Nutritional values and microencapsulation techniques of fish oil from different sources: A mini review (2023)

Microencapsulation of camphor by trimethylsilylcellulose was performed using oil-in-water emulsion method. Trimethylsilylcellulose (TMSC) with the DS value of 2.41 (CHN analysis) was synthesized by dissolving commercial cellulose in N, N-dimethylacetamide/LiCl followed by reacting with hexamethyldisilazane. Sodium dodecyl sulfate (SDS) in acidic aqueous solution and tetramethylammonium chloride (TMACl) in water were attempted as emulsifiers. The oil phase composed of TMSC and camphor in ethyl acetate was dispersed in emulsifier solution. The mass ratio of TMSC to camphor and emulsifier concentration were optimized to produce high quality microcapsules. Using the mass ratio of 3:7 and 1% (w/v) SDS solution gave well separated microcapsules of TMSC_C_SDS (1). The diameter size in the micron range (10–110mm) and high camphor content (∼21.07%) were obtained from this sample. The larger size of the capsules obtained from TMACl system indicated the coalescence of the oil droplets. The hydrolysis of the external surface of the microcapsules was observed in the SDS system. However, this caused a minor effect on the cellulose stability in TMSC_C_SDS (1). The freshly prepared microcapsules of TMSC_C_SDS (1) showed the fast release of camphor during first 2h and reached the equilibrium after 7h.

This study aimed to evaluate how lipids are being catabolized or retained when offered under restriction to optimum levels by determining the genes involved in the lipid metabolism of Seriola dorsalis (yellowtail) juveniles. An eight-week nutritional trial was carried out using four isoproteic diets with various levels of lipids. Four diets were then formulated to contain 60, 90, 130, and 150g crude fat kg⁻¹ diet. One hundred and twenty juvenile S. dorsalis (19.15g±0.67g, mean±SE) were located in 12 tanks of 500L each in triplicate groups. After eight weeks of feeding experiment, while no differences were revealed in growth, significant differences were obtained in lipid deposition and lipid gene expression. While FA profile and pparα expression results corroborate that ARA, EPA, and DHA are preserved, mainly in the liver, in the muscle tissue, EPA increased significantly, while ARA and DHA remained also preserved. The results suggested that the SFAs palmitic and stearic are mainly catabolized, and then the MUFAs with oleic acid and linoleic acid. However, the lipid metabolism is reflected by the gene expression, where we found several differences. The increase in pparα shows the activation from saturated fatty acids when the palmitoleic acid is increased to be used in the β-oxidation into the mitochondria. The cptl1, which mediates long-chain fatty acid uptake into the mitochondrion, decreases at higher crude fat (CF) levels. In comparison, the acadvl dedicated to catalyzing the LC-PUFAs into the mitochondrial β-oxidation is only expressed when the LC-PUFAs are in excess. It is concluded that apart from ratification that 13% CF is the ideal amount for S. dorsalis, it is suggested that SFAs primarily get oxidized and then the MUFAs, and linoleic acid, whereas the LC-PUFAs are only oxidized when offered in excess.

Materials Today: Proceedings, Volume 42, Part 1, 2021, pp. 165-171

Vatica Rassak wood waste-derived activated carbon (AC_VRW) was employed for lead (Pb(II)) adsorption. Batch adsorption tests were executed to investigate the influences of contact time (t = 0–60 min), AC_VRW dosage (m = 0–5 g L^-1), initial pH (pH = 2–10), and initial Pb(II) concentration (C_o = 10–200 mg L^-1) towards Pb(II) elimination. The best adsorption conditions were found at t = 55 min, pH = 6, and m = 2 g L^-1, with optimal Pb(II) uptake of 149.25 mg g⁻¹. The equilibrium data demonstrated high linearity with the pseudo-second-order kinetic model as well as the Langmuir isotherm model. The characterization results showed the vital role of AC_VRW’s physicochemical properties in the Pb(II) adsorption process. It is observed that the surface of the adsorbent after adsorption became ruptured and many fine particles attached on it. Moreover, the pore size of the adsorbent also decreased after adsorption. The practicability of AC_VRW was verified by its excellent performance in the reusability study with slight reduction in Pb(II) removal of 10.72% after five cycles. This study proved that AC_VRW possessed significant features to be employed as a low-cost activated carbon for the elimination of Pb(II).

Materials Today: Proceedings, Volume 42, Part 1, 2021, pp. 15-21

Current research involved fabrication of cadmium oxide-graphitic carbon nitride (CdO/g-C₃N₄) nanocomposite and evaluation of their photocatalytic properties by physical and electrochemical analysis techniques. The X-ray diffraction (XRD) test demonstrated that the nanocomposite consists of graphite and monteponite phases. UV–Vis absorption and photoluminescence (PL) analysis clearly pointed out both the band gap reduction and inhibition in recombination rate of charge carriers. Based on the photoelectrochemical (PEC) analysis, linear sweep voltammetry (LSV) data demonstrated that CdO/g-C₃N₄ nanocomposite shows higher anodic current (0.57 mA/cm²) under light emission as compared to dark environment (0.02 mA/cm²). This study was also deliberated with proposed mechanism on photoreforming of wastewater reaction scheme.

Materials Today: Proceedings, Volume 42, Part 1, 2021, pp. 33-38

The activity of the catalyst is markedly influenced by the physical and chemical properties of the support materials. Designing and developing excellent features of support materials is a crucial approach since it could directly affect the quality of metal active sites dispersion, strength of metal-support interaction, and quantity of oxygen vacancies, thus improving the catalytic performance and stability. Several modifications on support synthesis have been reported and the alteration into fibrous mesoporous silica material has attracted considerable attention over the recent years. Thus, the latest development of fibrous mesoporous silica for catalytic reaction has been reviewed through this work. Additionally, the governing factors of fibrous mesoporous silica in catalytic reaction was discussed in this review article.

Materials Today: Proceedings, Volume 42, Part 1, 2021, pp. 211-216

Fibrous silica BEA zeolite (FBEA) was synthesized by microemulsion method and tested for benzene methylation. The FESEM and N₂ physisorption verified that the FBEA exhibited a dendrimeric silica fiber morphology with large surface area and high ratio of mesopores and micropore volume. While the FTIR pre-adsorbed pyridine revealed that the FBEA possessed low Brönsted acid sites compared to commercial beta zeolite. The catalytic testing at 300 °C showed that FBEA was catalytically active towards benzene methylation to produce toluene with 97.8% conversion and 55.5% yield. It is suggested that the fibrous morphology might increase the mesopores volume and reduce the acidity, hence, improves the benzene alkylation reaction.

Materials Today: Proceedings, Volume 42, Part 1, 2021, pp. 94-100

The development of catalysts that afford excellent catalytic performance along with high resistance toward coke accumulation is fundamental in carbon dioxide reforming of methane (CDRM). Apart from Ni-based catalysts, the Co-based catalysts gained significant attention in CDRM accredited to the Co’s capability in improving catalytic stability and lowering the coke formation. However, the lower catalytic activities of Co-based catalysts when compared to Ni-based catalysts in reforming works are the real challenges that need to be solved. In this study, a short review of various approaches that have been implemented by researchers for improving the catalytic performance issues related to Co-based catalysts is presented. This paper also presents recent Co-bimetallic catalysts approached, covers the catalyst activity as well as issues related to catalyst deactivation when compared to Co monometallic catalysts. In addition, the outlook of the related bimetallic Co-based catalysts has been proposed to provide more critical information.

Materials Today: Proceedings, Volume 42, Part 1, 2021, pp. 131-137

Value-adding food/kitchen wastes have become a trend in view of the urge of reducing environmental impact and better exploitation of resources for a sustainable circular economy. As the wastes are full of nutrition but exist in various complex and simple forms, pre-treatment is required. The choice of method greatly depends on the type and nature of the waste; thus, comparison study is necessary. The objective of this study is to compare the pretreatment methods that are effective to treat kitchen waste in order to turn it into rich fermentation medium for subsequent value added compounds production. Three pretreatment methods were examined, i.e., hydrothermal, alkaline and enzymatic. Food to water ratio, temperature and holding time effects were studied in the hydrothermal pretreatment. While the effect of types of alkaline, alkaline concentration and reaction temperature were investigated in alkaline pretreatment. In enzymatic pretreatment, the effect of enzyme amount, incubation temperature, reaction time and pH were explored. The amount of nutrients hydrolyzed were determined through phenol–sulphuric acid (carbohydrate), Bradford (protein) and Bligh & Dyer (lipid) methods. The rough energy and chemical costs involved in each method was also compared. The results revealed that hydrothermal pretreatment and enzymatic pretreatment were comparable in terms of the ability to solubilize nutrients from the complex food wastes. Alkaline pretreatment was the cheapest method, but poor in nutrients extraction. Hence, hydrothermal pretreatment is the best pretreatment method to prepare nutritive food waste hydrolysate at a lower cost with acceptable performance.