BIODIVERSITAS ISSN: 1412-033X Volume 22, Number 8, August 2021 E-ISSN: 2085-4722 Pages: 3430-3439 DOI: 10.13057/biodiv/d220840 Composition, structure, and physicochemical characteristics of pigeon pea (Cajanus cajan) starches from Indonesia NUR ROHMAH LUFTI A’YUNI 1,2 , YUSTINUS MARSONO 1 , DJAGAL WISESO MARSENO 1 , PRIYANTO TRIWITONO 1, 1 Department of Food and Agricultural Product Technology, Faculty of Agricultural Technology, Universitas Gadjah Mada. Jl. Flora No. 1, Bulaksumur, Sleman, Yogyakarta 55281, Indonesia. Tel./fax.: +62-274-589797,  email: triwitono@ugm.ac.id 2 Politeknik Pembangunan Pertanian Yogyakarta-Magelang. Jl. Kusumanegara No. 2, Umbulharjo, Yogyakarta 55167, Indonesia Manuscript received: 26 March 2021. Revision accepted: 25 July 2021. Abstract. A’yuni NRL, Marsono Y, Marseno DW, Triwitoyo P. 2021. Composition, structure, and physicochemical characteristics of pigeon pea (Cajanus cajan) starches from Indonesia. Biodiversitas 22: 3430-3439. Information on the characteristics of pigeon pea (Cajanus cajan (L.) Millsp.) starch would provide a scientific basis for developing its application. However, data about characteristics of pigeon pea starch, especially from the Southeast Asia region, has been limited. This study determined the composition, structure, and physicochemical characteristics of pigeon pea starches from three different Indonesian regions, i.e., Bali, Yogyakarta, and West Nusa Tenggara (NTB). We also investigated the potential application of Indonesian pigeon pea starches. Pigeon pea starch was extracted using a wet method, and then pigeon pea starch was characterized. The yield of pigeon pea starches ranged from 29.83-31.68%. Pigeon pea starches showed a significant difference (P<0.05) in amylose content (54.74-58.51%), relative crystallinity (24.20-28.97%), water- binding capacity (0.70-0.76 g/g), oil binding capacity (0.55-0.58 g/g), swelling power (13.19-14.52 g/g), and solubility (9.48-11.15%). The pasting properties (except for final viscosity) and thermal properties (except for onset temperature and gelatinization enthalpy) differed significantly. Granules of pigeon pea starch were oval to elliptical, with a mean granule diameter of 18.41-19.98 μm. According to X-ray diffraction patterns, pigeon pea starches showed CA type, contained orthorhombic and hexagonal crystals. Pigeon pea starches also showed the same FTIR spectra. The results revealed that the differences in pigeon pea growing locations affect pigeon pea starch's composition and physicochemical properties. The highest amylose content and lowest relative crystallinity were found in Yogyakarta pigeon pea starch. In the future, our findings could be used to develop pigeon pea starch for various food applications. Keywords: Microstructure, physicochemical, pigeon pea, starch INTRODUCTION Starch is a complex microparticle consisting of two primary components, amylose and amylopectin, usually accompanied by water, lipids, phospholipids, soluble and insoluble fiber, and some minerals (Rodriguez-Garcia et al. 2021). Starch is a renewable substance with some biological properties like biocompatibility, nontoxicity, and biodegradability. Because of these starch properties, starch can be used in various industrial sectors, including tissue engineering, medicine, and food processing, such as confectionery, sauces, restructured meat products, puddings, and low-fat products (Chen et al. 2015; Wani et al. 2016). The global starch market is projected to reach US$ 75.4 billion in 2022, from a prediction of US$ 53 billion in 2016. Therefore, a new starch source is required (Acevedo et al. 2019). Legumes with a 25 to 50 % starch content are a potential source of starch (Alcázar-Alay and Meireles 2015). Legume starch contains more amylose, dietary fiber, and resistant starch than cereal and pseudocereal starches (Nissar et al. 2017). Therefore, further research on legume starches is required to develop food and non-food applications (Lima et al. 2017). Pigeon pea (Cajanus cajan (L.) Millsp.) is a legume that provides a starch source. Pigeon pea is widely grown in both tropical and subtropical areas worldwide (Lawal 2011). Pigeon pea has a starch content of 57.5% (Tayade et al. 2019) and a starch yield of 29.7-49.3% (Hoover et al. 2010). Previous studies on pigeon pea starch physicochemical characteristics have been conducted using pigeon pea from India (Hoover et al. 1993; Kaur and Sandhu 2010; Narina et al. 2014) and Argentina (Acevedo et al. 2019). Kaur and Sandhu (2010) reported that pigeon pea starch had a low hydrolysis index and high resistant starch, indicating that it was highly resistant to digestion. Acevedo et al. (2019) reported that pigeon pea starch is a potent starch source to provide tailor-made properties to food and industrial applications because of its high gel stability and amylose content. Research on pigeon pea starch from the Southeast Asia region has been limited. Previous studies had only focused on the characterization of various pigeon pea starch varieties. Therefore, there is a shortage of data on pigeon pea starch's composition, structure, and physicochemical characteristics from different growing locations. Differences in the environment (soil type, temperature, atmospheric composition, and meteorological factors) where plants grow can affect the biosynthesis and starch properties (Hood-Niefer et al. 2012; Beckles and Thitisaksakul 2014). Research on the physical and microscopic characteristics of pigeon pea starch from Indonesia has been performed by Widowati and Buckle (1991).