OGINNI Oluwatosin Jerry EFFECT OF PROCESSING METHODS ON THE PHYSICAL AND COOKING PROPERTIES OF DRUMSTICK (Moringa oleifera) SEEDS   BY OGINNI Oluwatosin Jerry AGE/2007/036

BACKGROUND Most part of the tropics are blessed with several species of underutilized seeds and legumes that have been found valuable for both man and livestock. Drumstick (Moringa oleifera) is a vegetable tree that grows in different parts of tropical Africa and Asia. The leaves, the pods and kernels are especially rich in protein and iron. Specifically the kernel also has substantial crude fat. All these are essential in human nutrition. Apart from consumption of its leaves as vegetable and utilization of the kernels in food systems, very little has been documented on its processing.

A pictorial view of Moringa tree products (Source: Ogunsina, 2009) a b c d e f A pictorial view of Moringa tree products (Source: Ogunsina, 2009) a) Tender Moringa leaves, b) Moringa flowers, c) Tender green pods d) Mature & dry pods, e) Whole seeds, f) Dehulled seeds. e f Fig. 1.2: A pictorial view of Moringa tree products (Source: Ogunsina, 2009) a) Tender Moringa leaves, b) Moringa flowers, c) Tender green pods prepared for use as vegetable, d) Mature & dry pods, and e) Whole seeds, f) Dehulled seeds.

Economic Importance of the Tree Products

OBJECTIVES This work aims to investigate the effect of processing methods on the physical and cooking properties of Moringa oleifera seeds. The specific objectives are: To determine the physical properties of moringa seeds To determine the cooking properties of moringa seeds using traditional and microwave cooking methods. To study the effects of processing on the properties in 1 and 2 above

MATERIALS AND METHODS Source of Materials Seeds that have been botanically identified as Moringa oleifera were obtained from samples already procured locally by the British Council – DFID project (DelPHE 643), Obafemi Awolowo University, Ile Ife.   Sample Preparation An attrition mill with adjusted plate clearance was adapted for dehulling the seeds (Ogunsina, 2009). The shelled sample were cleaned of dirts and chaffs, sealed in a polythene bag and kept under refrigeration until the time of use

Determination of Physical Properties Seed Dimension Length, L; width, W; and thickness, T- The shape indices; geometric mean dimension, Surface area, Sphericity and Aspect ratio were calculated from the linear dimensions. Bulk Density A weighted amount of the sample will be poured into a measuring jar from a fixed height. The volume occupied by the sample will be determined and the ratio will be calculated (Singh et al., 2005). Determination of Physical Properties

Determination of Cooking Properties of Dehulled Moringa Seeds Hydration properties The samples were weighed and combined with 100 ml of water at room temperature (25 0C) for a pre determined period of time. Later the water were drained; kernels were blotted to remove adhered water and weighed (Adebowale et al., 2005; Ibarz et al, 2004) Hydration capacity (g/kernel) =

Swelling properties A weighted amount of the samples were enumerated; its volume were determined and soaked overnight in distilled water. The volume of the soaked kernels were noted in a graduated cylinder (Adebowale et al., 2005 & Tiwari et al., 2008). Swelling capacity (mL/kernel) =

Water uptake ratio A weighed amount of the seeds sample were cooked in distilled water for a minimum cooking time in a boiling water bath, drained and blotted to remove superficial water. The cooked samples were weighed and water uptake ratio was calculated. (Ogunsina, 2009; Tiwari et al., 2008).

RESULTS

All values are means of triplicates ± SD Table 1: Physical Properties of Raw Moringa oleifera Seeds in Comparison with Soaked and Traditionally Cooked Samples Parameters Treatments   Raw 1 2 3 4 Number of Seeds 100 Length (mm) 7.55 + 1.11b 8.16 + 1.19a 7.90 + 0.78a 7.94 + 1.31a 8.12 + 1.17a Width (mm) 7.86 + 0.72c 8.32 + 0.94a,b 8.48 + 0.87a 8.11 + 1.0b 8.14 + 1.05b Thickness (mm) 7.34 + 0.77d 7.98 + 0.73a,b 8.09 + 0.88a 7.64 + 0.88c 7.77 + 0.98b,c Mass (g) 0.24 + 0.22c 0.37 + 0.09a 0.36 + 0.08b 0.37 + 0.07a 0.35 + 0.08b Geometric Mean Diameter (De) 2.83 + 0.07c 2.90 + 0.09a 2.90 + 0.08a 2.87 + 0.11b 2.88 + 0.11a,b Sphericity ( ) 0.38 + 0.48a 0.36 + 0.05a 0.37 + 0.03a 0.37 + 0.06a 0.36 + 0.04a Aspect Ratio (Ra) 1.06 + 0.17a,b 1.04 + 0.17a,b 1.08 + 0.12a 1.05 + 0.19a,b 1.02+0.15b Surface Area (Sa) 25.21 + 1.33c 26.45 + 1.61a 26.46 + 1.48a 25.88 + 1.90b 26.13 + 1.94a,b Bulk Density (g/cm3) 0.43 + 0.03a 0.5 + 0.02a 0.51+ 0.02a 0.52 + 0.03a 0.47 + 0.03a 1: Unsoaked/Traditionally Cooked 2: 2hrs Soaked/Traditionally Cooked 3: 4hrs Soaked/Traditionally Cooked 4: 6hrs Soaked/Traditionally Cooked All values are means of triplicates ± SD a,b,c,d Means with different letters on same row are significantly different (P ≤ 0.05).

Time of soaking (hours) Figure 1: Effect of Soaking Time on the Axial Dimension of Traditionally Cooked Moringa oleifera Seeds

All values are means of triplicates ± SD Table 2: Physical Properties of Raw Moringa oleifera Seeds in Comparison with Soaked and Microwave Cooked Samples Parameters Treatments   Raw 1 2 3 4 Number of Seeds 100 Length (mm) 7.55 + 1.11a 7.10 + 0.97b 7.48+ 0.98a 7.18+ 1.07b 7.13+ 0.94b Width (mm) 7.86 + 0.72b 7.34 + 0.80a 7.61+ 0.81b 7.26+ 1.30b 7.50 + 0.70b Thickness (mm) 7.34 + 0.77c 6.90 + 0.73 7.12+ 0.83b 7.14+ 0.80a 7.06 + 0.73b Mass (g) 0.24 + 0.22c 0.35 + 0.07a 0.30+ 0.08b 0.34+ 0.06a 0.24+ 0.07c Geometric Mean Diameter (De) 2.83 + 0.07b 2.77 + 0.07b 2.81+ 0.08a 2.78+0.07b 2.79+0.06a,b Sphericity ( ) 0.38 + 0.48a 0.40 + 0.05a 0.38+ 0.05a 0.40+0.06a 0.40+ 0.05a Aspect Ratio (Ra) 1.06 + 0.17a 1.06 + 0.20 a 1.04+ 0.18 a 1.04+ 0.25a 1.07+ 0.18a Surface Area (Sa) 25.21 + 1.33a 24.15 + 1.20c 24.81+ 1.41b 24.34+ 1.29c 24.43+ 1.10c Bulk Density (g/cm3) 0.43 + 0.02a 0.47 + 0.03a 0.45 + 0.02a 0.47 + 0.01a 0.46 + 0.02a All values are means of triplicates ± SD a,b,c Means with different letters on same row are significantly different (P ≤ 0.05). 1: Unsoaked/Microwave Cooked 2: 2hrs Soaked/Microwave Cooked 3: 4hrs Soaked/Microwave Cooked 4: 6hrs soaked/Microwave Cooked

Time of Soaking (Hours) Fig 2: Effect of Soaking Time on Axial Dimensions of Microwave Cooked Moringa oleifera Seeds.

Table 3: Cooking Properties of Moringa oleifera Seed Parameters *Treatments   1 2 3 4 5 6 7 8 Hydration capacity 0.15 0.16 0.10 0.11 0.13 0.14 Hydration Index 0.64 0.67 0.7 0.52 0.54 0.61 0.68 Swelling Capacity cm3/seed 0.21 0.18 0.2 0.19 Water uptake ratio 1.59 1.66 1.7 1.61 1.54 1.6 Cooked Seed Weight (g) 33.71 33.72 34.36 33.56 32.62 31.24 32.22 33.58 Moisture Absorbed (cm3) 10 9 Minimum Cooking Time (mins) 46 44 25 23 * 1: Unsoaked/Traditionally Cooked 2: 2hrs/Traditionally Cooked 3: 4hrs/Traditionally Cooked 4: 6hrs/Traditionally Cooked 5: Unsoaked/Microwave Cooked 6: 2hrs/Microwave Cooked 7: 4hrs/Microwave Cooked 8: 6hrs/Microwave Cooked

CONCLUSION The following conclusions can be drawn from this investigation: The length, width, thickness and mass of raw Moringa oleifera seeds are 7.55 mm, 7.86 mm, 7.34 mm and 0.24 g respectively. Shape indices: Geometric Mean Dimension (De), Sphericity ( ), Aspect Ratio (Ra), Surface Area (Sa) and Bulk Density (g/cm3) of raw Moringa oleifera seeds were 2.83, 0.38, 1.06, 25.21 and 0.43 g/cm3 respectively. The cooking time for traditionally cooking method decreased from 46 mins to 44 mins and 25 mins to 23 mins for microwave cooking method due to the duration of soaking, showing a reduction of about 50 % in cooking time compared to the traditional cooking method

Soaking of moringa seeds prior to cooking for 2, 4 and 6 h showed no significant difference in cooking time. There is a significant variation in the physical properties of moringa seeds that were subjected to treatments considered in this study.

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