2. Materials and Methods
2.1. Materials
Five improved lima beans (Phaseolus lunatus) accessions designated: Nkurakan black (NB01), Bososo cream black (BC02), Mampong white (MW03), Oseikrom cream (OsC04),
and Ohwum Mampong cream brown (OMC05), were collected from Crop Research Institute (CSIR), Kumasi Fumesua Ghana. The beans were selected and cleaned manually. It was ensured that the seeds were free of dirt, broken and immature ones, and other foreign materials.
2.2. Seed Dimensions
Hundred randomly selected seeds were used to measure length (L), breadth (B) and thickness (T), three principal dimensions which are in the three mutually perpendicular directions using A Vernier caliper reading 0.01 mm.
2.2.1. 1000-Seed Weight
1000-seed weight was determined by counting one hundred seeds manually and weighing. The obtained values were then multiplied by a factor 10 to get 1000-seed weight.
2.2.2. Length/Breadth Ratio
Ten (10) randomly selected seeds were observed for length/breadth ratio by simply dividing calculated length by calculated ratio of the 10 cooked seeds was determined by dividing the cumulative length to the cumulative breadth of cooked seeds.
2.2.3. Water Uptake Ratio
Thirty (30) grams of seeds was cooked in 400ml of double distilled water for minimum cooking time of 15 minutes at 60°C. The cooked seeds were then removed; drained and surface water on seeds was removed by using filter paper. The samples were weighed and the water uptake ratio was calculated as the ratio of weight gained after cooking to weight before cooking.
2.2.4 Bulk Density
Bulk density was determined according to the method of and expressed as g/L. The seeds were weighed before grinding and it was then weighed after grinding. The ground samples were measured in measuring cylinder.
2.3. Cooking Time
Cooking time was determined according to the method of. The seeds were weighed and cooked at 65°C with 550ml of distilled water.
2.3.1. Cooked Length–Breadth Ratio
The cumulative length and breadth of 10 seeds were measured after cooking for minimum cooking time. The length–breadth ratio of the 10 cooked seeds was determined by dividing the cumulative length to the cumulative breadth of cooked seeds.
2.3.2. Water Uptake Ratio
Thirty (30) grams of seeds was cooked in 400ml of double distilled water for minimum cooking time of 15minutes at 65°C. The cooked seeds were then removed; drained and surface water on seeds was removed by using filter paper. The samples were weighed and the water uptake ratio was calculated as the ratio of weight gained after cooking to weight before cooking.
3. Conclusions
The knowledge of physical and cooking properties of legumes is important because it provides as much data required for the design of various processing machines, processes and control in developing a new consumer product and in evaluating and retaining the quality of final products as well as very essential for the design of components of any machine. Seed length ranged from 19.12 to 25.50 mm, breadth from 12.41 to 15.41 mm with significant differences among the accessions. However, thickness which varied from 5.10 to 6.58 mm showed no statistical significant difference. The thousand (1000) seed weight significantly varied from 886.00 to 1311.65 g. All the five lima bean accessions belonged to the Andean gene pool or Meso-American large seeded type. Length/breadth & water uptake ratio, and bulk density were within the range of 1.49 to 1.76, 1.15 to 1.81 g, and 0.59 to 0.62 g/ml, respectively. The cooking time of all the accessions ranged from 81.00 to 91.50mins with no significant differences. Cooked Length-Breadth and water uptake ratios had minimum and maximum values of 1.39 to 1.78 and 1.15 to 1.31, respectively. Seed hydration capacity and index had values between 18.98-23.05 g/seed& 7.1410.45; swelling capacity ranged between 17.98-20.38ml/seed and swelling index recorded values between 3.88-5.10. All the accessions had higher cooking time in comparison with some cowpea varieties grown in Ghana. The higher hydration and swelling capacity of the improved lima beans make them useful in food products that require much water.