1277 Research Article Received: 28 November 2008 Revised: 26 February 2009 Accepted: 28 February 2009 Published online in Wiley Interscience: 6 April 2009 (www.interscience.wiley.com) DOI 10.1002/jsfa.3583 Physicochemical and functional properties of ten cultivars of seem (Lablab purpureus L.), an underexploited bean in Bangladesh Md Golam Mortuza a,b and Jason TC Tzen a* Abstract BACKGROUND: Increasing global protein consumption has led to the demand for new sources of food protein, particularly plant sources. Many inexpensive but protein-rich bean cultivars have not been well evaluated and are thus underutilised. In this study the physicochemical and functional properties of seeds of ten seem cultivars were assessed. RESULTS: In agreement with their sizes, seeds of Airet had the highest 1000-seed weight and volume, while those of Bari had the lowest. In terms of proximate composition (g kg -1 ), protein content ranged from 240.08 (Ashina) to 292.63 (Puti), fat content from 31.47 (Goalgadda) to 38.40 (Puti), ash content from 32.80 (Puli) to 45.53 (Goalgadda) and fibre content from 21.90 (Tatulia) to 28.90 (Noldog). Hydration (g kg -1 ) and swelling (mL L -1 ) capacities ranged from 1688.60 and 1850.43 (Goalgadda) to 1999.40 and 2208.66 (Rupbhan) respectively. Similarly, cooking time (min) varied from 114 (Rupbhan) to 179 (Goalgadda). Lowest gelation concentration was in the range 80–100 g kg -1 . Water and fat absorption capacities (g kg -1 ) ranged from 941.00 and 644.44 (Ashina) to 1043.33 and 749.26 (Puti) respectively. Foaming capacity and stability (mL L -1 ) ranged from 443 (Puli) to 635 (Puti) and from 314 (Ashina) to 643 (Rupbhan) respectively. CONCLUSION: Seeds of seem cultivars appear to be a promising food in terms of their protein content and functionality. c  2009 Society of Chemical Industry Keywords: seem; legumes; proximate composition; physicochemical properties; functional properties INTRODUCTION Legumes, especially pulses and beans, are important and inexpensive protein sources in the diet of Bangladesh and many other developing countries, 1 where they are called ‘poor man’s meat’. 2 Higher prices of meat and fish and the increasing need for protein-rich foods in Bangladesh have resulted in greater demand for legumes, especially pulses. 3 The conventional pulses grown in Bangladesh, lentil (Lens culinaris), grass pea (Lathyrus sativus), field pea (Pisum sativum), black gram (Vigna mungo) and green gram (Vigna radiata), can supply only a fraction of the requirement of protein for a large segment of the growing population. In this context, beans can offer a way to bridge the problem and play a crucial role in narrowing the protein deficiency gap in Bangladesh. Beans exist as a wide range of cultivars that are suited to a variety of climates and hence are economically and nutritionally important in some specific regions of the world. One such example in Bangladesh is that of an underexploited country bean, Lablab purpureus L. (previously known as Dolichos lablab L.), which is valued for its nutritional and sensory attributes. Believed to have originated in Asia, this bean has been taken to Africa and many other tropical countries. 4,5 Consequently, it is known by several other names, such as lablab bean (Australia), tonga bean (UK), lubia (Sudan), batao (Philippines), hyacinth bean (Brazil), frijol jacinto (Colombia), caroata chwata (Venezuela), poroto de Egipto (Argentina), dolique d’Egypte (France), fiwi bean (Zambia), frijol caballo (Puerto Rico), gallinita (Mexico), frijol de adorno (El Salvador) and val (India), to name but a few. However, in Bangladesh it is popularly known as Deshi seem or simply seem. Seem in Bangladesh is an important annual as well as perennial leguminous vegetable with a twining, creeping or bushy habit. Its cultivation is so widespread that it would be almost impossible to find a house in rural areas which lacks a bush of seem in the winter. In recent years, seem has become very popular and is now grown on a significant acreage. 6 Seem is used in various ways: young fresh pods are served as vegetables, while mature seeds are eaten directly after frying. It is also used as dhal (soup) and as a main ingredient of curry in some areas, especially in the southeastern part of the country. Dry seeds that are not suitable for human food in terms of quality and standards are generally used as feed for livestock. Postharvest plant remains are also used as feed for domesticated animals. 7 Therefore, because of the widespread uses of seem, it could play an important role in protein supplementation and crop diversification in Bangladesh. In recent years, because ∗ Correspondence to: Jason TC Tzen, Graduate Institute of Biotechnology, National Chung-Hsing University, Taichung, Taiwan. E-mail: TCTZEN@dragon.nchu.edu.tw a Graduate Institute of Biotechnology, National Chung-Hsing University, Taichung, Taiwan b Department of Biochemistry, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh J Sci Food Agric 2009; 89: 1277–1283 www.soci.org c  2009 Society of Chemical Industry