Preparation And Application Of Ferrous Sulfate Microcapsules

Iron is an essential trace element in animal and human nutrition. Iron deficiency induces many diseases such as anemia, which afflicts about nearly 30% of the world's population. Nowadays, Food fortification is the most practical and best long-term method of preventing iron deficiency in this population. Ferrous sulfate is a high bioavailability and relatively low cost. Nonetheless, ferrous sulfate, like others ferrous salts, may catalyze fat oxidation and cause an unacceptable flavor and color changes in several foods. Micro-encapsulation is defined as a technology of packing solids, liquids or gaseous materials with natural or synthetic high polymer coating materials in miniature, semi-permeable or sealed capsules that can release their contents at controlled rates under specific conditions. By micro-encapsulation, specific components can be isolated from other components, and sensitive components can be protected from oxygen, water, light and so on. In addition, bad taste or odour can be masked. Controlled release can also be achieved by micro-encapsulation. Today, micro-encapsulation has been widely used in many fields, including food, medicine and pharmacy, chemical engineering and agriculture and so on.In order to fortify iron, kinds of polysaccharides, including xanthan gum, arabic gum, carrageenan, maltodextrin and gelatin, were used as coating materials to prepare ferrous sulfate microcapsules by freeze-drying and spry-drying. Meanwhile, Product obtained thereof was added to whole milk powder to confirm its effect on oxidation. And tablets fortified with ferrous sulfate micro-encapsulation were prepared.Micro-encapsulation of ferrous sulfate with three kinds of polysaccharides, including Xanthan gum, Arabic gum and Carrageenan, as coating material were studied when classic freeze-drying technique was used. And it is confirmed that washing exterior iron of microcapsule was used 50% (v/v) ethanol as solvent and washing time was 5 minutes. The wall material concentrations had no significant effect on encapsulating efficiency. Also, with the increase of the ratio of wall material to core material, the encapsulating efficiency of the three polysaccharides all increased significantly, especially for Xanthan gum. When 5% Xanthan gum was as coating material, and the ratio of coating material to core material was 30:1, the encapsulating efficiency was relatively higher, up to 97%.Micro-encapsulation of ferrous sulfate with four kinds of polysaccharides ,including Gelatin, Arabic gum, Arabic gum composite with Gelatin, Arabic gum composite with Maltodextrin, as coating material were studied when classic spray-drying technique was used. Four kinds of coating material concentrations, composite coating material ratio and ratio of coating material to core material, were studied on effect of ferrous sulfate micro-encapsulation respectively. The results showed that encapsulation efficiency of Ferrous sulfate increased as ratio of coating material to core material increased. When concentration of Gelatin as coating material was 4% and ratio of coating material to core material was 10:1, encapsulation efficiency of ferrous sulfate was as high as 89%. However, encapsulation efficiency of other three coating materials decreased for some reasons of artificial error probably (53%~71%). Meanwhile, the suitable technique parameters for spray-drying were that air inlet temperature was 170℃and feeding flow capacity was 4mL·min-1 for spray-dryer employed.Micro-encapsulation product obtained thereof was added to whole milk powder to confirm its effect on oxidation, with control sample of ferrous sulfate directly added to whole milk powder, under the three kinds of storage conditions (auto-oxidation of room temperature, 35℃,50℃,RH=85%).During 90 days storage, oxidation of lipid in milk powder fortified with ferrous sulfate micro-encapsulation was lowered than control sample, which meant that the stability of milk powder treated was enhanced.Micro-encapsulation of ferrous sulfate admix with several adjuvant, including Vitamin C, pregelatinized starch, microcrystalline cellulose, colloidal silicon dioxide, magnesium stearate, chalk, cane sugar, essence and so on, were studied to prepare two kinds of tablets when direct compression technique was used. And its weight, hardness and sense organ were evaluated. The results showed that micro-encapsulation ferrous sulfate tablets achieve the qualities of tablets.