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

Research background: Deacetylation and the use of CaCl2 as a gelation agent improve the performance of glucomannan as iron encapsulant. This study was conducted to investigate the effects of deacetylation degree and pH of gelation on the characteristics of encapsulated iron using gelation in CaCl2 solution. 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 process of encapsulation by gelation. The pH of the gelation solution was also changed. The beads were subsequently vacuum-dried. Results and conclusions: Deacetylation led to lower endothermic peak of the glucomannan than that of the native one. The deacetylation degree and pH of gelation 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. 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 the solution at pH=10. The highest deacetylation degree of glucomannan caused the highest swelling of the beads, which led to the release of a higher amount of iron. Glucomannan deacetylation improves the iron encapsulation and enables higher iron release at pH=6.8 than at pH=1.2. The Weibull model was the best-fitting 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. Novelty and scientific contribution: This result supports the application of deacetylated glucomannan using NaOH as a pH-sensitive matrix for iron encapsulation and CaCl2 solution as gelation agent. A higher deacetylation degree leads to the release of a higher amount of iron from the matrix. The encapsulation does not only protect the iron but also delivers it to the absorption site and controls its release, which is useful in supplement formulation or food fortification. The results show that the deacetylated glucomannan as the matrix holds more iron in encapsulation process.

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

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. 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 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. RESULTS: 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. CONCLUSIONS: This study suggested the potency of modified glucomannan to be pH-sensitive for iron encapsulation.

Inhibition kinetics of lipid oxidation of model foods by using antioxidant extract of fermented soybeans.

Fermentation by using Aspergillus oryzae has been reported to increase antioxidant activity of soybeans significantly. The effectiveness of the extract from fermented soybeans was studied in 3 model foods with different complexities, i.e., linoleic acid emulsion, sunflower oil emulsions and bulk sunflower oil. For the emulsion systems, oxidation at two different pH values (4.5 and 7) was also compared. A reparameterised logistic equation was used to describe and to predict the experimental data. In general, a good agreement between experimental trends and simulated data from the model was found. A crude antioxidant extract (5 mg/g) showed a comparable antioxidant activity to 0.26 mg/g of butylated hydroxytoluene (BHT) in the linoleic acid emulsions. The extract exhibited a better capability to retard primary products in the linoleic acid systems than the secondary products. The opposite effect was observed in the bulk sunflower oil and its emulsion systems.