Modification of glucomannan of Amorphophallus oncophyllus as an excipient for iron encapsulation performed using the gelation method.

Abstract

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. 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 FeSO4 to obtain 25 mg of iron per 1 g of excipient. The mixture was dropped into either an ethanol or CaCl2 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. It was revealed that the highest iron efficiency (64%) was achieved using deacetylated glucoman- nan, which was gelled in CaCl2. 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 (R2 ≥ 0.958) for all excipient variations. This study suggested the potency of modified glucomannan to be pH-sensitive for iron encapsulation.