Background. Performing iron fortification by adding the iron compound directly into foods helps to tackle the problem of iron deficiency. However, the fortification brings about some problems as well, including undesirable organoleptic effects, oxidation, and reduced bioavailability. Ensuring appropriate encapsulation can overcome these problems. Hence, it is crucial to identify a proper excipient for protecting the iron. Glucomannan has the potential to be a suitable iron encapsulation excipient. The present work therefore sought to prepare an iron excipient from modified glucomannan using the gelation method. Glucomannan modification was conducted by either chemical reaction or in combination with another compound. Materials and methods. Glucomannan was isolated from Amorphophallus oncophyllus flour. To maximize encapsulation performance, glucomannan was modified by either deacetylation using NaOH (0.4 M) or in combination with alginate. After dissolving the excipient (1%), this solution was mixed with FeSO 4 to obtain 25 mg of iron per 1 g of excipient. The mixture was dropped into either an ethanol or CaCl 2 solution for gelation. The beads of seven variations of the resultant glucomannan-based excipient were investigated for their encapsulation efficiency, bead size, and swelling. The release of iron in the two pH solutions together with their respective release models were also evaluated. Results. It was revealed that the highest iron efficiency (64%) was achieved using deacetylated glucomannan, which was gelled in CaCl 2 . However, this matrix also resulted in the highest release rate in both pH solutions. The release rate of iron was lower in the low pH solution (pH: 1.2) than in the higher pH solution (pH: 6.8) for all matrix combinations. The Korsmeyer model was the most fitting model for describing the release profile of iron in both pH solutions (R 2 ≥ 0.958) for all excipient variations. Conclusion. This study suggested the potency of modified glucomannan to be pH-sensitive for iron encapsulation.

Background. Performing iron fortification by adding the iron compound directly into foods helps to tackle the problem of iron deficiency. However, the fortification brings about some problems as well, including undesirable organoleptic effects, oxidation, and reduced bioavailability. Ensuring appropriate encapsulation can overcome these problems. Hence, it is crucial to identify a proper excipient for protecting the iron. Glucomannan has the potential to be a suitable iron encapsulation excipient. The present work therefore sought to prepare an iron excipient from modified glucomannan using the gelation method. Glucomannan modification was conducted by either chemical reaction or in combination with another compound. Materials and methods. Glucomannan was isolated from Amorphophallus oncophyllus flour. To maximize encapsulation performance, glucomannan was modified by either deacetylation using NaOH (0.4 M) or in combination with alginate. After dissolving the excipient (1%), this solution was mixed with FeSO 4 to obtain 25 mg of iron per 1 g of excipient. The mixture was dropped into either an ethanol or CaCl 2 solution for gelation. The beads of seven variations of the resultant glucomannan-based excipient were investigated for their encapsulation efficiency, bead size, and swelling. The release of iron in the two pH solutions together with their respective release models were also evaluated. Results. It was revealed that the highest iron efficiency (64%) was achieved using deacetylated glucomannan, which was gelled in CaCl 2. However, this matrix also resulted in the highest release rate in both pH solutions. The release rate of iron was lower in the low pH solution (pH: 1.2) than in the higher pH solution (pH: 6.8) for all matrix combinations. The Korsmeyer model was the most fitting model for describing the release profile of iron in both pH solutions (R 2 ≥ 0.958) for all excipient variations. Conclusion. This study suggested the potency of modified glucomannan to be pH-sensitive for iron encapsulation.

Research background. Deacetylation and the use of CaCl2 as a gelation agent improve the performance of glucomannan as iron encapsulant using the gelation method. This study was conducted to investigate the effects of deacetylation using NaOH and pH gelation on the characteristics of encapsulated iron using the CaCl2 gelation method. Experimental approach. Glucomannan was deacetylated at various NaOH concentrations and was subsequently utilized as an iron excipient using the pipette-dropped gelation method in CaCl2 solution to directly investigate the gelation process of encapsulation. The pH of the gelation solution was also changed. The beads were subsequently vacuum-dried. Results and conclusions. Deacetylation led to lower endothermic peak temperature of the glucomannan than that of the native one. The deacetylation degree (DD) and gelation pH did not significantly affect the diameter of the beads but influenced their appearance and physical characteristics. The backbone of glucomannan was not changed by either the deacetylation degree or the pH of the gelation treatment. The highest encapsulation efficiency (73.27 %) was observed in the encapsulated iron using the glucomannan matrix of the highest deacetylation degree (82.56 %) and gelated in pH=10 solution. The highest deacetylation degree of glucomannan caused the beads to have the highest swelling, which led to the release of a higher amount of iron. Glucomannan deacetylation improved the pH sensitivity of iron encapsulation, in which more iron was released at a pH=6.8 than of pH=1.2. The Weibull model was the best-fitted model to represent the profile of iron release from the deacetylated glucomannan matrix using the gelation method (R2 > 0.93) at pH=6.8 and pH=1.2 solutions. Novelty and scientific contribution. This result supports the application of deacetylated glucomannan using NaOH as a pH-sensitive matrix on iron encapsulation using CaCl2 solution as gelation agent. A higher deacetylation degree leads to the release of a higher amount of iron from the matrix. The encapsulation is not only protecting the iron but also delivering it to the absorption site and controlling the iron release which are useful in supplement formulation. or food fortifications. The results show that the deacetylated glucomannan as the matrix holds more iron in encapsulation process.