Produção e armazenamento de extrato liofilizado de sementes de moringa e métodos de aplicação no tratamento de água.

Abstract

Several coagulants are being studied for water treatment; however, natural coagulants have shown advantages over chemicals, such as the coagulant based on moringa seeds. For a better use of the seeds, it is necessary to use technologies for the preservation of their constituents, especially when used in water treatment, since the active principle of proteins (lectins) responsible for water coagulation loses its effect in a short time. From this, it is proposed to produce and store the freeze-dried extract of moringa seeds and study methods of application in water treatment for human consumption. The seeds were peeled by hand and crushed in a domestic blender. The powder was characterized in natura regarding physical and physical-chemical parameters. For freeze-drying, a bench-top lyophilizer was used. 20, 30, 40 and 50 mL of distilled water were added to the extract to form the pastes, and they were submitted to freezing, and then lyophilized. After lyophilization, the powders were analyzed for physical and physicochemical parameters. The artificial water was evaluated for pH, turbidity and apparent color. For the coagulant, the dosages of 12, 16, 18 and 24 g of freeze-dried powder were applied in Jar Test. With the best dosage of the coagulant, the water sedimentation times were studied (60, 120, 180, 240, 300, 360, 420 and 480 min). After establishing the best dosage of the coagulant and the time of sedimentation of the water, the methods of application were studied: direct, liquid, filter and sachet. The efficiency of the powders in water treatment was evaluated according to the storage time. For 180 days the powder was stored in three types of packaging: laminated, sachet and mixed, in which the efficiency of the coagulant in water treatment was studied, by means of physical-chemical parameters, added of microbiological, physical-chemical and physical analysis of the powder. The freezedrying was presented to the moringa as an adequate method in the preservation of its constituents, being the addition of 50 mL of distilled water the one that presented better results. The dosage of 24 g resulted in better results for the pH and greater reduction in the level of turbidity; and that of 16 g showed greater efficiency in removing the apparent color from the water. For presenting greater efficiency for the pH, followed by greater reductions in the turbidity and apparent color of the water, the time of 480 min of sedimentation was defined as the best. The application methods selected based on the best results of each parameter studied were the direct, the filter and the sachet. The packages were efficient in preserving the physical-chemical characteristics of the freeze-dried extract. During the 180 days of storage, the extract did not present microbiological contamination. The packages were efficient in conserving the coagulant. The conservation of the active principle of the seeds responsible for the removal of turbidity depends on the packaging used and the storage time. The sachet packaging showed the highest efficiency in eliminating the apparent color. Even presenting high efficiency in the removal of turbidity and apparent color, the values are above the required.