Synergistic Effect of Chitosan and Metal Oxide Additives on Improving the Organic and Biofouling Resistance of Polyethersulfone Ultrafiltration Membranes.

The combination of chitosan and metal oxides was utilized as an addition to improve the fouling resistance of polyethersulfone (PES) ultrafiltration membranes. Pure water flux, membrane hydrophilicity by the contact angle, scanning electron micrographs, and Fourier-transform infrared spectra were used to characterize the membranes. With the addition of metal oxides, the modified membrane's water flux increased. The PES membrane with 0.25% wt chitosan and 2.0% wt AgNO3 had the highest flux and antibacterial activity among the membranes tested. Because of its potential to improve membrane hydrophilicity, the water flux increased with the addition of chitosan and AgNO3. Because of the improved hydrophilicity, the contact angle reduced as chitosan and Ag loading was increased. The PES-chitosan-Ag2O (from AgNO3 2.0% wt) membrane had high antibacterial activity against Escherichia coli and Staphylococcus aureus, whereas the PES-2.0% wt Ag membrane did not show the same result. Finally, the addition of chitosan in the PES-Ag membrane increased the membrane's antibacterial activity substantially.

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.

Micellar-Enhanced Ultrafiltration Using a Plant-Derived Surfactant for Dye Separation in Wastewater Treatment.

Micellar-enhanced ultrafiltration (MEUF) is one of several membrane methods used for the removal of trace organic pollutants from aqueous streams. In this process, a surfactant is added to a polluted aqueous solution at a concentration higher than its critical micelle concentration (CMC). Unlike synthetic surfactants, natural surfactants, from plants such as the saponin, while ecologically adaptable as surfactants in MEUF systems, are also biodegradable, renewable, and environmentally safe. This study applied Sapindus rarak extract as the natural surfactant in MEUF for Remazol dye separation. It was found that the presence of Sapindus rarak extract increased separation of Remazol red and blue dyes by up to 97.02% and 99.42%, respectively. However, the addition of surfactant decreased permeate fluxes due to membrane fouling and concentration polarization. In addition, loading micelle (Lm), representing the performance of the surfactant micelle for dye separation, as well as the blocking mechanism, was investigated. Lm was found to be in the range of 0.002-0.068 mM dyes/mM saponin. Ultrafiltration blocking mechanisms, as confirmed by the Hermia model, were: standard blocking, for cases without the addition of surfactant; cake formation, for cases with surfactant below the CMC; and complete blocking, for cases with surfactant above the CMC.

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.

Enzymatic purification of glucomannan from Amorphophallus oncophyllus using α-Amylase / Purificação enzimática de glucomanan de amorphophallus oncophyllus usando α -amilasas

The international standards for top glucomannan flour require a minimum of 70% glucomannan. The glucomannan content of Amorphophallus oncophyllus flour was approximately 60%, with starch as the major impurity. Elimination of starch was expected to increase the purity of glucomannan. The purpose of this research was to study starch hydrolysis of the flour using α-amylase. Temperature (35.5-84.5oC), time (0.4-3.6 h) and pH (2.2-8.8) of hydrolysis were selected as independent variables. A central composite design of response surface methodology (RSM) was performed to obtain the optimum condition. This approach was a novelty of this enzymatic purification of A. oncophyllus. Glucomannan content, starch content, and solubility were chosen as the response variables. The models were reliable for predicting the responses (R2≥ 0.771). It was predicted that the highest glucomannan content (93.0%) obtained at the lowest starch content (1.14%), which hydrolysed at pH 6.17, 84.5oC and 3.6 h. Prior the verification of the optimum hydrolysed condition from the model, the glucomannan and starch content was 81.59% and 2.27%, respectively. After purification, the absorbance of the ß-1,4 glycosidic bond increased as a sign of higher glucomannan purity. A less rough surface and irregular shape of the grain morphology was observed after purification.

Os padrões internacionais para a farinha de alta calidade de glucomanan requerem um mínimo de 70% de glucomanan. O conteúdo de glucomanano da farinha de Amorphophallus oncophyllus foi de aproximadamente 60%, com o amido como a maior impureza. Esperava-se que a eliminação do amido aumentasse a pureza do glucomanan. O objetivo desta pesquisa foi estudar a hidrólise do amido da farinha usando α-amilase. A temperature (35,5-84,5oC), o tempo (0,4-3,6 h) e o pH (2,2-8,8) da hidrólise foram selecionados como variáveis independentes. Um desenho central composto pertencente á metodologia da superfície de resposta (MSR) foi realizado para obter a condição ótima. Esta abordagem foi uma novidade desta purificação enzimática de A. oncophyllus. O conteúdo de glucomanan, conteúdo de amido e solubilidade foram escolhidos como as respostas. Os modelos foram confiáveis para predizer as respostas (R2≥ 0,771). Os modelos indicaram que o maior conteúdo de glucomanan (93,0%) foram obtidos no menor conteúdo de amido (1,14%),que hidrolisou a um pH 6,17, 84,5ºC e 3,6 h. Antes da verificação da condição hidrolisada ótima do modelo, o conteúdo de glucomanan e amido foi de 81,59% e 2,27%, respectivamente. Após a purificação, a absorbância da ligação ß-1,4 glicosídica aumentou com um sinal de maior pureza de glucomanan. Uma superfície mais lisa e forma irregular da morfologia do grão foi observada após a purificação.