LOCUST BEAN TREE The locust bean tree is

LOCUST BEAN TREE • The locust bean tree is named Parkia biglobosa in honour of Mungo Park • It grows tall , more than 20 m tall • It also provide food and tree cover

LOCUST BEAN POD • The pods are large and long • The seeds in the pods are its most prized possession

LOCUST BEAN SEED WITH PULP • The seed is enclosed in a yellow dry powdery fruit pulp called “dorowa” in Hausa • It contains more carbohydrate than the seed • It is sweet to taste and is popularly consumed in rural Africa when grains stores are empty

FERMENTED LOCUST BEAN • The fermented seed is nutritious and rich in protein • It is consumed as a condiment in soups and stews in fresh and dried forms

INTRODUCTION • Locust bean is very rich in protein and popularly consumed as condiment in soups and stew in fresh and dried form (Omafuvbe et al 2004). • Freshly prepared iru has short shelf life while drying preserves and improved the shelf life (Sanni et al 1999). • However the seed is underutilised in spite of the high protein content • Drying the seed may improve the utilisation and consumption • This is because drying removes water, concentrates nutrient and preserve materials for further usage (Suleiman et al 2013) • Little is known about the properties of the dehulled and dried unfermented seed • Therefore objective of the study is to:

Objective of the work To compare the effect of different drying methods: Sun drying, Oven drying and Microwave drying On Proximate and mineral composition of the dried seed.

Materials and method • Locust bean which has been removed from the pod was boiled for 16 hrs until the seed is soft • The softened seed coat was removed manually by scrubbing between the hands • The seed coat was separated from the cotyledons by washing with water • The separated cotyledons were dried to a moisture content of less than 10% using sun drying (5 days at 29 OC), oven drying 3 days at 59 o. C and microwave oven drying methods (15 mins) • Dried seed were milled and stored in air tight

Flow chart LOCUST BEAN SEED COOKING DEHULLING COTYLEDONS WASHING Seed coat SUN DRYING OVEN MICROWAVE

Results and discussion

Table 1 : Proximate composition of locust bean seeds before and after drying PARAMETER Fresh dehulled Sun dried Oven dried Microwave unfermented cotyledon dried unfermented cotyledon Protein % 18. 30 24. 01 24. 25 22. 43 Fat % 3. 06 7. 32 7. 23 6. 17 Fibre % 1. 85 4. 94 4. 75 3. 30 Ash % 2. 81 5. 89 5. 80 4. 84 Moisture % 42. 35 5. 15 5. 24 5. 03 CHO % 31. 64 52. 71 52. 74 58. 24

Fig 1: Proximate composition of locust bean before and after drying 70 60 50 protein 40 fat 30 ash fibre moisture 20 carbohydrate 10 0 FUC SUC OUC MUC

Table 2 : Mineral composition of locust bean seed before and after drying parameter Fresh dehulled unfermented cotyledon Sundried and unfermented cotyledon Oven dreid and Microwave unfermented dried and cotyledon unfermented cotyledon Na % 0. 068 0. 107 0. 108 0. 093 K% 0. 430 0. 848 0. 856 0. 705 Ca % 0. 168 0. 236 0. 240 0. 210 Mg % 0. 110 0. 242 0. 254 0. 224 P% 0. 215 0. 340 0. 346 0. 320 Fe % 0. 019 0. 038 0. 044 0. 031

Fig 2 : Mineral composition of locust bean seed before and after drying 0, 9 0, 8 0, 7 NA 0, 6 K 0, 5 ca 0, 4 mg 0, 3 p 0, 2 fe 0, 1 0 DUC SUC OUC MUC

Discussion • Table 1 and 2 shows the proximate and mineral content of the fresh and dried seeds • Apart from increasing the shelf life of the seed, drying increased the nutrient and mineral content of the seed in all the three methods (Fig 1 and Fig 2). • The nutrient and mineral content is influenced by the method of drying • Drying increased the protein content from 18. 30% (fresh) to range of 24. 01 -24. 25% • It reduced moisture content to less than 6% in all the drying methods

Discussion cont • The oven dried seeds had the highest nutrient content, while the microwave had the lowest • Mineral content doubled after drying except for sodium , while potassium and iron had the highest and lowest contents respectively (Fig 2) • While there was no significant difference in mineral content of seed using sun and oven drying, the microwave dried seed was significantly lower in mineral content • Even though the microwave had shortest drying time (15 mins), other factors like heat intensity and temperature may affect protein quality

conclusion • The dried seeds are nutritionally better than the fresh seed as they had better nutrient than fresh seed • The higher nutrient content and low moisture content will preserve the seed and increase their utilization especially in protein deficient food formulations • The drying properties of the sun dried and oven dried seeds were similar, they retained nutrients better than the microwave dried seed • Sun drying and oven drying are recommended than microwave drying