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

Abstract

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.

Iron Encapsulation by Deacetylated Glucomannan as an Excipient Using the Gelation Method: Characteristics and Controlled Release

“…With slight modifications, glucomannan was deacetylated using the method presented by Wardhani, Aryanti, Etnanta, and Ulya (21). Glucomannan (1 g) was deacetylated in 100 mL of various NaOH solutions (8-32 g/L) for 1 h under constant stirring.…”

“…Although many deacetylation glucomannan studies have been performed, a comprehensive study of glucomannan deacetylation using NaOH for iron encapsulation using CaCl2 as the gelation agent has not yet been explored. The combination of NaOH and CaCl2 was superior than that of NaOH and ethanol for the gelation of iron encapsulation (18). However, such a condition has been further studied.…”

“…Deacetylated glucomannan was found to be more firm, elastic, and stable than the native one at low pH and high temperature (15). These properties are important to support its applications, such as in films (16), in restructured seafood products (13), and in encapsulation using the gelation method (9,10,17,18). Deacetylation has been reported as a method for improving the loading efficiency of vitamin C (10) and controlling the drug release from the chitosan matrix (19).…”

“…The effects of KOH, NaOH, and Na 2CO3 under either homogeneous or heterogeneous reaction on the extension of the deacetylated glucomannan gelation have been studied (12,17,20,21).…”

“…Moreover, Ulya et al (9) reported that the encapsulation efficiency of deacetylated glucomannan in encapsulating iron using ethanol as gelation media was just above 60 %. Gelation process using ethanol resulted in the formation of a film-like layer instead of beads as the encapsulation product, which facilitated the loss of iron during gelation (18). Using the CaCl2 solution as a gelation agent, Wardhani et al (10) successfully encapsulated vitamin C using deacetylated glucomannan to form beads with an encapsulation efficiency of 85 %.…”