Cellulosic nanocomposites from natural fibers for medical applications: a review

The nanocellulose and its composites have been covered in this chapter which is confirmed to be a very versatile material having the wide range of medical applications, including cardiovascular implants, scaffolds for tissue engineering, repair of articular cartilage, vascular grafts, urethral catheters, mammary prostheses, penile prostheses, adhesion barriers, and artificial skin. These implants were produced from bioresorbable and/or biodegradable materials. Nanocellulose, such as that produced other than microfibrillated cellulose and cellulose nanowhiskers, is also produced by the bacteria (bacterial cellulose, BC) which is also an emerging biomaterial with great potential as a biological implant, wound and burn dressing material, and scaffolds for tissue regeneration. Moreover, the nanostructure and morphological similarities with collagen make cellulose attractive for cell immobilization and cell support. This article describes current and future applications of cellulosic nanofibers in the biomedical field. Cellulose micro-/nanofibril as a reinforcing material for composites is becoming more and more attractive to researchers in composite science because of its potential lightweight and high strength. In the present article, we have reviewed the nanocellulosic fibers-based nanocomposites for medical applications. Processing methods, properties, and various applications of cellulosic composites are also discussed in this article. However, the separation of cellulose nanofibers along with the manufacture of cellulose nanocomposites is still challengeable. The aim of this chapter is to demonstrate the current state of development in the field of cellulose nanofibril-based nanocomposite research and application through examples

Simultaneous extraction and fractionation of pufa from tropical tuna (thunnus tongol) head using pressure swing technique of supercritical CO2 (SC-CO2)

Tuna fishes are known as one of the main commodity of fisheries which is generally marketed as canned food or as loins/steaks. Tuna head is about 25% of body weight and discarded as processing leftover during canning process. The objective of this study was to use this fish waste (head) as a source of fish oil especially PUFA. Simultaneous extraction and fractionation of PUFA from tuna head were conducted using pressure swing technique of SC-CO2. The dry and grinded sample was pressurised with pure CO2 and then soaked in the vessel for 1 hrs, and extracted continuously for 20 min at optimal conditions of 35 MPa, 65 oC, 3 ml min-1. The pressurization-soaking-extraction treatment was denoted as “pressure swing method” in this study. The total fish oil (13.11 g/100 g wt.) from head was extracted in 7 successive pressurization-soaking-extraction steps and the yield of each step was defined as fractional yield. Fatty acid constituents of each fractional yield were analyzed separately by gas chromatography. The short chain fatty acid constituents were found to be extracted mainly in the first 3 fractions and the next 4 fractions were predominant in MUFA and PUFA. Significant amount of DHA (26.83%) were extracted from fraction 4 followed by fraction 7. During the holding periods the liquid CO2 penetrated into the sample matrix and dissolved the readily soluble SFA portion of the oil which was eluted preferentially faster compared with either MUFA or PUFA. Therefore, multiple pressure swing steps could extract and fractionate the short chain fatty acid from relatively less soluble portions of long chain PUFA-rich sample matrix. However, PUFA-rich fraction extracted from tuna head may effectively serve as a source of EPA and DHA in food and pharmaceutical industries

Supercritical carbon dioxide fractionation of palm kernel oil and formulation of cocoa butter replacers fat.

The extraction of dehulled ground palm kernel using supercritical carbon dioxide (SC-C02) as a solvent at temperatures of 40 and 80°C and pressures of 20.7,27.6, 34.5, 41.4 and 48.3 MPa was studied. Continuous extraction was fractionated into four fractions and each fraction was collected for every 10 minutes. Thus the total extraction process was performed for 40 minutes extraction time. Kajian ke atas pengekstrakan isirung sawit tanpa testa hancur menggunakan lampau genting karbon dioksida (LG-C02) sebagai pelarut pada suhu 40 dan 80°C dan tekanan 20.7, 26.7, 34.5, 41.4 dan 48.3 MPa. Pengekstrakan berterusan dipemeringkatkan kepada empat pemeringkat dan setiap pemeringkat dikumpul selarna 10 minit dengan jumlah proses pengekstrakan dibuat selama 40 minit masa pengekstrakan

Determination of acrylamide in banana based snacks by gas chromatography-mass spectrometry

Fried and baked banana-based snacks are popular in South East Asia and banana chip is popular in other countries, such as India, Indonesia, China, African countries, etc; these snacks may contain acrylamide in concentration which may be of concern due to its toxicity. This study was carried out to determine acrylamide concentration in popular banana based snacks in Malaysia using a modified method of gas chromatographymass spectrometry. The limit of detection and limit of quantitation of the modified method are 5 and 15 μg/kg, respectively. Acrylamide concentration of five types of Malaysian popular fried and baked banana based snacks from different local markets ranged from 74.0 to 7468.8 μg/ kg for banana fritter (pisang goreng), 28.9 to 243.7 μg/kg for banana chips (kerepek pisang), 160.7 to 500.4 μg/kg for sweet banana chips (kerepek pisang manis), not detected to 154.4 μg/kg for banana cake (kek pisang) and 31.7 to 609.1 μg/kg for banana balls (cekodok pisang). Analysis of variance showed a significant difference (P<0.05) in acrylamide concentration between different food types. From the estimate of banana fritter consumption data, the highest exposure to acrylamide in Malaysia is 1.2 μg/kg body weights

Squalene recovery from palm fatty acid distillate using supercritical fluid extraction

The objective of this research is recovery of squalene from palm fatty acid distillate (PFAD) using supercritical fluid extraction (SFE). The extraction process was performed by using the SFE and recovered squalene was analyzed from total lipid extracts using HPLC. A central composite design was used to study the effect of SFE variables namely pressure (X1) from 200 to 400 bar and temperature (X2) from 40 to 60°C on the total lipid extracts (Y1) and squalene concentration (Y2) and optimize the SFE conditions. The nonlinear regression equations were significantly (p 0.965), which had no indication of lack of fit. The results indicated that a combined pressure (200 bar) and temperature (50°C) was predicted to provide the optimum region in terms of total lipid extracts (13.84 ± 0.52%) and squalene concentration (418.31 ± 18.40 ppm) studied

Antioxidant activity and phenolic profile of four Saudi Arabia date palms (Phoenix dactylifera L.) varieties

Antioxidants as free radical scavengers can combat the oxidative stress that occurs in the body to prevent chronic diseases. Therefore, antioxidant rich foods have a high demand among the healthcare consumers to maintain healthy lifestyle. One of the most potential fruit that are expected to contain high antioxidant compound is Phoenix dactylifera that have a lot of varieties. This study was intended to investigate the total phenolic content, antioxidant activity and phenolic profiles of four varieties of P. dactylifera (Khudori, Sabaka, Nabtat Ali and Soukari). The fleshes of the fruit were extracted using ethanol as the solvent using soxhlet. Total phenolic content (TPC) was measured by using Folin-Ciocalteu calorimetric method and the antioxidant activity was determined by using the 2,2,diphenyl-2-picryl-hydrazyl (DPPH) method. Some phenolic acid and flavonoids profiles of the fruit (gallic acid, p-coumaric acid, ferulic acid and quercetin) were analyzed by using High Performance Liquid Chromatography (HPLC). TPC of the fruit was in the range of 5.8 to 3.8 mg gallic acid equivalents (GAE) per 1 g of fruit with Soukari have the highest value. As for the antioxidant activity, Soukari need the lowest concentration (27.41 ± 1.68 mg/ml) to achieve half inhibition concentration (IC50 ) whereas Khudori need the highest concentration among the four. The HPLC result shows significantly higher amount of gallic acid (15.35 to 8.56 mg/g), and very small amount of ferulic acid (0.19 to 0.006 mg/g) where Soukari have the highest value for all of the compounds. This study demonstrates Soukari variety might possessed the highest antioxidant capacities among the four. Further study by using advanced and green extraction method need to be carried out to comprehend and confirm the potential of this fruit to be developed as nutraceutical and functional food. Keywords: Pheonix dactylifera, Antioxidant, Phenolic profile, HPLC

Phenolics in Citrus hystrix leaves obtained using supercritical carbon dioxide extraction

The extraction of phenolics from Citrus hystrix leaf was carried out using supercritical fluid extraction and was optimized using response surface methodology (RSM). The effects of CO2 flow rate, extraction pressure and extraction temperature on yield, total phenolic content and diphenyl-picrylhydrazyl-IC50 were evaluated and compared with ethanol extraction. The extraction pressure was the most significant factor affecting the yield, TPC and DPPH-IC50 of the extracts, followed by CO2 flow rate and the extraction temperature. The optimum conditions of pressure, CO2 flow rate and temperature were at 267 bars, 18 g/min and 50oC, respectively. The yield, TPC and DPPH-IC50 obtained were 5.06%, 116.53 mg GAE/g extract and IC50 of 0.063 mg/ml, respectively. These values were not significantly different (p<0.05) to their predicted values. Better inhibition and TPC were obtained using SFE method whereas higher yield and phenolic acids were obtained in the ethanol extracts

Effects of polar cosolvents on cocoa butter extraction using supercritical carbon dioxide

Cocoa butter was successfully extracted from cocoa liquor by supercritical carbondi oxide (SC-CO2) at 35 MPa, 60 oC and 2 mL/min with 5%, 15% and 25% cosolvents. The extraction yield of tryglicerides (TG) and fatty acid (FA) compositions were significantly influenced by the concentration of polar cosolvents. The SC-CO2 extraction efficiency was increased with cosolvent significantly. Ethanol was found to be the best cosolvent for cocoa butter extraction using SC-CO2 followed by isopropanol and acetone. The triglycerides of POP, POS and SOS were contained in the extracted cocoa butter with POS being the major component. Where palmitic, stearic and oleic were the main fatty acids in the cocoa butter samples, with stearic being the highest component. The lower molecular weight (MW) of TGs and FAs showed the higher selectivity compared to the high MW of TGs and FAs. Thus, they were fractionated during the first stage of SC-CO2 process