Bean Institute

Health Promoting Bioactives

Dr. Clifford Hall

Dr. Hall is an Associate Professor of Food Sciences at North Dakota State University, Fargo, North Dakota, and a Member of the Bean Institute Editorial Board.  He can be reached at  Clifford.Hall@NDSU.edu.

Jump To:
Phytic acid
Phenolic Compounds

Total dietary fiber is broadly defined as the sum of non-digestible carbohydrates. The dietary fiber is further distinguished as soluble and insoluble. As the names imply, insoluble fiber is not soluble and acts to provide bulk to feces and enhances the passage of food through the digestive tract. Soluble fiber binds with water forming a gel-like material in the digestive tract (Anderson et al. 2009). Resistant starches are starch and starch degradation products that are not digested or absorbed in the small intestine (Asp, 1992; Englyst et al. 1992). Resistant starches are now considered dietary fiber (Jones et al. 2006).

Dietary fiber and resistant starches are associated with gut health, reduction in fecal transition time through the gastrointestinal tract, and delayed emptying of gastric content which may reduce postprandial blood glucose concentrations and thus benefiting individuals with diabetes or insulin sensitivity (http://www.nal.usda.gov/fnic/DRI//DRI_Energy/339-421.pdf). Dietary fiber may contribute to the reduction in disease such as cardiovascular disease, strokes, and obesity and aid in the reduction of blood cholesterol levels (Lee et al., 1992; Han et al., 2003; Anderson et al. 2009). Recently, Feregrino-Perez et al. (2008) showed that carbohydrate extracts from cooked beans were protective against colon cancer.

Pinto and kidney beans were a good source of dietary fiber (Li 1995; Li et al. 2002). The fiber contents ranged from 23.1 to 28.8% on a dry weight basis for cooked beans. Pinto had the lowest content whereas kidney beans had the highest. Small differences in bean composition did exist. Kahlon and Woodruff (2002) reported total dietary fiber contents of 25.4 and 25.7% for pinto and black beans, respectively. Further breakdown of the fiber showed that 87 and 13% of the pinto bean fiber was insoluble and soluble, respectively. A similar ratio of insoluble and soluble, i.e. 85 and 15 % respectively, existed in the black beans.

Perez-Hidalgo et al. (1997) reported a dietary fiber content of 26.3% for raw kidney beans. Further separation of the fiber showed that 78 % of the total fiber was insoluble fiber. Rosin et al. (2002) also supported the high insoluble fiber. They reported that brown beans had 28.1% total fiber of which 80% was insoluble fiber. Kutos et al. (2003) reported that pinto beans contained approximately 71% insoluble fiber and 25% soluble fiber. Resistant starch made up the remaining part of the total dietary fiber.

Chau et al. (1998) reported a fiber content of 13.5% in pink beans, of which 95 % was insoluble fiber. Fractionation of the bean shows that the hull contained 75% of the fiber. Rehinan et al. (2004) reported that red and white kidney beans fiber contents of 27.6 and 24.3%, respectively. Li and Zhao (1997) reported that dietary fiber polysaccharides (DFP) contents varied based on method used in the analysis. Navy beans had the highest DFP content whereas pink beans the lowest DFP content.

Tovar et al. (2003) determined the expected glycemic index of black beans was 44. This value was slightly higher than the expected glycemic index of 27 reported by Sayago-Ayerdi et al. (2005). Chung et al. (2008) reported expected glycemic index values of 12-12.2 for navy and light and dark kidney beans. They concluded that beans were a low glycemic food and that the resistant starch content was the like reason behind the low glycemic index of the beans.

Flours of navy beans had a resistant starch content of 32.4% followed by light red kidney beans (35.5%) and dark kidney beans (36%). Kutos et al. 2003 reported resistant starch levels of 46% in the insoluble fiber fraction. Campos-Vega et al. (2009) reported resistant starch levels of 28-32% in polysaccharide extracts of beans. Values reported on the extract and not on a bean weight basis will typically be in the 20-40% range. Other researchers have reported resistant starch levels in raw beans at values of 1.5 to 4% (Vargas-Torres et al. 2004a; Costa et al. 2006; Carmona-Garcia et al. 2007). Cooking of beans in general increases the resistant starch levels (Vargas-Torres et al. 2004b). Canned beans and precooked bean flours also have higher values of resistant starch compared to raw beans (Osorio-Diaz et al. 2002). Thus, data from previous research supports that beans are a good source of resistant starch and dietary fiber.

References
Anderson, J., Baird, P., Davis, R., Ferreri, S., Knudtson, M., Koraym, A., Waters, V., & Williams, C. (2009). Health benefits of dietary fiber. Nutrition Reviews, 67, 188-205.

 Asp, N. (1992). Resistant starch: Proceedings from the second plenary meeting of EURESTA. European Journal of Clinical Nutrition, 46, S1 (Supplement 2).

 Campos-Vega, R., Reynoso-Camacho, R., Pedraza-Aboytes, G., Acosta-Gallegos, J., Guzman-Maldonado, S., Paredes-Lopez, O., Oomah, B., & Loarca-Pina, G. (2009). Chemical composition and in vitro polysaccharide fermentation of different beans (Phaseolus vulgaris L.). Journal of  Food Science, 74(7), T59-T65.

Carmona-Garcia, R., Osorio-Diaz, P., Agama-Acevedo, E., Tovar, J., & Bello-Perez, L. (2007). Composition and effect of soaking on starch digestibility of Phaseolus vulgaris (L.) cv. ‘Mayocoba’.  International Journal of Food Science and Technology, 42, 296-302.

 Chau, C.F., Cheung, P.C.K., & Wong, Y.S. (1998). Chemical composition of three underutilized legume seeds grown in China. Food Chemistry, 61, 505-509.

 Chung, H., Liu, Q., Pauls, K.P., Fan, M., & Tada, R. (2008). In vitro starch digestibility, expected glycemic index and some physicochemical properties of starch and flour from common bean (Phaseolus vulgaris L.) varieties grown in Canada. Food Research International, 41, 869-875.

 Costa, G., Queiroz-Monici, K., Reis, S., & Oliveir, D. (2006). Chemical composition, dietary fibre and resistant starch contents of raw and cooked pea, common bean, chickpea and lentil legumes. Food Chemistry, 94, 327-330.

 Englyst, H., Kingman, S., & Cummings, J. (1992). Classification and measurement of nutritionally important starch fractions. European Journal of Clinical Nutrition, 46, S33-S50.

 Feregrino-Pérez, A., Berumen, L., García-Alcocer, G., Guevara-Gonzalez, R., Ramos-Gomez, M., Reynoso-Camacho, R., Acosta-Gallegos, J., & Loarca-Piña, G. (2008). Composition and chemopreventive effect of polysaccharides from common beans (Phaseolus vulgaris L.) on azoxymethane-induced colon cancer. Journal of Agricultural and Food Chemistry, 56, 8737-8744.

 Han, K.-H., Fukushima, M., Kato, T., Kojima, M., Ohba, K., Shimada, K., Sekikawa, M., & Nakano, M. (2003). Enzyme-resistant fractions of beans lowered serum cholesterol and increased sterol excretions and hepatic mRNA levels in rats. Lipids, 38, 919-924.

 Jones, J., Lineback, D., & Levine, M. (2006). Dietary reference intakes: implications for fiber labeling and consumption: A summary of the International Life Sciences Institute North American Fiber Workshop, June 1-2, 2004. Nutrition Reviews, 64, 31-38. 

 Kahlon, T.S., & Woodruff, C.L. (2002). In vitro binding of bile acids by soy protein, pinto beans, black beans and wheat gluten. Food Chemistry, 79, 425-429.

 Kutoš, T., Golob, T., Kac, M., & Plestenjak, A. (2003). Dietary fibre content of dry and processed beans. Food Chemistry, 80, 231-235.

 Lee, S., Prosky, L., & DeVries, J. (1992). Determination of total, soluble, and insoluble dietary fiber in foods: Enzymatic-gravimetric method, MES-TRIS buffer: collaborative study. Journal of AOAC International, 75, 395-416.

 Li, B.W. (1995). Comparison of three methods and two cooking times in the determination of total dietary fiber content of dried legumes. Journal of Food Composition and Analysis, 8, 27-31.

 Li, B.W., & Zhao, Z. (1997). Determination of starches and dietary fiber polysaccharides in cooked dried beans: Comparison of different temperatures and dimethyl sulfoxide treatments. Journal of Agricultural and Food Chemistry, 45, 2598-2601.

 Li, B.W., Andrews, K.W., & Pehrsson, P.R. (2002). Individual sugars, soluble and insoluble dietary fiber contents of 70 high consumption foods. Journal of Food Composition and Analysis,  15, 715-723.

 Osorio-Díaz, P., Bello-Pérez, L.,   Agama-Aceved, E.,  Vargas-Torres, A. Tovar, J,  & Paredes-López, O. (2002). In vitro digestibility and resistant starch content of some industrialized commercial beans (Phaseolus vulgaris L.). Food Chemistry, 78, 333-337. 

 Perez-Hidalgo, M.A., Guerra-Hernandez, E., & Garcia-Villanova, B. (1997). Dietary fiber in three raw legumes and processing effect on chick peas by an enzymatic-gravimetric method. Journal of Food Composition and Analysis, 10, 66-72.

 Rehinan, Z., Rashid, M., & Shah, W.H. (2004). Insoluble dietary fibre components of food legumes as affected by soaking and cooking processes. Food Chemistry, 85, 245-249.

 Rosin, P.M., Lajolo, F.M., & Menezes, E.W. (2002). Measurement and characterization of dietary starches. Journal of Food Composition and Analysis, 15, 367-377

 Tovar, J., Sáyago-Ayerdi, S., Peñalver, C., Paredes-López, O., & Bello-Pérez, L. (2003). In vitro starch hydrolysis index and predicted glycemic index of corn tortilla, black beans (Phaseolus vulgaris L.), and Mexican “taco”. Cereal Chemistry, 80, 533-535.

 Vargas-Torres, A., Osorio-Díaz, P., Tovar, J., Paredes-López, O., Ruales, J., & Bello-Pérez, L.  (2004a). Chemical composition, starch bioavailability and indigestible fraction of common beans (Phaseolus vulgaris L.). Starch/Stärke, 56, 74-78.

 Vargas-Torres, A., Osorio-Díaz, P., Islas-Hernández, J., Tovar, J., Paredes-López, O., & Bello-Pérez, L.  (2004b). Starch digestibility of five cooked black bean (Phaseolus vulgaris L.) varieties. Journal of Food Composition and Analysis, 17, 605-612.

Phytic acid

Phytic acid is the primary storage form of phosphorus in legumes. Until recently, phytic acid was solely considered as an antinutrient; however, recent studies have shown that phytic acid may play an important role in the prevention of cancers, heart disease, and diabetes (Harland and Morris, 1995; Jenab and Thompson, 2002; Shamsuddin, 2002; Phillippy, 2003).

Lu (1994) reported phytic acid levels between 1.1 to 1.5% for 11 navy bean cultivars. Growing location did not appear to dictate the composition of the phytic acid but instead cultivar played an important role. Tabekhia and Luh (1980) reported a phytic acid content of 1.17% for kidney beans. Pink beans phytic acid contents between 0.5 and 0.86% have been reported (Tabekhia and Luh, 1980; Chen, 2004). Pinto bean phytic acid levels between 0.84 and 1.22% have been reported. Oomah et al. (2008) reported phytic acid levels between 1.6 and 2.5%. They observed that navy beans contained the highest phytic acid while small reds had the lowest phytic acid level.

Most of the reported literature over estimates phytic acid. One reason for this is that traditional methods are all-inclusive, which means that the method measures all the phosphorus in the bean regardless of whether it comes from phytic acid. Newer methods can now measure phytic acid specifically. As a result, recent data (Figure 1) shows slightly lower phytic acid levels, which are more accurate indication of phytic acid levels.

Figure 1. Approximate phytic acid content (%) in various edible beans.

References
Chen, Q. (2004). Determination of phytic acid and inositol pentakisphosphates in foods by high-performance ion chromatography. Journal of Agricultural and Food Chemistry, 52, 4604-4613.

 Harland, B., & Morris, E. (1995). Phytate: A good or a bad food component. Nutrition Research, 15, 733–754.

 Jenab, M., & Thompson, I. (2002). Role of phytic acid in cancer and other diseases. In N. Reddy & S. Sathe (Eds.), Food phytates (pp. 225-248).  Boca Raton, FL: CRC Press.

 Lu, W. (1994). Searching for an early generation test to screen dry bean (Phaseolus vulgaris) breeding lines for improved cooking traits (master’s thesis). Department of Food and Nutrition, North Dakota State University. Fargo ND.

 Oomah, B., Blanchard, C., & Balasubramanian, P. (2008). Phytic acid, phytase, minerals, and antioxidant activity in Canadian dry bean (Phaseolus vulgaris L.) cultivars. Journal of Agricultural and Food Chemistry, 56, 11312-11319.

 Phillippy, B. Q. (2003). Inositol phosphates in foods. Advances in Food and Nutrition Research, 45, 1-60.

 Shamsuddin, A. (2002). Anti-cancer function of phytic acid. International Journal of Food Science and Technology, 37, 769-782.

 Tabekhia, M.M., and Luh, B.S. (1980). Effect of germination, cooking and canning on phosphorus and phytate retention in dry beans. Journal of Food Science, 45, 406-408

 Phenolic Compounds

Phenolic compounds are often responsible for the color of beans and are generally thought to be good antioxidants. However, from the plant perspective, the phenolic compounds act as a deterrent to pests due to the bitter nature of these compounds. For most individuals, the levels of phenolic compounds in beans are not high enough to give a bitter sensation, but can be a good source of phenolic antioxidants. Antioxidants, including those of beans, are thought to contribute to reduction of chronic diseases such as cardiovascular disease, cancers and diabetes (Cardador-Martinez et al., 2002; Aparicio-Fernandez et al. 2005). Phenolic compounds are generally grouped into two broad categories that include polyphenolics and phenolic acids. Polyphenolics for example include tannins, anthocyanins and flavonols.

Wu et al. (2004) reported on the total phenolic content of well over 50 food products. Total phenolic content was based on gallic acid equivalence and thus represents most of the phenolic compounds in food. Pinto, black, red kidney, and small red beans all had significantly higher  total phenolic contents, 10.23, 8.80, 12.47, and 11.85 mg gallic acid equivalence / g beans, respectively, than other foods. All these beans score very high on the oxygen radical scavenging absorbance (ORAC) assay suggesting the potential to be very good in vivo antioxidants. Oomah et al. (2005), Xu et al. (2007), and Xu and Chang (2009) further supported the antioxidant activity of beans using the ORAC test and other antioxidant testing methods.

The total phenolic content determined by other researchers might explain the observed antioxidant activity. Oomah et al. (2005) reported total phenolic contents in black, cranberry, dark red kidney, light red kidney, navy, and pinto beans of 3.28, 8.50, 16.61, 8.01, 3.62, 7.53 mg catechin equivalence / g beans, respectively. Towo et al. (2003) reported that the total phenolic content in kidney beans was 3.2 to 5.6 mg catechin equivalence / g beans. Xu et al. (2007) also determined total phenolic contents for black turtle, navy, pinto, red kidney, pink, and small red beans were 3.37, 0.57, 3.76, 4.05, 3.77 and 5.76 mg gallic acid equivalence / g beans, respectively. Thus, the range in total phenolic content of 3 to 17 mg/g bean can be expected using total phenolic content protocols.

Table 1. Anthocyanidin content in the seed coat of kidney beans. (Adapted from Choung et al. 2003).Anthocyanidin Content (mg/g bean)
Seed Color	cyanidin 3,5-diglucoside	delphinidin glucoside	cyandin 3-glucoside	petunidin 3- glucoside	pelargonidin 3-glucoside	Total
Red	0.04	0.05	0.09	0.00	0.37	0.55
Black	0.00	2.32	0.00	0.14	0.00	2.46
Brown	0.01	0.01	0.02	0.00	0.04	0.09
White	0.00	0.00	0.00	0.00	0.00	0.00

Tannin contents of 2.2 and 4.6 mg catechin / g cotyledon or whole seed, respectively, have been reported. The light colored beans had the greatest phenolic content whereas the brown beans had the greatest tannin content. Xu et al. (2007) reported tannin contents for black turtle, navy, pinto, red kidney, pink, and small red beans were 4.09, 0.47, 3.23, 2.87, 3.55 and 5.16 mg catechin equivalence / g beans, respectively.

Choung et al (2003) reported a number of anthocyanidins in kidney beans (Table 1). These values are representative of other researchers. Tsuda et al. (1994) found that delphinidin-3-O-β-D-glucoside, petunidin-O-β-D-glucoside, and malvidin-3-O-β-D-glucoside accounted for 56, 26, and 18%, respectively, of the anthocyanins in black bean and were responsible for the black color. The delphinidin-3-glucoside, petunidin-glucoside, malvidin-3,5-diglucoside, malvidin-3-galactoside and malvidin-3-glucoside contents of 2.2, 0.8, 0.5, 0.03, and 0.4 mg/g black bean were reported by Xu and Chang (2009). Pelargonidin 3-glucoside was the major anthocyanin in red kidney beans (Choung et al. 2003) and is responsible for the red pigmentation of this type of kidney bean.

Phenolic acid compounds are general free and bound or conjugated phenolic acid groups. Recently, Xu and Chang (2009) reported the phenolic acids in pinto and black beans varied depending on bean type. In general, pinto beans contained higher total phenolic acids than black beans. The free phenolic acids account for approximately 10 to 60% of the total phenolic acids, with the remaining being in the bound or conjugated form. Pinto beans contained approximately 1.5 mg/g bean and 0.9 mg/g bean of free and conjugated phenolic acids, respectively (Xu and Chang, 2009). Black beans contained approximately 0.61 mg/g bean and 0.63 mg/g bean of free and conjugated phenolic acids, respectively (Xu and Chang, 2009).

Tsuda et al. (1994) assessed the antioxidant of white, red and black bean seeds (Phaseolus vulgaris L.) and found that the seed coat and germ of the white varieties had no antioxidant activity. In contrast, the red and black seed coats had good antioxidant activity. This observation was later confirmed by Chou et al. (2003) who reported that a 50% ethanol extract of red beans had very good antioxidant activity and Wu et al. (2004) who found that red beans had very good in vivo antioxidant activity. Oomah et al. (2005) reported that dark red kidney beans had the highest antioxidant activity while navy beans had the lowest. However, the antiradical activity of the kidney bean low compared to other beans. Beans such as black, cranberry, and pinto had good antioxidant and antiradical activity (Oomah et al. (2005). These observations suggest that the colored beans have greater antioxidant and antiradical properties than less colored beans.

Numerous studies have demonstrated the antioxidant activity of phenolic compounds. Oomah et al. (2005) reported that total phenolic content was the best indicator of the antioxidant activity of bean phenolics. They calculated that 40-71% of the antiradical activity could be explained by total phenolics and that flavonols were responsible for 20-39% of the antioxidant activity depending on bean type. Boateng et al. (2008) reported a high correlation between total phenolic content of beans and ferric reducing antioxidant potential. Xu and Chang (2009) also reported that specific phenolic compounds correlated highly with antioxidant test such as ORAC and ferric reducing antioxidant potential. They specifically identified phenolic acids and flavonols as being important compounds for the antioxidant activity of pinto beans phenolics. The flavan-3-ols and flavonols were identified as the key phenolic compounds responsible for antioxidant activity in black beans.

References
Aparicio-Fernandez, X., Manzo-Bonilla, L., & Loarca-Pina, G. (2005). Comparison of antimutagenic activity of phenolic compounds in newly harvested and stored common beans Phaseolus vulgaris against aflatoxin B1. Journal of Food Science, 70, S73-S78.

 Boateng, J., Verghese, M., Walker, L., & Ogutu, S. (2008). Effect of processing on antioxidant contents in selected dry beans (Phaseolus spp. L.). LWT-Food Science and Technology, 41, 1541-1547.

 Cardador-Martinez, A., Castano-Tostado, E., & Loarca-Pina, G. (2002). Antimutagenic activity of natural phenolic compounds present in the common bean (Phaseolus vulgaris) against aflatoxin B-1. Food Additives & Contaminants, 19, 62-69.

 Chou, S.T., Chao, W.W., & Chung, Y.C. (2003). Antioxidative activity and safety of 50% ethanolic red bean extract (Phaseolus radiatus L. var. Aurea). Journal of Food Science, 68(1), 21-25.

 Choung,  M., Choi,  B., An, Y., Chu, Y., & Cho, Y. (2003). Anthocyanin profile of Korean cultivated kidney bean (Phaseolus vulgaris L.). Journal of Agricultural and Food Chemistry, 51, 7040-7043.

 Oomah, B., Cardador-Martinez, A., & Loarca-Pina, G. (2005). Phenolics and antioxidative activities in common beans (Phaseolus vulgaris L.). Journal of the Science of Food and Agriculture, 85, 935-942.

 Towo, E.E., Svanberg, U., & Ndossi, G.D. (2003). Effect of grain pre-treatment on different extractable phenolic groups in cereals and legumes commonly consumed in Tanzania. Journal of the Science of Food and Agriculture, 83, 980-986.

 Tsuda, T., Ohshima, K., Kawakishi, S., & Osawa T (1994). Antioxidative pigments isolated from seeds of phaseolus vulgaris L. Journal of Agricultural and Food Chemistry, 42, 248-251.

 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. Journal of Agricultural and Food Chemistry, 52, 4026-4037.

 Xu, B., & Chang, S. (2009). Total phenolic, phenolic acid, anthocyanin, flavan-3-ol, and flavonol profiles and antioxidant properties of pinto and black beans (Phaseolus vulgaris L.) as affected by thermal processing. Journal of Agricultural and Food Chemistry, 57, 4754-4764. 

 Xu, B., Yuan, S., & Chang, S. (2007). Comparative analysis of phenolic composition, antioxidant capacity, and color of cool season legumes and other selected food legumes. Journal of Food Science, 72,  S167-S177.