Effect of Storage Conditions on Coagulation Properties of Moringa Oleifera Seed

Abstract

The effects of shelf life, storage form and container on coagulation properties of Moringa oleifera seeds used for clarification of turbid water were investigated. Turbid water was collected from Ezu River in Amansea, Anambra State, Nigeria. Turbidity ranged between 65 NTU and 322 NTU, depending on the season the water sample was procured. The seeds were stored for150days in three different forms- seed inside pod, winged and shelled. Three storage vessels were used-bottle with plastic cork, locally made baskets with cover and black cellophane bag. The percentage content of the coagulant active ingredient (protein) was monitored through proximate analyses. The seeds of Moringa oleifera were ground and defatted with n-hexane using the Soxhlet apparatus. This was followed by aqueous extraction of the coagulant. The coagulant active ingredient (seed protein) was isolated through acetone precipitation and used in the purification of the water. Jar test apparatus was used to determine optimum coagulant dosage. Coagulant dosages of 30 mg/l, 40 mg/l and 50 mg/l were used. There were fluctuations in the efficiencies exhibited in the different modes of storage with time. Efficiency of the shelled in bottle, winged in bottle and Pod seed in basket decreased from 98%, 86% and 96% to 60%, 62% and 90% respectively. Shelled seed in basket and winged seed in cellophane bag started and ended with 95% and 92% respectively, while the efficiency of winged seed in basket rose from 71% to 94%. Shelled seeds stored in basket showed better consistency in coagulation property with time than all the other modes of storage. The percentage protein content of the seeds in all the containers decreased drastically with storage, which resulted in reduced yield in the extracted protein in gram per gram. This means that although stored seeds could be used effectively for water purification, higher quantities of seed will be required to obtain same amount of coagulant.