Physical characteristics, nutrients, and antinutrients composition of pigeon pea (Cajanus cajan (L.) Millsp.) grown in Indonesia

Pigeon pea is an underutilized legume in Indonesia. Information about the physical characteristics, nutrients, and antinutrients composition of pigeon pea is needed to develop pigeon pea-based food products. This research aimed to evaluate the physical characteristics, nutrients, and antinutrients composition of pigeon pea grown in different regions of Indonesia, i.e., Bali, Yogyakarta, and Nusa Tenggara Barat (NTB). The results showed that the physical characteristics, nutrients, and antinutrients composition differed significantly. The weight of pigeon pea seeds ranged from 7.49-13.29 g/100 seeds, hydration capacity was 0.07-0.15 g/seed, hydration index was 0.90-1.14, swelling capacity varied from 0.06-0.15 mL/seed, and the swelling index was 1.06-1.54. Pigeon pea was a potential source of protein (23.96-24.20%) and starch (40.55-42.80%). The highest protein content was found in pigeon pea from Yogyakarta, whereas the highest starch content was found in pigeon pea from NTB. The contents of vitamin C, E, A varied from 25.13-28.21 mg/100 g, 67.44-100.51 mg/100 g, and 1,248.83-2,303.86 μg/100 g, respectively. Potassium was the most abundant mineral in pigeon pea (479.66-1.455.51 mg/100 g). Pigeon pea from Yogyakarta had the highest phytic acid content, HCN, tannins at 841.24 ppm, 46.60 ppm, and 378.45 mg/100 g, respectively.


Introduction
Leguminosae is the family of a flowering plant comprising 650 to 750 genera and 18,000 to 19,000 species. This family is widely known as legumes, which are classified into four subfamilies: Caesalpinioideae, Mimosoideae, Papilionoideae, and Swartzioideade (Ahmed and Hasan, 2014). Legumes contain 20-40% protein, 50-60% carbohydrate with starch as the main component, 2-3% fat, 0.7-6.2% dietary fibre, vitamins, and minerals (Wani et al., 2016). Legumes also have a low glycemic index value and bioactive compounds with antioxidant properties, so legumes can be a source of functional food (Tayade et al., 2019). Narina et al. (2014) and Souza et al. (2015) reported that legumes could affect health positively, such as a supplement for diabetes mellitus patients, preventing cardiovascular risk, obesity, and bone disorder. Legumes are typically used as a cereal substitute to increase their finished product's nutrient composition and functional impact (Olagunju et al., 2018). Therefore, legumes can be an alternative to meet nutritional needs and fight several diseases, especially in developing countries. The developed countries face an increasing demand for protein food sources because of the growing population, inadequate fertile soil, cereal diet, and high food prices (Sharma et al., 2011;Narina et al., 2014;Moussou et al., 2019).
Various countries have used legumes as their primary food sources, such as pigeon pea, chickpea, and lentils in South Asia, kidney beans in Latin America, chickpea, lentils, faba beans in North Africa, and the Middle East (Ahmed and Hasan, 2014). In Indonesia, legumes utilization is still limited to soybean, red kidney bean, and mung bean. On the other hand, Indonesia has various legumes that Indonesian people have not utilized optimally, one of which is pigeon pea. Pigeon pea (Cajanus cajan (L.) Millsp.), including the Fabaceae family. Pigeon pea is an annual crop with more drought and high-temperature tolerance than other crops, allowing it to be grown in tropical and subtropical areas. The plant height is about 1-4 meters and has 2 meters of deep taproot (Akande et al., 2010;Al-Saeedi and Hossain, 2015). Pigeon pea pods are flat, dark purple, or Information about legume's physical characteristics is useful for processing, storing, and designing processing machinery (Khanbarad et al., 2014). The seed weight and hydration capacity of legumes are linked to the cooking process (Yadav et al., 2018). Legumes with a higher hydration capacity require less cooking time, affecting consumer preference for the seeds (Moussou et al., 2019). The shape and size of legume seeds are significant in designing the machines for sizing and grading (Firatligil-Durmuş et al., 2010). Information about nutrients composition is crucial for the dietary quality assessment, offering a valuable tool for the sector of public health nutrition, development, and implementation of food-based dietary standards (Elmadfa and Meyer, 2010). Some researchers evaluated the nutrients composition of pigeon pea from Botswana (Amarteifio et al., 2002) and Nigeria (Oshodi et al., 1993;Apata and Ologhobo, 1994;Akande et al., 2010). Some researchers also reported the physical characteristics of pigeon pea from India (Khanbarad et al., 2014;Khan et al., 2017), Botswana (Baryeh and Mangope, 2003), but there is no information yet about hydration capacity, swelling capacity, hydration index, and swelling index of pigeon pea seeds. There has been no research on the physical characteristics, nutrients, and antinutrients composition of pigeon pea from several regions in Indonesia to the author's knowledge. This research aimed to evaluate the physical characteristics, nutrients, and antinutrients composition of pigeon pea grown in various regions of Indonesia, i.e., Bali, Yogyakarta, and Nusa Tenggara Barat.

Materials
Pigeon pea seeds were obtained from local farmers in Buleleng Bali, Gunungkidul Yogyakarta, and Lombok Timur Nusa Tenggara Barat (NTB). Pigeon pea seeds were harvested in April-May 2019 (Yogyakarta and NTB) and June 2019 (Bali). For analysis of the nutrients and antinutrients contents, the pigeon pea seeds were ground using a blender (Philips) to become a powder until passing through a sieve no. 40. The pigeon pea powders were packed in aluminium foil packaging with silica gel and then placed in a container at ambient temperature until it was analysed.

Seed weight, volume, density, and dimensions
Seed weight, volume, and density were determined based on Williams et al. (1983). Pigeon pea seeds (100 seeds) were weighed on analytical scales. After that, seeds were moved to a 50 mL measuring cylinder containing 25 mL of distilled water. The difference in distilled water volume after and before the seeds was put into the measuring cylinder is the volume of seeds. Seed density was determined by dividing seed weight by its volume (g/mL). The seed dimensions (length, width, and thickness) were determined using a calliper with a count of at least 0.02 mm.

Hydration capacity and hydration index
Determination of hydration capacity and hydration index based on Williams et al. (1983). The seeds of pigeon pea (100 seeds) were weighed and placed into a beaker glass together with distilled water (100 mL). The beaker glass was enclosed with aluminium foil then left for 24 hrs at ambient temperature. The next day, the seeds were drained, redundant water was separated with filter paper, and the swollen seeds were weighed again. Hydration capacity and hydration index were calculated as follows: Hydration capacity per seed = (weight of seed afterbefore soaking)/100 Hydration index = hydration capacity per seed/average weight of seed

Swelling capacity and swelling index
Determination of swelling capacity and swelling index refers to Williams et al. (1983). After re-weighing the swollen seeds, they were put in a 100 mL measuring cylinder containing 50 mL of distilled water. Their volume was measured again to determine swelling capacity and swelling index, accordingly to this equation: Swelling capacity per seed = (volume of seed afterbefore soaking)/100 Swelling index = swelling capacity per seed/average volume of seed

Proximate composition, starch content, and gross energy
Proximate analysis (moisture, ash, fat, protein) was conducted using the AOAC method (1995). The moisture content was measured by drying the sample in an oven (105°C) until the sample weight was constant. The crude fat content was measured by extracting the sample with petroleum ether in an extractor of Soxhlet. The crude protein content was measured using the Kjeldahl method; then, the crude protein content was calculated by multiplying nitrogen content by 6.25. The ash content was measured using the gravimetric method by comparing the sample weight before and after ashing in the furnace. Carbohydrate by difference was calculated by 100 -(moisture% + fat% + ash% + protein%). The direct acid hydrolysis method was used to determine starch content, followed by the determination of glucose using a conversion factor of 0.9 (AOAC, 1995). The gross energy was measured using a bomb calorimeter (Gallenkamp auto bomb calorimeter), and benzoic acid was used as a calibration standard (Moussou et al., 2019).

Crude fibre content
Crude fibre analysis was performed using the AOAC method (1995). A gram (1 g) of the fat-free sample was added to 200 mL of 1.25% H 2 SO 4 . The suspension was heated at 100°C for 30 mins while being stirred. The suspension was filtered with filter paper then washed using hot distilled water until neutral. The residue was transferred quantitatively into the Erlenmeyer, and then the rest was washed with 200 mL of 1.25% NaOH until all residues entered the Erlenmeyer. The residue was heated in a water bath for 30 minutes at 100°C while being stirred, then filtered using filter paper with a constant weight (a). The residue was washed using 15 mL of 96% ethanol then washed with hot distilled water up to neutral. The residue in the filter paper was dried at 100 °C until it reached a constant weight (b). Crude fibre content was calculated as follow:

Minerals content
Determination of minerals content (Ca, Mg, Zn, Cu, K, and Na) was adopted from the AOAC method (1995). Sample preparation for minerals content analysis used the wet digestion method. The sample was digested using concentrated HNO 3 (1:3) then heated until the solution becomes clear and a dense white fume appeared. The sample was cooled, diluted with 50 mL of distilled water then filtered using Whatman filter paper. The filtrates were collected in a 100 mL volumetric flask, and the volume was adjusted with distilled water. The resulting solution was then measured for its absorbance using atomic absorption spectrophotometry (Perkin-Elmer 3110). The content of phosphorus was measured using a molybdovanadate method (AOAC, 1995). The digested sample (1 mL) was placed into a volumetric flask (10 mL), then 3 mL of vanadate-molybdate solution was added, followed by distilled water up to the mark. The solution was vortexed and then read its absorbance at 410 nm. For determination of iron content, 1 mL of digested sample was put in a 10 mL volumetric flask, followed by 2 mL of 1.5 M ammonium thiocyanate and distilled water up to the mark. Its absorbance was determined at 510 nm, and the iron content was determined from the Fe standard curve (Woods and Mellon, 1941).

Vitamin A content
Vitamin A content was determined as β carotene using the spectrophotometry method (AOAC, 1995). Sample (5 g) was extracted using petroleum ether and acetone (1:1). The extract was separated from the solvent using a separating funnel by adding distilled water. The top layer, which is the carotene fraction, was added with Na 2 SO 4 anhydrate to absorb the remaining distilled water, added petroleum ether up to a volume of 25 mL, then the absorbance was determined at 450 nm and used β carotene as a standard.

Vitamin C content
Vitamin C content was determined using the iodine titration method (Jacobs, 1962). The sample was placed into a 100 mL volumetric flask, and distilled water was added up to the mark, then the filtrate was filtered to separate it. The filtrate (5 mL) was placed into Erlenmeyer, added 2 mL of 1 % amylum and 20 mL of distilled water, then titrated with 0.01 N iodine standard. Calculation of vitamin C content was determined by standardizing iodine solution, in which the equivalent of 1 mL of 0.01 N iodine is 0.88 mg of ascorbic acid.

Vitamin E content
Vitamin E content was determined as the total tocopherol (AOAC, 1988). The sample (1 g) was dissolved using N-hexane. An aliquot (1 mL) of sample solution was taken, then added 3.5 mL of 0.07% 2.2 bipyridine solution and 0.5 mL of 0.02% FeCl 3 . The solution was diluted to 10 mL using 96% ethanol, and eISSN: 2550-2166 © 2022 The Authors. Published by Rynnye Lyan Resources FULL PAPER then the absorbance was determined at 520 nm and used tocopherol as a standard.

Phytic acid content
The content of phytic acid was determined based on Wheeler and Ferrel method (1971). The sample (2 g) was extracted with 50 mL of 3% TCA for 30 mins, then centrifuged. The supernatant was separated, then 10 mL was taken and put into a centrifuge tube and added with 4 mL of FeCl 3 solution, then boiled in a water bath for 45 mins. The aliquot was centrifuged, and the supernatant was separated. The precipitate was washed twice using 20-25 mL of 3% TCA, boiled in a water bath for 10-15 mins, centrifuged again, and the supernatant was separated. The precipitate was washed once with distilled water, centrifuged for 10-15 mins, and the supernatant was separated. The precipitate was dispersed with distilled water and 3 mL of 1.5 N NaOH. The precipitate was diluted to 30 mL and boiled in a water bath for 30 mins, then filtered. The precipitate was dissolved in hot HNO 3 then diluted to 100 mL. An aliquot (5 mL) was put into the 100 mL volumetric flask, followed by 60 mL of distilled water, 20 mL of 1.5 M KSCN, and diluted to the mark. The solution was read for absorbance at 480 nm. The phytic acid can be determined based on Fe's calculation from the standard curve with the molecular ratio of Fe:P = 4:6.

Tannins content
Tannins content was determined by Folin Denis colourimetric method (Harborne, 1973). Sample (5 g) was put into a 100 mL volumetric flask, then distilled water was added to the mark. The mixture was shaken until homogenous, then was filtered to obtain the extract. Put 1 mL of extract, 0.5 mL of Folin Denis reagent, 1 mL of saturated NaCO 3 , and distilled water until the volume reached 10 mL. The mixture was vortexed, then its absorbance was determined at 730 nm, and pure tannic acid was used as a standard. The tannins content was determined using the linear regression equation, expressed in mg/100 g from the standard curve.

Hydrogen Cyanide (HCN) content
The HCN content was determined using the alkaline picrate method (Williams and Edwards, 1980). Sample (5 g) was added with distilled water (50 mL). The mixture was shaken and filtered to obtain the extract. The extract (1 mL) was added with 4 mL of alkaline picrate solution; then, this was incubated in a water bath until it formed reddish-brown colour. The solution was determined for its absorbance at 480 nm and used potassium cyanide (KCN) as a standard. The HCN content was quantified based on the linear regression equation from the standard curve, and the result was given as ppm.

Statistical analysis
Data analysis used a one-way Analysis of Variance (ANOVA) with a significant level of 5%. If a significant difference were identified, the Duncan Multiple Range (DMRT) test would then proceed. SPSS software version 23 for statistical analysis.

Physical characteristics
The physical characteristics of pigeon pea seeds are presented in Table 1. The Indonesian pigeon pea dimensions were almost the same as pigeon pea from India and Botswana. Pigeon pea from India had length 5.37-6.24 mm, width 4.97-5.67 mm, and thickness 4.06-4.60 mm (Khanbarad et al., 2014), while pigeon pea from Botswana had length 5.074-6.502 mm and thickness 3.365-5.091 mm (Baryeh and Mangope, 2003). The dimensions of pigeon pea from Indonesia ranged from 5.07-5.99 mm (length), 4.83-5.58 mm (width), and 4.07-5.05 mm (thickness). The weight and volume of 100 seeds ranged from 7.49-13.29 g and 6.00-9.83 mL, respectively. Based on this result, pigeon pea seeds from Bali had the largest dimensions, weight, and volume, while the pigeon pea from Yogyakarta was the opposite. This difference due to the volume depends on the seed dimensions consisting of length, width, and thickness, so that the bigger the dimensions, the larger the volume (Khanbarad et al., 2014). The density ranged from 1.25-1.35 g/mL, with pigeon pea from Bali, having the highest density and pigeon pea from Yogyakarta having the lowest. The pigeon pea density was greater than water, which shows that pigeon pea seeds will not float on the water during cleaning (Ghadge and Prasad, 2012).
Pigeon pea seed colour was not significantly different for a* (0.76-0.95) and b* (1.52-2.15) values. Based on the L value (30.70-31.64), pigeon pea seed colour tends to be dark. The colour difference can indicate the number of antinutrient compounds in pigeon pea seeds. Antinutrient compounds primarily present in the dark seed genotypes commonly grow in Asia, different from the African pigeon pea has a cream or white colour, with fewer antinutrient compounds (Odeny, 2007). In this research, pigeon pea from Bali had the lowest antinutrient content, and the colour of pigeon pea seeds from Bali tends to be lighter than other pigeon pea seeds.
Pigeon pea seeds had the hydration index, swelling index, hydration capacity, and swelling capacity ranged from 0.90-1.14, 1.06-1.54, 0.07-0.15 g/seed, and 0.06-0.15 mL/seed, respectively. Pigeon pea seeds from Bali eISSN: 2550-2166 © 2022 The Authors. Published by Rynnye Lyan Resources FULL PAPER had the highest swelling capacity, swelling index, hydration capacity, and hydration index; therefore, it requires less cooking duration than other pigeon pea seeds (Bishnoi and Khetarpaul, 1993). These parameters indicated that pigeon pea seeds from Bali have the most permeable and soft seed coat than the other seeds (Seena and Sridhar, 2005). Pigeon pea seeds from Yogyakarta had the lowest hydration index, swelling index, hydration capacity, and swelling capacity. These parameters showed that pigeon pea seeds from Yogyakarta have a low water absorption capacity, which is influenced by the composition of the seed, cell wall structure, and compactness of the seed cells (Kaur et al., 2005). Pigeon pea from Yogyakarta had the highest crude fibre content of 5.50% (Table 2), causing the thicker coat seed, thus inhibiting water absorption. A similar result was reported on chickpea (Kaur et al., 2005). Pigeon pea from Yogyakarta also had the highest tannins content of 378.45 mg/100 g (Table 4). Tannins can bind to proteins in cell walls and the middle lamella, causing lignification, increasing the cell wall thickness (Yousif et al., 2003).

Proximate composition, starch content, and gross energy
The nutrient composition of pigeon pea seeds from different regions is shown in Table 2. According to these data, the biochemical composition of Indonesian pigeon pea was substantially different. In this report, all pigeon pea seeds are protein and starch sources. The pigeon pea protein content ranged from 23.96-24.20%, with pigeon pea from Yogyakarta, having the highest protein content. Pigeon pea protein content from Indonesia was higher than pigeon pea from Nigeria of 21.03% (Akande et al., 2010) and Botswana of 19.0-21.7% (Amarteifio et al., 2002). It showed that pigeon pea protein content could be affected by variations in growing locations. According to Bárta et al. (2004), growing location is the most important factor influencing the variability of crude protein content. Seeds grown in locations with a higher soil supply of plant-available nitrogen will contain higher crude protein. Starch content ranged from 40.55-42.80%, with pigeon pea from NTB having the highest starch content; this showed that the environment influences starch biosynthesis, as reported by Beckles and Thitisaksakul (2014 Moussou et al. (2019), i.e., 42.29%, 43.44%, 37.65%, 38.89%, and 44.40% for chickpea, lentil, faba bean, common bean, and pea. The crude fibre content of pigeon pea varied from 3.58-5.50%, with the highest crude fibre content, was found in pigeon pea from Yogyakarta. This result was lower than crude fibre content from Botswana (9.8-13.0%) (Amarteifio et al., 2002) and Nigeria (7.16%) (Akande et al., 2010). Gross energy is the amount of potential energy in foodstuffs that can't be directly used by humans. Humans can use gross energy contained in foodstuffs if it is processed into available energy in the body by digestion, absorption, and metabolism (Priska et al., 2020). The gross energy of pigeon pea ranged from 3,799.40-3,927.59 cal/g, lower than the reported gross energy of other legumes, which ranged from 4,927.19-5,214.22 cal/g (Moussou et al., 2019). According to Priska et al. (2020), the value of gross energy is affected by the nutritional content of foodstuffs. Foodstuffs with more nutritional content have a higher gross energy value.
Mineral consist of macromineral and micromineral. The macromineral is required for more than 100 mg/dl, and the micromineral is needed for less than 100 mg/dl (Soetan et al., 2010). According to the mineral's composition (Table 3), the pigeon pea from Indonesia had various minerals content and differed significantly among pigeon pea. This result showed that the different locations cause minerals content variations, appropriate to what was reported by Apata and Ologhobo (1994) and Moussou et al. (2019) Bella et al., 2016).
The potassium content varied from 479.66-1,455.51 mg/100 g, phosphorus 378.61-411.43 mg/100 g, magnesium 135.65-142.62 mg/100 g, calcium 87.21-128.85 mg/100 g and sodium 91.68-103.57 mg/100 g. In this study, sodium and calcium contents were lower than the other macrominerals. These results were comparable to those reported by Apata and Ologhobo (1994) that sodium and calcium contents in kidney bean, pigeon pea, Bambara groundnut, lima bean, and jack bean were lower than other macro-minerals. Based on the data, potassium was the main mineral in pigeon pea. The presence of potassium in the body can increase iron utilization and control hypertension through diuretics and for people who experience uncontrolled potassium excretion via body fluids (Elinge et al., 2012). The phosphorus content of pigeon pea was lower than faba bean (1,187.97 mg/100 g), chickpea (797.71 mg/100 g), and common bean (503.92 mg/100 g) (Moussou et al., 2019). The high dietary phosphorus burden is not suitable for chronic kidney suffers. It can deteriorate renal osteodystrophy, cardiovascular injury, hyperparathyroidism, and encourage vascular calcification (Kalantar-Zadeh et al., 2010). The Na/K ratio of pigeon pea was low (0.07-0.19). This value was lower than the Na/K ratio of Vigna mungo (0.16 -0.24) (Soris et al., 2010). The Na/K ratio is crucial from a nutritional perspective because a high Na/K ratio of diet is associated with hypertension incidence (Moussou et al., 2019). It is recommended less than one (Soris et al., 2010). Thus, pigeon pea has the potential to be developed as a diet for people with hypertension. The magnesium content of pigeon pea in this work was higher than pigeon pea from Botswana, 113-127 mg/100 g (Amerteifio et al., 2002), and Nigeria, 110 mg/100 g (Oshodi et al., 1993). Magnesium is a cofactor of some 300 enzymes that govern the body's metabolisms. Chronic deficiency of magnesium occurs when serum magnesium content is less than 0.75 mmol/L, known to increase the risk of hypertension, atherosclerosis, cardiac arrhythmias, stroke, lipid metabolism changes, insulin resistance, metabolic syndrome, type 2 diabetes, osteoporosis, depression, and neuropsychiatric conditions (Gröber et al., 2015). The calcium content of pigeon pea from Indonesia was lower than pigeon pea from Botswana, 120-167 mg/100 g (Amerteifio et al., 2002) but higher than pigeon pea from Nigeria, 81.4 mg/100 g (Oshodi et al., 1993). Calcium plays an important role in blood clotting, nerve transmission, muscle contraction, and bone health (Peters and Martini, 2010;Elinge et al., 2012).
The micromineral content consisting of iron, zinc, and copper was 19.70-35.18 mg/100 g, 3.25-5.03 mg/100 g, and 0.93-1.23 mg/100 g, respectively. Among microminerals, iron was the most abundant in pigeon pea. Iron plays a role in producing red blood cells in all body organs, including in the brain, and supporting haemoglobin synthesis in developing foetuses and young children (Georgieff et al., 2019). The zinc content of pigeon pea from Bali was higher than pigeon pea from Nigeria, 4.1 mg/100 g (Oshodi et al., 1993), comparable with chickpea (5.07 mg/100 g) and common bean (5.08 mg/100 g) (Moussou et al., 2019). Zinc is essential for maintaining the system of immune in the body. The zinc deficiency leads to a massive decrease in the adaptive and innate immune and the promotion of inflammatory systemic (Cabrera, 2015). Copper had the lowest content among other microminerals. In this study, pigeon pea's copper content was slightly lower than the copper content of pigeon pea from Nigeria, 1.3 mg/100 g (Oshodi et al., 1993). Intake copper of 0.6-3 mg/day can reduce the risk of cancer, cognitive decline, arthritis, and cardiovascular disease (Bost et al., 2016).

Antinutrients content
Pigeon pea, like other legumes, contains antinutrients. Antinutrients are generally secondary metabolites produced by plants for their defence (Popova and Mihaylova, 2019). Besides causing problems on the bioavailability of nutrients, antinutrients also provide beneficial effects on health (Bora, 2014). According to Table 4, there were variations in the content of antinutrients among pigeon pea seeds, caused by differences in location, climatic conditions, and soil type (Urbano et al., 2000).
Hydrogen cyanide (HCN) can cause central nervous system dysfunction, respiratory failure, and heart attacks (Sinha and Khare, 2017 (Onwuka, 2006). The HCN content of Indonesian pigeon pea is still below the lethal dose, 36 mg/100 g, or 360 ppm (Kalpanadevi and Mohan, 2013). Soaking pigeon pea seeds for 12 hrs, followed by boiling for 60 mins, can eliminate almost HCN (Onwuka, 2006) so that pigeon pea is relatively safe for consumption.

Conclusion
Pigeon pea grown in different regions of Indonesia have significantly different physical characteristics, nutrients, and antinutrients contents. Pigeon pea from Bali has the largest size, weight, and volume. Pigeon pea from Yogyakarta has the highest protein content, while pigeon pea from NTB has the highest starch content. Pigeon pea is a potent mineral source. A low Na/K ratio of pigeon pea (0.07-0.19) can prevent high blood pressure, especially pigeon pea from NTB, which has the lowest Na/K ratio. The highest antinutrient content is found in Yogyakarta pigeon pea. The presence of vitamins A, C, E, and tannins indicate the antioxidant properties of pigeon pea so pigeon pea has the potential to be developed into functional food.

Conflict of interest
The authors declare no conflict of interest.
Al-Saeedi, A.H. and Hossain, M.A. (2015). Total phenols, total flavonoids contents and free radical scavenging activity of seeds crude extracts of pigeon pea traditionally used in Oman for the treatment of several chronic diseases.