-20	68.33	-29	75.13	-22
Toffi	99.50	56.51	-43	81.40	-18	63.19	-36	70.95	-29	68.01	-32
Mean	80.51	60.85	-22	67.24	-15	61.40	-22	59.57	-25	X	X

* LSD for: factor I – cultivar, factor II – extrusion parameters, factor III – interaction (I×II)

The antioxidant activity of bean extrudates was always lower than that of the raw material (Table 2), which was probably associated with the decreased phenolic content. In most cases, the bean cultivars significantly differed in the antioxidant activity of extrudates. The mean decrease in antioxidant activity due to extrusion ranged from 11% for Rawela to 32% for Toffi. The activity of Augusta decreased by 15%, while that of the other two cultivars fell by more than 20%.

As regards the conditions of extrusion, there were no significant differences between the effects produced by three of the four combinations of initial moisture and process temperature (moisture 20%, temperature 180°C; moisture 14%, temperature 120°C and 180°C) for which the reduction in antioxidant activity ranged from 22 to 25% (Table 2). Only for a moisture of 20% and a temperature of 120°C, i.e. the higher moisture and the lower temperature, was the reduction significantly smaller, with the mean of all the cultivars amounting to 15%.

The antiradical activity determined with ABTS (Table 3) and DPPH (Table 4) appeared to be the highest for the Toffi cultivar showing the greatest antioxidant activity, and the lowest for Augusta. The ABTS method yielded the values of 91.52 and 62.33 mmol Trolox/kg, respectively, and the DPPH method, the values of 27.69 and 25.09 mmol Trolox/kg. Since the Augusta’s phenolic content was second to Toffi’s, the above results may confirm the earlier hypothesis that the composition of those antioxidants influences both the antiradical and antioxidant activity of the plant material. Among the plant phenolics examined by Gadow et al. [8], quercetin has shown a high antioxidant and antiradical activity, whereas caffeic acid has had a very strong DPPH radical-scavenging ability but the weakest antioxidant properties as measured in the β-carotene/linoleic acid system. In the present studies, the antioxidant activity of bean cultivars was in general well correlated with phenolic content (when Augusta was not considered, r = 0.960 for DPPH and 0.704 for ABTS). The relationship between the two activities can thus be regarded as a varietal characteristic connected with the amount and composition of phenolics. Such a view is supported by the results of Oomah et al. [16] who have found a correlation between those properties, ranging from strong negative to strong positive.

Table 3. Antiradical activity of beans and extrudates as determined with the ABTS cation-radical scavenging

Extrusion parameters (moisture content in percent/temperature in DC)
Cultivar	Raw seeds	14/120		20/120		14/180		20/180		Mean after extrusion		LSD** p = 0.01
	TEAC*	TEAC	change relative to raw seeds %	TEAC	change relative to raw seeds %	TEAC	change relative to raw seeds %	TEAC	change relative to raw seeds %	TEAC	change relative to raw seeds %
Augusta	63.33	57.60	-9	61.17	-3	60.37	-5	62.70	-1	60.46	-5	I – 1.837 II – 1.837 I×II – 4.109
Nigeria	76.61	60.17	-21	67.19	-12	61.41	-20	49.86	-35	59.66	-22
Rawela	83.66	64.14	-23	69.58	-17	65.96	-21	57.30	-31	64.25	-23
Tip-Top	83.32	67.74	-19	75.19	-10	69.96	-16	72.99	-12	71.47	-14
Toffi	91.52	61.69	-32	76.86	-16	55.89	-39	74.46	-19	67.23	-27
Mean	79.69	62.27	-21	70.00	-12	62.72	-20	63.46	-20	X	X

* mmol Trolox/kg d.m. of material ** LSD for: factor I – cultivar, factor II – extrusion parameters, factor III – interaction (I×II)

Table 4. Antiradical activity of beans and extrudates as determined with the DPPH radical scavenging

Extrusion parameters (moisture content in percent/temperature in DC)
Cultivar	Raw seeds	14/120		20/120		14/180		20/180		Mean after extrusion		LSD** p = 0.01
	TEAC*	TEAC	change relative to raw seeds %	TEAC	change relative to raw seeds %	TEAC	change relative to raw seeds %	TEAC	change relative to raw seeds %	TEAC	change relative to raw seeds %
Augusta	25.09	23.81	-5	24.33	-3	24.05	-4	24.65	-2	24.21	-4	I – 0.321 II – 0.321 I×II – 0.718
Nigeria	25.25	24.17	-4	24.93	-1	24.05	-5	23.57	-7	24.18	-4
Rawela	25.29	23.17	-8	23.85	-6	23.41	-7	23.57	-7	23.50	-7
Tip-Top	26.37	25.29	-4	25.29	-4	24.97	-5	25.29	-4	25.21	-4
Toffi	27.69	23.57	-15	25.73	-7	24.81	-10	25.25	-9	24.84	-10
Mean	25.94	24.00	-7	24.83	-4	24.26	-6	24.47	-6	X	X

* mmol Trolox/kg d.m. of material ** LSD for: factor I – cultivar, factor II – extrusion parameters, factor III – interaction (I×II)

In all cases, extrusion reduced antiradical activity compared to the raw material. The effect was the most pronounced for Toffi: with the ABTS radical the mean decrease in activity reached 27%, and with the DPPH radical it amounted to 10% and was significantly larger than in the other cultivars (4%-7%). The smallest decrease in antiradical activity was shown by Augusta: 5% for ABTS and 4% for DPPH, despite the second greatest loss of phenolics (33% on average). This provides a further evidence to suggest that the antioxidants contained in the latter bean cultivar have a relatively low antioxidant and antiradical potential, therefore the relatively big losses of those components do not translate into a corresponding reduction in both activities.

Compared to the raw material, also the antiradical activity of extrudates was decreased to the smallest extent (by 12% for ABTS and 4% for DPPH) when the conditions of extrusion were 20% moisture and 120°C temperature. Using the other values of extrusion parameters led to an average reduction of 20% and 6.5%, respectively, in the free-radical-scavenging ability studied with ABTS and DPPH.

CONCLUSIONS

Extrusion with a 20% moisture of the raw material (dry beans) and a temperature of 120 °C produced the least detrimental effect on the total phenolic content and the antioxidant and antiradical potential of the beans of all cultivars. The mean reduction in both potentials (as determined by three methods: FRAP, ABTS and DPPH) amounted to 10%, while for the other combinations of moisture and temperature it ranged from 16 to 17%. In the same conditions of the process, the phenolic content decreased by 24% on average compared to 30-34%.

The results of this study did not provide an unambiguous answer to the question which of the two factors: water content or temperature, has a more significant effect on the antioxidant and antiradical activity of common bean. Using an increased moisture of the raw material led to a smaller decrease in the antioxidant and antiradical activity of extrudates compared to raw seeds. For the lower moisture (14%) the reduction in both activities, as determined by the FRAP, ABTS and DPPH methods, was greater by 2.5, 4.5 and 1.5, respectively, than for the moisture of 20%. At the same time, using an elevated temperature of extrusion caused a larger decrease in both activities compared to the raw material. For the lower temperature (120°C) the reduction determined by the three above methods was smaller by 4.5, 3.5 and 0.5%, respectively, than for 180°C.

The results suggest that extrudates with the least decreased phenolic content and antioxidant activity would be produced through extrusion carried out at a relatively high moisture content and the lowest possible temperature. Such conditions would make it possible to obtain a ready-to-eat product of great health-giving properties, in which a considerable proportion of phenolic compounds contained in common bean is retained and its antiradical and antioxidant potential is preserved.

ACKNOWLEDGEMENTS

This work was supported by Ministry of Science, Poland, project PBZ-KBN 094/P06/2003/29.

REFERENCES

1. Amarowicz R., Piskuła M., Honke J., Rudnicka B., Troszyńska A., Kozłowska H., 1995. Extraction of phenolic compounds from lentil seeds (Lens culinaris) with various solvents. Pol. J. Food Nutr. Sci. 4/45, 53-61.

2. Bartoń H.J., Fołta M., Chłopicka J., Zachwieja Z., Gumul, D., 2005. Antioxidant activity of five varieties of buckwheat seeds (Fagopyrum esculentum Moench). Bromat. Chem. Toksykol., Supl. 71-74 [in Polish].

3. Beninger C.W., Hosfield G.L., 2003. Antioxidant activity of extracts, condensed tannin fractions, and pure flavonoids from Phaseolus vulgaris L. seed coat color genotypes. J. Agric. Food Chem. 51, 7879-7883.

4. Benzie I.F.F., Strain, J.J., 1996. The ferric reducing ability of plasma (FRAP) as a measure of antioxidant power: The FRAP Assay. Anal. Biochem. 239, 70-76.

5. Brand-Williams W., Cuvelier M.E., Berset C., 1995. Use of e free radical method to evaluate antioxidant activity. Lebensm.-Wiss.Technol. 28, 25-30.

6. Cardador-Martínez A., Loarca-Piña G., Oomah, B.D., 2002. Antioxidant activity in common beans (Phaseolus vulgaris L.). J. Agric. Food Chem. 50, 6975-6980.

7. Dewanto V., Wu X., Adom K.K., Liu R.H., 2002. Thermal processing enhances the nutritional value of tomatoes by icreasing total antioxidant activity. J. Agric. Food Chem. 50, 3010-3014.

8. Gadow A., Joubert E., Hansmann C.F., 1997. Comparison of the antioxidant activity of aspalathin with that of other plant phenols of rooibos tea (Aspalathus linearis), α-tocopherol, BHT and BHA. J. Agric. Food Chem. 45, 632-638.

9. Heimler D., Vignolini P., Dini M.G., Romani, A., 2005. Rapid tests to assess the antioxidant activity of Phaseolus vulgaris L. dry beans. J. Agric. Food Chem. 53,3053-3056.

10. Ismail F.A., Zahran G.H., 2002. Studies on extrusion conditions of some cereals and legumes. Egypt J. Food Sci. 30, 59-76.

11. Kahlon T.S., Smith G.E., Shao, Q., 2005. In vitro binding of bile acids by kidney bean (Phaseolus vulgaris), black bean (Vigna mungo), bengal gram (Cicer arietinum) and moth bean (Phaseolus aconitifolins). Food Chem. 90, 241-246.

12. Korus J., Gumul D., Achremowicz B., 2006. The influence of extrusion on chemical composition of dry seeds of bean (Phaseolus vulgaris L.). EJPAU, Food Sci. Technol. 9(1) www.ejpau.media.pl.

13. Martín-Cabrejas M.A., Sanfiz B., Vidal A., Mollá E., Esteban R., López-Andréu, F.J., 2004. Effect of fermentation and autoclaving on dietary fiber fractions and antinutritional factors of brans (Phaseolus vulgaris L.). J. Agric. Food Chem. 52, 261-266.

14. Marzo F., Alonso R., Urdaneta E., Arricibita F.J., Ibáñez F., 2002. Nutritional quality of extruded kidney bean (Phaseolus vulgaris L. var. Pinto) and its effects on growth and skeletal muscle nitrogen fractions in rats. J. Anim. Sci. 80, 875-879.

15. Nicoli M.C., Anese M., Parpinel M., 1999. Influence of processing on the antioxidant properties of fruit and vegetables. Trends Food Sci. Technol. 10, 94-100.

16. Oomah B.D., Cardador-Martinez A., Loarca-Piña G., 2005. Phenolics and antioxidative activities in common beans (Phaseolus vulgaris L). J. Sci. Food Agric. 85, 935-942.

17. Re R., Pellegrini N., Proteggente A., Pannala A., Yang M., Rice-Evans, C., 1999. Antioxidant activity applying an improved ABTS radical cation decolorization assay. Free Radic. Biol. Med. 26, 1231-37.

18. Scalbert A., Johnson I.T., Salmarsh M., 2005. Polyphenols: antioxidants and beyond. Am. J .Clin. Nutr. 81(suppl.), 215S-217S.

19. Schneider A.V.C., 2002. Overview of the market and consumption of pulses in Europe. Brit. J. Nutr. 88(suppl.3), S243-S250.

20. Singleton V.L., Orthofer R., Lamuela-Raventos R.M., 1999. Analysis of total phenols and other oxidation substrates and antioxidants by means of the Folin-Ciocalteu reagent. Method. Enzymol. 299, 152-178.

21. Vinson J.A., Hao Y., Su X., Zubik, L., 1998. Phenol antioxidant quantity and quality in foods: vegetables. J. Agric. Food Chem. 46, 3630-3634.

22. Wu X., Beecher G.R., Holden J.M., Haytowitz D.B., Gebhardt S.E., Prior R.L., 2004. Lipophilic and hydrophilic antioxidant capacities of common foods in the United States. J. Agric. Food Chem. 52, 4026-4037.

 

Accepted for print: 20.09.2007

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Jarosław Korus
Department of Carbohydrates Technology,
Agricultural University of Cracow, Poland
Balicka 122, 30-149 Cracow, Poland
ph./fax: (+48 12) 662 47 47
email: rrkorus@cyf-kr.edu.pl

Dorota Gumul
Department of Carbohydrates Technology,
Agricultural University of Cracow, Poland
Balicka 122, 30-149 Cracow, Poland
Phone: (+48 12) 662 47 71
Fax: (+48 12) 662 47 47
email: rrgumul@cyf-kr.edu.pl

Maria Fołta
Department of Food Chemistry and Nutrition,
Jagiellonian University, Medical College, Cracow, Poland
Medyczna 9, Cracow, Poland

Henryk Bartoń
Department of Food Chemistry and Nutrition,
Jagiellonian University, Medical College, Cracow, Poland
Medyczna 9, Cracow, Poland

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