No abstract

Riboflavin (Vitamin B2) plays an important role in the human tissue development, the production of red blood cells and helps release energy by breaking down proteins, fats and carbohydrates. Riboflavin cannot be produced the human body therefore must be supplied outside via dairy food. Riboflavin is very sensitive and unstable to environmental influence such as light and reduction agent. One of technology for maintaining the stability of riboflavin is microencapsulation which is composed of polymer matrix containing riboflavin. Na-alginate was chosen because it has properties such as biodegradable, biocompatibility, and non-toxic. Na-alginate also has a high loading capacity of riboflavin but Na-alginate is also easy to release riboflavin. Solving this issue, Na-alginate was coated with chitosan and the layer is then reinforced by crosslinking process with glutaraldehyde. The process of forming micro-sized particles was carried out by the emulsification ionic-gel method. This research aims to study the microencapsulation process of riboflavin with Na-alginate and chitosan. This research also studied the effect of Na-alginate and chiton concentrations upon encapsulation efficiency. The research showed that microencapsulation of riboflavin with alginate and chitosan can be done. The results showed that the Na-alginate and chitosan concentrations had an effect on the encapsulation efficiency. The increase in the concentration of alginate and chitosan will make the encapsulation efficiency higher until it finally reaches the optimum point. Encapsulation efficiency will drop past that point. The optimum point for Na-alginate and chitosan concentration are 3% and 2% respectively.

<p>During this time, the use of urea is not efficient, because about 40-70% of nitrogen in the fertilizer is not absorbed by plants. In order to increase the effectivity of nitrogen release in urea fertilizer, it needs to be coated with modified chitosan as slow releasing agent to form a hydrogel material by forming a cross linking with glutaraldehyde cross-linker.The aims of this research is to study the mechanism and the appropriate kinetic model of nitrogen release in slow releasing fertilizer of modified chitosan. This research was conducted by analyzing the ability of bio-hydrogel by calculating the percentage of swelling ratio and water retention of hydrogel and the nitrogen release in slow releasing fertilizer both in the soil and water. The experiments were conducted by varying the amount of urea used which  30 gram, 40 gram, 50 gram, 60 gram and 70 gram of urea fertilizer. The The release profile is then plotted on several models of diffusion kinetic such as zero order, first order, higuchi and korsmeyer peppas. The appropriate model of diffusion kinetic is chosen by the largest correction factor (R2).The results showed that nitrogen release of the slow releasing fertilizer in the soil with 50% urea content  and  the  water  followed  korsmeyer  peppas  model  with  fickian  mechanism. Nitrogen release in the soil with urea content of 30%, 40%, 60%, and 70% followed the korsmeyer peppas model with nonfickian mechanism.</p>

Riboflavin ( Vitamin B2) plays an important role in the development of human body tissue, the production of red blood cells and helps release energy derived from protein. Riboflavin cannot be produced and stored by the human body therefore must be supplied outside via food. Riboflavin is very sensitive and unstable to environmental influence such as light and reductor. One of technology for maintaining the stability of riboflavin is microencapsulation which is composed of polymer matrix containing riboflavin. Alginate was chosen as a polymer matrix because of riboflavin’s absorption ability, biodegradable, biocompatible and non-toxic. The matrix polymer is strengthened by coating it with chitosan. The layer is then reinforced by crosslinking with glutaraldehyde. This research aims to study the microencapsulation process of riboflavin with alginate and chitosan. This research also studied the effect of alginate and chiton concentrations upon the diameter of microcapsules.The results showed that microencapsulation of riboflavin with alginate and chitosan can be done. The increase in chitosan concentration will reduce the size of microcapsules diameter. The concentration of alginate does not significantly affect the size of microcapsules diameter. Average diameter microcapsule range 380 – 610 µm, smaller than other research studies